Radar device

Abstract

A radar device (1) is provided with a plurality of transmission antennas (TX), a plurality of reception antennas (RX), Ns transmission circuits (3), Nr reception circuits (4), and a control unit (6). Ns and Nr are each an integer of 2 or more. The plurality of transmission antennas (TX) and / or the plurality of reception antennas (RX) are arranged at unequal intervals. The plurality of transmission antennas (TX) and the plurality of reception antennas (RX) are arranged such that, assuming a group of mismatch pairs of virtual antennas (V) for which the patterns of combination of the transmission circuits (3) and the reception circuits (4) do not overlap with each other, Ns + Nr − 2 or more mismatch pairs are included in the group. The plurality of transmission antennas (TX) and the plurality of reception antennas (RX) are arranged such that, for each of the mismatch pairs in the group, the corresponding transmission antennas overlap with each other and the corresponding reception antennas overlap with each other in a specific direction (Y direction). The control unit (6) outputs sensing data in which a phase error between different transmission circuits and a phase error between different reception circuits are compensated in correlation with a result of comparison between reception signals of virtual antennas in each of the Ns + Nr − 2 or more mismatch pairs.

Description

radar equipment CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2024-108472 filed in Japan on July 4, 2024, the contents of which are incorporated by reference in their entirety.

[0002] This disclosure relates to radar technology.

[0003] Patent Document 1 discloses a radar device including multiple receiving antennas provided in multiple receiving circuits, first and second transmitting antennas, and a phase compensation unit. The first and second transmitting antennas are provided at a predetermined distance from the receiving antenna so that the receiving antennas are virtually overlapping. The phase compensation unit compensates for the phase difference between the receiving circuits of the reflected waves of the transmission waves transmitted from the first and second transmitting antennas based on a comparison result of the received signals received by each of the virtually overlapping receiving antennas.

[0004] Japanese Patent Application Laid-Open No. 2019-60732

[0005] In the radar device of Patent Document 1, only the phase difference between different receiving circuits can be compensated for. However, since there are other factors that cause errors in different received signals besides the difference in the receiving circuits, it is difficult to ensure compensation accuracy. Furthermore, in the radar device of Patent Document 1, the aperture length is shortened by the amount of virtual overlap between the receiving antennas, which reduces spatial resolution. Therefore, it is difficult for the radar device of Patent Document 1 to achieve both compensation accuracy and spatial resolution.

[0006] An object of the present disclosure is to provide a radar device that can achieve both high compensation accuracy and high spatial resolution.

[0007] The technical means of the present disclosure for solving the problems will be described below. Note that the reference numerals in parentheses in the claims indicate the correspondence with the specific means described in the embodiments described later in detail, and do not limit the technical scope of the present disclosure.

[0008] a control unit that outputs sensing data correlated with the received signals, wherein Ns and Nr are integers equal to or greater than 2, and wherein at least one of the plurality of transmitting antennas and the plurality of receiving antennas is arranged at uneven intervals, and a plurality of virtual antennas are virtually formed, which are assumed for each transmitting antenna in accordance with a phase difference of the received signals between the receiving antennas, and wherein a pair of virtual antennas whose assumed virtual positions overlap among the plurality of virtual antennas are arranged such that, with respect to a mismatched pair, which is a pair of virtual antennas whose combinations of transmitting circuits and receiving circuits corresponding to the virtual antennas do not match, when a group of mismatched pairs whose combination patterns of transmitting circuits and receiving circuits do not overlap each other is assumed, at least Ns+Nr-2 mismatched pairs are included in the group, and Furthermore, for at least Ns+Nr-2 mismatched pairs within the group, the corresponding transmitting antennas and receiving antennas are positioned so as to overlap in a specific direction, and the control unit is a radar device that outputs sensing data in which the phase errors between different transmitting circuits and different receiving circuits are compensated in correlation with the comparison results of the received signals between the virtual antennas in at least Ns+Nr-2 mismatched pairs.

[0009] According to this first aspect, phase differences between different transmitter circuits and different receiver circuits can be compensated for based on comparison results of received signals between virtual antennas in at least Ns + Nr - 2 mismatched pairs. Therefore, compensation processing for phase errors between different transmitter circuits as well as between different receiver circuits can be performed. Furthermore, corresponding transmitter antennas and receiver antennas in a mismatched pair are arranged in overlapping positions in a specific direction. Therefore, occurrence of phase errors between virtual antennas in a mismatched pair when a transmitted signal is reflected by a reflecting object other than the target on its outbound or inbound path can be avoided. Therefore, compensation accuracy can be improved. Furthermore, by arranging at least one of the transmitter antennas and the receiver antennas at uneven intervals, the aperture length of the virtual antenna can be larger than when the antennas are arranged at equal intervals. Therefore, both compensation accuracy and spatial resolution can be achieved.

[0010] a control unit that outputs sensing data correlated with the received signals, wherein Ns and Nr are integers equal to or greater than 2, and wherein at least one of the plurality of transmitting antennas and the plurality of receiving antennas is arranged at uneven intervals, and a plurality of virtual antennas are virtually formed, which are assumed for each transmitting antenna in accordance with a phase difference between the received signals between the receiving antennas, and wherein a pair of virtual antennas whose assumed virtual positions overlap among the plurality of virtual antennas are arranged such that, with respect to a mismatched pair, which is a pair of virtual antennas whose combinations of transmitting circuits and receiving circuits corresponding to the virtual antennas do not match, when a group of mismatched pairs whose combination patterns of transmitting circuits and receiving circuits do not overlap with each other is assumed, at least Ns+Nr-2 mismatched pairs are included in the group, and and the group is arranged so that the group includes at least one pair of virtual antennas whose virtual positions overlap and whose wiring lengths do not match, and the total number of belonging pairs, which are pairs of virtual antennas belonging to at least one of the mismatched pairs and the different wiring length pairs included in the group, is at least Ns+Nr-1 pairs, and the belonging pairs are arranged so that corresponding transmitting antennas and receiving antennas are positioned to overlap in a specific direction, and the control unit is a radar device that outputs sensing data in which phase errors corresponding to the wiring length difference between the virtual antennas, phase errors between different transmitting circuits, and phase errors between different receiving circuits are compensated in correlation with comparison results of received signals between the virtual antennas in at least Ns+Nr-1 belonging pairs.

