Radar device

Abstract

To improve the detection performance of a radar device.SOLUTION: A radar device includes: a radar transmitting circuit that transmits a radar signal using a transmitting array antenna; and a radar receiving circuit that receives a reflected wave signal which is the radar signal reflected from a target, using a receiving array antenna. One of the transmitting array antenna and the receiving array antenna is composed of a plurality of first antennas, and the plurality of first antennas are arranged based on a first interval in a first direction and a second interval in a second direction perpendicular to the first direction. The other of the transmitting array antenna and the receiving array antenna is composed of at least two or more second antenna groups, and a plurality of second antennas constituting each of the second antenna groups are arranged based on the first interval.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a radar device. [Background technology]

[0002] In recent years, radar devices using short-wavelength radar transmission signals, including microwaves and millimeter waves, which provide high resolution, have been under study. In addition, to improve outdoor safety, there is a demand for the development of radar devices that can detect objects (targets), including pedestrians, in a wider range than vehicles (hereinafter referred to as "wide-angle radar devices").

[0003] For example, a pulse radar device that repeatedly transmits pulse waves is known as a radar device. The received signal of a wide-angle pulse radar device that detects vehicles / pedestrians over a wider angle range is likely to be a mixture of multiple reflected waves from nearby targets (e.g., vehicles) and distant targets (e.g., pedestrians). For this reason, (1) the radar transmitter is required to be configured to transmit pulse waves or pulse-modulated waves with autocorrelation characteristics that result in low range side lobes (hereinafter referred to as low range side lobe characteristics), and (2) the radar receiver is required to be configured to have a wide receiving dynamic range.

[0004] The wide-angle radar device can be configured in the following two ways.

[0005] The first is a configuration in which pulse waves or modulated waves are mechanically or electronically scanned using a directional beam with a narrow angle (e.g., a beam width of about a few degrees) compared to the expected detection angle of the radar device to transmit radar waves, and the reflected waves are received using the narrow-angle directional beam. In this configuration, many scans are required to obtain high resolution, so the tracking ability for fast-moving targets is degraded.

[0006] The second is a configuration that uses a method (Direction of Arrival (DOA) estimation) in which reflected waves are received by an array antenna consisting of multiple antennas (antenna elements), and the arrival angle of the reflected wave is estimated by a signal processing algorithm based on the reception phase difference with respect to the element spacing (antenna spacing). In this configuration, even if the scanning angle spacing of the transmission beam is thinned, the arrival angle can be estimated in the receiving branch, so that the scanning time can be shortened and tracking performance is improved compared to the first configuration. For example, methods of estimating the arrival direction include Fourier transform based on matrix calculation, Capon method and LP (Linear Prediction) method based on inverse matrix calculation, or MUSIC (Multiple Signal Classification) and ESPRIT (Estimation of Signal Parameters via Rotational Invariance Techniques) based on eigenvalue calculation.

[0007] Also, a radar device has been proposed that has multiple antennas (array antennas) in the transmitting branch as well as the receiving branch, and performs beam scanning by signal processing using the transmitting and receiving array antennas (sometimes called a MIMO (Multiple Input Multiple Output) radar) (see, for example, Non-Patent Document 1).

[0008] In a MIMO radar, by devising an arrangement of antenna elements in the transmitting and receiving array antennas, it is possible to configure a virtual receiving array antenna (hereafter referred to as a virtual receiving array) whose maximum number is equal to the product of the number of transmitting antenna elements and the number of receiving antenna elements. This has the effect of increasing the effective aperture length of the array antenna with a small number of elements, thereby improving the angular resolution.

[0009] Furthermore, in addition to one-dimensional scanning (angle measurement) in the vertical or horizontal direction, the MIMO radar can also be applied to two-dimensional beam scanning in the vertical and horizontal directions (see, for example, Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0010] [Non-Patent Document 1] J. Li, P. Stoica, "MIMO Radar with Colocated Antennas," Signal Processing Magazine, IEEE Vol. 24, Issue: 5, pp. 106-114, 2007 [Non-Patent Document 2] PP Vaidyanathan, P. Pal,Chun-Yang Chen, "MIMO radar with broadband waveforms: Smearing filter banks and 2D virtual arrays," IEEE Asilomar Conference on Signals, Systems and Computers, pp.188 - 192, 2008. [Non-Patent Document 3] J. Wenger, "Automotive mm-wave radar: status and trends in system design and technology," IEE Colloquium on Automotive Radar and Navigation Techniques (Ref. No. 1998 / 230), pp. 144-147, 1998. [Non-Patent Document 4] M. Harte, T. Mahler, T. Schipper, A. Ziroff, and T. Zwick, “2-D antenna array geometries for MIMO radar imaging by digital beamforming,” 2013 European Microwave Conference, pp. 1695 - 1698, 2013. Summary of the Invention [Problem to be solved by the invention]

[0011] However, depending on the antenna arrangement of the transmitting and receiving branches in a MIMO radar, the detection performance of the radar device may be degraded.

[0012] Non-limiting embodiments of the present disclosure contribute to providing a radar device capable of improving detection performance. [Means for solving the problem]

[0013] A radar device according to an embodiment of the present disclosure includes a radar transmitter that transmits a radar signal by using a transmitting array antenna, and a radar receiver that receives a reflected wave signal of the radar signal reflected by a target by using a receiving array antenna, wherein the transmitting array antenna is composed of a plurality of transmitting antenna groups, each of which includes a plurality of transmitting antennas arranged at a second interval that is an integer multiple of a first interval in a first direction and arranged at a fourth interval that is an integer multiple of a third interval in a second direction orthogonal to the first direction, the receiving array antenna is composed of a plurality of receiving antenna groups, each of which includes a plurality of receiving antennas arranged at a fifth interval that is an integer multiple of the first interval in the first direction and arranged at a sixth interval that is an integer multiple of the third interval in the second direction, a difference between the second interval and the fifth interval is the first interval, and a difference between the fourth interval and the sixth interval is the third interval.

[0014] In addition, these comprehensive or specific embodiments may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. Effect of the Invention

[0015] According to an embodiment of the present disclosure, it is possible to improve the detection performance of a radar device.

[0016] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features. [Brief description of the drawings]

[0017] [Figure 1A] Diagram showing an example of the placement of transmitting and receiving antennas [Figure 1B] A diagram showing an example of the layout of a virtual receiving array [Figure 2A] A diagram showing the directivity pattern of a virtual receiving array (dV=0.5λ). [Figure 2B] A diagram showing the directivity pattern of a virtual receiving array (dV=0.5λ). [Figure 3A] A diagram showing the directivity pattern of a virtual receiving array (dV=λ) [Figure 3B] A diagram showing the directivity pattern of a virtual receiving array (dV=2λ) [Figure 4] Block diagram showing the configuration of a radar device [Diagram 5] FIG. 1 is a diagram showing an example of a radar transmission signal. [Figure 6] A block diagram showing another configuration of the radar transmission signal generating unit. [Figure 7] FIG. 1 is a diagram showing an example of a transmission timing and a measurement range of a radar transmission signal; [Figure 8] FIG. 1 shows an example of antenna arrangement according to basic arrangement 1. [Figure 9A] FIG. 1 shows an example of a subarray configuration. [Figure 9B] FIG. 1 shows an example of a subarray configuration. [Figure 9C] FIG. 1 shows an example of a subarray configuration. [Figure 10] A diagram showing an example of the configuration of a transmitting array antenna using subarrays. [Figure 11A] FIG. 13 is a diagram showing an example of a direction estimation result using a transmitting / receiving antenna arrangement according to Basic Arrangement 1. [Figure 11B]FIG. 1B is a diagram showing an example of a direction estimation result using the transmitting and receiving antenna arrangement of FIG. 1A; [Figure 12] FIG. 1 shows an example of an antenna arrangement according to a first modification of the first basic arrangement. [Figure 13] FIG. 1 shows an example of an antenna arrangement according to a first modification of the first basic arrangement. [Figure 14] FIG. 1 shows an example of an antenna arrangement according to a first modification of the first basic arrangement. [Figure 15] FIG. 1 shows an example of an antenna arrangement according to a first modification of the first basic arrangement. [Figure 16] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the first basic arrangement. [Figure 17] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the first basic arrangement. [Figure 18] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the first basic arrangement. [Figure 19] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the first basic arrangement. [Figure 20] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the first basic arrangement. [Figure 21] FIG. 13 is a diagram showing an example of an antenna arrangement according to a third modification of the first basic arrangement. [Figure 22] FIG. 13 is a diagram showing an example of an antenna arrangement according to a third modification of the first basic arrangement. [Figure 23] FIG. 13 is a diagram showing an example of an antenna arrangement according to a third modification of the first basic arrangement. [Figure 24] FIG. 13 is a diagram showing an example of an antenna arrangement according to a third modification of the first basic arrangement. [Figure 25A] FIG. 13 shows a configuration example of a subarray according to a third modification of the first basic arrangement. [Figure 25B] FIG. 13 is a diagram showing a configuration example of a transmitting array antenna using subarrays according to a third modification of the first basic arrangement. [Figure 25C] FIG. 13 is a diagram showing a configuration example of a transmitting array antenna using subarrays according to a third modification of the first basic arrangement. [Figure 26] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 1 and a modification 1 are combined. [Figure 27] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 1 and a modification 1 are combined. [Figure 28] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 1 and a modification 1 are combined. [Figure 29] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 1 and a modification 1 are combined. [Diagram 30] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 1 and a modification 1 are combined. [Diagram 31] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 1 and a modification 2 are combined. [Diagram 32] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 1 and a modification 2 are combined. [Diagram 33] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 1 and a modification 2 are combined. [Diagram 34] FIG. 1 shows an example of antenna arrangement according to basic arrangement 2. [Diagram 35] FIG. 1 shows an example of the configuration of a subarray according to basic arrangement 2. [Diagram 36] FIG. 1 shows an example of an antenna arrangement according to a first modification of a second basic arrangement. [Figure 37] FIG. 1 shows an example of an antenna arrangement according to a first modification of a second basic arrangement. [Figure 38] FIG. 1 shows an example of an antenna arrangement according to a first modification of a second basic arrangement. [Figure 39] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the second basic arrangement. [Diagram 40] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the second basic arrangement. [Diagram 41] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the second basic arrangement. [Diagram 42] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the second basic arrangement. [Diagram 43] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the second basic arrangement. [Diagram 44] FIG. 13 is a diagram showing an example of an antenna arrangement according to a third modification of the second basic arrangement. [Diagram 45] FIG. 13 is a diagram showing an example of an antenna arrangement according to a third modification of the second basic arrangement. [Diagram 46] FIG. 13 is a diagram showing an example of an antenna arrangement according to a third modification of the second basic arrangement. [Figure 47] FIG. 13 is a diagram showing an example of an antenna arrangement according to a third modification of the second basic arrangement. [Figure 48] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 2 and a combination of the modification 2 are used. [Figure 49] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 2 and a combination of the modification 2 are used. [Figure 50A] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 2 and a combination of the modification 2 are used. [Figure 50B] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 2 and a combination of the modification 2 are used. [Figure 51A] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 2 and a combination of the modification 2 are used. [Figure 51B] FIG. 13 shows an example of an antenna arrangement in which a modification 3 of the basic arrangement 2 and a combination of the modification 2 are used. [Figure 52A] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Figure 52B] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Figure 52C] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Fig. 52D] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Figure 53A] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Figure 53B] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Figure 53C] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Fig. 53D] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Figure 54A] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Figure 54B] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Fig. 54C] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Fig. 54D] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Figure 55A] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Figure 55B] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Figure 55C] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Fig. 55D] FIG. 1 shows an example of antenna arrangement according to basic arrangement 3. [Figure 56A] FIG. 13 shows a configuration example of a transmitting array antenna using subarrays according to basic arrangement 3. [Figure 56B] FIG. 13 shows a configuration example of a transmitting array antenna using subarrays according to basic arrangement 3. [Figure 57] FIG. 13 is a diagram showing an example of a direction estimation result using a transmitting / receiving antenna arrangement according to Basic Arrangement 3. [Figure 58] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the third basic arrangement. [Figure 59] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the third basic arrangement. [Figure 60] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the third basic arrangement. [Figure 61] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the third basic arrangement. [Figure 62] FIG. 13 is a diagram showing an example of a direction estimation result using a transmitting / receiving antenna arrangement according to Modification 1 of Basic Arrangement 3. [Figure 63] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the third basic arrangement. [Figure 64] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the third basic arrangement. [Figure 65] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the third basic arrangement. [Figure 66] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the third basic arrangement. [Figure 67] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the third basic arrangement. [Figure 68A] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the third basic arrangement. [Figure 68B] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the third basic arrangement. [Figure 69] FIG. 1 shows an example of antenna arrangement according to basic arrangement 4. [Figure 70A]FIG. 13 shows a configuration example of a transmitting array antenna using subarrays according to basic arrangement 4. [Figure 70B] FIG. 13 shows a configuration example of a transmitting array antenna using subarrays according to basic arrangement 4. [Figure 71] FIG. 13 is a diagram showing an example of a direction estimation result using a transmitting / receiving antenna arrangement according to Basic Arrangement 4. [Figure 72] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fourth basic arrangement; [Figure 73] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fourth basic arrangement; [Figure 74] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fourth basic arrangement; [Figure 75] FIG. 13 is a diagram showing an example of a direction estimation result using a transmitting / receiving antenna arrangement according to Modification 1 of Basic Arrangement 4. [Figure 76] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fourth basic arrangement; [Figure 77] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fourth basic arrangement; [Figure 78] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fourth basic arrangement; [Figure 79] An example of a direction estimation result using the transmitting and receiving antenna arrangement according to the first modification of the basic arrangement 4 [Figure 80] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fourth basic arrangement; [Figure 81] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fourth basic arrangement; [Figure 82] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fourth basic arrangement; [Figure 83] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the fourth basic arrangement. [Figure 84] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the fourth basic arrangement. [Figure 85] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the fourth basic arrangement. [Figure 86] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the fourth basic arrangement. [Figure 87] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the fourth basic arrangement. [Fig. 88A] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the fourth basic arrangement. [Fig. 88B] FIG. 13 is a diagram showing an example of an antenna arrangement according to a second modification of the fourth basic arrangement. [Figure 89] FIG. 1 shows an example of antenna arrangement according to basic arrangement 5. [Figure 90A] FIG. 1 shows an example of antenna arrangement according to basic arrangement 5. [Figure 90B] FIG. 1 shows an example of antenna arrangement according to basic arrangement 5. [Figure 91A] FIG. 1 shows an example of antenna arrangement according to basic arrangement 5. [Figure 91B] FIG. 1 shows an example of antenna arrangement according to basic arrangement 5. [Figure 92A] FIG. 1 shows an example of antenna arrangement according to basic arrangement 5. [Fig. 92B] FIG. 1 shows an example of antenna arrangement according to basic arrangement 5. [Fig. 92C] FIG. 1 shows an example of antenna arrangement according to basic arrangement 5. [Fig. 92D] FIG. 1 shows an example of antenna arrangement according to basic arrangement 5. [Figure 93A] FIG. 13 is a diagram showing a configuration example of a transmitting array antenna using subarrays according to basic arrangement 5. [Figure 93B] FIG. 13 is a diagram showing a configuration example of a transmitting array antenna using subarrays according to basic arrangement 5. [Figure 94] FIG. 13 is a diagram showing an example of a direction estimation result using a transmitting / receiving antenna arrangement according to Basic Arrangement 5. [Figure 95] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 96] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 97] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 98] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 99] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 100A] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 100B]FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 101] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 102] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 103] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 104] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 105] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 106A] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 106B] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 107] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 108] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Fig. 109] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 110] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Figure 111] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Fig. 112A] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. [Fig. 112B] FIG. 13 is a diagram showing an example of an antenna arrangement according to a first modification of the fifth basic arrangement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] As described above, in addition to one-dimensional scanning (angle measurement) in the vertical or horizontal direction, the MIMO radar that configures a virtual receiving array can also be applied to two-dimensional beam scanning in the vertical and horizontal directions.

[0019] As an example, Fig. 1A shows a transmitting array antenna including four transmitting antennas (Tx#1 to Tx#4) arranged in the vertical direction (longitudinal direction in Fig. 1A) and a receiving array antenna including four receiving antennas (Rx#1 to Rx#4) arranged in the horizontal direction (horizontal direction in Fig. 1A). In Fig. 1A, the transmitting antennas are arranged at equal intervals (d V ) and the receiving antennas are arranged at equal intervals (d H ) (see, for example, non-patent document 4).

[0020] FIG. 1B shows a virtual receiving array including the transmitting and receiving array antennas in the antenna arrangement shown in FIG. 1A. The virtual receiving array shown in FIG. 1B is composed of 16 virtual receiving antenna elements (VA#1 to VA#16) in which four antennas are arranged in the horizontal direction and four antennas are arranged in the vertical direction in a rectangular shape. In FIG. 1B, the element spacing in the horizontal and vertical directions of the virtual receiving array is d H , d V That is, the horizontal and vertical aperture lengths D of the virtual receiving array are H , D V are respectively, 3d H , 3d V It becomes.

[0021] 2A and 2B show the antenna arrangement of the MIMO radar shown in FIG. 1A and FIG. 1B, with the horizontal element spacing d H = 0.5λ, and the vertical element spacing d V = 0.5λ, where λ is the wavelength of the radar carrier wave.

[0022] As shown in FIG. 2A and FIG. 2B, a main beam (main lobe) is formed in the horizontal 0° and vertical 0° directions. Here, the narrower the beam width of the main beam, the better the angle separation performance for multiple targets. For example, in FIG. 2A and FIG. 2B, the beam width with a power value of 3 dB is about 13°. Also, as shown in FIG. 2A and FIG. 2B, a side lobe is generated around the main beam. In a radar device, the side lobe is a cause of erroneous detection as a virtual image. Therefore, the lower the peak level of the side lobe, the lower the probability of erroneous detection as a virtual image in the radar device. In FIG. 2A and FIG. 2B, the power ratio (Peak Sidelobe Level Ratio (PSLR)) of the side lobe to the peak level normalized by the peak level of the main beam is about -13 dB.

[0023] In order to expand the detection range of a radar device, it is effective to use an antenna with high gain. For example, the antenna gain can be improved by narrowing the directivity (beam width) of the antenna. The directivity of the antenna becomes narrower, for example, as the aperture surface of the antenna is widened. Therefore, in order to narrow the directivity of the antenna, the antenna size must be increased.

[0024] For example, in a radar device mounted on a vehicle (also called an on-board radar), a sub-array antenna configured by arranging multiple antenna elements in the vertical direction is used to narrow the vertical directivity (see, for example, Non-Patent Document 3). By narrowing the vertical directivity, the antenna gain in the vertical direction can be improved and reflected waves in unnecessary directions such as the road surface can be reduced.

[0025] However, when a subarray antenna is used as an antenna element constituting a transmitting array antenna or a receiving array antenna, the element spacing of the array antenna cannot be arranged at a spacing narrower than the size of the subarray antenna. For example, when the antenna elements constituting the subarray antenna are arranged in the vertical direction, the size of the subarray antenna may be one wavelength or more. Therefore, for example, when a subarray antenna is used in the vertical direction in the MIMO radar shown in FIG. 1A, the element spacing in the vertical direction d V is expanded to more than one wavelength.

[0026] 3A and 3B show the vertical element spacing d V 3A and 3B, the directivity of each antenna element sub-arrayed in the vertical direction is not taken into consideration.

[0027] In addition, in FIG. 3A, the element spacing in the vertical direction d V = λ, horizontal element spacing d H = 0.5λ, and in FIG. 3B, the vertical element spacing d V = 2λ, horizontal element spacing d H = 0.5λ.

[0028] As shown in Figures 3A and 3B, the main beam (main lobe) is directed in the horizontal 0° and vertical 0° directions, and, for example, compared to the side lobes in Figures 2A and 2B, high-level grating lobes are generated in the vertical direction around the main beam. In Figures 3A and 3B, the ratio of the peak level of the grating lobe to the peak level of the main lobe is 0 dB. Also, in Figure 3B (d V = 2λ), Fig. 3A(d V = λ), the angular interval where high-level grating lobes occur in the vertical direction is narrower. V It can be seen that the wider the angle, the narrower the angular interval at which grating lobes occur.

[0029] In this way, the larger the antenna size in the vertical direction of a radar device, the wider the vertical element spacing becomes, and therefore, grating lobes are more likely to occur at angles relatively close to the main beam. Therefore, if the detection angle range assumed by the radar device is wider than the angle at which grating lobes occur, the radar device is more likely to erroneously detect false peaks caused by grating lobes as targets within the detection angle range, and the detection performance of the radar device may deteriorate.

[0030] An embodiment of the present disclosure makes it possible to suppress the occurrence of grating lobes and improve the angular resolution in the vertical or horizontal direction when performing two-dimensional beam scanning in the vertical and horizontal directions using a MIMO radar, even when the antenna size (or element size) in the vertical or horizontal direction is one wavelength or more.

[0031] Hereinafter, an embodiment according to an example of the present disclosure will be described in detail with reference to the drawings. In the embodiment, the same components are denoted by the same reference numerals, and the description thereof will be omitted to avoid duplication.

[0032] In the following, a configuration of a radar device will be described in which a transmitting branch sends out different code division multiplexed transmission signals from multiple transmitting antennas, and a receiving branch separates each transmission signal and performs reception processing. However, the configuration of the radar device is not limited to this, and a transmitting branch may send out different frequency division multiplexed transmission signals from multiple transmitting antennas, and a receiving branch may separate each transmission signal and perform reception processing. Similarly, a radar device may send out time division multiplexed transmission signals from multiple transmitting antennas in a transmitting branch, and a receiving branch may perform reception processing.

[0033] [Embodiment 1] [Radar device configuration] FIG. 4 is a block diagram showing a configuration of a radar device 10 according to this embodiment.

[0034] The radar device 10 includes a radar transmitter (transmitting branch) 100, a radar receiver (receiving branch) 200, and a reference signal generator 300.

[0035] The radar transmitter 100 generates a high-frequency (radio frequency) radar signal (radar transmission signal) based on a reference signal received from the reference signal generator 300. The radar transmitter 100 then transmits the radar transmission signal at a predetermined transmission period using a transmission array antenna constituted by a plurality of transmission antennas 106-1 to 106-Nt.

[0036] The radar receiver 200 receives a reflected wave signal, which is a radar transmission signal reflected by a target (not shown), using a receiving array antenna including multiple receiving antennas 202-1 to 202-Na. The radar receiver 200 performs the following processing operations using a reference signal received from a reference signal generator 300, thereby performing processing synchronized with the radar transmitter 100. That is, the radar receiver 200 performs signal processing on the reflected wave signal received by each receiving antenna 202, and performs at least one process of detecting the presence or absence of a target and estimating the direction. The target is an object to be detected by the radar device 10, and includes, for example, a vehicle (including four-wheeled and two-wheeled vehicles) or a person.

[0037] The reference signal generating unit 300 is connected to both the radar transmitting unit 100 and the radar receiving unit 200. The reference signal generating unit 300 supplies a reference signal as a reference signal to the radar transmitting unit 100 and the radar receiving unit 200, and synchronizes the processing of the radar transmitting unit 100 and the radar receiving unit 200.

[0038] [Configuration of radar transmitter 100] The radar transmitter 100 includes radar transmission signal generators 101-1 to 101-Nt, radio transmission units 105-1 to 105-Nt, and transmission antennas 106-1 to 106-Nt. That is, the radar transmitter 100 includes Nt transmission antennas 106, and each transmission antenna 106 is connected to an individual radar transmission signal generator 101 and radio transmission unit 105.

[0039] The radar transmission signal generator 101 generates a timing clock by multiplying the reference signal received from the reference signal generator 300 by a predetermined number, and generates a radar transmission signal based on the generated timing clock. The radar transmission signal generator 101 then repeatedly outputs the radar transmission signal at a predetermined radar transmission period (Tr). The radar transmission signal is z (k, M)=I z (k, M)+j Q z (k, M), where z is a number corresponding to each transmitting antenna 106, z=1,...,Nt, j is an imaginary unit, k is a discrete time, and M is an ordinal number of the radar transmission period.

[0040] Each radar transmission signal generation unit 101 includes a code generation unit 102, a modulation unit 103, and an LPF (Low Pass Filter) 104. Below, each component of the radar transmission signal generation unit 101-z corresponding to the zth (z=1, ..., Nt) transmitting antenna 106 will be described.

[0041] For example, the code generator 102 generates a code a(z) of a code sequence having a code length L for each radar transmission period Tr. n (n=1, ..., L) (pulse code). The code a(z) generated in each code generation unit 102-1 to 102-Nt n Codes that are lowly correlated or uncorrelated with each other are used for (z=1, . . . , Nt). Examples of code sequences include Walsh-Hadamard codes, M-sequence codes, and Gold codes.

[0042] The modulation unit 103 modulates the code sequence (e.g., code a(z)) output from the code generation unit 102.n ), and outputs the modulated signal to the LPF 104.

[0043] The LPF 104 outputs signal components below a predetermined band limit, out of the modulated signal output from the modulation section 103, to the transmission radio section 105 as a baseband radar transmission signal.

[0044] The zth (z=1, ..., Nt) transmission radio unit 105 performs frequency conversion on the baseband radar transmission signal output from the zth radar transmission signal generation unit 101 to generate a radar transmission signal in the carrier frequency (Radio Frequency: RF) band, amplifies the signal to a predetermined transmission power P [dB] by a transmission amplifier, and outputs the signal to the zth transmission antenna 106.

[0045] The zth (z=1, . . . , Nt) transmitting antenna 106 radiates the radar transmission signal output from the zth radio transmission unit 105 into space.

[0046] FIG. 5 shows radar transmission signals transmitted from the Nt transmitting antennas 106 of the radar transmitter 100. A pulse code sequence of code length L is included in the code transmission interval Tw. In each radar transmission period Tr, the pulse code sequence is transmitted during the code transmission interval Tw, and the remaining interval (Tr-Tw) is a no-signal interval. One pulse code (a(z) n ), pulse modulation using No samples is performed, so that each code transmission interval Tw contains a signal of Nr (=No×L) samples. That is, the sampling rate in the modulation unit 103 is (No×L) / Tw. Also, a no-signal interval (Tr-Tw) contains Nu samples.

[0047] The radar transmitter 100 may include a radar transmission signal generator 101a shown in Fig. 6 instead of the radar transmission signal generator 101. The radar transmission signal generator 101a does not include the code generator 102, the modulator 103, and the LPF 104 shown in Fig. 4, but instead includes a code storage unit 111 and a DA converter 112. The code storage unit 111 stores in advance the code sequence generated by the code generator 102 (Fig. 4) and cyclically reads out the stored code sequences one by one. The DA converter 112 converts the code sequence (digital signal) output from the code storage unit 111 into an analog signal (baseband signal).

[0048] [Configuration of radar receiver 200] 4, the radar receiving unit 200 includes Na receiving antennas 202 forming an array antenna. The radar receiving unit 200 also includes Na antenna system processing units 201-1 to 201-Na and a direction estimating unit 214.

[0049] Each receiving antenna 202 receives a reflected wave signal, which is a radar transmission signal reflected by a target (object), and outputs the received reflected wave signal to the corresponding antenna system processor 201 as a received signal.

[0050] Each antenna system processing unit 201 includes a radio reception unit 203 and a signal processing unit 207 .

[0051] The radio reception unit 203 has an amplifier 204, a frequency converter 205, and a quadrature detector 206. The radio reception unit 203 generates a timing clock by multiplying the reference signal output from the reference signal generator 300 by a predetermined number, and operates based on the generated timing clock. Specifically, the amplifier 204 amplifies the reception signal output from the reception antenna 202 to a predetermined level, the frequency converter 205 frequency-converts the high-frequency band reception signal to a baseband band, and the quadrature detector 206 converts the baseband band reception signal to a baseband band reception signal including an I signal and a Q signal.

[0052] Signal processing section 207 has AD conversion sections 208 and 209, and separation sections 210-1 to 210-Nt.

[0053] The I signal is input to AD conversion unit 208 from quadrature detector 206, and the Q signal is input to AD conversion unit 209 from quadrature detector 206. AD conversion unit 208 samples the baseband signal including the I signal at discrete times to convert the I signal into digital data. AD conversion unit 209 samples the baseband signal including the Q signal at discrete times to convert the Q signal into digital data.

[0054] Here, in the sampling by the AD conversion units 208 and 209, Ns discrete samples are taken per time Tp (=Tw / L) of one subpulse in the radar transmission signal, i.e., the number of oversamples per subpulse is Ns.

[0055] In the following description, the baseband received signal at discrete time k of the Mth radar transmission cycle Tr[M] as the output of AD conversion units 208 and 209 is expressed as a complex signal x(k,M)=Ir(k,M)+jQr(k,M) using I signal Ir(k,M) and Q signal Qr(k,M). In the following description, discrete time k is based on the timing at which the radar transmission cycle (Tr) starts (k=1), and signal processing unit 207 operates periodically up to k=(Nr+Nu)Ns / No, which is the sampling point before the radar transmission cycle Tr ends. That is, k=1,...,(Nr+Nu)Ns / No. Here, j is the imaginary unit.

[0056] The signal processing unit 207 includes Nt separators 210, the number of which is equal to the number of systems of the transmitting antennas 106. Each separator 210 has a correlation calculation unit 211, an adder 212, and a Doppler frequency analysis unit 213. The configuration of the zth (z=1, ..., Nt) separator 210 will be described below.

[0057] The correlation calculation unit 211 calculates, for each radar transmission period Tr, discrete sample values ​​x(k,M) including discrete sample values ​​Ir(k,M) and Qr(k,M) received from the AD conversion units 208 and 209, and a pulse code a(z) having a code length L transmitted by the radar transmission unit 100. n (where z=1, . . . , Nt, n=1, . . . , L). For example, the correlation calculation unit 211 calculates the correlation between the discrete sample value x(k, M) and the pulse code a(z). n For example, the correlation calculation value AC (z) (k, M) is calculated based on the following formula:

number

[0058] In the above formula, the asterisk (*) represents the complex conjugate operator.

[0059] The correlation calculation unit 211 performs correlation calculation over a period of k=1, . . . , (Nr+Nu)Ns / No in accordance with, for example, equation (1).

[0060] Note that the correlation calculation unit 211 is not limited to performing correlation calculation for k=1,...,(Nr+Nu)Ns / No, and may limit the measurement range (i.e., the range of k) according to the range of the target to be measured by the radar device 10. This allows the radar device 10 to reduce the amount of calculation processing by the correlation calculation unit 211. For example, the correlation calculation unit 211 may limit the measurement range to k=Ns(L+1),...,(Nr+Nu)Ns / No-NsL. In this case, as shown in FIG. 7, the radar device 10 does not perform measurement in the time period corresponding to the code transmission period Tw.