[0011] According to this second aspect, based on the comparison results of the received signals between virtual antennas in mismatched pairs in at least Ns+Nr-1 non-overlapping groups, phase differences between different transmitter circuits and receiver circuits, as well as phase differences corresponding to differences in wiring length between the virtual antennas, can be compensated for. Therefore, compensation processing for phase errors between different transmitter circuits and phase errors due to differences in wiring length, as well as between different receiver circuits, can be performed. Furthermore, corresponding transmitter antennas and receiver antennas in a mismatched pair are arranged in overlapping positions in a specific direction. Therefore, the occurrence of phase errors between virtual antennas in a mismatched pair when a transmitted signal is reflected by a reflecting object other than the target on the outbound or inbound path, can be avoided. Therefore, compensation accuracy can be improved. Furthermore, by arranging at least one of the transmitter antennas and the receiver antennas at uneven intervals, the aperture length of the virtual antenna can be larger than when the antennas are arranged at equal intervals. Therefore, both compensation accuracy and spatial resolution can be achieved.

[0012] FIG. 1 is a schematic diagram showing a basic configuration of a radar device according to a first embodiment. FIG. 1 is a schematic diagram showing an example of a combination of a transmitting circuit and a transmitting antenna, and a receiving circuit and a receiving antenna according to the first embodiment. FIG. 2 is a schematic diagram showing an example of an arrangement of a transmitting antenna and a receiving antenna according to the first embodiment. FIG. 3 is a schematic diagram showing a virtual antenna virtually formed in the first embodiment. FIG. 4 is a table showing an example of a set of virtual antennas used for compensation processing. FIG. 4 is a block diagram showing a functional configuration of a control unit according to the first embodiment. FIG. 5 is a flowchart showing a control flow according to the first embodiment. FIG. 6 is a schematic diagram showing an arrangement of a transmitting antenna and a receiving antenna according to a comparative example of the first embodiment. FIG. 7 is a schematic diagram showing a virtual arrangement of virtual antennas according to a comparative example of the first embodiment. FIG. 8 is a schematic diagram showing an example of a usage environment of a radar device. FIG. 9 is a schematic diagram for explaining a phase difference that occurs when a signal arrives directly. FIG. 10 is a schematic diagram for explaining a phase difference that occurs when a signal is reflected by a road surface. FIG. 11 is a schematic diagram for explaining a phase difference on an outbound path in a direct path in the comparative example. FIG. 12 is a schematic diagram for explaining a phase difference on a return path in a direct path in the comparative example. FIG. 13 is a schematic diagram for explaining a phase difference between virtual antennas in a direct path in the comparative example. FIG. 1 is a schematic diagram for explaining a phase difference of a return path in a first triangular path of a comparative example. FIG. 1 is a schematic diagram for explaining a phase difference between virtual antennas in a first triangular path of a comparative example. FIG. 2 is a schematic diagram for explaining a phase difference of a return path in a second triangular path of a comparative example. FIG. 3 is a schematic diagram for explaining a phase difference between virtual antennas in a second triangular path of a comparative example. FIG. 4 is a schematic diagram for explaining a phase difference of an outgoing path in a first triangular path of a first embodiment. FIG. 5 is a schematic diagram for explaining a phase difference of a return path in a first triangular path of a first embodiment. FIG. 6 is a schematic diagram for explaining a phase difference between virtual antennas in a first triangular path of a first embodiment. FIG. 7 is a schematic diagram for explaining a phase difference of an outgoing path in a second triangular path of a first embodiment. FIG. 8 is a schematic diagram for explaining a phase difference of a return path in a second triangular path of a first embodiment. FIG. 9 is a schematic diagram for explaining a phase difference between virtual antennas in a second triangular path of a first embodiment.FIG. 10 is a schematic diagram showing an example of a combination of a transmitting circuit and a transmitting antenna, and a receiving circuit and a receiving antenna in a third embodiment. FIG. 11 is a schematic diagram showing an example of an arrangement of a transmitting antenna and a receiving antenna in the third embodiment. FIG. 12 is a schematic diagram showing a virtual antenna assumed in the third embodiment. FIG. 13 is a graph showing the relationship between a wiring length difference and a phase error. FIG. 14 is a table showing an example of a set of virtual antennas used in compensation processing. FIG. 15 is a schematic diagram showing an example of an arrangement of a transmitting antenna and a receiving antenna in a fourth embodiment. FIG. 16 is a schematic diagram showing the virtual position of a virtual antenna in the fourth embodiment.

[0013] Hereinafter, multiple embodiments of the present disclosure will be described with reference to the drawings. Note that corresponding components in each embodiment are designated by the same reference numerals, and redundant description may be omitted. Furthermore, when only a portion of the configuration is described in each embodiment, the configuration of another previously described embodiment may be applied to the remaining portions of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of multiple embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0014] First Embodiment A first embodiment of the present disclosure will be described with reference to FIGS. 1 to 25. In the following description, three mutually orthogonal directions will be referred to as the X direction, the Y direction, and the Z direction. In this embodiment, the Y direction is the vertical direction, and the X direction and the Z direction are horizontal directions. The X direction is the direction parallel to the surface on which the antennas TX and RX are disposed, and the Z direction is the direction perpendicular to the surface. A radar device 1 is mounted on a moving object such as a vehicle. The radar device 1 transmits a transmission signal and receives, as a received signal, the transmission signal reflected by a target, which is an object to be detected, and detects, as sensing data, the distance to the target, the relative speed with respect to the target, the direction of the target, and the like.

[0015] The sensing data output from the radar device 1 is input to an in-vehicle ECU (Electronic Control Unit) via an in-vehicle network such as a Control Area Network (CAN) (registered trademark) or Ethernet (registered trademark). The in-vehicle ECU executes various processes for autonomous driving of the vehicle and advanced driving assistance based on the acquired sensing data of each target.

[0016] The processes based on the sensing data include, for example, collision avoidance processing, warning processing, etc. The collision avoidance processing is a process of controlling the vehicle to avoid collision with the target by controlling the brake system, steering system, etc. based on the sensing data of each target. The warning processing is a process of warning the driver of the possibility of collision with the target based on the sensing data of each target.

[0017] 1 , the radar device 1 of this embodiment includes an oscillator 2, multiple transmission circuits 3, multiple transmission antennas TX, multiple reception antennas RX, multiple reception circuits 4, a temperature sensor 5, and a control unit 6. The radar device 1 is a so-called MIMO (Multiple-Input-Multiple-Output) radar that transmits transmission signals from multiple transmission antennas TX to artificially increase the number of reception antennas RX beyond the actual number.

[0018] The oscillator 2 receives a control signal from the control unit 6 and generates a modulated signal modulated in response to the control signal. The modulated signal is, for example, a so-called chirp signal whose frequency changes over time. The modulated signal is distributed and output to each channel of the transmitting circuit 3 and the receiving circuit 4. In the following, the modulated signal output from the oscillator 2 to the transmitting circuit 3 is referred to as a transmission signal. Also, the modulated signal output from the oscillator 2 to the receiving circuit 4 is referred to as a local signal.

[0019] The transmission circuit 3 and the reception circuit 4 are each mainly composed of a semiconductor integrated circuit device such as an MMIC (Monolithic Microwave Integrated Circuit). The transmission circuit 3 is connected to a transmission antenna TX and outputs a transmission signal to the transmission antenna TX. If the number of transmission circuits 3 mounted on one radar device 1 is Ns, Ns is an integer equal to or greater than 2. The transmission circuit 3 includes amplifiers 30, the number of which is the same as the number of connected transmission antennas TX. The amplifiers 30 amplify the transmission signal output from the oscillator 2 and output the amplified signal to the corresponding transmission antenna TX.

[0020] The transmitting antenna TX converts an electrical signal, as a transmission signal, supplied from the oscillator 2 into a radio wave signal and transmits it to the outside world. The transmitting antenna TX is configured to include at least one antenna element. For example, the transmitting antenna TX is a patch antenna having multiple flat antenna elements. The antenna elements are arranged on the surface opposite to the ground plane of a dielectric substrate having a ground plane on one surface, so as to face the ground plane. The multiple antenna elements are connected, for example, in series, by a feeder line that supplies the electrical signal.

[0021] The receiving antenna RX receives, as a received signal, a radio wave signal including a transmission signal reflected by a target in the external environment as a reflecting object. The receiving antenna RX is connected to a corresponding receiving circuit 4. The arrangement of the transmitting antenna TX and the receiving antenna RX will be described later.

[0022] The receiving antenna RX converts the received signal as a radio wave signal into an electrical signal and outputs it to the corresponding receiving circuit 4. The receiving antenna RX is, for example, a patch antenna in the same manner as the transmitting antenna TX, in which at least one antenna element is connected in series by a feeder line.

[0023] The receiving circuit 4 is connected to the receiving antenna RX and acquires the received signal received by the receiving antenna RX. If the number of receiving circuits 4 mounted on one radar device 1 is Nr, Nr is an integer equal to or greater than 2. The receiving circuit 4 includes amplifiers 40 and signal mixers 41, the number of which is the same as the number of connected receiving antennas RX.

[0024] The amplifier 40 amplifies the received signal received by the receiving antenna and outputs the amplified signal to the signal mixer 41. The signal mixer 41 generates a beat signal by mixing the local signal from the oscillator 2 with the received signal. The generated beat signal is an interference signal that represents the frequency difference between the received signal and the local signal. The beat signal is filtered by a low-pass filter (not shown) to remove high-frequency components that fall outside the frequency difference between the received signal and the local signal, and is then output to the control unit 6 as signal data correlated with the received signal.

[0025] The temperature sensor 5 detects the temperature inside the radar device 1. The temperature sensor 5 includes, for example, a thermistor, and outputs temperature information corresponding to the resistance value of the thermistor. The temperature sensor 5 detects temperature information of each of the transmission circuits 3 and the reception circuits 4, and outputs the information to the control unit 6.

[0026] The control unit 6 is a control unit including at least one dedicated computer. The dedicated computer constituting the control unit 6 may be, for example, an ECU (Electronic Control Unit) specialized for controlling the radar device 1.

[0027] The dedicated computer constituting the control unit 6 has at least one memory 6a and one processor 6b. The memory 6a is at least one type of non-transitory tangible storage medium, such as a semiconductor memory, a magnetic medium, or an optical medium, that non-temporarily stores computer-readable programs and data. Here, "storage" may refer to accumulation in which data is retained even when the sensor system is turned off, or temporary storage in which data is erased when the sensor system is turned off. The processor 6b may include at least one type of core, such as a central processing unit (CPU), a graphics processing unit (GPU), a reduced instruction set computer (RISC)-CPU, a data flow processor (DFP), or a graph streaming processor (GSP). Alternatively, the processor 6b may be at least one of a digital circuit and an analog circuit. Here, the digital circuit is at least one of, for example, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), an SOC (System on a Chip), a PGA (Programmable Gate Array), and a CPLD (Complex Programmable Logic Device), etc. Furthermore, such a digital circuit may have a memory 6 a that stores a program.

[0028] The control unit 6 processes the beat signals output from the receiver circuits 4 to perform angle measurement processing to calculate the angle of a reflecting object relative to the radar device 1. The radar device 1 ensures relatively high angular resolution by using a MIMO system to pseudo-ensure that the number of receiver antennas RX is greater than the actual number. In addition, the control unit 6 ensures relatively high angle measurement accuracy by performing compensation processing to compensate for signal phase differences and amplitude differences that occur between different transmitter circuits 3 and different receiver circuits 4.

[0029] For the above compensation process, the transmitting antennas TX and receiving antennas RX are mounted in a specified arrangement. The arrangement of the transmitting antennas TX and receiving antennas RX will be described below with reference to specific examples shown in Figures 2 to 4.