[0061] As a result, even if the radar transmission signal directly penetrates the radar receiving unit 200, the radar device 10 does not perform processing by the correlation calculation unit 211 during the period during which the radar transmission signal penetrates (at least a period shorter than τ1), and therefore can perform measurement without the influence of the penetration. Furthermore, when limiting the measurement range (range of k), processing that similarly limits the measurement range (range of k) can be applied to the processing of the adder 212, Doppler frequency analysis unit 213, and direction estimation unit 214 described below. This can reduce the amount of processing in each component, and can reduce power consumption in the radar receiving unit 200.

[0062] The adder 212 calculates the correlation calculation value AC output from the correlation calculation unit 211 at each discrete time k of the M-th radar transmission period Tr. (z) Using (k, M), the correlation calculation value AC is calculated over a period (Tr×Np) of a predetermined number (Np) of radar transmission cycles Tr. (z) (k, M) are summed (coherent integrated). The summation (coherent integration) process of the sum number Np over the period (Tr × Np) is expressed by the following equation.

number

[0063] Here, CI (z) (k, m) represents the sum of correlation calculation values ​​(hereinafter referred to as correlation sum), Np is an integer value of 1 or more, and m is an integer of 1 or more indicating the ordinal number of the number of additions when the number of additions Np in adder 212 is taken as one unit, and z=1,...,Nt.

[0064] The adder 212 performs addition Np times, with the output of the correlation calculator 211 obtained in units of the radar transmission period Tr as one unit. (z) (k, Np(m-1)+1)~AC (z) The correlation value CI obtained by adding the discrete time k in units of (k, Np×m) (z)(k, m) is calculated for each discrete time k. As a result, the adder 212 can improve the SNR (Signal to Noise Ratio) of the reflected wave signal in a range where the reflected wave signal from the target has a high correlation due to the effect of adding the correlation calculation value Np times. Therefore, the radar receiver 200 can improve the measurement performance regarding the estimation of the arrival distance of the target.

[0065] In order to obtain an ideal addition gain, a condition is required in which the phase components of the correlation calculation values ​​are aligned to a certain extent in the addition interval of the number of additions Np of the correlation calculation values. In other words, it is preferable to set the number of additions Np based on the assumed maximum moving speed of the target to be measured. This is because the greater the assumed maximum speed of the target, the greater the fluctuation amount of the Doppler frequency contained in the reflected wave from the target. For this reason, the time period with high correlation becomes shorter, so the number of additions Np becomes a small value, and the gain improvement effect by addition in the adder 212 becomes small.

[0066] The Doppler frequency analysis unit 213 calculates the CI (z) (k, Nc(w-1)+1)~CI (z) Coherent integration is performed by aligning the timing of discrete time k with (k, Nc×w) as one unit. For example, the Doppler frequency analysis unit 213 performs coherent integration after correcting the phase fluctuation Φ(fs)=2πfs(Tr×Np)ΔΦ corresponding to 2Nf different Doppler frequencies fsΔΦ as shown in the following equation.

number

[0067] Here, FT_CI (z) Nant(k, fs, w) is the wth output of the Doppler frequency analysis unit 213 and indicates the coherent integration result of the Doppler frequency fsΔΦ at the discrete time k in the Nantth antenna system processing unit 201. Here, Nant=1 to Na, fs=-Nf+1,...,0,...,Nf, k=1,...,(Nr+Nu)Ns / No, w is an integer equal to or greater than 1, and ΔΦ is a phase rotation unit.

[0068] As a result, each antenna system processor 201 calculates FT_CI, which is a coherent integration result corresponding to 2Nf Doppler frequency components at every discrete time k. (z) Nant (k, -Nf+1,w),…, FT_CI (z) Nant (k, Nf-1, w) is obtained for each period (Tr×Np×Nc) of Np×Nc times the radar transmission cycle Tr, where j is the imaginary unit and z=1,...,Nt.

[0069] When ΔΦ=1 / (Nc×Tr×Np), the processing of the Doppler frequency analysis unit 213 described above is equivalent to performing a Discrete Fourier Transform (DFT) process on the output of the adder 212 with a sampling interval Tm=(Tr×Np) and a sampling frequency fm=1 / Tm.

[0070] In addition, by setting Nf to a power of 2, the Doppler frequency analysis unit 213 can apply Fast Fourier Transform (FFT) processing, thereby reducing the amount of calculation processing. Note that when Nf>Nc, CI is not available in the region where q>Nc. (z) By performing zero-padding processing such that (k, Nc(w-1)+q)=0, FFT processing can be similarly applied, thereby reducing the amount of calculation processing.

[0071] In addition, the Doppler frequency analysis unit 213 may perform a process of sequentially calculating the product-sum operation shown in the above formula (3) instead of the FFT process. That is, the Doppler frequency analysis unit 213 calculates CI (z) For (k, Nc(w-1)+q+1), the coefficient exp[-j2πf s T r N p qΔφ] may be generated and sequentially processed by product-sum operations, where q=0 to Nc-1.

[0072] In the following description, the w-th output FT_CI obtained by performing the same processing in each of the Na antenna system processors 201 is used. (z) 1 (k, fs, w), FT_CI (z) 2 (k, fs, w),…, FT_CI (z) Na (k, fs, w) is expressed as a virtual receiving array correlation vector h(k, fs, w) as shown in the following equation. The virtual receiving array correlation vector h(k, fs, w) includes Nt×Na elements, which is the product of the number of transmitting antennas Nt and the number of receiving antennas Na. The virtual receiving array correlation vector h(k, fs, w) is used in the description of the process of estimating the direction of a reflected wave signal from a target based on the phase difference between the receiving antennas 202, which will be described later. Here, z=1, ..., Nt, and b=1, ..., Na.

number

number

[0073] The processing in each component of the signal processing unit 207 has been described above.

[0074] The direction estimation unit 214 calculates an array correction value h_cal for the virtual receiving array correlation vector h(k, fs, w) of the w-th Doppler frequency analysis unit 213 output from the antenna system processing units 201-1 to 201-Na. [y] The virtual receiving array correlation vector h _after_cal (k, fs, w) is calculated. The virtual receiving array correlation vector h _after_cal (k, fs, w) are expressed by the following equation, where y = 1, ..., (Nt x Na).

number

[0075] Virtual receiving array correlation vector h with correction for deviation between antennas _after_cal (k, fs, w) is a column vector consisting of Na × Nr elements. In the following, the virtual receiving array correlation vector h _after_cal Let each element of (k, fs, w) be h1(k, fs, w),…,h Na×Nr The notation (k, fs, w) is used to explain the direction estimation process.

[0076] [Antenna Arrangement in Radar Device 10] The arrangement of the Nt transmitting antennas 106 and the Na receiving antennas 202 in the radar device 10 having the above configuration will be described.

[0077] <Basic layout 1> FIG. 8 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 according to basic arrangement 1, and an example of the arrangement of a virtual receiving array.

[0078] In the following description, the horizontal distance D H , and the vertical (e.g., vertical in FIG. 8) spacing D V For example, the interval D H , and interval D V may be different.

[0079] (1) Arrangement of transmitting and receiving antennas In FIG. 8, the number of transmitting antennas 106 in the transmitting array antenna is Nt=4 (Tx#1, Tx#2, Tx#3, and Tx#4), and the number of receiving antennas 202 in the receiving array antenna is Na=4 (Rx#1, Rx#2, Rx#3, and Rx#4).

[0080] The transmitting array antenna shown in Fig. 8 is composed of a "first transmitting antenna group" (Tx#2, Tx#4 in Fig. 8) and a "second transmitting antenna group" (Tx#1, Tx#3 in Fig. 8). Each transmitting antenna group is located at the same position in the vertical direction, and the antenna spacing in the horizontal direction (horizontal direction in Fig. 8) is 2D. H The distance between the "first transmitting antenna group" and the "second transmitting antenna group" in the vertical direction (the vertical direction in FIG. 8) is, for example, 3D V It becomes.

[0081] The receiving array antenna shown in Fig. 8 is composed of a "first receiving antenna group" (Rx#2, Rx#4 in Fig. 8) and a "second receiving antenna group" (Rx#1, Rx#3 in Fig. 8). Each receiving antenna group is located at the same position in the vertical direction, and the antenna spacing in the horizontal direction is 3D. H The vertical distance between the "first receiving antenna group" and the "second receiving antenna group" is, for example, 2D V It becomes.

[0082] In other words, in FIG. 8, the vertical spacing between the transmit antenna groups (3D V ) and the horizontal antenna spacing within each receiving antenna group (3D H ) is the same as the horizontal antenna spacing (2D H ) and the vertical spacing between the receiving antennas (2D in Fig. 8). H ) are identical.

[0083] In addition, in FIG. 8, the spacing between the transmitting antenna groups is 3D V (or, antenna spacing within a receiving antenna group 3D H ) and the antenna spacing within the transmitting antenna group is 2D H (Or, the spacing between the receiving antennas is 2D V ) is D H Or D V It is.

[0084] In addition, in FIG. 8, the antenna spacing in the transmitting antenna group is 2D H (D H (intervals of an integer multiple of ) and antenna spacing within the receiving antenna group 3D H (D H The difference between this and the integer multiple of D H In addition, in FIG. 8, the spacing between the multiple transmitting antenna groups is 3D V (D V (intervals of an integer multiple of ) and intervals of 2D V (D V The difference between this and the integer multiple of D V It is.

[0085] (2) Virtual receiving array layout The arrangement of the virtual receiving array (virtual antennas VA#1 to VA#16) configured by the transmitting and receiving antenna arrangement shown in FIG. 8 described above has the following features.

[0086] Here, the arrangement of the virtual receiving array can be expressed by the following equation based on the positions (positions of the feed points) of the transmitting antennas that make up the transmitting array antenna and the positions (positions of the feed points) of the receiving antennas that make up the receiving array antenna.

number

[0087] Note that mod(x, y) is an operator that calculates the remainder after division (modulo operation) and returns the remainder when x is divided by y. Also, ceil(x) is an operator that returns a value rounded to the nearest integer equal to or greater than x. In addition, in equation (7), the X-axis corresponds to the horizontal direction (horizontal direction) shown in FIG. 8, and the Y-axis corresponds to the vertical direction (vertical direction) shown in FIG. 8.

[0088] Here, the position coordinates of the transmitting antenna 106 constituting the transmitting array antenna are expressed as (X T_#n ,Y T_#n ) (where n=1, ..,, Nt), and the position coordinates of the receiving antenna 202 constituting the receiving array antenna are (X R_#m ,Y R_#m ) (where m = 1, .., , Na), and the position coordinates of the virtual antennas that make up the virtual receiving array are (X V_#k ,Y V_#k ) (where k=1, ..,, Nt×Na). In equation (7), VA#1 is expressed as the position reference (0,0) of the virtual receiving array.

[0089] As an example, the antenna arrangement shown in FIG. 8 will be described.

[0090] The position coordinates of the transmitting antennas 106 constituting the transmitting array antenna are the position coordinates of the transmitting antenna Tx#1 (X T_#1 ,Y T_#1 ) as the reference, the position coordinates of the transmitting antenna Tx#2 (X T_#2 ,Y T_#2 )=(X T_#1 ,Y T_#1 +3D V ), the position coordinates of the transmitting antenna Tx#3 (X T_#3 ,Y T_#3 )=(X T_#1 +2D H ,Y T_#1 ), and the position coordinates of the transmitting antenna Tx#4 (X T_#4 ,Y T_#4 )=(X T_#1 +2D H ,Y T_#1 +3D V )

[0091] Similarly, the position coordinates of the receiving antenna 202 constituting the receiving array antenna are expressed as the position coordinates of the receiving antenna Rx#1 (X R_#1 ,Y R_#1 ) as the reference, the position coordinates of the receiving antenna Rx#2 (X R_#2 ,Y R_#2 )=(X R_#1 ,Y R_#1 +2D V ), the position coordinates of the receiving antenna Rx#3 (X R_#3 ,Y R_#3 )=(X R_#1 +3D H ,Y R_#1 ), and the position coordinates of the receiving antenna Rx#4 (X R_#4 ,Y R_#4 )=(X R_#1 +3D H ,Y R_#1 +2D V )

[0092] With such an arrangement of the transmitting array antenna and the receiving array antenna, the position coordinates (X V_#1 ,Y V_#1 )~(X V_#16 ,Y V_#16 ) are as follows, respectively: (0,0), (0, 3D V ), (2D H , 0), (2D H , 3D V ), (0, 2D V ), (0, 5D V ), (2D H , 2D V ), (2D H , 5D V ), (3D H ,0), (3D H , 3D V ), (5D H , 0), (5D H , 3D V ), (3D H , 2D V ), (3D H , 5D V ), (5D H, 2D V ), (5D H , 5D V )

[0093] In this way, in the arrangement of the virtual receiving array shown in Fig. 8, each virtual receiving array element is arranged at a different position without overlapping, so that the aperture length of the virtual receiving array can be expanded, the main lobe is narrowed, and the angular resolution can be improved.

[0094] As shown in FIG. 8, the virtual array elements VA#4, VA#7, VA#10, and VA#13 located near the center of the virtual receiving array are arranged in a horizontal direction D H Spacing, vertically D V As an example, in FIG. 8, the distance D H and interval D V When the distance is about 0.5λ, the virtual array elements VA#4, VA#7, VA#10, and VA#13 are D H = 0.5λ interval, D in the vertical direction V = 0.5λ apart. This makes it possible to reduce grating lobes. The effect of reducing grating lobes will be described later.

[0095] In addition, in the arrangement of the virtual receiving array, there is no dependency on the positional relationship between the transmitting array antenna and the receiving array antenna. Therefore, the positional relationship between the transmitting array antenna and the receiving array antenna is not limited to the arrangement shown in Fig. 8, but can be set arbitrarily. The same applies to other arrangement configurations described below.

[0096] Moreover, the horizontal and vertical arrangement of the transmitting array antenna and the receiving array antenna shown in Fig. 8 can be changed to a vertical and horizontal arrangement (for example, an arrangement rotated 90 degrees from that in Fig. 8) to obtain the same effect. The same applies to other arrangement configurations described below.

[0097] Furthermore, in the antenna arrangement shown in Fig. 8, the arrangement of the transmitting array antenna and the arrangement of the receiving array antenna may be interchanged. For example, the arrangement of the receiving array antenna shown in Fig. 8 may be used as the arrangement of the transmitting array antenna, and the arrangement of the transmitting array antenna shown in Fig. 8 may be used as the arrangement of the receiving array antenna. Even if the arrangement of the transmitting array antenna and the arrangement of the receiving array antenna are interchanged, the arrangement of the virtual receiving array will be the same, and therefore similar effects can be obtained. The same applies to other arrangement configurations described below.

[0098] Here, as an example, in FIG. H and interval D V As shown in Fig. 8, the spacing between antenna elements in both the transmitting and receiving antenna arrays is 2D H , 3D H , 2D V and 3D V In other words, in FIG. 8, the spacing between the transmitting antenna groups is 3D V , antenna spacing within the receiving antenna group 3D H , the antenna spacing in the transmitting antenna group is 2D H , and the spacing between the receiving antennas 2D V is an interval longer than one wavelength of a radar transmission signal (for example, a radar carrier wave). Therefore, in FIG. 8, the element sizes in the horizontal and vertical directions of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0099] As a result, for example, an antenna using four planar patch antenna elements arranged two by two in the vertical and horizontal directions as a subarray as shown in FIG. 9A can be applied to at least one of the antenna elements of the transmitting array antenna and the receiving array antenna shown in FIG. 8. However, in FIG. 9A, the antenna width W ANT < 2D H , and antenna height H ANT <2D V It is.

[0100] In the case of Fig. 8, the antenna spacing in the vertical direction of the transmitting array antenna is 3DV and the horizontal antenna spacing is 2D H Therefore, for example, an antenna using six planar patch antenna elements arranged as a sub-array, three elements vertically and two elements horizontally, as shown in FIG. 9B, can be applied to each antenna element of the transmitting array antenna shown in FIG. 8. However, in FIG. 9B, the antenna width W ANT < 2D H , and antenna height H ANT < 3D V It is.

[0101] In the case of Fig. 8, the horizontal antenna spacing of the receiving array antenna is 3D H and the vertical antenna spacing is 2D V Therefore, for example, an antenna using six planar patch antenna elements arranged as a sub-array, two elements vertically and three elements horizontally, as shown in FIG. 9C, can be applied to each antenna element of the receiving array antenna shown in FIG. 8. However, in FIG. 9C, the antenna width W ANT < 3D H , and antenna height H ANT <2D V It is.

[0102] In the antenna arrangement shown in Fig. 8, by using an antenna having a subarray configuration as shown in Fig. 9A, 9B, or 9C, it is possible to improve the directional gain of the antenna and improve the detection performance (e.g., detection distance) of the radar device 10. Note that the subarray configuration applied to the antenna element shown in Fig. 8 is not limited to the configurations shown in Fig. 9A, 9B, and 9C, and may be any subarray configuration that can be arranged so that the position shown in Fig. 8 can be the phase center of the antenna element (in other words, the antenna system).

[0103] As an example, Fig. 10 shows a case where the sub-array shown in Fig. 9B is applied to each antenna element of the transmitting array antenna shown in Fig. 8. As shown in Fig. 10, the transmitting array antenna has a size of 3D in the vertical direction. V , horizontal size 2D H The antenna elements are arranged in a subarray configuration.

[0104] Thus, according to the basic arrangement 1, for example, a size of 1λ or more (for example, D H =D V = 0.5λ) can be applied, and in the virtual receiving array, the virtual antennas can be densely arranged (for example, D H Or D V Therefore, it is possible to reduce (in other words, suppress) grating lobes while improving the directional gain of the antenna.

[0105] An example of the antenna arrangement in the radar device 10 has been described above.

[0106] The direction estimation unit 214 performs horizontal and vertical direction estimation processing as follows, using received signals of a virtual receiving array (see, for example, FIG. 8) obtained from the above-mentioned arrangement of transmitting and receiving antennas (see, for example, FIG. 8).

[0107] The element number (VA# number) of the virtual receiving array is calculated by the virtual receiving array correlation vector h _after_cal It corresponds to the element number of the column vector (k, fs, w). For example, VA#1 shown in Figure 8 is h _after_cal This corresponds to the first element h1(k, fs, w) of the column vector elements of (k, fs, w). The same applies to the other VA#2 to VA#16 shown in FIG.

[0108] In estimating the direction of arrival in the horizontal and vertical directions, the direction estimation unit 214 calculates a spatial profile by varying the azimuth direction θ and the elevation angle direction φ in the direction estimation evaluation function value P(θ, φ, k, fs, w) within a predetermined angle range. The direction estimation unit 214 extracts a predetermined number of maximum peaks from the calculated spatial profile in descending order, and outputs the azimuth direction and elevation angle direction of the maximum peaks as an estimated value of the direction of arrival.

[0109] The evaluation function value P(θ, φ, k, fs, w) can be calculated using various methods depending on the direction-of-arrival estimation algorithm. For example, an estimation method using an array antenna disclosed in the reference non-patent document may be used.

[0110] (Reference Non-Patent Document) Direction-of-arrival estimation using signal subspace modeling Cadzow, JA; Aerospace and Electronic Systems, IEEE Transactions on Volume: 28, Issue: 1 Publication Year: 1992, Page(s): 64 - 79

[0111] For example, the beamformer method can be expressed as follows: In addition, other methods such as Capon and MUSIC can also be applied in the same way.

number

[0112] Here, the superscript H is the Hermitian transpose operator. Also, a(θ u ,φ v ) indicates the direction vector of a virtual receiving array with respect to an arriving wave in the azimuth direction θ and the elevation direction φ.

[0113] As described above, direction estimation section 214 outputs, together with the calculated arrival direction estimate, the discrete time k at which the arrival direction estimate was calculated and the Doppler frequency fsΔΦ as radar positioning results.

[0114] In addition, the azimuth direction θ u is a vector obtained by changing the azimuth range for estimating the direction of arrival at a predetermined azimuth interval β1. For example, θ u is set as follows: θ u =θmin + uβ1, u=0,…, NU NU = floor [(θmax-θmin) / β1] + 1 Here, floor(x) is a function that returns the maximum integer value that does not exceed the real number x.

[0115] In addition, φ v is obtained by changing the elevation angle range for estimating the direction of arrival at a predetermined azimuth interval β2. For example, φ v is set as follows: φ v =φmin + vβ2, v=0,…, NV NV = floor [(φmax-φmin) / β2] + 1

[0116] In this embodiment, the direction vector a(θ) of the virtual receiving array is calculated based on the virtual receiving array arrangements VA#1, . . . , VA#(Nt×Na). u ,φ v ) is calculated in advance. Here, the direction vector a(θ u ,φ v ) is a (Nt × Na) order column vector whose elements are the complex response of the virtual receiving array when the radar reflection wave arrives from the azimuth direction θ and the elevation angle direction φ. Also, the complex response a(θ u ,φ v ) represents the phase difference calculated geometrically at the element spacing between the antennas.

[0117] The above-mentioned time information k may be converted into distance information and output. The following formula can be used to convert the time information k into distance information R(k). Here, Tw represents the code transmission section, L represents the pulse code length, and C0 represents the speed of light.

number

[0118] Furthermore, the Doppler frequency information (fsΔΦ) may be converted into a relative velocity component and output. The following equation may be used to convert the Doppler frequency fsΔΦ into the relative velocity component vd(fs). Here, λ is the wavelength of the carrier frequency of the RF signal output from the transmission radio unit 105.

number

[0119] 11A and 11B show an example of a direction estimation result when the beamformer method is used as the direction estimation algorithm of the direction estimation unit 214. In Fig. 11A and 11B, the output of the direction estimation evaluation function value in the horizontal range of ±90 degrees and the vertical range of ±90 degrees when the target true value is set to 0 degrees horizontally and 0 degrees vertically is plotted. Note that the directivity of each antenna is calculated as omnidirectional.

[0120] FIG. 11A shows the arrangement of transmitting and receiving antennas (for example, MIMO array arrangement) shown in FIG. 8 (however, D H =0.5λ, D V 11A shows an example of a direction estimation result when using a λ / 2 sigma (λ = 0.5λ). That is, in FIG. 11A, the condition is that the antenna spacing in the horizontal and vertical directions of transmitting antenna 106 is 1λ or more, and the antenna spacing in the horizontal and vertical directions of receiving antenna 202 is also 1λ or more.

[0121] In addition, for comparison with FIG. 11A, FIG. 11B shows an example of the MIMO radar antenna arrangement shown in FIG. 1, in which the antenna spacing in the vertical direction of the transmitting antennas is λ and the antenna spacing in the horizontal direction of the receiving antennas is λ (i.e., d V = λ, d H = λ) direction estimation results are shown below.

[0122] In Fig. 11B, grating lobes occur in the horizontal and vertical directions in directions other than 0 degrees horizontal and 0 degrees vertical of the target true value. In contrast, in Fig. 11A, it can be seen that grating lobes are reduced in directions other than 0 degrees horizontal and 0 degrees vertical of the target true value. For example, in Fig. 11A, the ratio (PSLR) of the peak power value of the highest side lobe excluding the main lobe in directions other than 0 degrees horizontal and 0 degrees vertical to the peak power value of the main lobe in the 0 degrees horizontal and 0 degrees vertical directions is about 0.44.

[0123] As described above, by using the MIMO array arrangement shown in Fig. 8, even if the vertical or horizontal element size of the antennas used for the transmitting array antenna and the receiving array antenna is about 1λ, the horizontal and vertical antenna spacing in the virtual receiving array can be arranged to include element spacing of about 0.5λ, thereby reducing grating lobes. Furthermore, for example, as shown in Fig. 8, the virtual array elements of the virtual receiving array are arranged without overlapping, so the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0124] In addition, sub-array antennas with element sizes of at least about 1λ in the vertical and horizontal directions can be used for the antenna elements used in the transmitting antenna 106 and the receiving antenna 202. This can improve the directional gain of the antennas and the detection performance (e.g., detection distance) of the radar device 10.

[0125] The MIMO array arrangement is not limited to the example shown in Fig. 8. For example, an arrangement in which the horizontal and vertical directions of the antenna arrangement shown in Fig. 8 are swapped may be used. In this case, the virtual receiving array arrangement is an arrangement in which the horizontal and vertical directions of the arrangement in Fig. 8 are swapped. This provides angular separation performance in which the horizontal and vertical directions of Fig. 8 and Fig. 8 are swapped. Similarly, an arrangement in which the horizontal and vertical directions are swapped may be used in the MIMO array arrangement described below.

[0126] <Modification 1 of Basic Layout 1> In the basic arrangement 1 (for example, FIG. 8), the number of transmitting antennas 106 is four (Nt=4), and the number of receiving antennas 202 is four (Nat=4). However, the number of transmitting antennas Nt and the number of receiving antennas Na are not limited to these numbers.

[0127] In the first modification of the first basic arrangement, the transmitting array antenna is arranged in the same manner as the first basic arrangement, for example, with a vertical spacing of 3D. VIn addition, as in the basic arrangement 1, each transmitting antenna group is located at the same position in the vertical direction, and the antenna spacing in the horizontal direction is 2D. H The antenna includes a plurality of transmit antenna elements, each of which is

[0128] In addition, in the first modification of the first basic arrangement, the receiving array antennas are arranged in the same manner as in the first basic arrangement, for example, with a vertical spacing of 2D. V Each receiving antenna group is located at the same position in the vertical direction, and the antenna spacing in the horizontal direction is 3D. H The receiving antenna includes a plurality of receiving antenna elements, each of which is

[0129] In other words, in the first modification of the first basic arrangement, the vertical spacing between the transmitting antenna groups (here, 3D V ) and the horizontal antenna spacing within each receiving antenna group (here, 3D H ) is the same as the horizontal antenna spacing (here, 2D H ) and the vertical spacing between the receiving antennas (here, 2D H ) are identical.

[0130] In the following, the number of transmit antenna groups is referred to as "N TxGroup ” and the number of transmit antennas in each transmit antenna group is represented as “N TxGroup_ANT " The number of receiving antenna groups is expressed as "N RxGroup ” and the number of transmit antennas included in each receive antenna group is represented as “N RxGroup_ANT " is expressed as ".

[0131] In the first modification of the basic arrangement 1, N TxGroup_ANT and N RxGroup Depending on the value of , it becomes possible to increase the number of antennas in the MIMO array.

[0132] Figure 12 shows the N TxGroup_ANT =4, N RxGroup2 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202, and an example of the arrangement of the virtual receiving array when .function..times ...

[0133] Figure 13 shows the N TxGroup_ANT =2, N RxGroup 4 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202, and an example of the arrangement of the virtual receiving array when .function..times ...

[0134] Figure 14 shows the N TxGroup_ANT =4, N RxGroup 4 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202, and an example of the arrangement of the virtual receiving array when .function..times ...

[0135] In addition, in Figs. 12, 13 and 14, N TxGroup = 2, and N RxGroup_ANT =2.

[0136] In each of the MIMO array arrangements shown in Figs. 12, 13, and 14, for example, D H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0137] In addition, for example, in each of the virtual receiving arrays shown in Figures 12, 13 and 14, the virtual array elements are arranged at different positions without overlapping, so that the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0138] In addition, the virtual array elements located near the center of each virtual receiving array shown in Figs. 12, 13, and 14 are denoted by D H , D V D H , D V The number of closely spaced virtual array elements is N TxGroup_ANT and N RxGroup increases depending on

[0139] For example, in the virtual receiving array, the horizontal direction is (N TxGroup_ANT ×NRxGroup_ANT )-2 virtual array element is D H The vertical direction is spaced apart by (N RxGroup ×N TxGroup )-2 virtual array element is D V The distance between the receiving array and the receiving array is D H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes are reduced.

[0140] Also, N TxGroup_ANT , N RxGroup_ANT The larger N, the more the number of virtual array elements arranged in the horizontal direction increases, so the aperture length of the virtual receiving array in the horizontal direction can be expanded and the angular resolution in the horizontal direction can be improved. RxGroup , N RxGroup The larger θ is, the more the number of virtual array elements arranged in the vertical direction increases, so that the aperture length of the virtual receiving array in the vertical direction can be expanded and the angular resolution in the vertical direction can be improved.

[0141] FIG. 15 shows a MIMO array arrangement (N TxGroup_ANT =4, N TxGroup =2, N RxGroup =3, N RxGroup_ANT =2, D H =0.5λ, D V 13 shows an example of a direction estimation result when a beamformer method is used as the arrival direction estimation algorithm of the direction estimator 214 when a λ=0.5λ is used. Note that the directivity of each antenna is calculated as omnidirectional.

[0142] FIG. 15 plots the output of the direction-of-arrival estimation evaluation function value in a range of ±90 degrees in the horizontal direction and a range of ±90 degrees in the vertical direction when the target true value is 0 degrees horizontally and 0 degrees vertically.

[0143] In Fig. 15, it can be seen that the grating lobes are reduced in directions other than the horizontal 0 degrees and vertical 0 degrees of the target true value, as compared to Fig. 11A, for example. For example, in Fig. 15, the ratio (PSLR) of the peak power value of the highest side lobe excluding the main lobe to the peak power value of the main lobe in the horizontal 0 degrees and vertical 0 degrees directions is about 0.22.

[0144] From this, in the case of Figure 14 (N TxGroup_ANT =4, N RxGroup In Figure 8 (N = 3), TxGroup_ANT =2, N RxGroup = 2) (see, for example, Figure 11A) (in both cases, N TxGroup =2, N RxGroup_ANT =2), N TxGroup_ANT and N RxGroup It can be seen that the side lobe reduction effect is improved by increasing N. Also, in FIG. 15, the peak of the main lobe is sharper than in FIG. 11A. TxGroup_ANT and N RxGroup The increase in the angular resolution can be seen.

[0145] <Modification 2 of Basic Layout 1> The antenna arrangement methods 1-2A and 1-2B in the second modification of the basic arrangement 1 will be described below.

[0146] (Placement method 1-2A) In the first modification of the basic arrangement 1, the number of receiving antenna groups included in the receiving array antenna is N RxGroup In this case, the number of virtual array elements arranged in the vertical direction is increased by increasing N RxGroup ≧3, the number of transmitting antenna groups in the transmitting array antenna is N TxGroup The number of virtual array elements arranged in the vertical direction in the virtual receiving array can also be increased by increasing

[0147] In this case, the antenna spacing in the vertical direction of the transmitting antenna group is set to a constant value (e.g., 3D V ), but the number of receiving antennas NRxGroup Depending on the configuration, the virtual receive array may have overlapping virtual array elements.

[0148] Therefore, in order to arrange the virtual receiving array so that there are no overlapping virtual array elements, for example, the spacing between even-numbered antennas in the vertical direction of the transmitting antenna group should be set to the following spacing D TxGroupV may be used.

number

[0149] For example, N RxGroup If = 3, D TxGroupV =3D V Then, N RxGroup If =4, D TxGroupV =5D V It becomes.

[0150] For example, the number of transmit antennas N TxGroup When = 3, the spacing between the three transmit antenna groups is {3D V , D TxGroupV}. In addition, the number of transmitting antenna groups N TxGroup For , the spacing between the four transmit antenna groups is {3D V , D TxGroupV , 3D V Similarly, the number of transmitting antenna groups N RxGroup_ANT For , the spacing between the five transmit antenna groups is {3D V , D TxGroupV , 3D V , D TxGroupV}.