[0030] With multiple transmitting antennas TX and multiple receiving antennas RX, multiple virtual antennas V corresponding to the phase differences of the received signals between the receiving antennas RX are assumed for each transmitting antenna TX. The virtual position of each virtual antenna V is defined by the relative position of the corresponding transmitting antenna TX with respect to the other transmitting antennas TX and the relative position of the corresponding receiving antenna RX with respect to the other receiving antennas RX.

[0031] The transmitting antennas TX and receiving antennas RX are arranged so that the virtual positions of the virtual antennas V assumed for each transmitting antenna TX overlap and mismatched pairs are formed with mismatched combinations of the transmitting circuits 3 and the receiving circuits 4. In addition, the transmitting antennas TX and receiving antennas RX are arranged so that the number of mismatched pairs in a non-overlapping group, which is a group of mismatched pairs in which the combination patterns of the transmitting circuits 3 and the receiving circuits 4 do not overlap with other pairs, is at least Ns+Nr-2 pairs.

[0032] As an example, assume that the radar device 1 is equipped with four transmitting antennas TX and six receiving antennas RX. Furthermore, in this example, the number of transmitting circuits 3 is Ns = 2, and the number of receiving circuits 4 is Nr = 2. In this case, as shown in FIG. 2 , the number of channels in each transmitting circuit 3 is at least two, and the number of channels in each receiving circuit 4 is at least three. Hereinafter, one of the transmitting circuits 3 is referred to as a first transmitting circuit 3_1, and the other as a second transmitting circuit 3_2. Furthermore, one of the receiving circuits 4 is referred to as a first receiving circuit 4_1, and the other as a second receiving circuit 4_2. In this embodiment, each circuit is mounted on a plurality of circuit chips C. Specifically, the first transmitting circuit 3_1 and the first receiving circuit 4_1 are mounted on the same first circuit chip C1. The second transmitting circuit 3_2 and the second receiving circuit 4_2 are mounted on the same second circuit chip C2. It is assumed that the wiring lengths Wt between the transmitting antennas TX and the corresponding transmitting circuits 3 are all substantially the same. Also, it is assumed that the wiring lengths of the wirings Wr between the receiving antennas RX and the corresponding receiving circuits 4 are all substantially the same.

[0033] Furthermore, in the following description, the four transmitting antennas TX and six receiving antennas RX may be distinguished by assigning different reference symbols to them. Specifically, the two transmitting antennas TX connected to the first transmitting circuit 3_1 are referred to as transmitting antennas TX1_1 and TX1_2, and the two transmitting antennas TX connected to the second transmitting circuit 3_2 are referred to as transmitting antennas TX2_1 and TX2_2. The three receiving antennas RX connected to the first receiving circuit 4_1 are referred to as receiving antennas RX1_1, RX1_2, and RX1_3, and the three receiving antennas RX connected to the second receiving circuit 4_2 are referred to as receiving antennas RX2_1, RX2_2, and RX2_3.

[0034] In this case, the transmitting antennas TX and receiving antennas RX are arranged so that the number of pairs of transmitting circuits 3 and receiving circuits 4 that do not overlap with other pairs in the above-mentioned group of virtual antennas V is at least Ns + Nr - 2 pairs, i.e., 2 pairs. In this embodiment, the transmitting antennas TX and receiving antennas RX are each arranged two-dimensionally. Specifically, the transmitting antennas TX and receiving antennas RX are both arranged so that they are aligned in at least two directions, the X direction and the Y direction.

[0035] 3, the transmitting antennas TX1_1 and TX2_1 are arranged side by side in this order with a gap of 2d between them in the X direction. In other words, the transmitting antennas TX1_1 and TX2_1 are arranged so that their positions overlap in the Y direction. The Y direction is an example of a "specific direction."

[0036] Furthermore, the transmitting antennas TX1_2, TX1_2 are also arranged side by side in this order from one side to the other in the X direction, with a gap of 2d between them, and are arranged so as to overlap in the Y direction. Furthermore, the transmitting antennas TX1_1, TX1_2 are arranged side by side with a gap of 2d between them in the Y direction. Similarly, the transmitting antennas TX2_1, TX2_2 are arranged side by side with a gap of 2d between them in the Y direction. That is, the transmitting antennas TX1_2, TX2_2 are arranged parallel to the transmitting antennas TX1_1, TX2_1, with a gap of 2d between them.

[0037] The receiving antennas RX1_1, RX1_2, and RX2_1 are arranged in this order from one side to the other in the X direction. That is, the receiving antennas RX1_1, RX1_2, and RX2_1 are arranged so that their positions overlap in the Y direction. The receiving antennas RX1_1 and RX1_2 are arranged with a distance d between them. The receiving antennas RX1_2 and RX2_1 are arranged with a distance 2d between them.

[0038] The receiving antennas RX1_3, RX2_2, and RX2_3 are arranged in this order from one side to the other in the X direction. That is, the receiving antennas RX1_3, RX2_2, and RX2_3 are arranged so that their positions in the Y direction overlap. The receiving antennas RX1_1 and RX1_2 are arranged with a distance d between them, and the receiving antennas RX1_2 and RX2_1 are arranged with a distance 2d between them.

[0039] Furthermore, the row of receiving antennas RX1_1, RX1_2, and RX2_1 and the row of receiving antennas RX1_3, RX2_2, and RX2_3 are arranged with a gap of 2d in the Y direction. Under this arrangement, the receiving antennas RX1_1 and RX1_3 are arranged so that their positions overlap in the X direction. Furthermore, the receiving antennas RX1_2 and RX2_2 are also arranged so that their positions overlap in the X direction. Similarly, the receiving antennas RX2_1 and RX2_3 are also arranged so that their positions overlap in the X direction.

[0040] The number of virtual antennas V is assumed to be the same as the number of receiving antennas RX, i.e., six, for each transmitting antenna TX1_1, TX1_2, TX2_1, and TX2_2. Therefore, a total of 24 virtual antennas V are virtually formed. The virtual antennas V are virtually placed for each transmitting antenna TX at virtual positions corresponding to the placement of the six receiving antennas RX.

[0041] Here, for the transmitting antenna TX1_1, the virtual antennas V formed virtually for the receiving antennas RX1_1, RX1_2, RX2_1, RX1_3, RX2_2, and RX2_3 are designated as virtual antennas V1, V2, V3, V4, V5, and V6, in that order. Furthermore, for the transmitting antenna TX1_2, the virtual antennas V formed virtually for each receiving antenna RX are designated as virtual antennas V7, V8, V9, V10, V11, and V12, in the order of the receiving antennas RX. Similarly, the virtual antennas V formed virtually for the transmitting antenna TX2_1 are designated as virtual antennas V13, V14, V15, V16, V17, and V18, in the same order. Similarly, the virtual antennas V assumed for the transmitting antenna TX2_2 are designated as virtual antennas V19, V20, V21, V22, V23, and V24.

[0042] In this embodiment, the transmitting antenna TX and the receiving antenna RX are arranged so that three or more virtual antennas V are virtually formed in the Y direction. In angle detection, in order to increase the maximum detection angle without angle ambiguity while increasing the angular resolution, it is necessary to narrow the minimum antenna spacing and widen the antenna aperture width. When the number of virtual antennas V is two, the minimum antenna spacing and the antenna aperture width are essentially the same, and therefore they cannot be designed independently. For example, if the maximum detection angle is prioritized, the antenna aperture width becomes smaller and the angular resolution decreases. On the other hand, if the angular resolution is prioritized, the maximum detection angle becomes narrower. Therefore, by arranging the antennas so that three or more virtual antennas V are virtually formed side by side, the minimum antenna spacing and the antenna aperture width can be designed independently.

[0043] 4 shows a virtual arrangement of virtual antennas V virtually formed in the arrangement of FIG. 3. Transmitting antennas TX adjacent to each other in the X direction are arranged at an interval of 2d. Therefore, the virtual antennas V assumed for a specific transmitting antenna TX are at a virtual position relatively shifted by 2d from the set of virtual antennas V assumed for transmitting antennas TX adjacent to each other in the X direction. Furthermore, transmitting antennas TX adjacent to each other in the Y direction are arranged at an interval of 2d. Therefore, the virtual antennas V assumed for a specific transmitting antenna TX are at a virtual position relatively shifted by 2d from the set of virtual antennas V assumed for transmitting antennas TX adjacent to each other in the Y direction.

[0044] In FIG. 4, the virtual positions of the multiple virtual antennas V for each transmitting antenna TX are illustrated shifted in the vertical direction of the page. In reality, virtual antennas V1 to V3 and virtual antennas V13 to V15 are virtually formed at virtual positions on a virtual line VL1 extending in the X direction. Virtual antennas V4 to V9 and virtual antennas V16 to V21 are virtually formed at virtual positions on a virtual line VL2. Virtual antennas V10 to V11 and virtual antennas V22 to V24 are virtually formed at virtual positions on a virtual line VL3. Virtual line VL2 is a virtual line extending parallel to virtual line VL1 at a distance 2d from virtual line VL1. Virtual line VL3 is a virtual line extending parallel to virtual line VL2 at a distance 2d from virtual line VL2.

[0045] Hereinafter, a specific pair of virtual antennas V whose virtual positions overlap will be denoted as (Vn, Vm) using the symbols assigned to each individual virtual antenna V (n and m are natural numbers). As shown in Fig. 4 , in this arrangement, (V3, V14), (V4, V7), (V5, V8), (V6, V9), (V6, V17), (V6, V20), (V9, V17), (V9, V20), (V12, V23), (V16, V19), (V17, V20), and (V18, V21) are assumed pairs of virtual antennas V whose virtual positions overlap.

[0046] Among these, seven pairs, (V3, V14), (V5, V8), (V6, V17), (V6, V20), (V9, V17), (V9, V20), and (V12, V23), are mismatched pairs in which the combinations of the transmitter circuits 3 and receiver circuits 4 corresponding to the respective virtual antennas V do not match among the virtual antennas V. For example, for the pair (V3, V14), the combination of the transmitter circuit 3_1 and receiver circuit 4_2 corresponds to the virtual antenna V3. The combination of the transmitter circuit 3_2 and receiver circuit 4_1 corresponds to the virtual antenna V14, which is mismatched with the combination of the virtual antenna V3. Similarly, for the pair (V6, V17), the combination of the transmitter circuit 3_1 and receiver circuit 4_2 corresponds to the virtual antenna V6. The combination of the transmitter circuit 3_2 and receiver circuit 4_2 corresponds to the virtual antenna V17. In this pair, the receiving circuit 4_2 is common but the transmitting circuits 3_1 and 3_2 are different, so it is a mismatched pair as a combination of the circuits 3 and 4. (V5, V8), (V6, V20), (V9, V17), (V9, V20), (V12, V23), and (V17, V20) are also mismatched pairs.

[0047] Among these, (V3, V14), (V6, V20), and (V9, V20) are combination patterns of the transmitter circuit 3 and the receiver circuit 4 that overlap. Specifically, the circuits 3 and 4 corresponding to (V3, V14) are combination patterns that combine the transmitter circuit 3_1 and the receiver circuit 4_2, and the transmitter circuit 3_2 and the receiver circuit 4_1. Similarly, (V6, V20) and (V9, V20) are combination patterns that overlap. Similarly, the circuits 3 and 4 corresponding to (V6, V17) are combination patterns that combine the transmitter circuit 3_1 and the receiver circuit 4_2, and the transmitter circuit 3_2 and the receiver circuit 4_2, and this pattern overlaps with (V9, V17) and (V12, V23).