[0151] Figure 16 shows the N TxGroup =4, N TxGroup_ANT =4, N RxGroup =3, N RxGroup_ANT FIG. 16 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202, and an example of the arrangement of the virtual receiving array when D TxGroupV =3D V It becomes.

[0152] Also, Figure 17 shows N TxGroup =4, N TxGroup_ANT =4, N RxGroup =4, N RxGroup_ANT FIG. 17 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202, and an example of the arrangement of the virtual receiving array when D TxGroupV =5D V It becomes.

[0153] In addition, the virtual receiving array is placed at irregular intervals (e.g., D H and D. V If it is acceptable to include arrangements with a spacing greater than TxGroupV may be greater than the value of equation (11).

[0154] (Placement method 1-2B) In the variation 1 of the basic arrangement 1, the number of transmitting antennas included in each transmitting antenna group of the transmitting array antenna is N TxGroup_ANT In this case, the number of virtual array elements arranged in the horizontal direction is increased by increasing N TxGroup_ANT ≧3, the number of receiving antennas in the receiving antenna group in the receiving array antenna is N RxGroup_ANT The number of virtual array elements arranged horizontally in the virtual receiving array can also be increased by increasing

[0155] In this case, the horizontal antenna spacing of the receiving antenna group is set to a constant value (e.g., 3D H ), but the number of transmitting antennas included in the transmitting antenna group N TxGroup_ANT Depending on the configuration, the virtual receive array may have overlapping virtual array elements.

[0156] Therefore, in order to arrange the virtual receiving array so that there are no overlapping virtual array elements, for example, the horizontal antenna spacing of the receiving antennas included in the receiving antenna group should be set to the following spacing D RxAntH may be used.

number

[0157] For example, N TxGroup_ANT If = 3, D RxAntH =3D H Then, N TxGroup_ANT If =4, D RxAntH =5D H It becomes.

[0158] For example, the number of receiving antennas included in the receiving antenna group is N RxGroup_ANT When = 3, the antenna spacing of the three receiving antennas is {3D H , D RxAntH}. In addition, the number of receiving antennas is N RxGroup_ANT = 4, the antenna spacing for the four receiving antennas is {3D H , D RxAntH , 3D H Similarly, the number of receiving antennas N RxGroup_ANT = 5, the antenna spacing for the five receiving antennas is {3D H , D RxAntH , 3D H , D RxAntH}.

[0159] Figure 18 shows the TxGroup =2, N TxGroup_ANT =3, N RxGroup =2, N RxGroup_ANT FIG. 18 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202, and an example of the arrangement of the virtual receiving array, when D RxAntH =3D H It becomes.

[0160] Figure 19 shows the N TxGroup =2, N TxGroup_ANT =4, N RxGroup =2, N RxGroup_ANT FIG. 19 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202, and an example of the arrangement of the virtual receiving array, when D RxAntH =5D H It becomes.

[0161] In addition, the virtual receiving array is placed at irregular intervals (e.g., D H and D.V If it is acceptable to include arrangements with a spacing greater than RxAntH may be greater than the value of equation (12).

[0162] The arrangement methods 1-2A and 1-2B in the modification 2 of the basic arrangement 1 have been described above.

[0163] For example, in the transmitting and receiving antenna arrangements (e.g., MIMO array arrangements) shown in Figs. 16 to 19, D H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0164] Furthermore, for example, in each of the virtual receiving arrays shown in Figs. 16 to 19, the virtual array elements are arranged at different positions without overlapping, so that the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0165] For example, the virtual array elements located near the center of the virtual receiving array shown in Figs. 16 to 19 are denoted as D H , D V D H , D V The number of closely spaced virtual array elements is N TxGroup , N TxGroup_ANT , N RxGroup and N RxGroup_ANT increases depending on

[0166] For example, in the virtual receiving array, the horizontal direction is (N TxGroup_ANT ×N RxGroup_ANT )-2 virtual array element is D H The vertical direction is spaced apart by (N RxGroup ×N TxGroup )-2 virtual array element is D V The distance between the receiving array and the receiving array is D H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes can be reduced.

[0167] Also, N TxGroup_ANT , N RxGroup_ANT The larger N, the more the number of virtual array elements arranged in the horizontal direction increases, so the aperture length of the virtual receiving array in the horizontal direction can be expanded and the angular resolution in the horizontal direction can be improved. TxGroup , N RxGroup The larger θ is, the more the number of virtual array elements arranged in the vertical direction increases, so that the aperture length of the virtual receiving array in the vertical direction can be expanded and the angular resolution in the vertical direction can be improved.

[0168] In addition, in the variation 2 of the basic arrangement 1, it is also possible to combine the arrangement method 1-2A and the arrangement method 1-2B. TxGroup =4, N TxGroup_ANT =4, N RxGroup =4, N RxGroup_ANT FIG. 20 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 for D = 4, and an example of the arrangement of the virtual receiving array. TxGroupV =5D H Then, D in equation (12) RxAntH =5D H This provides the effect of combining the arrangement methods 1-2A and 1-2B.

[0169] <Modification 3 of Basic Layout 1> The antenna arrangement methods 1-3A, 1-3B, and 1-3C in the third modification of the basic arrangement 1 will be described below.

[0170] (Placement method 1-3A) In the basic arrangement 1, the horizontal positions of the transmitting antennas included in each transmitting antenna group in the transmitting array antenna have been described as being the same. However, this is not limiting, and the horizontal arrangement positions of the transmitting antennas included in each transmitting antenna group may be different between the transmitting antenna groups.

[0171] For example, in the transmitting array antenna, the horizontal positions of each transmitting antenna included in the first transmitting antenna group and the second transmitting antenna group are D HThey may be arranged in a staggered manner (in other words, shifted).

[0172] Horizontally D H The shift direction may be either to the right or to the left of each transmitting antenna included in the second transmitting antenna group with respect to each transmitting antenna included in the first transmitting antenna group.

[0173] FIG. 21 shows a case where, in a transmitting array antenna, each transmitting antenna (for example, Tx#1, Tx#3) included in a second transmitting antenna group is shifted to the right with respect to each transmitting antenna (for example, Tx#2, Tx#4) included in a first transmitting antenna group. H 13 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 when they are shifted, and an example of the arrangement of the virtual receiving array.

[0174] In FIG. 21, the horizontal positions of Tx#1 and Tx#2 are D H Also, the horizontal positions of Tx#3 and Tx#4 are different. H different.

[0175] (Placement method 1-3B) In the basic arrangement 1, the horizontal positions of the receiving antennas included in each receiving antenna group in the receiving array antenna are the same. However, this is not limited to the above, and the horizontal positions of the receiving antennas included in each receiving antenna group may differ between the receiving antenna groups.

[0176] For example, in the receiving array antenna, each receiving antenna included in the first receiving antenna group and the second receiving antenna group has a horizontal position D H They may be staggered.

[0177] Horizontally D H The direction of shift may be either to the right or to the left of each receiving antenna included in the second receiving antenna group with respect to each receiving antenna included in the first receiving antenna group.

[0178] FIG. 22 shows a receiving array antenna in which each receiving antenna (e.g., Rx#1, Rx#3) included in the second receiving antenna group is shifted to the right with respect to each receiving antenna (e.g., Rx#2, Rx#4) included in the first receiving antenna group. H 13 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 when they are shifted, and an example of the arrangement of the virtual receiving array.

[0179] In FIG. 22, the horizontal positions of Rx#1 and Rx#2 are D H Also, the horizontal positions of Rx#3 and Rx#4 are different. H different.

[0180] (Placement method 1-3C) Arrangement method 1-3C is a combination of arrangement methods 1-3A and 1-3B.

[0181] For example, in a transmitting array antenna, the transmitting antenna is located between the first transmitting antenna group and the second transmitting antenna group at a horizontal position of D H Similarly, in the receiving array antenna, the receiving antennas are positioned horizontally between the first receiving antenna group and the second receiving antenna group by D H are staggered and positioned.

[0182] In addition, the horizontal direction is D H The shift direction may be, for example, either to the right or to the left of each transmitting antenna included in the second transmitting antenna group with respect to each transmitting antenna included in the first transmitting antenna group. H The shift direction may be, for example, to the right or left of each receiving antenna included in the second receiving antenna group with respect to each receiving antenna included in the first receiving antenna group.

[0183] 23 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 and an example of the arrangement of the virtual receiving array according to the arrangement method 1-3C. In FIG. 23, in the transmitting array antenna, the transmitting antennas (e.g., Tx#1, Tx#3) included in the second transmitting antenna group are arranged in the left direction with respect to the transmitting antennas (e.g., Tx#2, Tx#4) included in the first transmitting antenna group. H In addition, in FIG. 23, in the receiving array antenna, the receiving antennas (e.g., Rx#1, Rx#3) included in the second receiving antenna group are shifted to the left with respect to the receiving antennas (e.g., Rx#2, Rx#4) included in the first receiving antenna group. H are staggered and positioned.

[0184] 24 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 and an example of the arrangement of the virtual receiving array according to the arrangement method 1-3C. In FIG. 24, in the transmitting array antenna, the transmitting antennas (e.g., Tx#1, Tx#3) included in the second transmitting antenna group are arranged in the left direction with respect to the transmitting antennas (e.g., Tx#2, Tx#4) included in the first transmitting antenna group. H In addition, in FIG. 24, in the receiving array antenna, the receiving antennas (e.g., Rx#1, Rx#3) included in the second receiving antenna group are shifted to the right with respect to the receiving antennas (e.g., Rx#2, Rx#4) included in the first receiving antenna group. H are staggered and positioned.

[0185] For example, the horizontal distance between the receiving antenna group and the transmitting antenna group is D H Compared with an arrangement in which the shift direction is different (for example, Fig. 24), the horizontal shift of the receiving antenna group and the transmitting antenna group is D H An arrangement in which the shift direction is the same (eg, FIG. 23) is more preferable since the virtual receiving array elements are arranged more densely near the center of the virtual receiving array arrangement.

[0186] The arrangement methods 1-3A to 1-3C have been described above.

[0187] For example, in the transmitting and receiving antenna arrangement (e.g., MIMO array arrangement) shown in Figs. 21 to 24, D H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ.

[0188] As a result, in the third modification of the basic arrangement 1, for example, an antenna using four planar patch antennas arranged in two rows and two columns as shown in FIG. 9A as a subarray (where the antenna width W ANT < 2D H , Antenna height H ANT <2D V ) can be applied (not shown).

[0189] In addition, the vertical spacing between the transmitting antennas is 3D V and the horizontal spacing between the transmit antennas in each transmit antenna group is 2D H In the case of the transmitting array antenna, the vertical spacing is wider than the horizontal spacing. For this reason, in the third modification of the basic layout 1, for example, an antenna using six planar patch antenna elements arranged vertically and horizontally, as shown in FIG. 9B (where the antenna width W ANT < 2D H , Antenna height H ANT <3D V ) can be applied.

[0190] In addition, in the third modification of the basic arrangement 1, in at least one of the transmitting array antennas and the receiving array antennas, the horizontal positions of the transmitting antennas included in each transmitting antenna group or the receiving antennas included in each receiving antenna group are different from each other. ANT The element size of D H As long as the size of the elements in the vertical direction of the subarray is smaller than , the size of the elements in the vertical direction of the subarray may be any size.

[0191] For example, Fig. 25A shows an example of a subarray in which planar patch antennas are arranged in a vertical arrangement of eight elements and a horizontal arrangement of one element. Note that the configuration of the subarray is not limited to the configuration shown in Fig. 25A.

[0192] FIG. 25B shows an example in which the subarray shown in FIG. 25A is applied to the transmitting antenna array shown in FIG. 23 or FIG. 24. In addition to the transmitting array antenna shown in FIG. 25B, parasitic elements (dummy elements) may be arranged as shown in FIG. 25C. The parasitic elements can equalize the effect of inter-antenna coupling due to adjacent antennas for each antenna, and can equalize the directional characteristics of each transmitting antenna (Tx#1 to #4). Furthermore, by installing the parasitic elements, the effect of electrical characteristics such as antenna radiation, impedance matching, or isolation can be equalized. The arrangement of the parasitic elements is not limited to that shown in FIG. 25C, and they may be arranged at positions and sizes that do not physically interfere with each antenna.

[0193] In this way, by using antennas in a subarray configuration in the antenna arrangement according to the third modification of the first basic arrangement, the directional gain of the antennas can be improved, and the detection performance (for example, detection distance) of the radar device 10 can be improved.

[0194] In addition, in the third modification of the first basic arrangement, the virtual array elements of the virtual receiving array are arranged without overlapping, so that the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0195] (Combination of Modification 3 and Modification 1) In addition, the third modification of the first basic layout may be combined with the first modification of the first basic layout.

[0196] For example, in the arrangement of the transmitting array antenna according to the first modification of the basic arrangement 1, the horizontal positions of the transmitting antennas included in the transmitting antenna groups are further changed to D H A staggered arrangement is acceptable.

[0197] Similarly, for example, for the arrangement of the receiving array antennas according to the modification 1 of the basic arrangement 1, the horizontal positions of the receiving antennas included in the receiving antenna group are further changed to D H A staggered arrangement is acceptable.

[0198] 26 to 30 show an example of antenna arrangement in a combination of the third modification and the first modification.

[0199] Figure 26 shows the TxGroup =2, N TxGroup_ANT =4, N RxGroup =3, N RxGroup_ANT = 2, and the horizontal position of each transmitting antenna in the transmitting antenna group is D H 1 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 in the case of a staggered arrangement, and an example of the arrangement of the virtual receiving array.

[0200] Also, Figure 27 shows N TxGroup =2, N TxGroup_ANT =4, N RxGroup =3, N RxGroup_ANT = 2, and the horizontal position of each receiving antenna in the receiving antenna group is D H 1 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 in the case of a staggered arrangement, and an example of the arrangement of the virtual receiving array.

[0201] Also, Figure 28 shows N TxGroup =2, N TxGroup_ANT =4, N RxGroup =3, N RxGroup_ANT = 2, and the horizontal position of each transmitting antenna in the transmitting antenna group is D H The horizontal position of each receiving antenna in the receiving antenna group is shifted by D H 28 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 and an example of the arrangement of the virtual receiving array in the case of the shifted arrangement. In FIG. 28, the transmitting antennas (e.g., Tx#1, Tx#3, Tx#5, Tx#7) included in the second transmitting antenna group are shifted to the left with respect to the transmitting antennas (e.g., Tx#2, Tx#4, Tx#6, Tx#8) included in the first transmitting antenna group. HIn addition, in FIG. 28, in the receiving array antenna, the receiving antennas (e.g., Rx#2, Rx#5) included in the second receiving antenna group are shifted to the left with respect to the receiving antennas (e.g., Rx#3, Rx#6) included in the first receiving antenna group. H In FIG. 28, the receiving antennas (for example, Rx#1, Rx#4) included in the third receiving antenna group are arranged to be shifted to the left with respect to the receiving antennas included in the second receiving antenna group. H are staggered and positioned.

[0202] Also, Figure 29 shows N TxGroup =2, N TxGroup_ANT =4, N RxGroup =3, N RxGroup_ANT = 2, and the horizontal position of each transmitting antenna in the transmitting antenna group is D H The horizontal position of each receiving antenna in the receiving antenna group is shifted by D H 29 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 and an example of the arrangement of the virtual receiving array in the case of the shifted arrangement. In FIG. 29, the transmitting antennas (e.g., Tx#1, Tx#3, Tx#5, Tx#7) included in the second transmitting antenna group are shifted to the right with respect to the transmitting antennas (e.g., Tx#2, Tx#4, Tx#6, Tx#8) included in the first transmitting antenna group. H In addition, in FIG. 29, in the receiving array antenna, the receiving antennas (e.g., Rx#2, Rx#5) included in the second receiving antenna group are shifted to the left with respect to the receiving antennas (e.g., Rx#3, Rx#6) included in the first receiving antenna group. H In FIG. 29, the receiving antennas (for example, Rx#1, Rx#4) included in the third receiving antenna group are shifted to the left with respect to the receiving antennas included in the second receiving antenna group. H are staggered and positioned.

[0203] For example, in each MIMO array arrangement shown in Figs. 26 to 29, D H and D. VBy setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be 1λ or more.

[0204] Furthermore, for example, in each of the virtual receiving arrays shown in Figs. 26 to 29, the virtual array elements are arranged at different positions without overlapping, so that the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0205] The horizontal position of each transmitting antenna between the first transmitting antenna group and the second transmitting antenna group in the transmitting array antenna is defined as D H When the antennas are arranged in a staggered manner, or when the horizontal position of each receiving antenna is set to D between the first receiving antenna group and the second receiving antenna group in the receiving array antenna, H Even if the array elements are arranged in a shifted manner, the virtual array elements located near the center of the virtual receiving array are H , D V D H , D V The number of closely spaced virtual array elements is, for example, N TxGroup_ANT and N RxGroup increases depending on

[0206] For example, in the virtual receiving array, the horizontal direction is (N TxGroup_ANT ×N RxGroup_ANT )-2 virtual array element is D H The vertical direction is spaced apart by (N RxGroup ×N TxGroup )-2 virtual array element is D V The distance between the receiving array and the receiving array is D H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes are reduced.

[0207] Also, N TxGroup_ANT The larger N, the more the number of virtual array elements arranged in the horizontal direction increases, so the aperture length of the virtual receiving array in the horizontal direction can be expanded and the angular resolution in the horizontal direction can be improved. RxGroupThe larger θ is, the more the number of virtual array elements arranged in the vertical direction increases, so that the aperture length of the virtual receiving array in the vertical direction can be expanded and the angular resolution in the vertical direction can be improved.

[0208] In addition, in FIG. 28 and FIG. 29, the number of receiving antenna groups N RxGroup When the number of receiving antenna groups N is 3 or more, the horizontal positions of the receiving antennas in each receiving antenna group are shifted in a certain direction (to the right or left). However, the direction in which the horizontal positions of the receiving antennas are shifted is not limited to this. For example, when the number of receiving antenna groups N RxGroup When the number of antennas is three or more, the horizontal position of each receiving antenna included in each receiving antenna group may be shifted to the right or left, but the direction may be variable for each receiving antenna group.

[0209] Figure 30 shows N TxGroup =2, N TxGroup_ANT =4, N RxGroup =3, N RxGroup_ANT = 2, and the horizontal position of each transmitting antenna in the transmitting antenna group is D H The horizontal position of each receiving antenna in the receiving antenna group is shifted by D H An example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 and an example of the arrangement of the virtual receiving array in the case of the shifted arrangement is shown in FIG. 30. In FIG. 30, the transmitting antennas (e.g., Tx#1, Tx#3, Tx#5, Tx#7) included in the second transmitting antenna group are shifted to the left with respect to the transmitting antennas (e.g., Tx#2, Tx#4, Tx#6, Tx#8) included in the first transmitting antenna group. H In addition, in FIG. 30, in the receiving array antenna, the receiving antennas (e.g., Rx#2, Rx#5) included in the second receiving antenna group are shifted to the left with respect to the receiving antennas (e.g., Rx#3, Rx#6) included in the first receiving antenna group. H In FIG. 30, the receiving antennas (for example, Rx#1, Rx#4) included in the third receiving antenna group are arranged to be shifted to the right with respect to the receiving antennas included in the second receiving antenna group. H are staggered and positioned.

[0210] In the antenna arrangement of Fig. 30, the virtual array element located near the center of the virtual receiving array is D H , D V D H , D V The number of closely spaced virtual array elements is, for example, N TxGroup_ANT and N RxGroup For example, in the horizontal direction, (N TxGroup_ANT ×N RxGroup_ANT )-2 virtual array element is D H The vertical direction is spaced apart by (N RxGroup ×N TxGroup )-2 virtual array element is D V The distance between the receiving array and the receiving array is D H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes can be reduced.

[0211] (Combination of Modification 3 and Modification 2) In addition, the third modification of the first basic arrangement may be combined with the second modification of the first basic arrangement.

[0212] For example, in the arrangement of the transmitting array antenna according to the modification 2 of the basic arrangement 1, the horizontal positions of the transmitting antennas included in the transmitting antenna groups are further changed by D H A staggered arrangement is acceptable.

[0213] Similarly, for example, for the arrangement of the receiving array antenna according to the modification 2 of the basic arrangement 1, the horizontal positions of the receiving antennas included in the receiving antenna group are further changed to D H A staggered arrangement is acceptable.

[0214] The number of transmitting antenna groups N TxGroupWhen the number of transmitting antennas included in each transmitting antenna group is three or more, the horizontal position of each transmitting antenna included in each transmitting antenna group may be shifted in a fixed direction (to the right or left), or the horizontal position of each transmitting antenna included in each transmitting antenna group may not be shifted to the right or left, but the direction may be variable for each transmitting antenna group.

[0215] 31 and 32 show an example of an antenna arrangement in a combination of the third modification and the second modification.

[0216] Figure 31 shows N TxGroup =4, N TxGroup_ANT =4, N RxGroup =4, N RxGroup_ANT = 2, and the horizontal position of each antenna included in the transmitting antenna group and the receiving antenna group is D H An example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 in the case of the shifted arrangement, and an example of the arrangement of the virtual receiving array are shown in FIG. TxGroupV =5D V It becomes.

[0217] In FIG. 31, in the transmitting array antenna, each transmitting antenna (for example, Tx3, Tx#7, Tx#11, Tx#15) included in the second transmitting antenna group is shifted to the left with respect to each transmitting antenna (for example, Tx#4, Tx#8, Tx#12, Tx#16) included in the first transmitting antenna group. H In FIG. 31, the transmitting antennas (for example, Tx2, Tx#6, Tx#10, and Tx#14) included in the third transmitting antenna group are shifted to the left with respect to the transmitting antennas included in the second transmitting antenna group. H In FIG. 31, the transmitting antennas (for example, Tx1, Tx#5, Tx#9, and Tx#13) included in the fourth transmitting antenna group are shifted to the left with respect to the transmitting antennas included in the third transmitting antenna group. H are staggered and positioned.

[0218] In addition, in FIG. 31, in the receiving array antenna, each receiving antenna (for example, Rx#3, Rx#7) included in the second receiving antenna group is located to the left of each receiving antenna (for example, Rx#4, Rx#8) included in the first receiving antenna group. H In FIG. 31, the receiving antennas (for example, Rx#2, Rx#6) included in the third receiving antenna group are shifted to the left with respect to the receiving antennas included in the second receiving antenna group. H In FIG. 31, the receiving antennas (for example, Rx#1, Rx#5) included in the fourth receiving antenna group are shifted to the left with respect to the receiving antennas included in the third receiving antenna group. H are staggered and positioned.

[0219] Next, Figure 32 shows N TxGroup =2, N TxGroup_ANT =4, N RxGroup =2, N RxGroup_ANT = 4, and the horizontal position of each antenna included in the transmitting antenna group and the receiving antenna group is D H An example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 when they are shifted, and an example of the arrangement of the virtual receiving array are shown in FIG. RxGroupH =5D H It becomes.

[0220] In FIG. 32, each transmitting antenna (for example, Tx#1, Tx#3, Tx#5, Tx#7) included in the second transmitting antenna group is shifted to the left with respect to each transmitting antenna (for example, Tx#2, Tx#4, Tx#6, Tx#8) included in the first transmitting antenna group. H In addition, in FIG. 32, in the receiving array antenna, the receiving antennas (e.g., Rx#1, Rx#3, Rx#5, Rx#7) included in the second receiving antenna group are shifted to the left with respect to the receiving antennas (e.g., Rx#2, Rx#4, Rx#6, Rx#8) included in the first receiving antenna group. H are staggered and positioned.

[0221] For example, in each MIMO array arrangement shown in FIG. 31 and FIG. 32, D H and D. V By setting the width of the transmission antenna 106 and the width of the reception antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmission antenna 106 and the reception antenna 202 can be set to 1λ or more.

[0222] Furthermore, for example, in each of the virtual receiving arrays shown in FIGS. 31 and 32, the virtual array elements are arranged at different positions without overlapping, so that the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0223] The virtual array elements located near the center of the virtual receiving array shown in Figs. 31 and 32 are denoted by D H , D V D H , D V The number of closely spaced virtual array elements is, for example, N TxGroup , N TxGroup_ANT , N RxGroup and N RxGroup_ANT increases depending on

[0224] For example, in the horizontal direction (N TxGroup_ANT ×N RxGroup_ANT )-2 virtual array element is D H In the vertical direction, the RxGroup ×N TxGroup )-2 virtual array element is D V The distance between the receiving array and the receiving array is D H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes are reduced.

[0225] Also, N TxGroup_ANT and N RxGroup_ANT The larger N, the more the number of virtual array elements arranged in the horizontal direction increases, so the aperture length of the virtual receiving array in the horizontal direction can be expanded and the angular resolution in the horizontal direction can be improved. TxGroup , N RxGroupThe larger θ is, the more the number of virtual array elements arranged in the vertical direction increases, so that the aperture length of the virtual receiving array in the vertical direction can be expanded and the angular resolution in the vertical direction can be improved.

[0226] In addition, the third modification of the basic arrangement 1 is, for example, a combination of the arrangement methods A and B in the second modification of the basic arrangement 1 shown in FIG. 20, and further, in the transmitting array antennas and the receiving array antennas, the horizontal positions of each antenna are changed to D H A staggered arrangement is acceptable.

[0227] Figure 33 shows N TxGroup =4, N TxGroup_ANT =4, N RxGroup =4, N RxGroup_ANT = 4, and the horizontal position of each antenna included in the transmitting antenna group and the receiving antenna group is D H An example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 in the case of the shifted arrangement, and an example of the arrangement of the virtual receiving array are shown in FIG. TxGroupV =5D V Then, D in equation (12) RxGroupH =5D H It becomes.

[0228] In FIG. 33, in the transmitting array antenna, each transmitting antenna (for example, Tx3, Tx#7, Tx#11, Tx#15) included in the second transmitting antenna group is shifted to the left with respect to each transmitting antenna (for example, Tx#4, Tx#8, Tx#12, Tx#16) included in the first transmitting antenna group. H In FIG. 33, the transmitting antennas included in the third transmitting antenna group (e.g., Tx2, Tx#6, Tx#10, Tx#14) are arranged at the same horizontal position as the transmitting antennas included in the second transmitting antenna group. In FIG. 33, the transmitting antennas included in the fourth transmitting antenna group (e.g., Tx1, Tx#5, Tx#9, Tx#13) are arranged at the same horizontal position as the transmitting antennas included in the third transmitting antenna group. H are staggered and positioned.

[0229] In addition, in FIG. 33, in the receiving array antenna, each receiving antenna (e.g., Rx#3, Rx#7, Rx#11, Rx#15) included in the second receiving antenna group is shifted to the left with respect to each receiving antenna (e.g., Rx#4, Rx#8, Rx#12, Rx#16) included in the first receiving antenna group. H In FIG. 33, the receiving antennas (for example, Rx#2, Rx#6, Rx#10, and Rx#14) included in the third receiving antenna group are shifted to the right with respect to the receiving antennas included in the second receiving antenna group. H In FIG. 33, the receiving antennas (for example, Rx#1, Rx#5, Rx#9, and Rx#13) included in the fourth receiving antenna group are shifted to the left with respect to the receiving antennas included in the third receiving antenna group. H are staggered and positioned.

[0230] As a result, in addition to the effect obtained in the third modification of the basic layout 1, the effect obtained by combining the layout methods 1-2A and 1-2B in the second modification of the basic layout 1 can be obtained.

[0231] <Basic layout 2> FIG. 34 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 according to basic arrangement 2, and an example of the arrangement of a virtual receiving array.

[0232] (1) Arrangement of transmitting and receiving antennas In FIG. 34, the number of transmitting antennas 106 in the transmitting array antenna is Nt=4 (Tx#1, Tx#2, Tx#3, and Tx#4), and the number of receiving antennas 202 in the receiving array antenna is Na=4 (Rx#1, Rx#2, Rx#3, and Rx#4).

[0233] The transmitting array antenna shown in Fig. 34 is composed of a "first transmitting antenna group" (Tx#2, Tx#4 in Fig. 34) and a "second transmitting antenna group" (Tx#1, Tx#3 in Fig. 34). Each transmitting antenna group is located at the same position in the vertical direction, and the antenna spacing in the horizontal direction (horizontal direction in Fig. 34) is 3D.H The distance between the "first transmitting antenna group" and the "second transmitting antenna group" in the vertical direction (the vertical direction in FIG. 34) is, for example, 3D V It becomes.

[0234] The receiving array antenna shown in Fig. 34 is composed of a "first receiving antenna group" (Rx#2, Rx#4 in Fig. 34) and a "second receiving antenna group" (Rx#1, Rx#3 in Fig. 34). Each receiving antenna group is located at the same position in the vertical direction, and the antenna spacing in the horizontal direction is 2D. H The vertical distance between the "first receiving antenna group" and the "second receiving antenna group" is, for example, 2D V It becomes.

[0235] In this way, in the transmitting and receiving antenna arrangement shown in FIG. 34, the transmitting array antenna is composed of a plurality of transmitting antenna groups, and each of the plurality of transmitting antenna groups has, for example, a D H (Here, 3D H ) in the vertical direction. V In other words, the antenna spacing between the transmitting antenna groups in the vertical direction (3D in FIG. 34) is V ) and the horizontal antenna spacing within each transmit antenna group (3D H ) are identical.

[0236] In the arrangement of transmitting and receiving antennas shown in FIG. 34, the receiving array antenna is composed of a plurality of receiving antenna groups, and each of the plurality of receiving antenna groups is arranged, for example, in the horizontal direction as D H Intervals of integer multiples of (here, 2D H ) are arranged at intervals of 2D in the vertical direction. V In other words, the horizontal antenna spacing in each receiving antenna group (2D in FIG. 34) is H ) and the vertical antenna spacing between the receiving antennas (2D in Fig. 34).H ) are identical.

[0237] In addition, in FIG. 34, the antenna spacing in the transmitting antenna 106 (3D H ) and the antenna spacing in the receiving antenna 202 (2D H ), for example, the difference is D H In addition, in FIG. 34, the spacing between the multiple transmitting antenna groups is 3D V (D V (intervals of an integer multiple of ) and intervals of 2D V (D V The difference between this and the integer multiple of D V It is.

[0238] For example, it is assumed that the horizontal direction (horizontal direction) shown in FIG. 34 corresponds to the X-axis, and the vertical direction (vertical direction) shown in FIG. 34 corresponds to the Y-axis direction.