[0048] Here, among the seven mismatched pairs, a non-overlapping group is assumed, which is a group of mismatched pairs whose combination patterns of the transmitter circuits 3 and receiver circuits 4 do not overlap with each other. The assumed non-overlapping group is a group of nine different groups consisting of one of (V3, V14), (V6, V20), and (V9, V20), one of (V6, V17), (V9, V17), and (V12, V23), and (V5, V8). Among these mismatched pairs, (V5, V8), (V6, V20), and (V9, V17) are pairs in which at least one of the corresponding transmitter antennas TX and the corresponding receiver antennas RX do not overlap in the Y direction. For example, for (V5, V8), the antennas TX and RX corresponding to virtual antenna V5 are transmitter antenna TX1_1 and receiver antenna 2_2. On the other hand, the antennas TX and RX corresponding to virtual antenna V8 are transmitting antenna TX1_2 and receiving antenna 1_2. The transmitting antennas TX1_1 and TX1_2 are spaced apart 2d in the Y direction, so their Y-directional positions do not overlap. Similarly, the receiving antennas RX2_2 and RX1_2 do not overlap in the Y direction. Similarly, for (V6, V20) and (V9, V17), the transmitting antennas TX and the receiving antennas RX do not overlap in the Y direction. On the other hand, for (V3, V14), (V6, V17), (V9, V20), and (V12, V23), the corresponding transmitting antennas TX and the receiving antennas RX do overlap in the Y direction. For example, for (V3, V14), the transmitting antenna TX1_1 and the receiving antenna 2_1 correspond to virtual antenna V3. On the other hand, transmitting antenna TX2_1 and receiving antenna 1_2 correspond to virtual antenna V14. Since transmitting antennas TX1_1 and TX2_1 are arranged side by side in the X direction, their positions in the Y direction overlap. Similarly, receiving antennas RX2_1 and RX1_2 also overlap in the Y direction. The same is true for (V6, V17), (V9, V20), and (V12, V23).

[0049] As a result, there are four non-overlapping groups formed by mismatched pairs in which corresponding transmitting antennas TX and receiving antennas RX are overlapped in the Y direction. Each group is composed of one of (V3, V14) and (V9, V20) and one of (V6, V17) and (V12, V23). Each of these four groups is composed of two mismatched pairs. The number of pairs satisfies the condition that the number of pairs is equal to or greater than Ns + Nr - 2. The reception processing unit 62 compensates for errors between the transmitting circuits 3 and the receiving circuits 4 based on the reception results of at least one of (V3, V14) and (V9, V20) and at least one of (V6, V17) and (V12, V23).

[0050] The control unit 6 may additionally use mismatched pairs in which the combination patterns of the transmitter circuit 3 and the receiver circuit 4 overlap with the mismatched pairs in the non-overlapping group as pairs to be used in the compensation process.

[0051] To control the radar device 1, including the compensation process described above, the processor 6b executes a plurality of instructions contained in a control program stored in the memory 6a. In this way, the control unit 6 implements a functional section for controlling the radar device 1. Specifically, as shown in FIG. 6, the control unit 6 implements a transmission processing section 61 and a reception processing section 62 as functional sections.

[0052] The radar control method in which the control unit 6 controls the radar device 1 by using the functions of the processor 6b is executed according to the control flow shown in Figure 7. This control flow is executed repeatedly while the vehicle is running. Note that each "S" in this control flow represents a plurality of steps executed by a plurality of instructions included in the control program.

[0053] First, in S10, the transmission processing unit 61 causes the oscillator 2 to output a transmission signal. Subsequently, in S20, the reception processing unit 62 acquires, from the receiving circuit 4, a beat signal corresponding to a received signal received by the receiving antenna RX after the transmission signal transmitted to the outside world from the transmitting antenna TX is reflected by a target. Subsequently, in S30, the reception processing unit 62 converts the beat signal into a digital signal by A / D conversion processing, which samples the beat signal at predetermined time intervals. Subsequently, in S40, the reception processing unit 62 performs FFT (Fast Fourier Transform) processing for each chirp of the A / D converted beat signal. As a result, the reception processing unit 62 acquires, for each chirp, a frequency spectrum (distance spectrum) showing a peak at a frequency position corresponding to the distance to the target. The distance spectrum is data indicating the signal strength for each distance bin according to the distance resolution.

[0054] The reception processing unit 62 then performs FFT processing on the distance spectrum. That is, the reception processing unit 62 performs a second FFT processing on a waveform in which the phases at the distance bins obtained by the first FFT processing for the multiple chirps are arranged in time series. This results in a frequency spectrum (velocity spectrum) showing peaks at positions corresponding to the relative velocity from the target for each velocity bin. Through the above two-dimensional FFT, the reception processing unit 62 acquires two-dimensional information (RV map) showing peaks at positions corresponding to the distance to the target and the relative velocity of the target.

[0055] Next, in S50, the reception processing unit 62 extracts a peak from the RV map. Subsequently, in S60, the reception processing unit 62 acquires the intensity of the extracted peak. Then, in S70, the reception processing unit 62 determines whether the extracted peak is valid. For example, the reception processing unit 62 determines that the peak is valid if the intensity of the peak is within an allowable intensity range. Here, the allowable intensity range is a range in which the intensity is equal to or greater than a predetermined threshold. If it is determined that a valid peak exists, the flow proceeds to S80.

[0056] In S75, the reception processing unit 62 determines whether the target distance is within an allowable range. The allowable range is a range in which the distance is equal to or less than a predetermined threshold distance. The target distance is an estimated distance estimated based on peaks in the distance spectrum, etc. If it is determined that the target distance is within the allowable range, the flow proceeds to S80.

[0057] In S80, the reception processing unit 62 compensates for the phase error between the transmission circuits 3 and the reception circuits 4 based on the phase of the effective peak in each virtual channel.

[0058] In the phase compensation process, the reception processing unit 62 defines a linear equation based on the phase difference of the peaks in the beat signal for each of Ns + Nr - 2 or more pairs of virtual antennas V, each pair of which does not overlap with other pairs in terms of the combination of the transmission circuit 3 and the reception circuit 4. This linear equation is defined with the relative phase error between the transmission circuits 3 and the reception circuits 4 as the unknown. The reception processing unit 62 obtains the solution of this linear equation as the relative phase error. Because the beat signal is a signal correlated with the reception signal, the phase difference of the peaks in the beat signal is an example of the result of comparing the reception signals between virtual antennas V.

[0059] The acquisition of the relative phase error will be described in detail below. In the following description, the phase at the peak of the beat signal corresponding to the virtual antenna Vn is defined as θ Ｖｎ (n is a natural number). In the compensation process, for example, a pair of virtual antennas V shown in Fig. 5 is used. That is, the reception processing unit 62 additionally uses two pairs of (V3, V14) and (V6, V17) included in the group, as well as (V9, V20), which is a combination of the transmission circuit 3 and the reception circuit 4 that overlaps with (V3, V14).