[0239] In the case of the antenna arrangement shown in FIG. 34, the position coordinates of the transmitting antennas 106 constituting the transmitting array antenna are the position coordinates of the transmitting antenna Tx#1 (X T_#1 ,Y T_#1 ) as the reference, the position coordinates of the transmitting antenna Tx#2 (X T_#2 ,Y T_#2 )=(X T_#1 ,Y T_#1 +3D V ), the position coordinates of the transmitting antenna Tx#3 (X T_#3 ,Y T_#3 )=(X T_#1 +3D H ,Y T_#1 ), and the position coordinates of the transmitting antenna Tx#4 (X T_#4 ,Y T_#4 )=(X T_#1 +3D H ,Y T_#1 +3D V )

[0240] Similarly, the position coordinates of the receiving antenna 202 constituting the receiving array antenna are expressed as the position coordinates of the receiving antenna Rx#1 (X R_#1 ,Y R_#1) as the reference, the position coordinates of the receiving antenna Rx#2 (X R_#2 ,Y R_#2 )=(X R_#1 ,Y R_#1 +2D V ), the position coordinates of the receiving antenna Rx#3 (X R_#3 ,Y R_#3 )=(X R_#1 +2D H ,Y R_#1 ), and the position coordinates of the receiving antenna Rx#4 (X R_#4 ,Y R_#4 )=(X R_#1 +2D H ,Y R_#1 +2D V )

[0241] (2) Virtual receiving array layout The arrangement of the virtual receiving array (virtual antennas VA#1 to VA#16) configured by the transmitting and receiving antenna arrangement shown in FIG. 34 described above has the following features.

[0242] For example, in the arrangement of the transmitting array antenna and the receiving array antenna shown in FIG. 34, the position coordinates (X V_#1 ,Y V_#1 )~(X V_#16 ,Y V_#16 ) are as follows: Note that here, VA#1 is expressed as the position reference (0,0) of the virtual receiving array. (0,0), (0, 3D V ), (3D H , 0), (3D H , 3D V ), (0, 2D V ), (0, 5D V ), (3D H , 2D V ), (3D H , 5D V ), (2D H ,0), (2D H , 3D V ), (5D H , 0), (5D H , 3D V), (2D H , 2D V ), (2D H , 5D V ), (5D H , 2D V ), (5D H , 5D V )

[0243] 34, each virtual receiving array element is arranged at a different position without overlapping, which allows the aperture length of the virtual receiving array to be expanded, narrowing the main lobe and improving the angular resolution.

[0244] As shown in FIG. 34, the virtual array elements VA#4, VA#7, VA#10, and VA#13 located near the center of the virtual receiving array are arranged in a horizontal direction D H Spacing, vertically D V As an example, in FIG. 34, the distance D H and interval D V When the distance is about 0.5λ, the virtual array elements VA#4, VA#7, VA#10, and VA#13 are D H = 0.5λ interval, D in the vertical direction V = 0.5λ apart. This makes it possible to reduce grating lobes in the same way as in basic arrangement 1 (see, for example, Figure 8).

[0245] For example, in the MIMO array arrangement shown in FIG. H and interval D V is set to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be 1λ or more.

[0246] As a result, for example, an antenna using four planar patch antennas arranged in two elements vertically and horizontally as a sub-array (where the antenna width W ANT < 2D H , Antenna height H ANT <2D V) can be applied to each antenna element of at least one of the transmitting array antenna and the receiving array antenna shown in FIG.

[0247] In Fig. 34, the horizontal antenna spacing of the transmitting array antenna is 3D H and the vertical antenna spacing is 3D V In other words, the antenna spacing (3D H and 3D V ) is the antenna spacing (2D H and 2D V ) is wider than the horizontal antenna spacing (3D H ) is the horizontal antenna spacing of the transmitting array antenna in basic configuration 1 (for example, 2D H ) wider.

[0248] Therefore, the transmitting array antenna shown in FIG. 34 may be, for example, an antenna using nine planar patch antennas arranged three elements vertically and three elements horizontally as a subarray, which has a wider spacing in the vertical and horizontal directions than the four-element subarray shown in FIG. 9A (however, the antenna width W ANT < 3D H , Antenna height H ANT <3D V ) can be applied.

[0249] The direction estimation unit 214 performs direction estimation processing in the horizontal and vertical directions using the received signals of the virtual receiving array obtained from the above-mentioned transmitting / receiving antenna arrangement (for example, see FIG. 34). For example, the virtual receiving array of basic arrangement 2 shown in FIG. 34 has the same configuration as the virtual receiving array of basic arrangement 1 (for example, see FIG. 8), and therefore can obtain similar performance.

[0250] As described above, by using the MIMO array arrangement shown in Fig. 34, even if the vertical or horizontal element size of the antennas used for the transmitting array antenna and the receiving array antenna is about 1λ, the horizontal and vertical antenna spacing in the virtual receiving array can be arranged to include element spacing of about 0.5λ, thereby reducing grating lobes. Furthermore, for example, as shown in Fig. 34, since the virtual array elements of the virtual receiving array are arranged without overlapping, the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0251] In addition, sub-array antennas with element sizes of at least about 1λ in the vertical and horizontal directions can be used for the antenna elements used in the transmitting antenna 106 and the receiving antenna 202. This can improve the directional gain of the antennas and the detection performance (e.g., detection distance) of the radar device 10.

[0252] In addition, in basic layout 2, the antenna spacing can be set wider in either the transmitting array antenna or the receiving array antenna (the transmitting array antenna in FIG. 34) than in the other. This allows a larger-sized subarray to be used in one of the array antennas, improving the directional gain of the antenna.

[0253] <Variation 1 of Basic Layout 2> In the basic arrangement 2 (for example, FIG. 34), the number of transmitting antennas 106 is four (Nt=4), and the number of receiving antennas 202 is four (Na=4). However, the number of transmitting antennas Nt and the number of receiving antennas Na are not limited to these numbers.

[0254] In the first modification of the basic arrangement 2, the transmitting array antennas are arranged in the same manner as the basic arrangement 2 (for example, FIG. 34), for example, with a vertical spacing of 3D. V In addition, as in basic arrangement 2, each transmitting antenna group is located at the same position in the vertical direction, and the antenna spacing in the horizontal direction is 3D. H The antenna includes two transmit antenna elements,

[0255] In addition, in the first modification of the second basic arrangement, the receiving array antennas are arranged in the same manner as the second basic arrangement, for example, with a vertical spacing of 2D. V N RxGroup receive antenna groups (e.g., 1st to Nth RxGroup Each receiving antenna group is located at the same position in the vertical direction, and the antenna spacing in the horizontal direction is 2D. H N RxGroup_ANT The antenna includes receive antenna elements.

[0256] In the first modification of the basic arrangement 2, N RxGroup and N RxGroup_ANT Depending on the value of , it becomes possible to increase the number of antennas in the MIMO array (for example, the number of receiving antennas Na).

[0257] Figure 36 shows N RxGroup =3, N RxGroup_ANT 2 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202, and an example of the arrangement of the virtual receiving array when .function..times ...

[0258] Figure 37 shows N RxGroup =2, N RxGroup_ANT 4 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202, and an example of the arrangement of the virtual receiving array when .function..times ...

[0259] Figure 38 shows N RxGroup =3, N RxGroup_ANT 4 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202, and an example of the arrangement of the virtual receiving array when .function..times ...

[0260] In addition, in Figs. 36, 37 and 38, N TxGroup = 2, and N TxGroup_ANT =2.

[0261] In each of the MIMO array arrangements shown in Figs. 36, 37, and 38, for example, D H and D. VBy setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0262] Furthermore, for example, in each of the virtual receiving arrays shown in Figures 36, 37, and 38, the virtual array elements are arranged at different positions without overlapping, so that the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0263] The virtual array elements located near the center of each virtual receiving array shown in Figs. 36, 37, and 38 are denoted by D H , D V D H , D V The number of closely spaced virtual array elements is N RxGroup and N RxGroup_ANT increases depending on

[0264] For example, in the virtual receiving array, the horizontal direction is (N RxGroup_ANT ×N TxGroup_ANT )-2 virtual array element is D H The vertical direction is spaced apart by (N RxGroup ×N TxGroup_ANT )-2 virtual array element is D V The distance between the receiving array and the receiving array is D H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes are reduced.

[0265] Also, N RxGroup_ANT The larger N, the more the number of virtual array elements arranged in the horizontal direction increases, so the aperture length of the virtual receiving array in the horizontal direction can be expanded and the angular resolution in the horizontal direction can be improved. RxGroup The larger θ is, the more the number of virtual array elements arranged in the vertical direction increases, so that the aperture length of the virtual receiving array in the vertical direction can be expanded and the angular resolution in the vertical direction can be improved.

[0266] <Modification 2 of Basic Layout 2> The antenna arrangement methods 2-2A and 2-2B in the second modification of the second basic arrangement will be described below.

[0267] (Placement method 2-2A) In the first modification of the basic arrangement 2, the number of receiving antenna groups included in the receiving array antenna is N RxGroup In this case, the number of virtual array elements arranged in the vertical direction is increased by increasing N RxGroup ≧3, the number of transmitting antenna groups in the transmitting array antenna is N TxGroup The number of virtual array elements arranged in the vertical direction in the virtual receiving array can also be increased by increasing

[0268] In this case, the antenna spacing in the vertical direction of the transmitting antenna group is set to a constant value (e.g., 3D V ), but the number of receiving antennas N RxGroup Depending on the configuration, the virtual receive array may have overlapping virtual array elements.

[0269] Therefore, in order to arrange the virtual receiving array so that there are no overlapping virtual array elements, for example, the spacing between even-numbered antennas in the vertical direction of the transmitting antenna group should be set to the following spacing D TxGroupV2 may be used.

number

[0270] For example, N RxGroup If = 3, D TxGroupV2 =3D V Then, N RxGroup If =4, D TxGroupV2 =5D H It becomes.

[0271] For example, the number of transmit antennas N TxGroup When = 3, the spacing between the three transmit antenna groups is {3D V , D TxGroupV2}. In addition, the number of transmitting antenna groups N TxGroupFor , the spacing between the four transmit antenna groups is {3D V , D TxGroupV2 , 3D V}. In addition, the number of transmitting antenna groups N RxGroup_ANT For , the spacing between the five transmit antenna groups is {3D V , D TxGroupV2 , 3D V , D TxGroupV2}.

[0272] Figure 39 shows N TxGroup =4, N TxGroup_ANT =2, N RxGroup =3, N RxGroup_ANT FIG. 39 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202, and an example of the arrangement of the virtual receiving array when D TxGroupV2 =3D V It becomes.

[0273] Also, Figure 40 shows N TxGroup =4, N TxGroup_ANT =2, N RxGroup =4, N RxGroup_ANT FIG. 40 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202, and an example of the arrangement of the virtual receiving array when D TxGroupV2 =5D V It becomes.

[0274] In addition, the virtual receiving array is placed at irregular intervals (e.g., D H and D. V If it is acceptable to include arrangements with a spacing greater than TxGroupV2 may be greater than the value of equation (13).

[0275] <Placement method 2-2B> In the first modification of the notation arrangement 2, the number of receiving antennas included in each receiving antenna group of the receiving array antenna is N RxGroup_ANT In this case, the number of virtual array elements arranged in the horizontal direction is increased by increasing N RxGroup_ANT ≧3, the number of transmitting antennas in the transmitting antenna group in the transmitting array antenna is N TxGroup_ANTThe number of virtual array elements arranged horizontally in the virtual receiving array can also be increased by increasing

[0276] In this case, the horizontal antenna spacing of the receiving antenna group is set to a constant value (e.g., 3D H ), but the number of receiving antennas included in the receiving antenna group N RxGroup_ANT Depending on the virtual array arrangement, the virtual array elements may overlap.

[0277] Therefore, in order to arrange the virtual receiving array so that it does not include overlapping virtual array elements, for example, the following spacing may be used for the even-numbered antenna spacings among the horizontal antenna spacings of the transmitting antennas included in the transmitting antenna group.

number

[0278] For example, N RxGroup_ANT If = 3, D TxAntH =3D H Then, N RxGroup_ANT If =4, D TxAntH =5D H It becomes.

[0279] For example, the number of transmitting antennas included in the transmitting antenna group is N TxGroup_ANT For , the antenna spacing for the three transmit antennas is {3D H , D TxAntH}. In addition, the number of transmitting antennas is N TxGroup_ANT For , the antenna spacing for the four transmit antennas is {3D H , D TxAntH , 3D H Similarly, the number of transmitting antennas N TxGroup_ANT For , the antenna spacing for the five transmit antennas is {3D H , D TxAntH , 3D H , D TxAntH}.

[0280] Figure 41 shows N TxGroup =2, NTxGroup_ANT =4, N RxGroup =2, N RxGroup_ANT FIG. 41 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202, and an example of the arrangement of the virtual receiving array, when D TxAntH =3D H It becomes.

[0281] Figure 42 shows N TxGroup =2, N TxGroup_ANT =4, N RxGroup =2, N RxGroup_ANT FIG. 41 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202, and an example of the arrangement of the virtual receiving array, when D TxAntH =5D H It becomes.

[0282] In addition, the virtual receiving array is placed at irregular intervals (e.g., D H and D. V If it is acceptable to include arrangements with a spacing greater than TxAntH may be greater than the value of equation (14).

[0283] The arrangement methods 2-2A and 2-2B in the modification 2 of the basic arrangement 2 have been described above.

[0284] For example, in the transmitting and receiving antenna arrangements (e.g., MIMO array arrangements) shown in Figs. 39 to 42, D H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0285] Furthermore, for example, in each of the virtual receiving arrays shown in FIGS. 39 to 42, the virtual array elements are arranged at different positions without overlapping, so that the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0286] For example, the virtual array elements located near the center of the virtual receiving array shown in Figs. 39 to 42 are designated as D H , DV D H , D V The number of closely spaced virtual array elements is N TxGroup , N TxGroup_ANT , N RxGroup and N RxGroup_ANT increases depending on

[0287] For example, in the virtual receiving array, the horizontal direction is (N RxGroup_ANT ×N TxGroup_ANT )-2 virtual array element is D H The vertical direction is spaced apart by (N RxGroup ×N TxGroup )-2 virtual array element is D V The distance between the receiving array and the receiving array is D H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes can be reduced.

[0288] Also, N TxGroup_ANT , N RxGroup_ANT The larger N, the more the number of virtual array elements arranged in the horizontal direction increases, so the aperture length of the virtual receiving array in the horizontal direction can be expanded and the angular resolution in the horizontal direction can be improved. TxGroup , N RxGroup The larger θ is, the more the number of virtual array elements arranged in the vertical direction increases, so that the aperture length of the virtual receiving array in the vertical direction can be expanded and the angular resolution in the vertical direction can be improved.

[0289] In addition, in the second modification of the basic arrangement 2, the arrangement method 2-2A and the arrangement method 2-2B can be combined. TxGroup =4, N TxGroup_ANT =4, N RxGroup =4, N RxGroup_ANT FIG. 43 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 for D = 4, and an example of the arrangement of the virtual receiving array. TxGroupV2 =5D H Then, D in equation (14) TxAntH =5D HThis provides the effect of combining the arrangement methods 2-2A and 2-2B.

[0290] <Variation 3 of Basic Layout 2> The antenna arrangement methods 2-3A, 2-3B, and 2-3C in the third modification of the basic arrangement 2 will be described below.

[0291] (Placement method 2-3A) In the basic arrangement 2, the horizontal positions of the transmitting antennas included in each transmitting antenna group in the transmitting array antenna have been described as being the same. However, this is not limiting, and the horizontal arrangement positions of the transmitting antennas included in each transmitting antenna group may differ between the transmitting antenna groups.

[0292] For example, in the transmitting array antenna, the horizontal positions of each transmitting antenna included in the first transmitting antenna group and the second transmitting antenna group are D H They may be arranged in a staggered manner (in other words, shifted).

[0293] Horizontally D H The shift direction may be either to the right or to the left of each transmitting antenna included in the second transmitting antenna group with respect to each transmitting antenna included in the first transmitting antenna group.

[0294] FIG. 44 shows a case where, in a transmitting array antenna, each transmitting antenna (for example, Tx#1, Tx#3) included in a second transmitting antenna group is shifted to the right with respect to each transmitting antenna (for example, Tx#2, Tx#4) included in a first transmitting antenna group. H 13 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 when they are shifted, and an example of the arrangement of the virtual receiving array.

[0295] In FIG. 44, the horizontal positions of Tx#1 and Tx#2 are D H Also, the horizontal positions of Tx#3 and Tx#4 are different. H different.

[0296] (Placement method 2-3B) In the basic arrangement 2, the horizontal positions of the receiving antennas included in each receiving antenna group in the receiving array antenna have been described as being the same. However, this is not limited to the above, and the horizontal arrangement positions of the receiving antennas included in each receiving antenna group may differ between the receiving antenna groups.

[0297] For example, in the receiving array antenna, each receiving antenna included in the first receiving antenna group and the second receiving antenna group has a horizontal position D H They may be staggered.

[0298] Horizontally D H The direction of shift may be either to the right or to the left of each receiving antenna included in the second receiving antenna group with respect to each receiving antenna included in the first receiving antenna group.

[0299] FIG. 45 shows a receiving array antenna in which each receiving antenna (e.g., Rx#1, Rx#3) included in the second receiving antenna group is shifted to the left with respect to each receiving antenna (e.g., Rx#2, Rx#4) included in the first receiving antenna group. H 13 shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 when they are shifted, and an example of the arrangement of the virtual receiving array.

[0300] In FIG. 45, the horizontal positions of Rx#1 and Rx#2 are D H Also, the horizontal positions of Rx#3 and Rx#4 are different. H different.

[0301] (Placement method 2-3C) Arrangement method 2-3C is a combination of arrangement methods 2-3A and 2-3B.

[0302] For example, in a transmitting array antenna, the transmitting antenna is located between the first transmitting antenna group and the second transmitting antenna group at a horizontal position of D HSimilarly, in the receiving array antenna, the receiving antennas are positioned horizontally between the first receiving antenna group and the second receiving antenna group by D H are staggered and positioned.

[0303] In addition, the horizontal direction is D H The shift direction may be, for example, either to the right or to the left of each transmitting antenna included in the second transmitting antenna group with respect to each transmitting antenna included in the first transmitting antenna group. H The shift direction may be, for example, to the right or left of each receiving antenna included in the second receiving antenna group with respect to each receiving antenna included in the first receiving antenna group.

[0304] 46 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 and an example of the arrangement of the virtual receiving array according to the arrangement method 2-3C. In FIG. 46, in the transmitting array antenna, the transmitting antennas (e.g., Tx#1, Tx#3) included in the second transmitting antenna group are arranged in the D direction to the right with respect to the transmitting antennas (e.g., Tx#2, Tx#4) included in the first transmitting antenna group. H In FIG. 46, in the receiving array antenna, the receiving antennas (e.g., Rx#1, Rx#3) included in the second receiving antenna group are shifted to the right with respect to the receiving antennas (e.g., Rx#2, Rx#4) included in the first receiving antenna group. H are staggered and positioned.

[0305] 47 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 and an example of the arrangement of the virtual receiving array according to the arrangement method 2-3C. In FIG. 47, in the transmitting array antenna, the transmitting antennas (e.g., Tx#1, Tx#3) included in the second transmitting antenna group are arranged in the D direction to the right with respect to the transmitting antennas (e.g., Tx#2, Tx#4) included in the first transmitting antenna group. HIn FIG. 47, in the receiving array antenna, the receiving antennas (e.g., Rx#1, Rx#3) included in the second receiving antenna group are shifted to the left with respect to the receiving antennas (e.g., Rx#2, Rx#4) included in the first receiving antenna group. H are staggered and positioned.

[0306] For example, the horizontal distance between the receiving antenna group and the transmitting antenna group is D H Compared with an arrangement in which the shift direction is different (for example, Fig. 47), the horizontal shift of the receiving antenna group and the transmitting antenna group is D H An arrangement in which the shift direction is the same (eg, FIG. 46) is more preferable since the virtual receiving array elements are arranged more densely near the center of the virtual receiving array arrangement.

[0307] Arrangement methods 2-3A to 2-3C have been described above.

[0308] For example, in the transmitting and receiving antenna arrangement (e.g., MIMO array arrangement) shown in Figs. 45 to 47, D H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ.

[0309] As a result, in the third modification of the basic arrangement 1, for example, an antenna using four planar patch antennas arranged in two rows and two columns as shown in FIG. 9A as a subarray (where the antenna width W ANT < 2D H , Antenna height H ANT <2D V ) can be applied (not shown).

[0310] 45 to 47, for example, a subarray of nine planar patch antennas arranged three elements vertically and three elements horizontally, which has a wider spacing in the vertical and horizontal directions than the four-element subarray shown in FIG. 9A (however, the antenna width W ANT < 3D H , Antenna height HANT <3D V ) can be applied.

[0311] In addition, in the third modification of the basic arrangement 2, in at least one of the transmitting array antennas and the receiving array antennas, the horizontal positions of the transmitting antennas included in each transmitting antenna group or the receiving antennas included in each receiving antenna group are different from each other. ANT The element size of D H The size of the elements in the vertical direction of the subarray may be any size as long as it is smaller than . For example, in each of the transmitting array antennas in Fig. 45 to Fig. 47, a subarray in which eight planar patch antenna elements are arranged vertically and one horizontally as shown in Fig. 25A may be used.

[0312] (Combination of Modification 3 with Modification 1 or Modification 2) In addition, Modification 3 of Basic Arrangement 2 may be combined with Modification 1 or Modification 2 of Basic Arrangement 2.

[0313] For example, for the arrangement of the transmitting array antennas according to the modification 1 or modification 2 of the basic arrangement 2, the horizontal positions of the transmitting antennas included in the transmitting antenna groups are further changed by D H A staggered arrangement is acceptable.

[0314] Similarly, for example, for the arrangement of the receiving array antennas according to the modification 1 or modification 2 of the basic arrangement 2, the horizontal positions of the receiving antennas included in the receiving antenna group are further changed to D H A staggered arrangement is acceptable.

[0315] 48, 49, 50A, 50B, 51A, and 51B show examples of antenna arrangements in a combination of Modification 3 and Modification 2.

[0316] Figure 48 shows N TxGroup =4, N TxGroup_ANT =4, N RxGroup =4, N RxGroup_ANT= 4, and the horizontal position of each antenna in the transmitting antenna group is D H An example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 in the case of the shifted arrangement, and an example of the arrangement of the virtual receiving array are shown in FIG. TxGroupV2 =5D H Then, D in equation (14) TxAntH =5D H It becomes.

[0317] Figure 49 shows N TxGroup =4, N TxGroup_ANT =4, N RxGroup =4, N RxGroup_ANT = 4, and the horizontal position of each antenna in the receiving antenna group is D H An example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 in the case of the shifted arrangement, and an example of the arrangement of the virtual receiving array are shown in FIG. TxGroupV2 =5D H Then, D in equation (14) TxAntH =5D H It becomes.

[0318] In FIG. 49, in the receiving array antenna, each receiving antenna (e.g., Rx#4, Rx#8, Rx#12, Rx#16) included in the first receiving antenna group is D H In FIG. 49, the receiving antennas (for example, Rx2, Rx#6, Rx#10, and Rx#14) included in the third receiving antenna group are shifted to the right with respect to the receiving antennas included in the second receiving antenna group. H In FIG. 49, the receiving antennas (for example, Rx1, Rx#5, Rx#9, and Rx#13) included in the fourth receiving antenna group are shifted to the left with respect to the receiving antennas included in the third receiving antenna group. H are staggered and positioned.

[0319] FIG. 50A shows N TxGroup =4, N TxGroup_ANT =4, N RxGroup=4, N RxGroup_ANT = 4, and the horizontal position of each antenna included in the transmitting antenna group and the receiving antenna group is D H FIG. 50A shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 in the case of a staggered arrangement, and FIG. 50B shows an example of the arrangement of the virtual receiving array. In FIG. 50A, D TxGroupV2 =5D H Then, D in equation (14) TxAntH =5D H It becomes.

[0320] In FIG. 50A, in the transmitting array antenna, each transmitting antenna (for example, Tx3, Tx#7, Tx#11, Tx#15) included in the second transmitting antenna group is shifted to the left with respect to each transmitting antenna (for example, Tx#4, Tx#8, Tx#12, Tx#16) included in the first transmitting antenna group. H In FIG. 50A, the transmitting antennas (for example, Tx2, Tx#6, Tx#10, and Tx#14) included in the third transmitting antenna group are shifted to the left with respect to the transmitting antennas included in the second transmitting antenna group. H In FIG. 50A, the transmitting antennas (for example, Tx1, Tx#5, Tx#9, and Tx#13) included in the fourth transmitting antenna group are shifted to the left with respect to the transmitting antennas included in the third transmitting antenna group. H are staggered and positioned.

[0321] In FIG. 50A, in the receiving array antenna, each receiving antenna (e.g., Rx#3, Rx#7, Rx#11, Rx#15) included in the second receiving antenna group is directed to the right with respect to each receiving antenna (e.g., Rx#4, Rx#8, Rx#12, Rx#16) included in the first receiving antenna group. H In FIG. 50A, the receiving antennas (for example, Rx#2, Rx#6, Rx#10, and Rx#14) included in the third receiving antenna group are shifted to the right with respect to the receiving antennas included in the second receiving antenna group. HIn FIG. 50A, the receiving antennas (for example, Rx#1, Rx#5, Rx#9, and Rx#13) included in the fourth receiving antenna group are shifted to the right with respect to the receiving antennas included in the third receiving antenna group. H are staggered and positioned.

[0322] FIG. 51A shows N TxGroup =4, N TxGroup_ANT =4, N RxGroup =4, N RxGroup_ANT = 4, and the horizontal position of each antenna included in the transmitting antenna group and the receiving antenna group is D H FIG. 51A shows an example of the arrangement of the transmitting antenna 106 and the receiving antenna 202 in the case of a shifted arrangement, and FIG. 51B shows an example of the arrangement of the virtual receiving array. In FIG. 50A, D TxGroupV2 =5D H Then, D in equation (14) TxAntH =5D H It becomes.

[0323] In FIG. 51A, in the transmitting array antenna, each transmitting antenna (for example, Tx3, Tx#7, Tx#11, Tx#15) included in the second transmitting antenna group is shifted to the left with respect to each transmitting antenna (for example, Tx#4, Tx#8, Tx#12, Tx#16) included in the first transmitting antenna group. H In FIG. 51A, the transmitting antennas (for example, Tx2, Tx#6, Tx#10, and Tx#14) included in the third transmitting antenna group are shifted to the right with respect to the transmitting antennas included in the first transmitting antenna group. H In FIG. 51A, the transmitting antennas (for example, Tx1, Tx#5, Tx#9, and Tx#13) included in the fourth transmitting antenna group are shifted to the left with respect to the transmitting antennas included in the third transmitting antenna group. H are staggered and positioned.

[0324] In addition, in FIG. 51A, in the receiving array antenna, each receiving antenna (for example, Rx#3, Rx#7, Rx#11, Rx#15) included in the second receiving antenna group is oriented in the left direction relative to each receiving antenna (for example, Rx#4, Rx#8, Rx#12, Rx#16) included in the first receiving antenna group. H In FIG. 51A, the receiving antennas (for example, Rx#2, Rx#6, Rx#10, and Rx#14) included in the third receiving antenna group are shifted to the right with respect to the receiving antennas included in the second receiving antenna group. H In FIG. 51A, the receiving antennas (for example, Rx#1, Rx#5, Rx#9, and Rx#13) included in the fourth receiving antenna group are shifted to the left with respect to the receiving antennas included in the third receiving antenna group. H are staggered and positioned.

[0325] For example, in each of the MIMO array arrangements shown in Figs. 48, 49, 50A, and 51A, D H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be 1λ or more.

[0326] Furthermore, for example, in each of the virtual receiving arrays shown in Figures 48, 49, 50B, and 51B, the virtual array elements are arranged at different positions without overlapping, so that the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0327] The number of transmitting antenna groups N TxGroup When the number of receiving antenna groups N is 3 or more, the horizontal positions of the transmitting antennas included in each transmitting antenna group may be shifted in a fixed direction (to the right or left), or the horizontal positions of the transmitting antennas included in each transmitting antenna group may be shifted to the right or left, but the direction may be variable for each transmitting antenna group. RxGroupWhen the number is three or more, the horizontal position of each receiving antenna included in each receiving antenna group may be shifted in a fixed direction (to the right or left), or the horizontal position of each receiving antenna included in each receiving antenna group may not be shifted to the right or left, but the direction may be variable for each receiving antenna group.

[0328] In any antenna arrangement, the virtual array element located near the center of the virtual receiving array is defined as D H , D V D H , D V The number of closely spaced virtual array elements is, for example, N TxGroup , N TxGroup_ANT , N RxGroup and N RxGroup_ANT increases depending on

[0329] For example, in the horizontal direction, (N TxGroup_ANT ×N RxGroup_ANT )-2 virtual array element is D H The vertical direction is spaced apart by (N RxGroup ×N TxGroup )-2 virtual array element is D V The distance between the receiving array and the receiving array is D H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes can be reduced.

[0330] Also, N TxGroup_ANT and N RxGroup_ANT The larger N, the more the number of virtual array elements arranged in the horizontal direction increases, so the aperture length of the virtual receiving array in the horizontal direction can be expanded and the angular resolution in the horizontal direction can be improved. TxGroup , N RxGroup The larger θ is, the more the number of virtual array elements arranged in the vertical direction increases, so that the aperture length of the virtual receiving array in the vertical direction can be expanded and the angular resolution in the vertical direction can be improved.

[0331] <Basic layout 3> 52A to 52D show examples of arrangements of the transmitting antennas 106 and the receiving antennas 202 according to basic arrangement 3, and an example of an arrangement of a virtual receiving array.

[0332] (1) Arrangement of transmitting and receiving antennas In Figures 52A to 52D, the number of transmitting antennas 106 in the transmitting array antenna is Nt = 4 (Tx #1, Tx #2, Tx #3 and Tx #4), and the number of receiving antennas 202 in the receiving array antenna is Na = 4 (Rx #1, Rx #2, Rx #3 and Rx #4).

[0333] The transmitting array antenna shown in Fig. 52A to D is composed of a "first transmitting antenna group" (Tx#2, Tx#4 in Fig. 52A to D) and a "second transmitting antenna group" (Tx#1, Tx#3 in Fig. 52A to D). Each transmitting antenna group is located at the same position in the vertical direction, and the antenna spacing in the horizontal direction (horizontal direction in Fig. 52A to D) is 2D. H The distance between the "first transmitting antenna group" and the "second transmitting antenna group" in the vertical direction (the vertical direction in Figs. 52A to 52D) is, for example, 2D V It becomes.

[0334] In addition, in FIG. 52A to FIG. 52D, the horizontal positions of the transmitting antennas included in the first transmitting antenna group and the second transmitting antenna group are D H For example, the horizontal positions of the transmitting antennas included in the second transmitting antenna group are shifted from the horizontal positions of the transmitting antennas included in the first transmitting antenna group by +D H Staggered or -D H It is a staggered arrangement.

[0335] The receiving array antenna shown in Fig. 52A to D is composed of a "first receiving antenna group" (Rx#1, Rx#2 in Fig. 52A to D) and a "second receiving antenna group" (Rx#3, Rx#4 in Fig. 52A to D). Each receiving antenna group is located at the same position in the horizontal direction, and the antenna spacing in the vertical direction is 2D. VThe horizontal distance between the "first receiving antenna group" and the "second receiving antenna group" is, for example, 2D H It becomes.

[0336] In addition, in FIG. 52A to FIG. 52D, the vertical positions of the receiving antennas included in the first receiving antenna group and the second receiving antenna group are D V For example, the vertical position of each receiving antenna included in the second receiving antenna group is +D V Staggered or -D V It is a staggered arrangement.

[0337] For example, in the transmit / receive antenna arrangements shown in Figures 52A and 52C, the arrangement positions of the respective transmitting antennas included in the transmit array antenna and the arrangement positions of the respective receiving antennas included in the receive array antenna are rotated, for example, by +90° or -90° in a two-dimensional plane formed by the horizontal and vertical directions.

[0338] Furthermore, in the transmit / receive antenna arrangements shown in Figures 52B and 52D, the arrangement positions of the respective transmitting antennas included in the transmit array antenna and the arrangement positions of the respective receiving antennas included in the receive array antenna are rotated, for example, by +90° or -90° and inverted in a two-dimensional plane formed by the horizontal and vertical directions.

[0339] The horizontal offset ΔH of the second transmitting antenna group relative to the first transmitting antenna group is Tx Two combinations of (+D H , -D H ), and the vertical offset ΔV of the second receiving antenna group relative to the first receiving antenna group. Rx Two combinations of (+D V , -D V ) may be any combination. For example, in FIG. 52A to D, +D H The direction is rightward, -D HIn addition, in Figures 52A to 52D, +D V The direction is upwards, -D V is the downward direction.

[0340] For example, four combinations (ΔH Tx , ΔV Rx )=(+D H , +D V ), (+D H , -D V ), (-D H , +D V ), (D H , -D V ) may be used. As an example, FIGS. 52A to 52D show a combination of (ΔH Tx , ΔV Rx )=(-D H , -D V ), (-D H , +D V ), (+D H , +D V ), (+D H , -D V ) and the arrangement of the virtual receiving array are shown in FIG.

[0341] The virtual receiving array arrangements obtained by the MIMO array arrangements in the case of each antenna group deviation amount shown in Figs. 52A to 52D are rotationally symmetric arrangements, and similar angle measurement performance characteristics are obtained.

[0342] For example, it is assumed that the horizontal direction (horizontal direction) shown in FIG. 52A corresponds to the X-axis, and the vertical direction (lengthwise direction) shown in FIG. 52A corresponds to the Y-axis direction.

[0343] For example, in the case of the antenna arrangement shown in FIG. 52A, the position coordinates of the transmitting antenna 106 constituting the transmitting array antenna are the position coordinates (X T_#1 ,Y T_#1 ) as the reference, the position coordinates of the transmitting antenna Tx#2 (X T_#2 ,Y T_#2 )=(X T_#1 +D H ,Y T_#1 +2D V), the position coordinates of the transmitting antenna Tx#3 (X T_#3 ,Y T_#3 )=(X T_#1 +2D H ,Y T_#1 ), and the position coordinates of the transmitting antenna Tx#4 (X T_#4 ,Y T_#4 )=(X T_#1 +3D H ,Y T_#1 +2D V )

[0344] Similarly, the position coordinates of the receiving antenna 202 constituting the receiving array antenna are expressed as the position coordinates of the receiving antenna Rx#1 (X R_#1 ,Y R_#1 ) as the reference, the position coordinates of the receiving antenna Rx#2 (X R_#2 ,Y R_#2 )=(X R_#1 ,Y R_#1 +2D V ), the position coordinates of the receiving antenna Rx#3 (X R_#3 ,Y R_#3 )=(X R_#1 + 2D H ,Y R_#1 -D V ), and the position coordinates of the receiving antenna Rx#4 (X R_#4 ,Y R_#4 )=(X R_#1 +2D H ,Y R_#1 +D V )

[0345] (2) Virtual receiving array layout The arrangement of the virtual receiving array (virtual antennas VA#1 to VA#16) configured by the transmitting and receiving antenna arrangements shown in the above-mentioned FIGS. 52A to 52D has the following features.

[0346] For example, in the arrangement of the transmitting array antenna and the receiving array antenna shown in FIG. 52A, the position coordinates (X V_#1 ,Y V_#1 )~(X V_#16 ,Y V_#16) are as follows: Note that here, VA#1 is expressed as the position reference (0,0) of the virtual receiving array. (0,0), (D H , 2D V ), (2D H , 0), (3D H , 2D V ), (0, 2D V ), (D H , 4D V ), (2D H , 2D V ), (3D H , 4 V ), (2D H , -D V ), (3D H , D V ), (4D H , -D V ), (5D H , D V ), (2D H , D V ), (3D H , 3D V ), (4D H , D V ), (5D H , 3D V )

[0347] 52A to 52D, the virtual receiving array elements are arranged at different positions without overlapping, which allows the aperture length of the virtual receiving array to be expanded, narrowing the main lobe and improving the angular resolution.

[0348] In addition, the virtual array elements VA#4, VA#7, VA#10, and VA#13 located near the center of the virtual receiving array shown in FIGS. H Spacing, vertically D V As an example, in FIG. 52A to FIG. 52D, the distance D H and interval D V When the distance is about 0.5λ, the virtual array element located near the center of the virtual receiving array has a horizontal distance of D H= 0.5λ interval, D in the vertical direction V = 0.5λ apart. This makes it possible to reduce grating lobes in the same way as in basic arrangement 1 (see, for example, Figure 8).

[0349] For example, in the MIMO array arrangement shown in FIG. 52A to FIG. 52D, the interval D H and interval D V is set to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be 1λ or more.

[0350] As a result, for example, an antenna using four planar patch antennas arranged in two elements vertically and horizontally as a sub-array (where the antenna width W ANT < 2D H , Antenna height H ANT <2D V ) can be applied to at least one of the transmitting array antennas and the receiving array antennas shown in FIGS.

[0351] The number of transmitting antennas included in the first transmitting antenna group (hereinafter, “N TxHGroup1_ANT ") and the number of transmitting antennas included in the second transmitting antenna group (hereinafter, "N TxHGroup2_ANT ") may be the same number or may have a difference of one antenna. For example, |N TxHGroup1_ANT -N TxHGroup2_ANT |=0 or 1.

[0352] Similarly, the number of receiving antennas included in the first receiving antenna group (hereinafter, “N RxVGroup1_ANT ") and the number of receiving antennas included in the second receiving antenna group (hereinafter, "N RxVGroup2_ANT ") may be the same number or may have a difference of one antenna. For example, |N RxVGroup1_ANT -N RxVGroup2_ANT |=0 or 1.

[0353] 53A to 53D show the number of transmitting antennas N included in the first transmitting antenna group. TxHGroup1_ANT and the number of transmitting antennas included in the second transmitting antenna group NTxHGroup2_ANT There is a difference of one antenna between the first and second receiving antenna groups, and the number of receiving antennas included in the first receiving antenna group is N RxVGroup1_ANT and the number of receiving antennas included in the second receiving antenna group N RxVGroup2_ANT FIG. 1 shows an example of a configuration in which the number of MIMO array antennas is minimized when the numbers of and are the same.

[0354] As shown in Figures 53A to 53D, |N TxHGroup1_ANT -N TxHGroup2_ANT |=1 and |N RxVGroup1_ANT -N RxVGroup2_ANT When |=0, the configuration with the minimum number of MIMO array antennas has three transmit antennas and four receive antennas (N RxVGroup1_ANT =N RxVGroup2_ANT =2), and there are, for example, four patterns as shown in FIGS. 53A to 53D.

[0355] FIG. 53A shows N TxHGroup1_ANT =1(Tx#2), N TxHGroup2_ANT = 2 (Tx#1, Tx#3), (ΔH Tx , ΔV Rx )=(-D H , -D V ) and an example of a virtual receiving array arrangement are shown.

[0356] FIG. 53B shows N TxHGroup1_ANT =1(Tx#2), N TxHGroup2_ANT = 2 (Tx#1, Tx#3), (ΔH Tx , ΔV Rx )=(-D H , +D V ) and an example of a virtual receiving array arrangement are shown.

[0357] Figure 53C shows N TxHGroup1_ANT = 2 (Tx#2, Tx#3), N TxHGroup2_ANT = 1 (Tx#1), ​​(ΔH Tx , ΔV Rx )=(+D H , -D V ) and an example of a virtual receiving array arrangement are shown.

[0358] Figure 53D shows NTxHGroup1_ANT = 2 (Tx#2, Tx#3), N TxHGroup2_ANT =1(Tx#1), ​​(ΔH Tx , ΔV Rx )=(+D H , +D V ) and an example of a virtual receiving array arrangement are shown.

[0359] 54A to 54D show the number of transmitting antennas N TxHGroup1_ANT and the number of transmitting antennas included in the second transmitting antenna group N TxHGroup2_ANT and the number of receiving antennas included in the first receiving antenna group is N RxVGroup1_ANT and the number of receiving antennas included in the second receiving antenna group N RxVGroup2_ANT In this example, the number of MIMO array antennas is minimized when there is a difference of one antenna between the two.

[0360] As shown in Figures 54A to 54D, |N TxHGroup1_ANT -N TxHGroup2_ANT |=0 and |N RxVGroup1_ANT -N RxVGroup2_ANT When |=1, the configuration with the minimum number of MIMO array antennas is one with 4 transmit antennas (N TxVGroup1_ANT =N TxVGroup2_ANT = 2), and the number of receiving antennas is 3. For example, there are four patterns as shown in Figs. 54A to 54D.

[0361] FIG. 54A shows N RxHGroup1_ANT =1(Rx#1), ​​N RxHGroup2_ANT = 2(Rx#2, Rx#3), (ΔH Tx , ΔV Rx )=(-D H , +D V ) and an example of a virtual receiving array arrangement are shown.

[0362] FIG. 54B shows N RxHGroup1_ANT =1(Rx#1), ​​N RxHGroup2_ANT = 2(Rx#2, Rx#3), (ΔH Tx , ΔV Rx )=(+D H , +D V) and an example of a virtual receiving array arrangement are shown.

[0363] Figure 54C shows N RxHGroup1_ANT =2(Rx#1,Rx#2),N RxHGroup2_ANT = 1 (Rx#3), (ΔH Tx , ΔV Rx )=(-D H , -D V ) and an example of a virtual receiving array arrangement are shown.

[0364] Figure 54D shows N RxHGroup1_ANT =2(Rx#1,Rx#2),N RxHGroup2_ANT = 1 (Rx#3), (ΔH Tx , ΔV Rx )=(+D H , -D V ) and an example of a virtual receiving array arrangement are shown.

[0365] 55A to 55D show the number of transmitting antennas N included in the first transmitting antenna group. TxHGroup1_ANT and the number of transmitting antennas included in the second transmitting antenna group N TxHGroup2_ANT There is a difference of one antenna between the first and second receiving antenna groups, and the number of receiving antennas included in the first receiving antenna group is N RxVGroup1_ANT and the number of receiving antennas included in the second receiving antenna group N RxVGroup2_ANT In this example, the number of MIMO array antennas is minimized when there is a difference of one antenna between the two.

[0366] As shown in Figures 55A to 55D, |N TxHGroup1_ANT -N TxHGroup2_ANT |=1 and |N RxVGroup1_ANT -N RxVGroup2_ANT When |=1, the configuration with the smallest number of MIMO array antennas is a configuration with three transmitting antennas and three receiving antennas, and there are, for example, four patterns in FIGS. 55A to 55D.

[0367] FIG. 55A shows N TxVGroup1_ANT =1(Tx#2), N TxVGroup2_ANT = 2 (Tx#1, Tx#3), N RxHGroup1_ANT =2(Rx#1,Rx#2),NRxHGroup2_ANT = 1 (Rx#3), (ΔH Tx , ΔV Rx )=(-D H , -D V ) and an example of a virtual receiving array arrangement are shown.

[0368] FIG. 55B shows N TxVGroup1_ANT =1(Tx#2), N TxVGroup2_ANT = 2 (Tx#1, Tx#3), N RxHGroup1_ANT =1(Rx#1), ​​N RxHGroup2_ANT = 2(Rx#2, Rx#3), (ΔH Tx , ΔV Rx )=(-D H , +D V ) and an example of a virtual receiving array arrangement are shown.

[0369] Figure 55C shows N TxVGroup1_ANT = 2 (Tx#2, Tx#3), N TxVGroup2_ANT =1(Tx#1), ​​N RxHGroup1_ANT =2(Rx#1,Rx#2),N RxHGroup2_ANT = 1 (Rx#3), (ΔH Tx , ΔV Rx )=(+D H , -D V ) and an example of a virtual receiving array arrangement are shown.

[0370] Figure 55D shows N TxVGroup1_ANT = 2 (Tx#2, Tx#3), N TxVGroup2_ANT =1(Tx#1), ​​N RxHGroup1_ANT =1(Rx#1), ​​N RxHGroup2_ANT = 2(Rx#2, Rx#3), (ΔH Tx , ΔV Rx )=(+D H , +D V ) and an example of a virtual receiving array arrangement are shown.

[0371] For example, in FIGS. 55A to 55D, the transmitting array antenna includes three transmitting antennas, and the receiving array antenna includes three receiving antennas.

[0372] In addition, two of the three transmitting antennas (for example, transmitting antennas included in one transmitting antenna group) are, for example, 2D in the horizontal direction. H (In other words, D H The remaining one of the three transmitting antennas is placed at a distance of, for example, D H The antenna is placed at a distance (i.e., at the midpoint) and is 2D away from the two transmitting antennas in the vertical direction. V Interval (in other words, D V The devices are spaced apart at twice the distance from each other.

[0373] Similarly, two of the three receive antennas (e.g., receive antennas included in one receive antenna group) are, for example, 2D in the vertical direction. V (In other words, D V The remaining one of the three receiving antennas is, for example, located at a distance of D from the two receiving antennas mentioned above in the vertical direction. V The receiving antenna is placed at a distance (i.e., at the midpoint) and is 2D away from the two receiving antennas in the horizontal direction. H Interval (in other words, D H The devices are spaced apart at twice the distance from each other.

[0374] In other words, in Figures 55A to 55D, the arrangement positions of the three transmitting antennas and the arrangement positions of the three receiving antennas are in a rotationally symmetric relationship on a two-dimensional plane defined by a horizontal direction (e.g., X-axis) and a vertical direction (e.g., Y-axis). For example, in Figures 52A to 52D, the transmitting array antenna and the receiving array antenna are rotated by ±90 degrees.

[0375] The transmitting / receiving antenna arrangements according to the basic arrangement 3 and the modifications of the basic arrangement 3 include at least an antenna arrangement having the above-mentioned arrangement relationship of the three transmitting antennas or the three receiving antennas.

[0376] Since the virtual array elements of the virtual receiving arrays shown in FIGS. 52A to D, 53A to D, 54A to D, and 55A to D are arranged at different positions without overlapping, the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0377] In addition, the virtual array element located near the center of the virtual receiving array is D H , D V As an example, in Figs. 52A to D, 53A to D, 54A to D, and 55A to D, H and interval D V When the distance is about 0.5λ, the virtual array element located near the center of the virtual receiving array has a horizontal distance of D H = 0.5λ interval, D in the vertical direction V = 0.5λ apart, which helps reduce grating lobes.

[0378] For example, in the MIMO array arrangement of basic arrangement 3, the spacing D H and interval D V is set to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0379] As a result, for example, an antenna using four planar patch antennas arranged in two elements vertically and horizontally as a sub-array as shown in FIG. 9A (where the antenna width W ANT < 2D H , Antenna height H ANT <2D V ) can be applied to at least one of the antenna elements of the transmitting array antennas and the receiving array antennas shown in FIGS. 52A to D, 53A to D, 54A to D, and 55A to D.

[0380] In the case of the transmitting antenna 106, the horizontal direction W ANT The element size of D H As long as the antenna is smaller than 100 mm, any size antenna can be used in the vertical direction.

[0381] For example, Fig. 56A shows an example in which a sub-array in which eight planar patch antenna elements shown in Fig. 25A are arranged vertically and one horizontally is applied to the antenna arrangement shown in Fig. 52A. Note that, as shown in Fig. 56B, parasitic elements (dummy elements) may be arranged in addition to the transmitting array antenna shown in Fig. 56A. The parasitic elements can equalize the effect of inter-antenna coupling due to adjacent antennas for each antenna, and can equalize the directional characteristics of each transmitting antenna (Tx #1 to #4).

[0382] In this way, by using antennas in a sub-array configuration in the antenna arrangement according to the basic arrangement 3, the directional gain of the antennas can be improved, and the detection performance (for example, detection distance) of the radar device 10 can be improved.

[0383] The direction estimation unit 214 performs direction estimation processing in the horizontal and vertical directions using the received signals of the virtual receiving array obtained from the above-mentioned transmitting and receiving antenna arrangements. Note that the processing by the direction estimation unit 214 for the virtual receiving array of basic arrangement 3 is the same as that of basic arrangement 1, so a description thereof will be omitted here.

[0384] FIG. 57 shows a MIMO array arrangement (D H =0.5λ, D V 57 shows an example of a direction estimation result when a beamformer method is used as the arrival direction estimation algorithm of direction estimation unit 214 when using a beamwidth of 1.0 λ (=0.5 λ). That is, in Fig. 57, the antenna spacing in the horizontal and vertical directions of transmitting antenna 106 is 1 λ or more, and the antenna spacing in the horizontal and vertical directions of receiving antenna 202 is also 1 λ or more. Note that the directivity of each antenna is calculated as omnidirectional.

[0385] FIG. 57 plots the output of the direction-of-arrival estimation evaluation function value in a range of ±90 degrees in the horizontal direction and a range of ±90 degrees in the vertical direction when the target true value is 0 degrees horizontally and 0 degrees vertically.

[0386] In Fig. 57, it can be seen that the grating lobes are reduced in directions other than the horizontal 0 degrees and vertical 0 degrees of the target true value, as compared to, for example, Fig. 1A. For example, in Fig. 57, the ratio (PSLR) of the peak power value of the highest side lobe excluding the main lobe in directions other than the horizontal 0 degrees and vertical 0 degrees to the peak power value of the main lobe in the horizontal 0 degrees and vertical 0 degrees direction is about 0.3.

[0387] As described above, by using the MIMO array arrangement according to basic arrangement 3, even if the vertical or horizontal element size of the antennas used for the transmitting array antenna and the receiving array antenna is about 1λ, the horizontal and vertical antenna spacings in the virtual receiving array can be arranged to include element spacings of about 0.5λ, thereby reducing grating lobes. Furthermore, since the virtual array elements of the virtual receiving array shown in Fig. 52A, for example, are arranged without overlapping, the aperture length of the virtual receiving array can be extended and the angular resolution can be improved.

[0388] <Variation 1 of Basic Layout 3> In basic arrangement 3, the numbers of transmitting antennas 106 and receiving antennas 202 have been described as being four transmitting elements (Nt=4) and four receiving elements (Na=4) (e.g., Figs. 52A-D), three transmitting elements (Nt=3) and four receiving elements (Na=4) (e.g., Figs. 53A-D), four transmitting elements (Nt=4) and three receiving elements (Na=3) (e.g., Figs. 54A-D), and a minimum configuration of three transmitting elements (Nt=3) and three receiving elements (Na=3) (e.g., Figs. 55A-D). However, the number of transmitting antennas Nt and the number of receiving antennas Na are not limited to these numbers.

[0389] In the first modification of the basic arrangement 3, an arrangement in which the number of antennas in the MIMO array is increased compared to the basic arrangement 3 will be described.

[0390] For example, in a transmitting array antenna, the number of transmitting antennas included in the first transmitting antenna group is N TxHGroup1_ANT , and the number of antennas included in the second transmitting antenna group N TxHGroup2_ANTIn addition, in the receiving array antenna, the number of antennas included in the first receiving antenna group N RxVGroup1_ANT , and the number of antennas included in the second receiving vertical antenna group N RxVGroup2_ANT may be increased.

[0391] Figure 58 shows N TxHGroup1_ANT = 2 (Tx#2, Tx#4), N TxHGroup2_ANT = 2 (Tx#1, Tx#3), N RxVGroup1_ANT =3(Rx#1,Rx#2,Rx#3),N RxVGroup2_ANT 58 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when (ΔH Tx , ΔV Rx )=(-D H , -D V ), but (ΔH Tx , ΔV Rx )=(-D H , +D V ), (+D H , -D V )(+D H , +D V ) can also be used.

[0392] Figure 59 shows N TxHGroup1_ANT = 2 (Tx#2, Tx#4), N TxHGroup2_ANT = 2 (Tx#1, Tx#3), N RxVGroup1_ANT =3(Rx#1,Rx#2,Rx#3),N RxVGroup2_ANT 59 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when (ΔH Tx , ΔV Rx )=(-D H , -D V ), but (ΔH Tx , ΔV Rx )=(+D H , -D V ) can also be used.

[0393] Figure 60 shows N TxHGroup1_ANT =4(Tx#2,Tx#4,Tx#6,Tx#8), N TxHGroup2_ANT = 4 (Tx#1, Tx#3, Tx#5, Tx#7), NRxVGroup1_ANT =3(Rx#1,Rx#2,Rx#3),N RxVGroup2_ANT 60 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when (ΔH Tx , ΔV Rx )=(-D H , -D V ), but (ΔH Tx , ΔV Rx )=(-D H , +D V ), (+D H , -D V )(+D H , +D V ) can also be used.

[0394] Figure 61 shows N TxHGroup1_ANT =3(Tx#2,Tx#4,Tx#6), N TxHGroup2_ANT = 4 (Tx#1, Tx#3, Tx#5, Tx#7), N RxVGroup1_ANT =3(Rx#1,Rx#2,Rx#3),N RxVGroup2_ANT 61 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when (ΔH Tx , ΔV Rx )=(-D H , -D V ), but (ΔH Tx , ΔV Rx )=(-D H , +D V ) can also be used.

[0395] In each of the MIMO array configurations shown in Figs. 58 to 61, for example, D H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0396] Furthermore, for example, in each of the virtual receiving arrays shown in FIGS. 58 to 61, the virtual array elements are arranged at different positions without overlapping, so that the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0397] The virtual array elements located near the center of each virtual receiving array shown in Figs. 58 to 61 are designated as D H , D V D H , D V The number of closely spaced virtual array elements is N TxHGroup1_ANT , N TxHGroup2_ANT , N RxVGroup1_ANT and N RxVGroup2_ANT increases depending on

[0398] For example, in the virtual receiving array, the horizontal direction is (N TxHGroup1_ANT +N TxHGroup2_ANT ) virtual array element is D H The vertical direction is spaced apart by (N RxVGroup1_ANT +N RxVGroup2_ANT ) virtual array element is D V In addition, in the virtual receiving array, the horizontal TxHGroup1_ANT +N TxHGroup2_ANT )-2 of D H The virtual array elements are spaced at intervals of 1000 MHz, and the vertical RxVGroup1_ANT +N RxVGroup2_ANT )-2 of D V The virtual array elements are arranged in a rectangular shape with a vertical and horizontal spacing.

[0399] D near the center of the virtual receiving array H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes are reduced.

[0400] Also, N TxGroup1_ANT , N TxHGroup2_ANT The larger N, the more the number of virtual array elements arranged in the horizontal direction increases, so the aperture length of the virtual receiving array in the horizontal direction can be expanded and the angular resolution in the horizontal direction can be improved. RxVGroup1_ANT , N RxVGroup2_ANT The larger θ is, the more the number of virtual array elements arranged in the vertical direction increases, so that the aperture length of the virtual receiving array in the vertical direction can be expanded and the angular resolution in the vertical direction can be improved.

[0401] FIG. 62 shows a MIMO array arrangement (N TxGroup1_ANT =4, N TxGroup2_ANT =4, N RxGroup1_ANT =3, N RxGroup2_ANT =3, D H =0.5λ, D V 13 shows an example of a direction estimation result when a beamformer method is used as the arrival direction estimation algorithm of the direction estimator 214 when a λ=0.5λ is used. Note that the directivity of each antenna is calculated as omnidirectional.

[0402] FIG. 62 plots the output of the direction-of-arrival estimation evaluation function value in a range of ±90 degrees in the horizontal direction and a range of ±90 degrees in the vertical direction when the target true value is 0 degrees horizontally and 0 degrees vertically.

[0403] In Fig. 62, it can be seen that the grating lobes are reduced in directions other than the horizontal 0 degrees and vertical 0 degrees of the target true value. For example, in Fig. 62, the ratio (PSLR) of the peak power value of the highest side lobe excluding the main lobe to the peak power value of the main lobe in the horizontal 0 degrees and vertical 0 degrees directions is about 0.13. TxHGroup1_ANT , N TxHGroup2_ANT and N RxVGroup1_ANT , N RxVGroup2_ANT By increasing N, it can be confirmed that the side lobe reduction effect is improved. In addition, in Figure 62, the peak of the main lobe is sharper than in Figure 57, and N TxHGroup1_ANT , N TxHGroup2_ANT and N RxVGroup1_ANT , N RxVGroup2_ANT The increase in the angular resolution can be seen.

[0404] <Modification 2 of Basic Layout 3> The antenna arrangement methods 3-2A and 3-2B in the second modification of the basic arrangement 3 will be described below.

[0405] (Placement method 3-2A) In the first modification of the basic arrangement 3, the number of receiving antennas included in the receiving antenna group of the receiving array antenna is N RxVGroup1_ANT , N RxVGroup2_ANT In the above description, the number of virtual array elements arranged in the vertical direction is increased by increasing the number of transmitting antenna groups N TxGroup The number of virtual array elements arranged in the vertical direction in the virtual receiving array can also be increased by increasing

[0406] In this case, the antenna spacing in the vertical direction of the transmitting antenna group is set to a constant value (e.g., 2D V ), but the number of receiving antennas in the receiving antenna group N RxVGroup1_ANT , N RxVGroup2_ANT Depending on the configuration, the virtual receive array may have overlapping virtual array elements.

[0407] Therefore, in order to arrange the virtual receiving array so that there are no overlapping virtual array elements, for example, the spacing between even-numbered antennas in the vertical direction of the transmitting antenna group should be set to the following spacing D TxHGroupV may be used.

number

[0408] For example, N RxVGroup1_ANT =N RxVGroup2_ANT If =2, D TxHGroupV =2D V Then, N RxVGroup1_ANT =N RxVGroup2_ANT If = 3, D TxHGroupV =4D V It becomes.

[0409] For example, the number of transmit antennas N TxHGroup For = 3, the spacing between the three transmit antenna groups is {2D V , D TxHGroupV}. In addition, the number of transmitting antenna groups N TxHGroup For , the spacing between the four transmit antenna groups is {2D V , D TxHGroupV , 2DV} Similarly, N RxGroup_ANT For =5, the spacing between the five transmit antenna groups is {2D V , D TxHGroupV , 2D V , D TxHGroupV}.

[0410] Figure 63 shows N RxVGroup =2, N TxHGroup =4, N TxHGroup1_ANT =2, N TxHGroup2_ANT =2, N TxHGroup3_ANT =2, N TxHGroup4_ANT =2, N RxVGroup1_ANT =2, N RxVGroup2_ANT The following shows an example of a MIMO array arrangement and a virtual receiving array arrangement for N = 2. TxHGroup3_ANT " represents the number of transmitting antennas included in the third transmitting antenna group, and "N TxHGroup4_ANT " represents the number of transmitting antennas included in the fourth transmitting antenna group. In FIG. 63, D TxHGroupV =2D V It becomes.

[0411] In FIG. 63, the shift amount ΔV of the second receiving antenna group (Rx#3, Rx#4) relative to the first receiving antenna group (Rx#1, Rx#2) is Rx(2,1) is ΔV Rx(2,1) =-D V This shows the case of ΔV Rx(2,1) =+D V It is also possible to use the following.

[0412] In FIG. 63, the shift amount ΔH of the second transmitting antenna group (Tx#3, Tx#7) relative to the first transmitting antenna group (Tx#4, Tx#8) is Tx(2,1) A-D H The shift amount ΔH of the third transmitting antenna group (Tx#2, Tx#6) relative to the second transmitting antenna group is Tx(3,2) +D H The shift amount ΔH of the fourth transmitting antenna group (Tx#1, Tx#5) relative to the third transmitting antenna group is Tx(4,3) A-D H However, there are two types of deviations (+D V , -D V) can be used. In FIG. 63, +D V The direction is upwards, -D V is downwards, +D H The direction is rightward, -D H is to the left.

[0413] Also, Figure 64 shows N RxVGroup =2, N TxHGroup =4, N TxHGroup1_ANT =2, N TxHGroup2_ANT =2, N TxHGroup3_ANT =2, N TxHGroup4_ANT =2, N RxVGroup1_ANT =3, N RxVGroup2_ANT An example of a MIMO array arrangement and an example of a virtual receiving array arrangement for D = 3 are shown in FIG. TxHGroupV =4D V It becomes.

[0414] In FIG. 64, the shift amount ΔV of the second receiving antenna group (Rx#4, Rx#5, Rx#6) relative to the first receiving antenna group (Rx#1, Rx#2, Rx#3) is Rx(2,1) is ΔV Rx(2,1) =-D V This shows the case of ΔV Rx(2,1) =+D V It is also possible to use the following.

[0415] In FIG. 64, the shift amount ΔH of the second transmitting antenna group (Tx#3, Tx#7) relative to the first transmitting antenna group (Tx#4, Tx#8) is Tx(2,1) -D H The shift amount ΔH of the third transmitting antenna group (Tx#2, Tx#6) relative to the second transmitting antenna group is Tx(3,2) +D H The shift amount ΔH of the fourth transmitting antenna group (Tx#1, Tx#5) relative to the third transmitting antenna group is Tx(4,3) -D H However, there are two types of deviations (+D V , -D V ) can be used. In FIG. 64, +D V The direction is upwards, -D V is downwards, +D HThe direction is rightward, -D H is to the left.

[0416] In addition, the virtual receiving array is placed at irregular intervals (e.g., D H and D. V If it is acceptable to include arrangements with a spacing greater than TxHGroupV may be greater than the value of equation (15).

[0417] (Placement method 3-2B) In the variation 1 of the basic arrangement 3, the number of transmitting antennas included in each transmitting antenna group of the transmitting array antenna is N TxHGroup1_ANT , N TxHGroup2_ANT In the above description, the number of virtual array elements arranged in the horizontal direction is increased by increasing the number of receiving antenna groups N RxVGroup The number of virtual array elements arranged horizontally in the virtual receiving array can also be increased by increasing

[0418] In this case, the horizontal antenna spacing of the receiving antenna group is set to a constant value (e.g., 2D H ), but the number of transmitting antennas included in the transmitting antenna group N TxHGroup1_ANT , N TxHGroup2_ANT Depending on the configuration, the virtual receive array may have overlapping virtual array elements.

[0419] Therefore, in order to arrange the virtual receiving array so that there are no overlapping virtual array elements, for example, the horizontal spacing between the receiving antennas should be set to the even-numbered spacing D RxVGroupH may be used.

number

[0420] For example, N TxHGroup1_ANT =N TxHGroup2_ANT If =2, D RxVGroupH =2D H Then, N TxHGroup1_ANT =N TxHGroup2_ANT If = 3, DRxVGroupH =4D H It becomes.