[0060] In this case, the phase difference θ of the peak for (V3, V14) Ｖ３ -θ Ｖ１４ is the phase difference θ of the peaks related to equation (1), (V6, V17) Ｖ６ -θ Ｖ１７ is the phase difference θ of the peaks related to equation (2), (V9, V20) Ｖ９ -θ Ｖ２０can be defined by the relationship shown in equation (3).

[0061] In the above formula, Θ ａ , Θ ｂ , Θ ｃ are the target-induced phase errors, and e ｔｘ１ is the phase error of the signal generated in the first transmission circuit 3_1, e ｔｘ２ is the phase error of the signal generated in the second transmission circuit 3_2. ｒｘ１ is the phase error of the signal generated in the first receiving circuit 4_1, e ｒｘ２ is the phase error of the signal generated in the second receiving circuit 4_2.

[0062] Here, in the phase compensation, it is sufficient to consider the relative phase error between the transmission circuits 3 and the relative phase error between the reception circuits 4. Therefore, when the relative phase error of the second transmission circuit 3_2 relative to the first transmission circuit 3_1 and the relative phase error of the second reception circuit 4_2 relative to the first reception circuit 4_1 are considered, e ｔｘ１ , e ｒｘ１ = 0. Therefore, the formulas (1) to (3) can be transformed into the following formulas (4) to (6).

[0063] When equations (4) to (6) are converted into a matrix format, the phase difference and relative phase error of each pair satisfy the relationship expressed by equation (7) below.

[0064] Here, the term on the left side of Equation (7) is a phase difference vector Y1 between the overlapping virtual antennas V. The first term on the right side of Equation (7) is a coefficient matrix A1. The second term is a phase error vector X1. In Equation (7), the phase difference vector Y1 can be calculated from the phase of the peak in each beat signal. The coefficient matrix A1 is a constant matrix defined by the combination of the transmitting circuit 3 and the receiving circuit 4 of each set of virtual antennas V. Therefore, Equation (7) can be expressed as e ｔｘ２ , e ｒｘ２That is, the reception processing unit 62 can solve the simultaneous equations with e as the solution of the equation (7). ｔｘ２ , e ｒｘ２ are obtained as the relative phase error of the second transmission circuit 3_2 with respect to the first transmission circuit 3_1 and the relative phase error of the second reception circuit 4_2 with respect to the first reception circuit 4_1.

[0065] In the next step S90, the reception processing unit 62 obtains the amplitude error between the transmission circuits 3 and the reception circuits 4 based on the amplitude of the effective peak in each virtual antenna V.

[0066] In the amplitude compensation process, similar to the phase compensation process, the reception processing unit 62 defines a linear equation based on the amplitude difference of the peaks of the beat signals for each mismatched pair in the non-overlapping group, with the amplitude error between the transmission circuits 3 and the reception circuits 4 as unknowns. The reception processing unit 62 obtains the solution of this linear equation as the relative amplitude error. The amplitude difference of the peaks in the beat signals is an example of the comparison result of the reception signals between the virtual antennas V.

[0067] In the following description, it is assumed that the same set of virtual antennas V as in the above-described phase compensation process is also used in the amplitude compensation process. In the following description, the amplitude at the peak of the beat signal corresponding to the virtual antenna Vn is denoted as A Ｖｎ (n is a natural number). In this case, the amplitude difference A of the peak for (V3, V14) Ｖ３ -A Ｖ１４ is the amplitude difference A of the peaks related to equation (8), (V6, V17) Ｖ６ -A Ｖ１７ is the amplitude difference A of the peaks related to equation (9), (V9, V20) Ｖ９ -A Ｖ２０ can be defined by the relationship shown in Equation (10).

[0068] In the above formula, G ａ , G ｂ , G ｃ are the amplitude errors caused by the target, and G ｔｘ１ is the amplitude error of the signal generated in the first transmission circuit 3_1, Gｔｘ２ is the amplitude error of the signal generated in the second transmission circuit 3_2. ｒｘ１ is the amplitude error of the signal generated in the first receiving circuit 4_1, G ｒｘ２ is the amplitude error of the signal generated in the second receiving circuit 4_2.

[0069] Here, similarly to the phase compensation, when the relative amplitude error of the second transmission circuit 3_2 with respect to the first transmission circuit 3_1 and the relative amplitude error of the second reception circuit 4_2 with respect to the first reception circuit 4_1 are taken into consideration, G ｔｘ１ , G ｒｘ１ = 0. Therefore, the formulas (8) to (10) can be transformed into the following formulas (11) to (13).

[0070] Here, equations (11) to (13) are converted into a matrix format, and the amplitude difference and relative amplitude error of each pair satisfy the relationship expressed in equation (14) below after conversion.

[0071] Here, the term on the left side of Equation (14) is an amplitude difference vector Y2 between the overlapping virtual antennas V. The first term on the right side of Equation (14) is a coefficient matrix A2. The second term is an amplitude error vector X2. The amplitude difference vector Y2 is obtained from the amplitude of the peak in each beat signal. The coefficient matrix A2 is a constant matrix, just like the coefficient matrix A1. That is, the reception processing unit 62 calculates G as a solution of Equation (14). ｔｘ２ , G ｒｘ２ are obtained as the relative amplitude error of the second transmission circuit 3_2 with respect to the first transmission circuit 3_1 and the relative amplitude error of the second reception circuit 4_2 with respect to the first reception circuit 4_1.

[0072] Then, in S100, the reception processing unit 62 compensates for the phase error between the transmission circuits 3 and between the reception circuits 4. For example, the reception processing unit 62 stores the acquired relative phase error in the memory 6a as compensation data to be used when acquiring a relative angle, which will be described later. Furthermore, in S110, the reception processing unit 62 compensates for the relative amplitude error between the transmission circuits 3 and between the reception circuits 4 by storing it in the memory 6a as compensation data.

[0073] After S110, the flow proceeds to S180. If it is determined in S75 that the target distance is outside the allowable range, the flow skips the processes of S80 to S110 and proceeds to S180.