[0421] For example, the number of receiving antennas N RxVGroup For , the horizontal spacing between the three receive antenna groups is {2D H , D RxVGroupH}. In addition, the number of receiving antenna groups N RxVGroup When = 4, the horizontal spacing of the four receive antenna groups is {2D H , D RxVGroupH , 2D H Similarly, the number of receiving antenna groups N RxVGroup When = 5, the horizontal spacing of the five receiving antenna groups is {2D H , D RxVGroupH , 2D H , D RxVGroupH}.

[0422] Figure 65 shows N TxHGroup =2, N RxVGroup =4, N TxHGroup1_ANT =2, N TxHGroup2_ANT =2, N RxVGroup1_ANT =2, N RxVGroup2_ANT =2, N RxVGroup3_ANT =2, N RxVGroup4_ANT The following shows an example of a MIMO array arrangement and a virtual receiving array arrangement for N = 2. RxVGroup3_ANT " represents the number of receiving antennas included in the third receiving antenna group, and "N RxVGroup4_ANT " represents the number of receiving antennas included in the fourth receiving antenna group. In FIG. 65, D RxVGroupH =2D H It becomes.

[0423] In FIG. 65, the shift amount ΔH of the second transmitting antenna group (Tx#1, Tx#3) relative to the first transmitting antenna group (Tx#2, Tx#4) is Tx(2,1) The reason is ΔH Tx(2,1) =-D H This shows the case of ΔH Tx(2,1) =+D H It is also possible to use the following.

[0424] In FIG. 65, the shift amount ΔV of the second receiving antenna group (Rx#3, Rx#4) relative to the first receiving antenna group (Rx#1, Rx#2) is Rx(2,1) A-D V The deviation amount ΔV of the third receiving antenna group (Rx#5, Rx#6) relative to the second receiving antenna group is Rx(3,2) +D V The deviation amount ΔV of the fourth receiving antenna group (Rx#7, Rx#8) relative to the third receiving antenna group is Rx(4,3) A-D V However, there are two types of deviations (+D V , -D V ) can be used. In FIG. 65, +D V The direction is upwards, -D V is the downward direction.

[0425] Figure 66 shows N TxHGroup =2, N RxVGroup =4, N TxHGroup1_ANT =3, N TxHGroup2_ANT =3, N RxVGroup1_ANT =2, N RxVGroup2_ANT =2, N RxVGroup3_ANT =2, N RxVGroup4_ANT An example of a MIMO array arrangement and an example of a virtual receiving array arrangement for D = 2 are shown in FIG. RxVGroupH =4D H It becomes.

[0426] The shift amount ΔH of the second transmitting antenna group (Tx#1, Tx#3, Tx#5) relative to the first transmitting antenna group (Tx#2, Tx#4, Tx#6) is Tx(2,1) is ΔH Tx(2,1) =-D H This shows the case of ΔH Tx(2,1) =+D H It is also possible to use the following.

[0427] In FIG. 66, the amount of deviation ΔV of the second vertical receiving antenna group (Rx#3, Rx#4) relative to the first receiving antenna group (Rx#1, Rx#2) is Rx(2,1) A-D V The deviation amount ΔV of the third receiving antenna group (Rx#5, Rx#6) relative to the second receiving antenna group is Rx(3,2)+D V The deviation amount ΔV of the fourth receiving antenna group (Rx#7, Rx#8) relative to the third receiving antenna group is Rx(4,3) A-D V However, there are two types of deviations (+D V , -D V ) can be used. In FIG. 66, +D V The direction is upwards, -D V is downwards, +D H The direction is rightward, -D H is to the left.

[0428] In addition, the virtual receiving array is placed at irregular intervals (e.g., D H and D. V If it is acceptable to include arrangements with a spacing greater than RxVGroupH may be greater than the value of equation (16).

[0429] The arrangement methods 3-2A and 3-2B in the modification 2 of the basic arrangement 3 have been described above.

[0430] For example, in the transmitting and receiving antenna arrangement (for example, MIMO array arrangement) shown in FIG. 63 to FIG. 66, for example, D H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0431] Furthermore, for example, in the virtual receiving arrays shown in FIGS. 63 to 66, the virtual array elements are arranged at different positions without overlapping, so that the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0432] For example, the virtual array elements located near the center of the virtual receiving array shown in Figs. 63 to 66 are designated as D H , D V D H , D V The number of closely spaced virtual array elements is the number of transmitting antennas, NTxHGroup , and the number of transmitting antennas included in each transmitting antenna group N TxHGroup(ntvg)_ANT (where ntvg=1,…, N TxHGroup ) and the number of receiving antennas N RxVGroup , and the number of receiving antennas included in each receiving antenna group N RxVGroup(nrhg)_ANT (where nrhg=1,…, N RxVGroup The increase depends on

[0433] For example, in the virtual receiving array, the horizontal direction is 0.5×(N TxHGroup1_ANT +N TxHGroup2_ANT )×N RxVGroup The virtual array element of D H In the vertical direction, RxVGroup1_ANT +N RxVGroup2_ANT )×N TxHGroup The virtual array element of D V In addition, the horizontal distance is 0.5×(N TxHGroup1_ANT +N TxHGroup2_ANT )×N RxVGroup -2D H The virtual array elements are spaced 0.5×(N RxVGroup1_ANT +N RxVGroup2_ANT )×N TxHGroup -2D V The virtual array elements are arranged vertically and horizontally in a rectangular shape.

[0434] D near the center of the virtual receiving array H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes can be reduced.

[0435] In addition, the number of transmitting antennas included in each transmitting antenna group is N TxHGroup(ntvg)_ANT , and the number of receiving antenna groups N RxVGroup The larger the number of virtual array elements arranged in the horizontal direction, the larger the aperture length of the virtual receiving array in the horizontal direction, and the better the angular resolution in the horizontal direction. Similarly, the number of receiving antennas included in each receiving antenna group, N RxVGroup(nrhg)_ANT , and the number of transmit antenna groups N TxHGroupThe larger θ is, the more the number of virtual array elements arranged in the vertical direction increases, so that the aperture length of the virtual receiving array in the vertical direction can be expanded and the angular resolution in the vertical direction can be improved.

[0436] In addition, in the variation 2 of the basic layout 3, a layout in which the layout method 3-2A and the layout method 3-2B are combined is also possible.

[0437] Figure 67 shows N RxVGroup =N TxHGroup =4, N TxHGroup1_ANT =N TxHGroup2_ANT =N TxHGroup3_ANT =N TxHGroup4_ANT =2, N RxVGroup1_ANT =N RxVGroup2_ANT =N RxVGroup3_ANT =N RxVGroup4_ANT An example of a MIMO array arrangement and an example of a virtual receiving array arrangement for D = 2 are shown in FIG. TxHGroupV =2D V Then, D in equation (16) RxVGroupH =2D H It becomes.

[0438] In FIG. 67, the shift amount ΔH of the second transmitting antenna group (Tx#3, Tx#7) relative to the first transmitting antenna group (Tx#4, Tx#8) is Tx(2,1) -D H The shift amount ΔH of the third transmitting antenna group (Tx#2, Tx#6) relative to the second transmitting antenna group is Tx(3,2) -D H The shift amount ΔH of the fourth transmitting antenna group (Tx#1, Tx#5) relative to the third transmitting antenna group is Tx(4,3) -D H However, there are two types of deviations (+D V , -D V ) may be any combination.

[0439] In FIG. 67, the shift amount ΔV of the second receiving antenna group (Rx#3, Rx#4) relative to the first receiving antenna group (Rx#1, Rx#2) is Rx(2,1) -D V The deviation amount ΔV of the third receiving antenna group (Rx#5, Rx#6) relative to the second receiving antenna group is Rx(3,2)+D V The deviation amount ΔV of the fourth receiving antenna group (Rx#7, Rx#8) relative to the third receiving antenna group is Rx(4,3) -D V However, there are two types of deviations (+D V , -D V ) may be any combination.

[0440] Also, in Figure 67, +D V The direction is upwards, -D V The direction is downwards, +D H The direction is rightward, -D H The direction is to the left.

[0441] Also, FIG. 68A shows N RxVGroup =N TxHGroup =4, N TxHGroup1_ANT =N TxHGroup2_ANT =N TxHGroup3_ANT =N TxHGroup4_ANT =4, N RxVGroup1_ANT =N RxVGroup2_ANT =N RxVGroup3_ANT =N RxVGroup4_ANT FIG. 68A shows an example of a MIMO array arrangement for D = 4, and FIG. 68B shows an example of a virtual receiving array arrangement. In FIG. 68A, D TxHGroupV =6D V Then, D in equation (16) RxVGroupH =6D H It becomes.

[0442] In FIG. 68A, the shift amount ΔH of the second transmitting antenna group (Tx#3, Tx#7, Tx#11, Tx#15) relative to the first transmitting antenna group (Tx#4, Tx#8, Tx#12, Tx#16) is Tx(2,1) -D H The shift amount ΔH of the third transmitting antenna group (Tx#2, Tx#6, Tx#10, Tx#14) relative to the second transmitting antenna group is Tx(3,2) +D H The shift amount ΔH of the fourth transmitting antenna group (Tx#1, Tx#5, Tx#9, Tx#13) relative to the third transmitting antenna group is Tx(4,3) -D H However, there are two types of deviations (+D V , -D V) may be any combination.

[0443] In FIG. 68A, the shift amount ΔV of the second receiving antenna group (Rx#5, Rx#6, Rx#7, Rx#8) relative to the first receiving antenna group (Rx#1, Rx#2, Rx#3, Rx#4) is Rx(2,1) -D V The deviation amount ΔV of the third receiving antenna group (Rx#9, Rx#10, Rx#11, Rx#12) relative to the second receiving antenna group is Rx(3,2) +D V The deviation amount ΔV of the fourth receiving antenna group (Rx#13, Rx#14, Rx#15, Rx#16) relative to the third receiving antenna group is Rx(4,3) -D V However, there are two types of deviations (+D V , -D V ) may be any combination.

[0444] Also, in Figures 68A and 68B, +D V The direction is upwards, -D V The direction is downwards, +D H The direction is rightward, -D H The direction is to the left.

[0445] <Basic layout 4> FIG. 69 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 according to basic arrangement 4, and an example of the arrangement of a virtual receiving array.

[0446] (1) Arrangement of transmitting and receiving antennas In FIG. 69, the number of transmitting antennas 106 in the transmitting array antenna is Nt = 4 (Tx#1, Tx#2, Tx#3 and Tx#4), and the number of receiving antennas 202 in the receiving array antenna is Na = 4 (Rx#1, Rx#2, Rx#3 and Rx#4).

[0447] The transmitting array antenna shown in Fig. 69 is composed of, for example, a "first transmitting antenna group" (Tx#2, Tx#4 in Fig. 69) and a "second transmitting antenna group" (Tx#1, Tx#3 in Fig. 69). Each transmitting antenna group is spaced 2D apart in the horizontal direction. H and the vertical spacing is D V In each of the transmitting antenna groups shown in FIG. 69, adjacent transmitting antennas are arranged in a 2D H Interval (in other words, D H 2x the distance between the vertical V In other words, in FIG. 69, the transmitting antennas included in each transmitting antenna group are arranged at intervals of 2D in the horizontal direction. H , vertically D V The antennas are arranged in a straight line in a diagonally downward to the right (in other words, in a diagonally upward to the left) with an antenna spacing of

[0448] In FIG. 69, the second transmitting antenna group is shifted to the left in the horizontal direction with respect to the first transmitting antenna group. H , vertically downwards in 2D V In other words, the adjacent transmitting antenna groups shown in FIG. H and 2D vertically V (In other words, D V The two are shifted by twice the interval.

[0449] The receiving array antenna shown in Fig. 69 is composed of, for example, a "first receiving antenna group" (Rx#2, Rx#4 in Fig. 69) and a "second receiving antenna group" (Rx#1, Rx#3 in Fig. 69). Each receiving antenna group has an antenna spacing of 2D in the horizontal direction. H and the antenna spacing in the vertical direction is D V In each of the receiving antenna groups shown in FIG. 69, adjacent receiving antennas are arranged in a 2D H Interval (in other words, D H 2x the distance between the verticalV In other words, in FIG. 69, the receiving antennas included in each receiving antenna group are arranged at intervals of 2D in the horizontal direction. H , vertically D V The antennas are arranged in a straight line in the upper right direction (in other words, in the lower left direction) with an antenna spacing of

[0450] In FIG. 69, the second receiving antenna group is located to the right in the horizontal direction with respect to the first receiving antenna group. H , vertically downwards in 2D V In other words, the adjacent receiving antenna groups shown in FIG. H and 2D vertically V (In other words, D V The two are shifted by twice the interval.

[0451] Also, for example, as shown in Fig. 69, each of the transmitting antennas Tx#1 to Tx#4 is disposed at a different position in both the horizontal and vertical directions. Similarly, as shown in Fig. 69, each of the receiving antennas Rx#1 to Rx#4 is disposed at a different position in both the horizontal and vertical directions.

[0452] Furthermore, in the transmitting and receiving antenna arrangement shown in Figure 69, the respective positions of the transmitting antennas and the respective positions of the receiving antennas are in a line-symmetric relationship (in other words, in an inverted relationship) with respect to a line parallel to the horizontal or vertical direction.

[0453] For example, it is assumed that the horizontal direction (horizontal direction) shown in FIG. 69 corresponds to the X-axis, and the vertical direction (lengthwise direction) shown in FIG. 69 corresponds to the Y-axis direction.

[0454] In the case of the antenna arrangement shown in FIG. 69, the position coordinates of the transmitting antennas 106 constituting the transmitting array antenna are the position coordinates of the transmitting antenna Tx#1 (X T_#1 ,Y T_#1 ) as the reference, the position coordinates of the transmitting antenna Tx#2 (X T_#2 ,Y T_#2 )=(XT_#1 +D H ,Y T_#1 +2D V ), the position coordinates of the transmitting antenna Tx#3 (X T_#3 ,Y T_#3 )=(X T_#1 +2D H ,Y T_#1 -D V ), and the position coordinates of the transmitting antenna Tx#4 (X T_#4 ,Y T_#4 )=(X T_#1 +3D H ,Y T_#1 +D V )

[0455] Similarly, the position coordinates of the receiving antenna 202 constituting the receiving array antenna are expressed as the position coordinates of the receiving antenna Rx#1 (X R_#1 ,Y R_#1 ) as the reference, the position coordinates of the receiving antenna Rx#2 (X R_#2 ,Y R_#2 )=(X R_#1 -D H ,Y R_#1 +2D V ), the position coordinates of the receiving antenna Rx#3 (X R_#3 ,Y R_#3 )=(X R_#1 +2D H ,Y R_#1 +D V ), and the position coordinates of the receiving antenna Rx#4 (X R_#4 ,Y R_#4 )=(X R_#1 +D H ,Y R_#1 +3D V )

[0456] (2) Virtual receiving array layout The arrangement of the virtual receiving array (virtual antennas VA#1 to VA#16) configured by the transmitting and receiving antenna arrangement shown in FIG. 69 described above has the following features.

[0457] For example, in the arrangement of the transmitting array antenna and the receiving array antenna shown in FIG. 69, the position coordinates (X V_#1,Y V_#1 )~(X V_#16 ,Y V_#16 ) are as follows: Note that here, VA#1 is expressed as the position reference (0,0) of the virtual receiving array. (0,0), (D H , 2D V ), (2D H , -D V ), (3D H , D V ), (-D H , 2D V ), (0, 4D V ), (D H , D V ), (2D H , 3D V ), (2D H , D V ), (3D H , 3D V ), (4D H , 0), (5D H , 2D V ), (D H , 3D V ), (2D H , 5D V ), (3D H , 2D V ), (4D H , 4D V )

[0458] In this way, in the arrangement of the virtual receiving array shown in Figure 69, each virtual receiving array element is arranged at a different position without overlapping. Therefore, the aperture length of the virtual receiving array can be expanded, the main lobe is narrowed, and the angular resolution can be improved.

[0459] In addition, the virtual array elements VA#2, VA#7, VA#9, VA#4, VA#15, VA#10, VA#8, and VA#13 located near the center of the virtual receiving array shown in FIG. H Spacing, vertically D V As an example, in FIG. 69, the interval D H and interval D VWhen the distance between the virtual array elements VA#2, VA#7, VA#9, VA#4, VA#15, VA#10, VA#8, and VA#13 is about 0.5λ, the distance between the virtual array elements VA#2, VA#7, VA#9, VA#4, VA#15, VA#10, VA#8, and VA#13 is about 0.5λ. H = 0.5λ interval, D in the vertical direction V = 0.5λ apart. This makes it possible to reduce grating lobes in the same way as in basic arrangement 1 (see, for example, Figure 8).

[0460] In addition, in the vicinity of the center of the virtual receiving array shown in FIG. 69, the distance D H and interval D V However, the radar device 10 is missing an element at a position corresponding to the coordinates surrounded by closely arranged virtual array elements (e.g., VA#2, VA#7, VA#9, VA#4, VA#15, VA#10, VA#8, and VA#13) at an interval D surrounding the missing portion. H and interval D V By performing an interpolation process using the received signals of the densely arranged virtual array elements, it is possible to approximately receive the received signals of the elements in the missing locations.

[0461] For example, in the MIMO array arrangement of basic arrangement 4, the spacing D H and interval D V is set to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0462] As a result, for example, an antenna using four planar patch antennas arranged in two elements vertically and horizontally as a sub-array (where the antenna width W ANT < 2D H , Antenna height H ANT <2D V ) can be applied to at least one antenna element of the transmitting array antenna and the receiving array antenna shown in Fig. 69. For example, Fig. 70A shows an example in which a sub-array in which the planar patch antenna shown in Fig. 9A is arranged in two elements vertically and two elements horizontally is applied to the transmitting antenna arrangement shown in Fig. 69.

[0463] In addition, in the transmission antenna 106 and the reception antenna 202, ANT The element size of D H As long as the antenna size is smaller than , an antenna of any size can be used in the vertical direction. For example, Fig. 70B shows an example in which a sub-array in which the planar patch antenna shown in Fig. 25A is arranged in eight elements vertically and one element horizontally is applied to the antenna arrangement shown in Fig. 69. In addition to the transmitting array antenna shown in Fig. 70B, a parasitic element (dummy element) may be arranged (not shown).

[0464] In this way, by using antennas in a subarray configuration in the antenna arrangement according to the basic arrangement 4, the directional gain of the antennas can be improved, and the detection performance (for example, detection distance) of the radar device 10 can be improved.

[0465] The direction estimation unit 214 performs direction estimation processing in the horizontal and vertical directions using the received signals of the virtual receiving array obtained from the above-mentioned transmitting and receiving antenna arrangements. Note that the processing by the direction estimation unit 214 for the virtual receiving array of basic arrangement 4 is the same as that of basic arrangement 1, so a description thereof will be omitted here.

[0466] FIG. 71 shows a MIMO array arrangement (D H =0.5λ, D V 71 shows an example of a direction estimation result when a beamformer method is used as the direction of arrival estimation algorithm of the direction estimation unit 214 when a beamwidth of 1.0 GHz (λ = 0.5 λ) is used. That is, in Fig. 71, the antenna spacing in the horizontal and vertical directions of the transmitting antenna 106 is 1 λ or more, and the antenna spacing in the horizontal and vertical directions of the receiving antenna 202 is also 1 λ or more. Note that the directivity of each antenna is calculated as omnidirectional.

[0467] FIG. 71 plots the output of the direction-of-arrival estimation evaluation function value in a range of ±90 degrees in the horizontal direction and a range of ±90 degrees in the vertical direction when the target true value is 0 degrees horizontally and 0 degrees vertically.

[0468] In Fig. 71, it can be seen that the grating lobes are reduced in directions other than the horizontal 0 degree and vertical 0 degree of the target true value, as compared to Fig. 1A, for example. For example, in Fig. 71, the ratio (PSLR) of the peak power value of the highest side lobe excluding the main lobe in directions other than the horizontal 0 degree and vertical 0 degree to the peak power value of the main lobe in the horizontal 0 degree and vertical 0 degree directions is about 0.35.

[0469] As described above, by using the MIMO array arrangement according to basic arrangement 4, even if the vertical or horizontal element size of the antennas used for the transmitting array antenna and the receiving array antenna is about 1λ, the horizontal and vertical antenna spacing in the virtual receiving array can be arranged to include element spacing of about 0.5λ, thereby reducing grating lobes. Also, for example, since the virtual array elements of the virtual receiving array shown in Fig. 69 are arranged without overlapping, the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0470] <Variation 1 of Basic Layout 4> In the basic arrangement 4 (for example, FIG. 69), the number of transmitting antennas 106 is four (Nt=4), and the number of receiving antennas 202 is four (Na=4). However, the number of transmitting antennas Nt and the number of receiving antennas Na are not limited to these numbers.

[0471] In the first modification of the basic arrangement 4, for example, an arrangement will be described in which the number of transmitting antennas Nt and the number of receiving antennas Na are increased using the antenna arrangement shown in FIG. 69 as the basic configuration.

[0472] Hereinafter, antenna arrangement methods 4-1A, 4-1B, 4-1C, and 4-1D in the first modification of the basic arrangement 4 will be described.

[0473] (Placement method 4-1A) For example, the transmitting array antenna is composed of a first transmitting antenna group and a second transmitting antenna group. Each transmitting antenna group is arranged in a 2D array in the horizontal direction. H , vertically D VThe antenna includes a plurality of transmitting antenna elements arranged in a straight line in a diagonally downward direction to the right with an antenna spacing of .

[0474] In addition, the second transmitting antenna group is arranged to the left of the first transmitting antenna group. H , 2D downwards V are staggered and positioned.

[0475] Here, the number of transmitting antennas included in the first transmitting antenna group is "N TxLowerRightGr1_ANT For example, N TxLowerRightGr1_ANT ≧2. In addition, the number of transmitting antennas included in the second transmitting antenna group is set to “N TxLowerRightGr2_ANT For example, N TxLowerRightGr2_ANT ≧2.

[0476] The receiving array antenna is composed of a first receiving antenna group and a second receiving antenna group. Each receiving antenna group is arranged in a 2D array in the horizontal direction. H , vertically D V The antenna includes a plurality of receiving antenna elements arranged in a straight line obliquely upward to the right at intervals of .

[0477] In addition, the second receiving antenna group is aligned to the right of the first receiving antenna group. H , 2D downwards V are staggered and positioned.

[0478] Here, the number of receiving antennas included in the first receiving antenna group is defined as "N RxUpperRightGr1_ANT For example, N RxUpperRightGr1_ANT ≧2. In addition, the number of receiving antennas included in the second receiving antenna group is set to “N RxUpperRightGr2_ANT For example, N RxUpperRightGr2_ANT ≧2.

[0479] Figure 72 shows N TxLowerRightGr1_ANT =4(Tx#2,Tx#4,Tx#6,Tx#8), N TxLowerRightGr2_ANT = 4 (Tx#1, Tx#3, Tx#5, Tx#7), N RxUpperRightGr1_ANT =2(Rx#2,Rx#4),N RxUpperRightGr2_ANT4 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#3 are used.

[0480] Also, Figure 73 shows N TxLowerRightGr1_ANT = 2 (Tx#2, Tx#4), N TxLowerRightGr2_ANT = 2 (Tx#1, Tx#3), N RxUpperRightGr1_ANT =3(Rx#2,Rx#4,Rx#6),N RxUpperRightGr2_ANT 4 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#3, Rx#5 are used.

[0481] Also, Figure 74 shows N TxLowerRightGr1_ANT =4(Tx#2,Tx#4,Tx#6,Tx#8), N TxLowerRightGr2_ANT = 4 (Tx#1, Tx#3, Tx#5, Tx#7), N RxUpperRightGr1_ANT =3(Rx#2,Rx#4,Rx#6),N RxUpperRightGr2_ANT 4 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#3, Rx#5 are used.

[0482] In each of the MIMO array arrangements shown in Figs. 72, 73, and 74, for example, D H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0483] Also, for example, in each of the virtual receiving arrays shown in Figures 72, 73, and 74, some of the virtual array elements are arranged at overlapping positions, but the aperture length of the virtual receiving array can be expanded, improving the angular resolution. Note that in Figures 72 and 73, there is no overlap of the virtual array elements, but in Figure 74, the virtual array elements overlap in two places.

[0484] The virtual array elements located near the center of each virtual receiving array shown in Figs. 72, 73, and 74 are designated as D H , D VAs shown in Figs. 72, 73, and 74, near the center of each virtual receiving array, elements corresponding to some coordinates are missing. However, the radar device 10 can detect the missing elements by using the D H , D V By performing an interpolation process using the received signals of closely spaced virtual array elements, the received signals of the missing elements can be approximately received.

[0485] The number of virtual array elements densely arranged near the center of each virtual receiving array shown in Figs. 72, 73, and 74 is N TxLowerRightGr1_ANT , N TxLowerRightGr2_ANT N RxUpperRightGr1_ANT , N RxUpperRightGr2_ANT increases depending on

[0486] For example, in the virtual receiving array, the horizontal direction is (N TxLowerRightGr1_ANT +N TxLowerRightGr2_ANT +N RxUpperRightGr1_ANT +N RxUpperRightGr2_ANT )-5 virtual array elements are D H The vertical direction is 0.5×(N TxLowerRightGr1_ANT +N TxLowerRightGr2_ANT +N RxUpperRightGr1_ANT +N RxUpperRightGr2_ANT )-1 is the virtual array element D V In the virtual receiving array, H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes are reduced.

[0487] Also, N TxLowerRightGr1_ANT , N TxLowerRightGr2_ANT N RxUpperRightGr1_ANT , N RxUpperRightGr2_ANT As θ is larger, the number of virtual array elements arranged in the horizontal and vertical directions increases, so that the aperture length of the virtual receiving array in the horizontal and vertical directions can be expanded, and the angular resolution in the horizontal and vertical directions can be improved.

[0488] FIG. 75 shows a MIMO array arrangement (NTxLowerRightGr1_ANT =N TxLowerRightGr2_ANT =4, N RxUpperRightGr1_ANT =N RxUpperRightGr2_ANT =3, D H =0.5λ, D V 13 shows an example of a direction estimation result when a beamformer method is used as the arrival direction estimation algorithm of the direction estimator 214 when a λ=0.5λ is used. Note that the directivity of each antenna is calculated as omnidirectional.

[0489] FIG. 75 plots the output of the arrival direction estimation evaluation function value in a range of ±90 degrees in the horizontal direction and a range of ±90 degrees in the vertical direction when the target true value is 0 degrees horizontally and 0 degrees vertically.

[0490] In FIG. 75, it can be seen that the grating lobes are reduced in directions other than the horizontal 0 degrees and vertical 0 degrees of the target true value, as compared to, for example, FIG. 1A. For example, in FIG. 75, the ratio (PSLR) of the peak power value of the highest side lobe excluding the main lobe to the peak power value of the main lobe in the horizontal 0 degrees and vertical 0 degrees directions is about 0.28. For example, in the configuration of basic layout 4 shown in FIG. 69 (N TxLowerRightGr1_ANT =N TxLowerRightGr2_ANT =N RxUpperRightGr1_ANT =N RxUpperRightGr2_ANT = 2) (see, for example, Figure 71) TxLowerRightGr1_ANT , N TxLowerRightGr2_ANT , N RxUpperRightGr1_ANT , N RxUpperRightGr2_ANT By increasing N, it can be confirmed that the side lobe reduction effect is improved. In addition, in Figure 75, the peak of the main lobe is sharper than in Figure 71, and N TxLowerRightGr1_ANT , N TxLowerRightGr2_ANT , N RxUpperRightGr1_ANT , N RxUpperRightGr2_ANT The increase in the angular resolution can be seen.

[0491] In addition, N TxLowerRightGr1_ANT , N TxLowerRightGr2_ANT , N RxUpperRightGr1_ANT , N RxUpperRightGr2_ANTAs the value of θ increases, the aperture length of the virtual array in the horizontal direction can be expanded more than that in the vertical direction, resulting in a MIMO array configuration in which the horizontal angular resolution can be more easily improved compared to the vertical angular resolution.

[0492] (Placement method 4-1B) In the arrangement method 4-1B, the aperture length of the virtual receiving array is expanded in the vertical direction more than in the horizontal direction, resulting in a MIMO array configuration that can improve the angular resolution in the vertical direction more than the angular resolution in the horizontal direction.

[0493] For example, the transmitting array antenna is composed of a first transmitting antenna group and a second transmitting antenna group. Each transmitting antenna group has a width of D H , vertically 2D V The antenna includes a plurality of transmitting antenna elements arranged in a straight line obliquely upward to the right with an antenna spacing of .

[0494] In addition, the second transmitting antenna group is 2D aligned to the right of the first transmitting antenna group. H , Downward D V are staggered and positioned.

[0495] Here, the number of transmitting antennas included in the first transmitting antenna group is "N TxUpperRightGr1_ANT For example, N TxUpperRightGr1_ANT ≧2. In addition, the number of transmitting antennas included in the second transmitting antenna group is set to “N TxUpperRightGr2_ANT For example, N TxUpperRightGr2_ANT ≧2.

[0496] The receiving array antenna is composed of a first receiving antenna group and a second receiving antenna group. Each receiving antenna group is arranged in a horizontal direction. H , vertically 2D V The antenna includes a plurality of receiving antenna elements arranged in a straight line in a diagonally downward direction to the right with an antenna spacing of .

[0497] In addition, the second receiving antenna group is 2D to the left of the first receiving antenna group. H , Down DV are staggered and positioned.

[0498] Here, the number of receiving antennas included in the first receiving antenna group is defined as "N RxLowerRightGr1_ANT For example, N RxLowerRightGr1_ANT ≧2. In addition, the number of receiving antennas included in the second receiving antenna group is set to “N RxLowerRightGr1_ANT For example, N RxLowerRightGr2_ANT ≧2.

[0499] Figure 76 shows N TxUpperRightGr1_ANT =4(Tx#2,Tx#4,Tx#6,Tx#8), N TxUpperRightGr2_ANT = 4 (Tx#1, Tx#3, Tx#5, Tx#7), N RxLowerRightGr1_ANT =2(Rx#4,Rx#3),N RxLowerRightGr2_ANT 4 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1=2 (Rx#2, Rx#1).

[0500] Figure 77 shows N TxUpperRightGr1_ANT = 2 (Tx#2, Tx#4), N TxUpperRightGr2_ANT = 2 (Tx#1, Tx#3), N RxLowerRightGr1_ANT =3(Rx#2,Rx#4,Rx#6),N RxLowerRightGr2_ANT An example of a MIMO array arrangement and an example of a virtual receiving array arrangement when (Rx#1, Rx#3, Rx#5)=3 are shown.

[0501] Figure 78 shows N TxUpperRightGr1_ANT =4(Tx#2,Tx#4,Tx#6,Tx#8), N TxUpperRightGr2_ANT = 4 (Tx#1, Tx#3, Tx#5, Tx#7), N RxLowerRightGr1_ANT =3(Rx#2,Rx#4,Rx#6),N RxLowerRightGr2_ANT 4 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#3, Rx#5 are used.

[0502] In each of the MIMO array arrangements shown in Figs. 76, 77, and 78, for example, D H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0503] Also, for example, in each of the virtual receiving arrays shown in Figures 76, 77, and 78, some of the virtual array elements are arranged at overlapping positions, but the aperture length of the virtual receiving array can be expanded, improving the angular resolution. Note that in Figures 76 and 77, there is no overlap of the virtual array elements, but in Figure 78, the virtual array elements overlap in two places.

[0504] The virtual array elements located near the center of each virtual receiving array shown in Figs. 76, 77, and 78 are designated as D H , D V As shown in Figs. 76, 77, and 78, near the center of each virtual receiving array, elements corresponding to some coordinates are missing. However, the radar device 10 can use the D H , D V By performing an interpolation process using the received signals of closely spaced virtual array elements, the received signals of the missing elements can be approximately received.

[0505] The number of virtual array elements densely arranged near the center of each virtual receiving array shown in Figs. 76, 77, and 78 is N TxUpperRightGr1_ANT , N TxUpperRightGr2_ANT N RxLowerRightGr1_ANT , N RxLowerRightGr2_ANT increases depending on

[0506] For example, in the virtual receiving array, the horizontal direction is 0.5×(N TxUpperRightGr1_ANT +N TxUpperRightGr2_ANT +N RxLowerRightGr1_ANT +N RxLowerRightGr2_ANT )-1 is the virtual array element D H The vertical direction is spaced apart by (N TxUpperRightGr1_ANT +N TxUpperRightGr2_ANT +N RxLowerRightGr1_ANT +N RxLowerRightGr2_ANT )-5 virtual array elements are D V In the virtual receiving array, H , D VThe more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes are reduced.

[0507] Also, N TxUpperRightGr1_ANT , N TxUpperRightGr2_ANT N RxLowerRightGr1_ANT , N RxLowerRightGr2_ANT As θ is larger, the number of virtual array elements arranged in the horizontal and vertical directions increases, so that the aperture length of the virtual receiving array in the horizontal and vertical directions can be expanded, and the angular resolution in the horizontal and vertical directions can be improved.

[0508] FIG. 79 shows a MIMO array arrangement (N TxUpperRightGr1_ANT =N TxUpperRightGr2_ANT =4, N RxLowerRightGr1_ANT =N RxLowerRightGr2_ANT =3, D H =0.5λ, D V 13 shows an example of a direction estimation result when a beamformer method is used as the arrival direction estimation algorithm of the direction estimator 214 when a λ=0.5λ is used. Note that the directivity of each antenna is calculated as omnidirectional.

[0509] FIG. 79 plots the output of the direction-of-arrival estimation evaluation function value in a range of ±90 degrees in the horizontal direction and a range of ±90 degrees in the vertical direction when the target true value is 0 degrees horizontally and 0 degrees vertically.

[0510] In Fig. 79, it can be seen that the grating lobes are reduced in directions other than the horizontal 0 degrees and vertical 0 degrees of the target true value, as compared to, for example, Fig. 1A. For example, in Fig. 79, the ratio (PSLR) of the peak power value of the highest side lobe excluding the main lobe to the peak power value of the main lobe in the horizontal 0 degrees and vertical 0 degrees directions is about 0.28. TxUpperRightGr1_ANT =N TxUpperRightGr2_ANT =N RxLowerRightGr1_ANT =N RxLowerRightGr2_ANT =) (see, for example, Figure 71) compared to N TxUpperRightGr1_ANT , N TxUpperRightGr2_ANT , N RxLowerRightGr1_ANT, N RxLowerRightGr2_ANT By increasing N, it can be confirmed that the side lobe reduction effect is improved. In addition, in Figure 79, the peak of the main lobe is sharper than in Figure 71, and N TxUpperRightGr1_ANT , N TxUpperRightGr2_ANT , N RxLowerRightGr1_ANT , N RxLowerRightGr2_ANT The increase in the angular resolution can be seen.

[0511] In addition, N TxUpperRightGr1_ANT , N TxUpperRightGr2_ANT N RxLowerRightGr1_ANT , N RxLowerRightGr2_ANT As the value of θ is increased, the aperture length of the virtual array in the vertical direction can be expanded more than that in the horizontal direction, resulting in a MIMO array configuration in which the angular resolution in the vertical direction can be more easily improved compared to the angular resolution in the horizontal direction.

[0512] (Placement method 4-1C) Arrangement method 4-1C is a combination of arrangement methods 4-1A and 4-1B.

[0513] For example, the transmitting array antenna is composed of a first transmitting antenna group and a second transmitting antenna group. Each transmitting antenna group is arranged in a 2D array in the horizontal direction. H , vertically D V The antenna includes a plurality of transmitting antenna elements arranged in a straight line in a diagonally downward direction to the right with an antenna spacing of .

[0514] In addition, the second transmitting antenna group is arranged to the left of the first transmitting antenna group. H , 2D downwards V are staggered and positioned.

[0515] Here, the number of transmitting antennas included in the first transmitting antenna group is "N TxLowerRightGr1_ANT For example, N TxLowerRightGr1_ANT ≧2. In addition, the number of transmitting antennas included in the second transmitting antenna group is set to “N TxLowerRightGr2_ANT For example, N TxLowerRightGr2_ANT ≧2.

[0516] For example, the receiving array antenna is composed of a first receiving antenna group and a second receiving antenna group. Each receiving antenna group has a width of D H , vertically 2D V The antenna includes a plurality of receiving antenna elements arranged in a straight line in a diagonally downward direction to the right with an antenna spacing of .

[0517] In addition, the second receiving antenna group is 2D to the left of the first receiving antenna group. H , Down D V are staggered and positioned.

[0518] Here, the number of receiving antennas included in the first receiving antenna group is defined as "N RxLowerRightGr1_ANT For example, N RxLowerRightGr1_ANT ≧2. In addition, the number of receiving antennas included in the second receiving antenna group is set to “N RxLowerRightGr2_ANT For example, N RxLowerRightGr2_ANT ≧2.

[0519] Figure 80 shows N TxLowerRightGr1_ANT =4(Tx#2,Tx#4,Tx#6,Tx#8), N TxLowerRightGr2_ANT = 4 (Tx#1, Tx#3, Tx#5, Tx#7), N RxLowerRightGr1_ANT =4(Rx#2,Rx#4,Rx#6,Rx#8),N RxLowerRightGr2_ANT 4 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#3, Rx#5, Rx#7 are used.

[0520] In the MIMO array configuration shown in FIG. H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0521] In the virtual receiving array shown in Fig. 80, some of the virtual array elements are arranged at overlapping positions, but the aperture length of the virtual receiving array can be expanded, so that the angular resolution can be improved. Note that in Fig. 80, the virtual array elements overlap at one location.

[0522] The virtual array element located near the center of the virtual receiving array shown in Fig. 80 is defined as D H , D V As shown in FIG. 80, near the center of each virtual receiving array, elements corresponding to some coordinates are missing. However, the radar device 10 can use the D H , D V By performing an interpolation process using the received signals of closely spaced virtual array elements, the received signals of the missing elements can be approximately received.

[0523] The number of virtual array elements densely arranged near the center of each virtual receiving array shown in FIG. TxLowerRightGr1_ANT , N TxLowerRightGr2_ANT N RxLowerRightGr1_ANT , N RxLowerRightGr2_ANT increases depending on

[0524] For example, in the virtual receiving array, the horizontal direction is 0.5×(N TxLowerRightGr1_ANT +N TxLowerRightGr2_ANT +N RxLowerRightGr1_ANT +N RxLowerRightGr2_ANT ) + 1 virtual array element is D H The vertical direction is 0.5×(N TxLowerRightGr1_ANT +N TxLowerRightGr2_ANT +N RxLowerRightGr1_ANT +N RxLowerRightGr2_ANT ) + 1 virtual array element is D V In the virtual receiving array, H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes are reduced.

[0525] Also, N TxLowerRightGr1_ANT , N TxLowerRightGr2_ANT N RxLowerRightGr1_ANT , N RxLowerRightGr2_ANT As θ is larger, the number of virtual array elements arranged in the horizontal and vertical directions increases, so that the aperture length of the virtual receiving array in the horizontal and vertical directions can be expanded, and the angular resolution in the horizontal and vertical directions can be improved.

[0526] (Placement method 4-1D) Arrangement method 4-1D is a combination of arrangement methods 4-1A and 4-1B.

[0527] For example, the transmitting array antenna is composed of a first transmitting antenna group and a second transmitting antenna group. Each transmitting antenna group is arranged in a 2D array in the horizontal direction. H , vertically D V The antenna includes a plurality of transmitting antenna elements arranged in a straight line obliquely upward to the right with an antenna spacing of .

[0528] In addition, the second transmitting antenna group is 2D aligned to the right of the first transmitting antenna group. H , Down D V are staggered and positioned.

[0529] Here, the number of transmitting antennas included in the first transmitting antenna group is "N TxUpperRightGr1_ANT For example, N TxUpperRightGr1_ANT ≧2. In addition, the number of transmitting antennas included in the second transmitting antenna group is set to “N TxUpperRightGr2_ANT For example, N TxUpperRightGr2_ANT ≧2.

[0530] For example, the receiving array antenna is composed of a first receiving antenna group and a second receiving antenna group. Each receiving antenna group is arranged in a 2D array in the horizontal direction. H , vertically D V It includes a plurality of receiving antenna elements arranged in a straight line obliquely upward to the right with an antenna spacing of

[0531] In addition, the second receiving antenna group is aligned to the right of the first receiving antenna group. H , 2D downwards V are staggered and positioned.

[0532] Here, the number of receiving antennas included in the first receiving antenna group is defined as "N RxUpperRightGr1_ANT For example, N RxUpperRightGr1_ANT ≧2. In addition, the number of receiving antennas included in the second receiving antenna group is set to “N RxUpperRightGr2_ANT For example, NRxUpperRightGr2_ANT ≧2.

[0533] Figure 81 shows N TxUpperRightGr1_ANT =4(Tx#2,Tx#4,Tx#6,Tx#8), N TxUpperRightGr2_ANT = 4 (Tx#1, Tx#3, Tx#5, Tx#7), N RxUpperRightGr1_ANT =4(Rx#2,Rx#4,Rx#6,Rx#8),N RxLUpperRightGr2_ANT 4 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#3, Rx#5, Rx#7 are used.

[0534] In the MIMO array configuration shown in FIG. H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0535] In the virtual receiving array shown in Fig. 81, some of the virtual array elements are arranged at overlapping positions, but the aperture length of the virtual receiving array can be expanded, so that the angular resolution can be improved. Note that in Fig. 81, the virtual array elements overlap at one location.

[0536] The virtual array element located near the center of the virtual receiving array shown in Fig. 81 is defined as D H , D V As shown in FIG. 81, near the center of each virtual receiving array, elements corresponding to some coordinates are missing. However, the radar device 10 can use the D H , D V By performing an interpolation process using the received signals of closely spaced virtual array elements, the received signals of the missing elements can be approximately received.

[0537] The number of virtual array elements densely arranged near the center of each virtual receiving array shown in Fig. 81 is N TxUpperRightGr1_ANT , N TxLUpperRightGr2_ANT N RxUpperRightGr1_ANT , N RxUpperRightGr2_ANT increases depending on

[0538] For example, in the virtual receiving array, the horizontal direction is 0.5×(N TxUpperRightGr1_ANT +N TxUpperRightGr2_ANT +N RxUpperRightGr1_ANT +N RxUpperRightGr2_ANT ) + 1 virtual array element is D H The vertical direction is 0.5×(N TxUpperRightGr1_ANT +N TxUpperRightGr2_ANT +N RxUpperRightGr1_ANT +N RxUpperRightGr2_ANT ) virtual array element is D V In the virtual receiving array, H , D V The more densely spaced the virtual array elements are, the more effectively the grating lobes and side lobes are reduced.

[0539] Also, N TxUpperRightGr1_ANT , N TxUpperRightGr2_ANT N RxUpperRightGr1_ANT , N RxUpperRightGr2_ANT As θ is larger, the number of virtual array elements arranged in the horizontal and vertical directions increases, so that the aperture length of the virtual receiving array in the horizontal and vertical directions can be expanded, and the angular resolution in the horizontal and vertical directions can be improved.

[0540] The antenna arrangement methods 4-1A, 4-1B, 4-1C and 4-1D in the first modification of the basic arrangement 4 have been described above.

[0541] In the arrangement methods 4-1A, 4-1B, 4-1C, and 4-1D, the transmitting array antenna is configured with the first transmitting antenna group and the second transmitting antenna group. However, when the number N of transmitting antenna groups included in the transmitting array antenna is TxGroup In this case, the ntx-th transmitting antenna group is arranged with respect to the (ntx-1)-th transmitting antenna group according to any one of the arrangement methods 4-1A, 4-1B, 4-1C, and 4-1D. Here, ntx=1, ..., N TxGroup It is.

[0542] Similarly, in the arrangement methods 4-1A, 4-1B, 4-1C and 4-1D, the receiving array antenna is configured with a first receiving antenna group and a second receiving antenna group. However, when the number of receiving antenna groups N RxGroup In this case, the nrx-th receiving antenna group is arranged with respect to the (nrx-1)-th receiving antenna group according to any one of the arrangement methods 4-1A, 4-1B, 4-1C, and 4-1D. Here, nrx=1, ..., N RxGroup It is.

[0543] FIG. 82 shows an example of the arrangement method 4-1B in which the number of transmitting antenna groups N TxGroup = 3, the number of receiving antenna groups N RxGroup = 3, and N TxUpperRightGr1_ANT =3(Tx#3,Tx#6,Tx#9), N TxUpperRightGr2_ANT =3(Tx#2,Tx#5,Tx#8), N TxUpperRightGr3_ANT = 3 (Tx#1, Tx#4, Tx#7), N RxLowerRightGr1_ANT =3(Rx#7,Rx#8,Rx#9),N RxLowerRightGr2_ANT =3(Rx#4,Rx#5,Rx#6),N RxLowerRightGr3_ANT 4 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#2, Rx#3.

[0544] For example, in the MIMO array configuration shown in FIG. H and D. V By setting the width of the antenna 106 and the width of the antenna 202 to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0545] In the virtual receiving array shown in Fig. 82, some of the virtual array elements are arranged at overlapping positions, but the aperture length of the virtual receiving array can be expanded, improving the angular resolution. Note that in Fig. 82, the virtual array elements overlap at eight locations.

[0546] The virtual array element located near the center of the virtual receiving array shown in Fig. 82 is defined as D H , D VAs shown in FIG. 82, near the center of the virtual receiving array, elements corresponding to some coordinates are missing. However, the radar device 10 can use the D H , D V By performing an interpolation process using the received signals of closely spaced virtual array elements, the received signals of the missing elements can be approximately received.

[0547] The number of virtual array elements densely arranged near the center of each virtual receiving array shown in Fig. 82 is N TxGroup , N RxGroup increases depending on

[0548] <Modification 2 of Basic Layout 4> In the second variation of basic arrangement 4, the arrangement of the four-element transmitting array antenna and the arrangement of the four-element receiving array antenna shown in basic arrangement 4 are each defined as a "basic set," and a MIMO array arrangement in which the arrangement positions of multiple basic sets are offset will be described.

[0549] In the arrangement shown below, the offset of the basic set of transmitting array antennas in the horizontal and vertical directions, or the offset of the basic set of receiving array antennas in the horizontal and vertical directions, is determined so that there are no overlapping elements in the virtual receiving array arrangement and more virtual array elements are arranged near the center of the virtual receiving array. V Or D H However, the present invention is not limited to this, and for example, it is also possible to increase the number of arrangements with unequal intervals in the virtual receiving array arrangement, or to increase the number of arrangements in which virtual array elements overlap in the virtual receiving array arrangement, by adjusting the offset of the arrangement positions.

[0550] Figure 83 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet83, the horizontal offset of the arrangement position of the second basic set (for example, Tx#5, Tx#6, Tx#7, and Tx#8) relative to the first basic set (for example, Tx#1, Tx#2, Tx#3, and Tx#4) is set as D Hoffset_TxBaseSet2 =5D H and the vertical offset of the placement position is D Voffset_TxBaseSet2 As shown in Figure 83, the two basic sets of transmitting array antennas are offset horizontally, resulting in a horizontal D H The number of closely spaced virtual array elements can be increased, improving the horizontal angular resolution.

[0551] Figure 84 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet 84, the horizontal offset of the arrangement position of the second basic set (Tx#5, Tx#6, Tx#7, Tx#8) relative to the first basic set (for example, Tx#1, Tx#2, Tx#3, and Tx#4) is set as D Hoffset_TxBaseSet2 = 0, and the vertical offset of the placement position D Voffset_TxBaseSet2 =5D V As shown in Figure 84, the two basic sets of transmitting array antennas are arranged with an offset in the vertical direction, so that the vertical V The number of closely spaced virtual array elements can be increased, improving the horizontal angular resolution.

[0552] Figure 85 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 1, and the number of basic sets of receiving array antennas is N RxBaseSet85 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#2, Rx#3, and Rx#4 are set as D Hoffset_RxBaseSet2 =5D H and the vertical offset of the placement position is D Voffset_RxBaseSet2 As shown in Figure 85, the two basic sets of receiving array antennas are offset horizontally, resulting in a horizontal D H The number of closely spaced virtual array elements can be increased, improving the horizontal angular resolution.

[0553] Figure 86 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 1, and the number of basic sets of receiving array antennas is N RxBaseSet 86 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#2, Rx#3, and Rx#4 are set as D Hoffset_RxBaseSet2 = 0, and the vertical offset of the placement position D Voffset_RxBaseSet2 =5D V As shown in Figure 86, the two basic sets of receiving array antennas are arranged with an offset in the vertical direction, so that the vertical V The number of closely spaced virtual array elements can be increased, improving the angular resolution in the vertical direction.

[0554] Figure 87 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet87 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when D = 2. In FIG. 87, the offset of the horizontal arrangement position of the second basic set (Tx#5, Tx#6, Tx#7, Tx#8) of the transmitting array antenna relative to the first basic set (for example, Tx#1, Tx#2, Tx#3, and Tx#4) is D Hoffset_TxBaseSet2 =8D H and the vertical offset of the placement position is D Voffset_TxBaseSet2 In FIG. 87, the offset of the horizontal arrangement position of the second basic set (Rx#5, Rx#6, Rx#7, Rx#8) relative to the first basic set (for example, Rx#1, Rx#2, Rx#3, and Rx#4) of the receiving array antenna is D Hoffset_RxBaseSet2 =5D H and the vertical offset of the placement position is D Voffset_RxBaseSet2 As shown in Figure 87, the two basic sets of transmitting array antennas are offset in the horizontal direction, and the two basic sets of receiving array antennas are offset in the horizontal direction, resulting in a horizontal D H The number of closely spaced virtual array elements can be further increased as compared with, for example, FIG. 83 or FIG. 85, and the horizontal angular resolution can be further improved.

[0555] FIG. 88A shows the number of basic sets of transmitting array antennas, N TxBaseSet = 4, and the number of basic sets of receiving array antennas is N RxBaseSet FIG. 88B shows an example of a virtual receiving array arrangement when R is 1 / 4.

[0556] In FIG. 88A, the horizontal offset of the arrangement position of the second basic set (Tx#5, Tx#6, Tx#7, Tx#8) of the transmitting array antenna relative to the first basic set (for example, Tx#1, Tx#2, Tx#3, and Tx#4) is denoted by D Hoffset_TxBaseSet2 =8D H and the vertical offset of the placement position is D Voffset_TxBaseSet2 = 0, and the offset of the horizontal placement position of the third basic set (Tx#9, Tx#10, Tx#11, Tx#12) is DHoffset_TxBaseSet3 = 0, and the vertical offset of the placement position D Voffset_TxBaseSet3 =5D V The horizontal offset of the placement position of the fourth basic set (Tx#13, Tx#14, Tx#15, Tx#16) is D Hoffset_TxBaseSet4 =8D H and the vertical offset of the placement position is D Voffset_TxBaseSet4 =5D V Let us assume that.

[0557] In FIG. 88A, the offset of the horizontal arrangement position of the second basic set (Rx#5, Rx#6, Rx#7, and Rx#8) of the receiving array antenna relative to the first basic set (for example, Rx#1, Rx#2, Rx#3, and Rx#4) is denoted by D Hoffset_RxBaseSet2 =5D H and the vertical offset of the placement position is D Voffset_RxBaseSet2 = 0, and the horizontal offset of the placement position of the third basic set (Rx#9, Rx#10, Rx#11, Rx#12) is D Hoffset_RxBaseSet3 = 0, and the vertical offset of the placement position D Voffset_RxBaseSet3 =8D V The horizontal offset of the placement position of the fourth basic set (Rx#13, Rx#14, Rx#15, Rx#16) is D Hoffset_RxBaseSet4 =5D H and the vertical offset of the placement position is D Voffset_RxBaseSet4 =8D V Let us assume that.

[0558] As shown in Fig. 88A and Fig. 88B, the basic set of transmitting array antennas is offset in the horizontal direction, and the basic set of receiving array antennas is offset in the horizontal direction. H The number of closely spaced virtual array elements can be further increased compared to, for example, FIG. 83 or FIG. 85, and the horizontal angular resolution can be further improved. (Note that in the case of FIG. 88, virtual array elements overlap at eight locations.)

[0559] Similarly, as shown in Figs. 88A and 88B, by offsetting the basic set of transmitting array antennas in the vertical direction and by offsetting the basic set of receiving array antennas in the vertical direction, V The number of closely spaced virtual array elements can be further increased as compared to, for example, FIG. 84 or FIG. 86, and the angular resolution in the vertical direction can be further improved.

[0560] In addition, in the second modification, the case where the antenna arrangement of the basic arrangement 4 is used as the basic set has been described. However, the basic set is not limited to the antenna arrangement of the basic arrangement 4, and may be, for example, the antenna arrangement of the first modification of the basic arrangement 4.

[0561] In addition, the number of basic sets included in the transmitting array antenna and the receiving array antenna (N TxBaseSet , N RxBaseSet ) is not limited to the above example and may be other values.

[0562] <Basic layout 5> FIG. 89 shows an example of the arrangement of the transmitting antennas 106 and the receiving antennas 202 according to basic arrangement 5, and an example of the arrangement of a virtual receiving array.

[0563] (1) Arrangement of transmitting and receiving antennas In FIG. 89, the number of transmitting antennas 106 in the transmitting array antenna is Nt=4 (Tx#1, Tx#2, Tx#3, and Tx#4), and the number of receiving antennas 202 in the receiving array antenna is Na=4 (Rx#1, Rx#2, Rx#3, and Rx#4).

[0564] The transmitting array antenna shown in FIG. 89 is composed of, for example, a "first transmitting antenna group" (Tx#2, Tx#4 in FIG. 89) and a "second transmitting antenna group" (Tx#1, Tx#3 in FIG. 89). Each transmitting antenna group has an antenna spacing of D in the horizontal direction. H and the antenna spacing in the vertical direction is D V In each of the transmitting antenna groups shown in FIG. 89, adjacent transmitting antennas are spaced apart from each other by DH are spaced apart by a distance of D V In other words, in FIG. 89, the transmitting antennas included in each transmitting antenna group are arranged at intervals of D H , vertically D V The antennas are arranged in a straight line in a diagonally downward to the right (in other words, in a diagonally upward to the left) with an antenna spacing of

[0565] In FIG. 89, the second transmitting antenna group is 2D to the left in the horizontal direction with respect to the first transmitting antenna group. H , vertically downwards D V In other words, the adjacent transmit antenna groups shown in FIG. H Interval (in other words, D H 2 times the spacing) and vertically D V It's a shifted relationship.

[0566] In FIG. 89, the second transmitting antenna group is shifted to the left in the horizontal direction with respect to the first transmitting antenna group. H , vertically downwards in 2D V are staggered and positioned.

[0567] The receiving array antenna shown in FIG. 89 is composed of, for example, a "first receiving antenna group" (Rx#2, Rx#4 in FIG. 89) and a "second receiving antenna group" (Rx#1, Rx#3 in FIG. 89). Each receiving antenna group has an antenna spacing of D in the horizontal direction. H and the antenna spacing in the vertical direction is D V In each of the receiving antenna groups shown in FIG. 89, adjacent receiving antennas are spaced apart from each other by D H are spaced apart by a distance of D V In other words, in FIG. 89, the transmitting antennas included in each receiving antenna group are arranged at intervals of D H , vertically D V The antennas are arranged in a straight line in the upper right direction (in other words, in the lower left direction) with an antenna spacing of

[0568] In FIG. 89, the second receiving antenna group is 2D to the right in the horizontal direction with respect to the first receiving antenna group. H , vertically downwards D V In other words, the adjacent receiving antenna groups shown in FIG. H Interval (in other words, D H 2 times the spacing) and vertically D V It's a shifted relationship.

[0569] Also, for example, as shown in Fig. 89, each of the transmitting antennas Tx#1 to Tx#4 is disposed at a different position in the horizontal direction. Similarly, as shown in Fig. 89, each of the receiving antennas Rx#1 to Rx#4 is disposed at a different position in the horizontal direction.

[0570] Furthermore, in the transmitting and receiving antenna arrangement shown in FIG. 89, the respective positions of the transmitting antennas and the respective positions of the receiving antennas are in a line-symmetric relationship (in other words, in an inverted relationship) with respect to a line parallel to the horizontal or vertical direction.

[0571] For example, it is assumed that the horizontal direction (horizontal direction) shown in FIG. 89 corresponds to the X-axis, and the vertical direction (vertical direction) shown in FIG. 89 corresponds to the Y-axis direction.

[0572] For example, in the case of the antenna arrangement shown in FIG. 89, the position coordinates of the transmitting antenna 106 constituting the transmitting array antenna are the position coordinates (X T_#1 ,Y T_#1 ) as the reference, the position coordinates of the transmitting antenna Tx#2 (X T_#2 ,Y T_#2 )=(X T_#1 +2D H ,Y T_#1 +D V ), the position coordinates of the transmitting antenna Tx#3 (X T_#3 ,Y T_#3 )=(X T_#1 +D H ,Y T_#1 -D V), and the position coordinates of the transmitting antenna Tx#4 (X T_#4 ,Y T_#4 )=(X T_#1 +3D H ,Y T_#1 )

[0573] Similarly, the position coordinates of the receiving antenna 202 constituting the receiving array antenna are expressed as the position coordinates of the receiving antenna Rx#1 (X R_#1 ,Y R_#1 ) as the reference, the position coordinates of the receiving antenna Rx#2 (X R_#2 ,Y R_#2 )=(X R_#1 -2D H ,Y R_#1 +D V ), the position coordinates of the receiving antenna Rx#3 (X R_#3 ,Y R_#3 )=(X R_#1 +D H ,Y R_#1 +D V ), and the position coordinates of the receiving antenna Rx#4 (X R_#4 ,Y R_#4 )=(X R_#1 -D H ,Y R_#1 +2D V )

[0574] (2) Virtual receiving array layout The arrangement of the virtual receiving array (virtual antennas VA#1 to VA#16) configured by the transmitting and receiving antenna arrangement shown in FIG. 89 described above has the following features.

[0575] For example, in the arrangement of the transmitting array antenna and the receiving array antenna shown in FIG. 89, the position coordinates (X V_#1 ,Y V_#1 )~(X V_#16 ,Y V_#16 ) are as follows: Note that here, VA#1 is expressed as the position reference (0,0) of the virtual receiving array. (0,0), (2D H , D V ), (D H , -DV ), (3D H , 0), (-2D H , D V ), (0, 2D V ), (-D H , 0), (D H , D V ), (D H , D V ), (3D H , 2D V ), (2D H , 0), (4D H , D V ), (-D H , 2D V ), (D H , 3D V ), (0, D V ), (2D H , 2D V ),

[0576] 89, each virtual receiving array element is arranged at a different position without overlapping, except for some virtual array elements (e.g., VA#8, #9). Therefore, the aperture length of the virtual receiving array can be expanded, the main lobe is narrowed, and the angular resolution can be improved.

[0577] In addition, the virtual array elements VA#4, #11, #2, #16, #10, #7, #1, #15, #6, #13, VA#8, and #9 located near the center of the virtual receiving array shown in FIG. H Spacing, vertically D V As an example, in FIG. 89, the interval D H and interval D V When the distance is about 0.5λ, the virtual array elements VA#4, #11, #2, #16, #10, #7, #1, #15, #6, #13, VA#8, and #9 have a horizontal distance of D H = 0.5λ interval, D in the vertical direction V = 0.5λ apart. This makes it possible to reduce grating lobes in the same way as in basic arrangement 1 (see, for example, Figure 8).

[0578] In addition, in the vicinity of the center of the virtual receiving array shown in FIG. H and interval D V However, the radar device 10 can detect the missing element by, for example, detecting the missing element at a coordinate that is surrounded by the virtual array elements densely arranged at a distance D H and interval D V By performing an interpolation process using the received signals of the densely arranged virtual array elements, it is possible to approximately receive the received signals of the elements in the missing locations.

[0579] For example, in the MIMO array arrangement shown in FIG. H and interval D V is set to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be 1λ or more.

[0580] As a result, the width W of the transmitting antenna 106 and the receiving antenna 202 ANT The element size of D H Any size of antenna can be used in the vertical direction as long as it is smaller than 1. For example, an antenna using eight planar patch antennas arranged vertically and horizontally as a sub-array as shown in Fig. 25A can be applied to at least one of the transmitting array antenna and the receiving array antenna shown in Fig. 89.

[0581] The number of transmitting antennas included in the first transmitting antenna group (hereinafter, “N TxGroup1_ANT ") and the number of transmitting antennas included in the second transmitting direction antenna group (hereinafter, "N TxGroup2_ANT ") may be the same number or may have a difference of one antenna. For example, |N TxGroup1_ANT -N TxGroup2_ANT |=0 or 1.

[0582] Similarly, the number of receiving antennas included in the first receiving antenna group (hereinafter, “N RxGroup1_ANT ") and the number of receiving antennas included in the second receiving antenna group (hereinafter, "N RxGroup2_ANT") may be the same number or may have a difference of one antenna. For example, |N RxGroup1_ANT -N RxGroup2_ANT |=0 or 1.

[0583] 90A and 90B show the number of transmitting antennas N included in the first transmitting antenna group. TxGroup1_ANT and the number of transmitting antennas included in the second transmitting antenna group N TxGroup2_ANT There is a difference of one antenna between the first and second receiving antenna groups, and the number of receiving antennas included in the first receiving antenna group is N RxGroup1_ANT and the number of receiving antennas included in the second receiving antenna group N RxGroup2_ANT 13 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when the numbers of

[0584] As shown in FIG. 90A and FIG. 90B, |N TxGroup1_ANT -N TxGroup2_ANT |=1 and |N RxGroup1_ANT -N RxGroup2_ANT In the case of |=0, the number of transmitting antennas is 3 and the number of receiving antennas is 4 (N RxGroup1_ANT =N RxGroup2_ANT =2), and there are, for example, two different patterns.

[0585] Figure 90A shows N TxGroup1_ANT =1(Tx#2), N TxGroup2_ANT FIG. 90B shows an example of a MIMO array arrangement for N = 2 (Tx#1, Tx#3). TxGroup1_ANT =2(Tx#2, Tx#3), N TxGroup2_ANT 4 is an example of a MIMO array arrangement for .DELTA..times ...

[0586] Next, FIG. 91A and FIG. 91B show the number of transmitting antennas N included in the first transmitting antenna group. TxGroup1_ANT and the number of transmitting antennas included in the second transmitting antenna group N TxGroup2_ANT and the number of receiving antennas included in the first receiving antenna group is N RxGroup1_ANT and the number of receiving antennas included in the second receiving antenna group N RxGroup2_ANT The figure shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when there is a difference of one antenna between the two.

[0587] As shown in FIG. 91A and FIG. 91B, |N TxGroup1_ANT -N TxGroup2_ANT |=0 and |N RxGroup1_ANT -N RxGroup2_ANT In the case of |=1, the number of transmit antennas is 4 (N TxGroup1_ANT =N TxGroup2_ANT = 2), and the number of receiving antennas is 3. For example, there are two patterns.

[0588] Figure 91A shows N RxGroup1_ANT =1(Rx#3), N RxGroup2_ANT FIG. 91B shows an example of a MIMO array arrangement for N = 2 (Rx#1, Rx#2). RxGroup1_ANT =2(Rx#2, Rx#3), N RxGroup2_ANT 4 is an example of a MIMO array arrangement when Rx=1 (Rx#1).

[0589] Next, FIG. 92A to FIG. 92D show the number of transmitting antennas N included in the first transmitting antenna group. TxGroup1_ANT and the number of transmitting antennas included in the second transmitting antenna group N TxHGroup2_ANT There is a difference of one antenna between the first and second receiving antenna groups, and the number of receiving antennas included in the first receiving antenna group is N RxGroup1_ANT and the number of receiving antennas included in the second receiving antenna group N RxGroup2_ANT The figure shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when there is a difference of one antenna between the two.

[0590] As shown in Figures 92A to 92D, |N TxGroup1_ANT -N TxGroup2_ANT |=1 and |N RxGroup1_ANT -N RxGroup2_ANT When |=1, the MIMO array arrangement is a configuration in which the number of transmitting antennas is 3 and the number of receiving antennas is 3, and there are, for example, four patterns as shown in FIGS. 92A to 92D.

[0591] Figure 92A shows N TxVGroup1_ANT =1(Tx#2), N TxVGroup2_ANT = 2 (Tx#1, Tx#3), N RxHGroup1_ANT =1(Rx#3), N RxHGroup2_ANT4 is an example of a MIMO array arrangement when Rx#1, Rx#2 are in the same order.

[0592] FIG. 92B shows N TxVGroup1_ANT =1(Tx#2), N TxVGroup2_ANT = 2 (Tx#1, Tx#3), N RxHGroup1_ANT =2(Rx#2,Rx#3),N RxHGroup2_ANT 4 is an example of a MIMO array arrangement when Rx=1 (Rx#1).

[0593] Figure 92C shows N TxVGroup1_ANT = 2 (Tx#2, Tx#3), N TxVGroup2_ANT =1(Tx#1), ​​N RxHGroup1_ANT =1(Rx#3), N RxHGroup2_ANT 4 is an example of a MIMO array arrangement when Rx#1, Rx#2 are in the same order.

[0594] Figure 92D shows N TxVGroup1_ANT = 2 (Tx#2, Tx#3), N TxVGroup2_ANT =1(Tx#1), ​​N RxHGroup1_ANT =2(Rx#2,Rx#3),N RxHGroup2_ANT 4 is an example of a MIMO array arrangement when Rx=1 (Rx#1).

[0595] In the virtual receiving arrays shown in Figures 90A, 90B, 91A, 91B, and 92A to D, each virtual array element is arranged at a different position without overlapping, so that the aperture length of the virtual receiving array can be expanded and the angular resolution can be improved.

[0596] In addition, the virtual array element located near the center of the virtual receiving array is D H , D V As an example, in Figs. 90A, 90B, 91A, 91B, and 92A to 92D, H and interval D V When the distance is about 0.5λ, the virtual array element located near the center of the virtual receiving array has a horizontal distance of D H = 0.5λ interval, D in the vertical direction V = 0.5λ apart, which helps reduce grating lobes.

[0597] For example, in the MIMO array arrangement of basic arrangement 5, the spacing D H and interval D V is set to about 0.5λ, the horizontal and vertical element sizes of the transmitting antenna 106 and the receiving antenna 202 can be designed to be about 1λ or more.

[0598] As a result, for example, the horizontal direction W ANT The element size of D H As long as the size of the antenna is smaller than the size shown in FIG. 89, an antenna of any size can be used in the vertical direction. For example, FIG. 93A shows an example in which a sub-array in which eight planar patch antenna elements shown in FIG. 25A are arranged vertically and one horizontally is applied to the antenna arrangement shown in FIG. 89. As shown in FIG. 93B, parasitic elements (dummy elements) may be arranged in addition to the transmitting array antenna shown in FIG. 93A. The parasitic elements can equalize the effect of inter-antenna coupling due to adjacent antennas for each antenna, and can equalize the directional characteristics of each transmitting antenna (Tx#1-#4).

[0599] In this way, by using antennas in a subarray configuration in the antenna arrangement according to the basic arrangement 5, the directional gain of the antennas can be improved, and the detection performance (for example, detection distance) of the radar device 10 can be improved.

[0600] The direction estimation unit 214 performs direction estimation processing in the horizontal and vertical directions using the received signals of the virtual receiving array obtained from the above-mentioned transmitting and receiving antenna arrangements. Note that the processing by the direction estimation unit 214 for the virtual receiving array of basic arrangement 5 is the same as that of basic arrangement 1, so a description thereof will be omitted here.

[0601] FIG. 94 shows a MIMO array arrangement (D H =0.5λ, D V94 shows an example of a direction estimation result when a beamformer method is used as the arrival direction estimation algorithm of direction estimation unit 214 when a beamwidth of 1.0 GHz (λ = 0.5 λ) is used. That is, in Fig. 94, the antenna spacing in the horizontal and vertical directions of transmitting antenna 106 is 1 λ or more, and the antenna spacing in the horizontal and vertical directions of receiving antenna 202 is also 1 λ or more. Note that the directivity of each antenna is calculated as omnidirectional.

[0602] FIG. 94 plots the output of the arrival direction estimation evaluation function value in a range of ±90 degrees in the horizontal direction and a range of ±90 degrees in the vertical direction when the target true value is 0 degrees horizontally and 0 degrees vertically.

[0603] In Fig. 94, it can be seen that the grating lobes are reduced in directions other than the horizontal 0 degree and vertical 0 degree of the target true value, as compared to Fig. 1A, for example. For example, in Fig. 94, the ratio (PSLR) of the peak power value of the highest side lobe excluding the main lobe in directions other than the horizontal 0 degree and vertical 0 degree to the peak power value of the main lobe in the horizontal 0 degree and vertical 0 degree directions is about 0.35.

[0604] As described above, by using the MIMO array arrangement according to basic arrangement 5, even if the vertical or horizontal element size of the antennas used for the transmitting array antenna and the receiving array antenna is about 1λ, the horizontal and vertical antenna spacings in the virtual receiving array can be arranged to include element spacings of about 0.5λ, thereby reducing grating lobes. Furthermore, for example, since the virtual array elements of the virtual receiving array shown in Fig. 52A are arranged without overlapping, the aperture length of the virtual receiving array can be extended and the angular resolution can be improved.

[0605] <Variation 1 of Basic Layout 5> In the first variation of basic arrangement 5, the arrangement of the transmitting array antennas and the arrangement of the receiving array antennas shown in basic arrangement 5 are each defined as a “basic set,” and a MIMO array arrangement in which the arrangement positions of multiple basic sets are offset will be described.

[0606] Hereinafter, arrangement methods 5-1A, 5-1B, and 5-1C according to the first modification of the basic arrangement 5 will be described.

[0607] (Placement method 5-1A) In arrangement method 5-1A, the arrangement of the four-element transmitting array antenna and the arrangement of the four-element receiving array antenna shown in basic arrangement 5 are each defined as a "basic set," and a MIMO array arrangement in which the arrangement positions of multiple basic sets are offset will be described.

[0608] In the arrangement shown below, the offset of the basic set of transmitting array antennas in the horizontal and vertical directions, or the offset of the basic set of receiving array antennas in the horizontal and vertical directions, is determined so that there are no overlapping elements in the virtual receiving array arrangement and more virtual array elements are arranged near the center of the virtual receiving array. V Or D H However, the present invention is not limited to this, and for example, it is also possible to increase the number of arrangements with unequal intervals in the virtual receiving array arrangement, or to increase the number of arrangements in which virtual array elements overlap in the virtual receiving array arrangement, by adjusting the offset of the arrangement positions.

[0609] Figure 95 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet 95 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when .times. ... Hoffset_TxBaseSet2 =5D H and the vertical offset of the placement position is D Voffset_TxBaseSet2 As shown in Figure 95, the two basic sets of transmitting array antennas are offset horizontally, resulting in a horizontal D HThe number of closely spaced virtual array elements can be increased, improving the horizontal angular resolution. In the case of Figure 95, virtual array elements are arranged in two overlapping positions.

[0610] Figure 96 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet 96 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when .times. ... Hoffset_TxBaseSet2 = 0, and the vertical offset of the placement position D Voffset_TxBaseSet2 =3D V As shown in Figure 96, the two basic sets of transmitting array antennas are arranged with an offset in the vertical direction, so that the vertical V This increases the number of densely spaced virtual array elements, improving the horizontal angular resolution. In the case of Figure 96, virtual array elements are arranged in two overlapping positions.

[0611] Figure 97 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 1, and the number of basic sets of receiving array antennas is N RxBaseSet 97 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#2, Rx#3, and Rx#4 are set. In FIG. 97, the offset D Hoffset_RxBaseSet2 =5D H and the vertical offset of the placement position is D Voffset_RxBaseSet2 As shown in Figure 97, the two basic sets of receiving array antennas are offset horizontally, resulting in a horizontal D H The number of densely spaced virtual array elements can be increased, improving the horizontal angular resolution. In the case of Figure 97, the virtual array elements are arranged in two overlapping positions.

[0612] Figure 98 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 1, and the number of basic sets of receiving array antennas is N RxBaseSet 98 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#2, Rx#3, and Rx#4 are set. In FIG. 98, the offset D Hoffset_RxBaseSet2 = 0, and the vertical offset of the placement position D Voffset_RxBaseSet2 =3D V As shown in Figure 98, the two basic sets of receiving array antennas are arranged with an offset in the vertical direction, so that the vertical V This increases the number of densely spaced virtual array elements, improving the angular resolution in the vertical direction. In the case of Figure 98, virtual array elements are arranged in two overlapping positions.

[0613] Figure 99 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet 99 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when = 2. In FIG. 99, the offset D Hoffset_TxBaseSet2 =10D H and the vertical offset of the placement position is D Voffset_TxBaseSet2 In FIG. 99, the offset D of the horizontal arrangement position of the second basic set (Rx#5, Rx#6, Rx#7, and Rx#8) of the receiving array antenna with respect to the first basic set (for example, Rx#1, Rx#2, Rx#3, and Rx#4) is Hoffset_RxBaseSet2 =5D H and the vertical offset of the placement position is D Voffset_RxBaseSet2As shown in Figure 99, by arranging two basic sets of transmitting array antennas with a horizontal offset and arranging two basic sets of receiving array antennas with a horizontal offset, the horizontal D H The number of closely spaced virtual array elements can be further increased, and the horizontal angular resolution can be further improved, as compared with, for example, Figure 95 or Figure 97. In the case of Figure 99, virtual array elements are arranged in overlapping relation at four locations.

[0614] FIG. 100A shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet 100B shows an example of a virtual receiving array arrangement when R is 1 / 4, and FIG. 100C shows an example of a virtual receiving array arrangement when R is 1 / 4.

[0615] In FIG. 100A, the horizontal offset D of the arrangement position of the second basic set (Tx#5, Tx#6, Tx#7, and Tx#8) of the transmitting array antenna relative to the first basic set (for example, Tx#1, Tx#2, Tx#3, and Tx#4) is Hoffset_TxBaseSet2 =5D H and the vertical offset of the placement position is D Voffset_TxBaseSet2 =00.

[0616] In FIG. 100A, the horizontal offset D of the arrangement position of the second basic set (Rx#5, Rx#6, Rx#7, and Rx#8) of the receiving array antenna with respect to the first basic set (for example, Rx#1, Rx#2, Rx#3, and Rx#4) is Hoffset_RxBaseSet2 =5D H and the vertical offset of the placement position is D Voffset_RxBaseSet2 =-3D V The horizontal offset D of the third basic set (Rx#9, Rx#10, Rx#11, and Rx#12) Hoffset_RxBaseSet3 =-5D H and the vertical offset of the placement position is D Voffset_RxBaseSet3 =-3D VThe horizontal offset D of the fourth basic set (Rx#13, Rx#14, Rx#15, and Rx#16) Hoffset_RxBaseSet4 = 0, and the vertical offset of the placement position D Voffset_RxBaseSet4 =-6D V Let us assume that.

[0617] As shown in Figs. 100A and 100B, the basic set of transmitting array antennas is offset in the horizontal direction, and the basic set of receiving array antennas is offset in the horizontal direction, resulting in a horizontal D H The number of closely spaced virtual array elements can be further increased, as compared to, for example, FIG. 95 or FIG. 97, and the horizontal angular resolution can be further improved.

[0618] Similarly, as shown in Figs. 100A and 100B, by offsetting the basic set of receiving array antennas in the vertical direction, V The number of densely spaced virtual array elements can be increased, improving the angular resolution in the vertical direction. In the case of FIG. 100B, virtual array elements are arranged in overlapping fashion at eight locations.

[0619] <Placement method 5-1B> In arrangement method 5-1B, the arrangement of a four-element transmitting array antenna and a three-element receiving array antenna, or the arrangement of a three-element transmitting array antenna and a four-element receiving array antenna shown in basic arrangement 5 is defined as a "basic set," and a MIMO array arrangement in which the arrangement positions of multiple basic sets are offset will be described.

[0620] In the following, as an example, a case where the antenna arrangement shown in Fig. 90A is used for the "basic set" will be described. However, the antenna arrangement is not limited to the example shown in Fig. 90A, and other antenna arrangements (for example, Fig. 90B, Fig. 91A, or Fig. 91B) may be used.

[0621] In the arrangement shown below, the offset of the basic set of transmitting array antennas in the horizontal and vertical directions, or the offset of the basic set of receiving array antennas in the horizontal and vertical directions, is such that there are no overlapping elements in the virtual receiving array arrangement, and more virtual array elements are arranged near the center of the virtual receiving array. V Or D H However, the present invention is not limited to this, and for example, it is also possible to increase the number of arrangements with unequal intervals in the virtual receiving array arrangement, or to increase the number of arrangements in which virtual array elements overlap in the virtual receiving array arrangement, by adjusting the offset of the arrangement positions.

[0622] Figure 101 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet 101 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when .times. ... Hoffset_TxBaseSet2 =4D H and the vertical offset of the placement position is D Voffset_TxBaseSet2 =D V As shown in Figure 101, the two basic sets of transmitting array antennas are offset horizontally to create a horizontal D H The number of closely spaced virtual array elements can be increased, improving the horizontal angular resolution.

[0623] Figure 102 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet 102, the horizontal offset of the arrangement position of the second basic set (Tx#4, Tx#5, and Tx#6) relative to the first basic set (Tx#1, Tx#2, and Tx#3) is set as DHoffset_TxBaseSet2 = 0, and the vertical offset of the placement position D Voffset_TxBaseSet2 =3D V As shown in Figure 102, the two basic sets of transmitting array antennas are arranged with an offset in the vertical direction, so that the vertical V The number of closely spaced virtual array elements can be increased, improving the angular resolution in the vertical direction.

[0624] Figure 103 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 1, and the number of basic sets of receiving array antennas is N RxBaseSet 103, the horizontal offset of the arrangement position of the second basic set (Rx#5, Rx#6, Rx#7, and Rx#8) with respect to the first basic set (for example, Rx#1, Rx#2, Rx#3, and Rx#4) is set as D Hoffset_RxBaseSet2 =4D H and the vertical offset of the placement position is D Voffset_RxBaseSet2 =D V As shown in Figure 103, the two basic sets of receiving array antennas are offset horizontally to create a horizontal D H The number of closely spaced virtual array elements can be increased, improving the horizontal angular resolution.

[0625] Figure 104 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 1, and the number of basic sets of receiving array antennas is N RxBaseSet 104 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#2, Rx#3, and Rx#4 are set as 1, Rx#5, Rx#6, Rx#7, and Rx#8. In FIG. 104, the horizontal offset D Hoffset_RxBaseSet2 = 0, and the vertical position offset D Voffset_RxBaseSet2 =3D VAs shown in Figure 104, the two basic sets of receiving array antennas are arranged with a vertical offset, so that the vertical V The number of closely spaced virtual array elements can be increased, improving the angular resolution in the vertical direction.

[0626] Figure 105 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet 105 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when D = 2. In FIG. 105, the offset of the arrangement position in the horizontal direction of the second basic set (Tx#4, Tx#5, and Tx#6) of the transmitting array antenna relative to the first basic set (Tx#1, Tx#2, and Tx#3) is set as D Hoffset_TxBaseSet2 =4D H and the vertical offset of the placement position is D Voffset_TxBaseSet2 =-2D V In addition, in FIG. 105, the offset D of the horizontal arrangement position of the second basic set (Rx#5, Rx#6, Rx#7, and Rx#8) of the receiving array antenna with respect to the first basic set (for example, Rx#1, Rx#2, Rx#3, and Rx#4) is Hoffset_RxBaseSet2 =4D H and the vertical offset of the placement position is D Voffset_RxBaseSet2 =D V As shown in FIG. 105, by arranging two basic sets of transmitting array antennas offset in the horizontal direction and arranging two basic sets of receiving array antennas offset in the horizontal direction, the horizontal H The number of closely spaced virtual array elements can be further increased, as compared to, for example, FIG. 101 or FIG. 103, and the horizontal angular resolution can be further improved.

[0627] FIG. 106A shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet 106B shows an example of a virtual receiving array arrangement when R is 1 / 4, and FIG. 106C shows an example of a virtual receiving array arrangement when R is 1 / 4.

[0628] In FIG. 106A, the offset of the horizontal arrangement position of the second basic set (Tx#4, Tx#5, and Tx#6) of the transmitting array antenna relative to the first basic set (Tx#1, Tx#2, and Tx#3) is denoted by D Hoffset_TxBaseSet2 =4D H and the vertical offset of the placement position is D Voffset_TxBaseSet2 =D V Let us assume that.

[0629] In FIG. 106A, the offset D of the horizontal arrangement position of the second basic set (Tx#5, Tx#6, Tx#7, and Tx#8) of the receiving array antenna with respect to the first basic set (for example, Rx#1, Rx#2, Rx#3, and Rx#4) is Hoffset_RxBaseSet2 =4D H and the vertical offset of the placement position is D Voffset_RxBaseSet2 =-2D V The horizontal offset of the arrangement position of the third basic set (Tx#9, Tx#10, Tx#11, and Tx#12) is D Hoffset_RxBaseSet3 =-6D H and the vertical offset of the placement position is D Voffset_RxBaseSet3 =-3D V The horizontal offset of the arrangement position of the fourth basic set (Tx#13, Tx#14, Tx#15 and Tx#16) is D Hoffset_RxBaseSet4 =-2D H and the vertical offset of the placement position is D Voffset_RxBaseSet4 =-5D V Let us assume that.

[0630] As shown in Figs. 106A and 106B, the basic set of transmitting array antennas is offset in the horizontal direction, and the basic set of receiving array antennas is offset in the horizontal direction. H The number of closely spaced virtual array elements can be further increased, as compared to, for example, FIG. 101 or FIG. 103, and the horizontal angular resolution can be further improved.

[0631] Similarly, as shown in Figs. 106A and 106B, by offsetting the basic set of receiving array antennas in the vertical direction, V The number of closely spaced virtual array elements can be increased, improving the angular resolution in the vertical direction.

[0632] <Placement method 5-1C> In arrangement method 5-1C, the arrangement of the three-element transmitting array antenna and the arrangement of the three-element receiving array antenna shown in basic arrangement 5 are each defined as a "basic set," and a MIMO array arrangement in which the arrangement positions of multiple basic sets are offset is described.

[0633] In the following, as an example, a case where the antenna arrangement shown in Fig. 92B is used for the "basic set" will be described. However, the antenna arrangement is not limited to the example shown in Fig. 92B, and other antenna arrangements (for example, Fig. 92A, Fig. 92C, or Fig. 92D) may be used.

[0634] In the arrangement shown below, the offset of the basic set of transmitting array antennas in the horizontal and vertical directions, or the offset of the basic set of receiving array antennas in the horizontal and vertical directions, is such that there are no overlapping elements in the virtual receiving array arrangement, and more virtual array elements are arranged near the center of the virtual receiving array. V Or D H However, the present invention is not limited to this, and for example, it is also possible to increase the number of arrangements with unequal intervals in the virtual receiving array arrangement, or to increase the number of arrangements in which virtual array elements overlap in the virtual receiving array arrangement, by adjusting the offset of the arrangement positions.

[0635] Figure 107 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet107 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when D = 1. In FIG. 107, the offset of the arrangement position of the second basic set (Tx#4, Tx#5, and Tx#6) in the horizontal direction relative to the first basic set (Tx#1, Tx#2, and Tx#3) is set as D Hoffset_TxBaseSet2 =3D H and the vertical offset of the placement position is D Voffset_TxBaseSet2 As shown in Figure 107, the two basic sets of transmitting array antennas are offset horizontally, resulting in a horizontal D H The number of closely spaced virtual array elements can be increased, improving the horizontal angular resolution.

[0636] Figure 108 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet 108 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when .times. ... Hoffset_TxBaseSet2 = 0, and the vertical offset of the placement position D Voffset_TxBaseSet2 =3D V As shown in Figure 108, the two basic sets of transmitting array antennas are arranged with an offset in the vertical direction, so that the vertical V The number of closely spaced virtual array elements can be increased, improving the horizontal angular resolution.

[0637] Figure 109 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 1, and the number of basic sets of receiving array antennas is N RxBaseSet 109 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#2, and Rx#3 are set as follows. In FIG. 109, the offset D Hoffset_RxBaseSet2 =3D Hand the vertical offset of the placement position is D Voffset_RxBaseSet2 As shown in Figure 109, the two basic sets of receiving array antennas are offset horizontally to reduce the horizontal D H The number of closely spaced virtual array elements can be increased, improving the horizontal angular resolution.

[0638] FIG. 110 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 1, and the number of basic sets of receiving array antennas is N RxBaseSet 110 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when Rx#1, Rx#2, and Rx#3 are set as follows. In FIG. 110, the offset D Hoffset_RxBaseSet2 = 0, and the vertical offset of the placement position D Voffset_RxBaseSet2 =3D V As shown in Figure 110, the two basic sets of receiving array antennas are arranged with an offset in the vertical direction, so that the vertical V The number of closely spaced virtual array elements can be increased, improving the angular resolution in the vertical direction.

[0639] Figure 111 shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet 111 shows an example of a MIMO array arrangement and an example of a virtual receiving array arrangement when = 2. In FIG. 111, the offset D Hoffset_TxBaseSet2 =6D H and the vertical offset of the placement position is D Voffset_TxBaseSet2 In FIG. 111, the offset D of the horizontal arrangement position of the second basic set (Rx#4, Rx#5, Rx#6) of the receiving array antenna with respect to the first basic set (Rx#1, Rx#2, and Rx#3) is Hoffset_RxBaseSet2 =3DH and the vertical offset of the placement position is D Voffset_RxBaseSet2 As shown in FIG. 111, by arranging two basic sets of transmitting array antennas offset in the horizontal direction and arranging two basic sets of receiving array antennas offset in the horizontal direction, the horizontal D H The number of closely spaced virtual array elements can be further increased, as compared with, for example, FIG. 107 or FIG. 109, and the horizontal angular resolution can be further improved.

[0640] FIG. 112A shows the number of basic sets of transmitting array antennas, N TxBaseSet = 2, and the number of basic sets of receiving array antennas is N RxBaseSet 112B shows an example of a virtual receiving array arrangement when R is 1 / 4, and FIG. 112C shows an example of a virtual receiving array arrangement when R is 1 / 4.

[0641] In FIG. 112A, the offset D of the horizontal arrangement position of the second basic set (Tx#4, Tx#5, Tx#6) of the transmitting array antenna relative to the first basic set (Tx#1, Tx#2, and Tx#3) is Hoffset_TxBaseSet2 =3D H and the vertical offset of the placement position is D Voffset_TxBaseSet2 =0.

[0642] In FIG. 112A, the offset D of the horizontal arrangement position of the second basic set (Rx#4, Rx#5, and Rx#6) of the receiving array antenna with respect to the first basic set (Rx#1, Rx#2, and Rx#3) is Hoffset_RxBaseSet2 =-3D H and the vertical offset of the placement position is D Voffset_RxBaseSet2 =-3D V The horizontal offset D of the third basic set (Rx#7, Rx#8, Rx#9) Hoffset_RxBaseSet3 =6D H and the vertical offset of the placement position is D Voffset_RxBaseSet3 = 0, and the horizontal offset D of the placement position of the fourth basic set (Rx#10, Rx#11, Rx#12) Hoffset_RxBaseSet4 =3DH and the vertical offset of the placement position is D Voffset_RxBaseSet4 =-3D V Let us assume that.

[0643] As shown in Figs. 112A and 112B, the basic set of transmitting array antennas is offset in the horizontal direction, and the basic set of receiving array antennas is offset in the horizontal direction, resulting in a horizontal D H The number of closely spaced virtual array elements can be further increased, as compared with, for example, FIG. 107 or FIG. 109, and the horizontal angular resolution can be further improved.

[0644] Similarly, as shown in Figs. 112A and 112B, by offsetting the basic set of receiving array antennas in the vertical direction, V The number of closely spaced virtual array elements can be increased, improving the angular resolution in the vertical direction.

[0645] The arrangement methods 5-1A, 5-1B and 5-1C have been described above.

[0646] In the arrangement methods 5-1A, 5-1B, and 5-1C, the number of basic sets included in the transmitting array antenna and the receiving array antenna (N TxBaseSet , N RxBaseSet ) is not limited to the above example and may be other values.

[0647] An embodiment according to one embodiment of the present disclosure has been described above.

[0648] The operations according to the above-described embodiment and the variations may be combined as appropriate.

[0649] [Other embodiments] The number of transmitting antennas Nt and the number of receiving antennas Na are not limited to the above example, and may be other values. V and D. H is not limited to 0.5λ, and may be, for example, a value between 0.5λ and 1λ. V and DH may be the same value or may be different values.

[0650] In the above embodiment, a case has been described in which a coded pulse radar is used, but the present disclosure is also applicable to a radar system that uses a frequency-modulated pulse wave, such as a chirp pulse radar.

[0651] In the radar device 10 shown in FIG. 4, the radar transmitter 100 and the radar receiver 200 may be individually arranged at physically separate locations.

[0652] Although not shown, the radar device 10 has, for example, a central processing unit (CPU), a recording medium such as a read only memory (ROM) storing a control program, and a working memory such as a random access memory (RAM). In this case, the functions of each of the above-mentioned units are realized by the CPU executing the control program. However, the hardware configuration of the radar device 10 is not limited to this example. For example, each functional unit of the radar device 10 may be realized as an integrated circuit (IC). Each functional unit may be individually implemented as a single chip, or may be implemented as a single chip that includes some or all of the functional units.

[0653] In the above-described embodiments, the notation "... part" used for each component may be replaced with other notations such as "... circuitry", "... device", "... unit", or "... module".

[0654] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is clear that a person skilled in the art can come up with various modified or amended examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure. In addition, the components in the above embodiments may be arbitrarily combined within the scope of the disclosure.

[0655] The present disclosure can be realized by software, hardware, or software linked to hardware. Each functional block used in the description of the above embodiment may be realized, in part or in whole, as an LSI, which is an integrated circuit, and each process described in the above embodiment may be controlled, in part or in whole, by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip to include some or all of the functional blocks. The LSI may have input and output data. Depending on the degree of integration, the LSI may be called an IC, a system LSI, a super LSI, or an ultra LSI. The method of integration is not limited to LSI, and may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. In addition, a field programmable gate array (FPGA) that can be programmed after LSI manufacture, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may be used. The present disclosure may be realized as digital processing or analog processing. Furthermore, if a new integrated circuit technology that can replace LSI appears due to the progress of semiconductor technology or a derivative technology, it is possible to integrate the functional blocks using that technology. The application of biotechnology is also a possibility.

[0656] The present disclosure may be implemented in any type of apparatus, device, or system with communications capabilities (collectively, communications apparatus), including, but not limited to, telephones (e.g., cell phones, smartphones, etc.), tablets, personal...

Claims

1. a radar transmission circuit for transmitting a radar signal using a transmission array antenna; a radar receiving circuit for receiving a reflected wave signal, which is a radar signal reflected from a target, using a receiving array antenna; Equipped with one of the transmitting array antenna and the receiving array antenna is composed of a plurality of first antennas; the first antennas are arranged based on a first interval in a first direction and a second interval in a second direction perpendicular to the first direction; the other of the transmitting array antenna and the receiving array antenna is composed of at least two second antenna groups, the second antennas constituting each of the second antenna groups are arranged based on the first intervals; Radar equipment.

2. the plurality of first antennas are composed of at least two or more first antenna groups, a plurality of third antennas constituting each of the first antenna groups are disposed in an oblique direction based on the first interval and the second interval; The radar device according to claim 1 .

3. At least one of the plurality of third antennas constituting one of the first antenna groups is disposed at the same position in the first direction as at least one of the plurality of third antennas constituting another of the first antenna groups. The radar device according to claim 2 .

4. The positions of the second antennas in the first direction are different from each other. The radar device according to claim 1 .

5. The at least two or more second antenna groups are arranged to be shifted from each other at intervals equal to one time the intervals in the first direction. The radar device according to claim 1 .

6. The positions of the at least two or more second antenna groups in the second direction are different from each other. The radar device according to claim 1 .

7. The third antennas are arranged at intervals that are twice the first intervals in the first direction. The radar device according to claim 2 .

8. The at least two second antenna groups are arranged at intervals that are twice the first interval in the first direction. The radar device according to claim 1 .

9. The at least two or more first antenna groups are arranged at intervals that are twice the second interval in the second direction. The radar device according to claim 2 .

10. The at least two second antenna groups are arranged at intervals that are twice the second interval in the second direction. The radar device according to claim 1 .

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