[0074] On the other hand, if it is determined in S70 that no valid peak exists, the flow proceeds to S110. In S110, the reception processing unit 62 acquires the temperatures of each transmission circuit 3 and each reception circuit 4 from the temperature sensor 5. Then, in S120, the reception processing unit 62 reads from the memory 6a a correction table for the phase error and amplitude error between the transmission circuits 3 according to temperature.

[0075] Next, in S130, the reception processing unit 62 compares the acquired temperature with a correction table to acquire the relative phase error between the transmission circuits 3 and between the reception circuits 4. Then, in S140, the reception processing unit 62 compensates for the relative phase error between the transmission circuits 3 and between the reception circuits 4. After S140, the flow proceeds to S150.

[0076] In S180, the reception processing unit 62 acquires the relative angle of the target. The reception processing unit 62 acquires the relative angle according to the phase difference between the received signals at each virtual antenna V. Specifically, the reception processing unit 62 performs FFT processing on a waveform in which the phases of each peak in an integrated spectrum obtained by integrating the compensated Doppler spectra corresponding to each virtual antenna V are aligned. In this way, the reception processing unit 62 acquires an angular spectrum showing peaks at positions corresponding to the relative angle from the target. The reception processing unit 62 acquires the relative angle by extracting the peaks of the angular spectrum.

[0077] Then, in S190, the reception processing unit 62 outputs the sensing data to the in-vehicle ECU, etc. The sensing data includes, for example, at least one of the target distance, speed, and relative angle.

[0078] According to this first embodiment, phase differences between different transmission circuits and different reception circuits can be compensated for based on the comparison results of the received signals between virtual antennas in at least Ns + Nr - 2 mismatched pairs. Therefore, error compensation processing can be performed not only between different reception circuits 4 but also between different transmission circuits 3. Furthermore, the corresponding transmission antennas TX and receiving antennas RX of a mismatched pair are arranged in overlapping positions in a specific direction. Therefore, the occurrence of phase errors between virtual antennas in a mismatched pair can be avoided when a transmitted signal is reflected by a reflecting object other than the target on the outbound or return path. Therefore, compensation accuracy can be improved.

[0079] Furthermore, by arranging at least one of the transmitting antennas TX and the receiving antennas RX at unequal intervals in at least one direction, the virtual aperture length can be larger than when the receiving antennas TX and RX are arranged at equal intervals. Specifically, in this embodiment, the receiving antennas TX are arranged at unequal intervals of d and 2d, so the aperture length in the X direction is larger than when the receiving antennas TX are arranged at equal intervals aligned with the smaller interval d. The aperture length here is the distance from one end to the other end of the virtual antenna V. Specifically, when the receiving antennas TX are arranged at equal intervals of d, the aperture length in the X direction is 4d, while in this embodiment, the aperture length in the X direction is 5d. Therefore, it is possible to achieve both compensation accuracy and spatial resolution.

[0080] Here, the elimination of the phase difference caused by the triangular path will be described in detail below. Figure 8 shows the arrangement of antennas TX and RX in a comparative example. In this comparative example, transmitting antennas TX1_1, TX2_1, TX2_2, and TX1_2 are arranged side by side in the Y direction. Specifically, transmitting antennas TX1_1, TX2_1, TX2_2, and TX1_2 are arranged in this order from top to bottom with a distance d between them. Furthermore, the number and arrangement of receiving antennas RX are the same as in the first embodiment. That is, in the comparative example, the arrangement positions of the transmitting antennas TX do not overlap in the Y direction.

[0081] In this case, the virtual antennas V are arranged as shown in Fig. 9. Among the pairs of virtual antennas V whose virtual positions overlap, there are seven mismatched pairs: (V4, V7), (V5, V8), (V6, V9), (V11, V14), (V16, V19), (V17, V20), and (V18, V21).

[0082] Among these, (V4, V7) and (V16, V19) have overlapping combination patterns of the transmitting circuit 3 and the receiving circuit 4. Similarly, (V6, V9) and (V18, V21) have overlapping combination patterns of the transmitting circuit 3 and the receiving circuit 4.

[0083] Therefore, the non-overlapping group can be, for example, (V4, V7), (V5, V8), (V6, V9), (V11, V14), or (V17, V20). Note that a group in which at least one of (V4, V7) and (V16, V19) in this non-overlapping group is replaced with a mismatched pair of overlapping combination patterns is also a non-overlapping group.

[0084] 10, it is assumed that the radar device 1 is used on a road. The signal path between a signal transmission / reception point Pa in the radar device 1 and a specific reflection point Pb on a certain target may be a non-coincident path, where the outbound path and the return path do not match.

[0085] One specific path mismatch is a first triangular path in which a signal travels directly from a transmission / reception point Pa to a reflection point Pb on the outbound path, and is reflected at a specific reflection point Pc on the road surface on the return path before reaching the transmission / reception point Pa. Another specific path is a second triangular path in which a signal travels from the transmission / reception point Pa to a reflection point Pc on the outbound path, and is reflected at a reflection point Pc before reaching the reflection point Pb, and is directed from the reflection point Pb to the transmission / reception point Pa on the return path.

[0086] 11 and 12, a relative phase difference occurs between the signals received at each virtual antenna V according to the Y-direction positions of the transmitting antenna TX and receiving antenna RX corresponding to the virtual antenna V. As a result, the phase angle of the received signal of a virtual antenna V in which at least one of the transmitting antenna TX and receiving antenna RX is shifted from the reference position in the Y-direction is shifted relative to the virtual antenna V formed by the transmitting antenna TX and receiving antenna RX at the reference position.

[0087] For example, in the case of a direct path in which a signal travels directly between a transmitting / receiving point Pa and a reflecting point Pb on both the outbound and return paths, if the transmitting antenna TX1_1 is set as the reference position (i.e., phase angle 0) for the transmitting antenna TX, the phase angle shift shown in Fig. 13 occurs on the outbound path of the signal transmitted from each of the transmitting antennas TX2_1, TX2_2, and TX1_2. Also, if the receiving antennas RX1_1, RX1_2, and RX2_1 are set as the reference positions for the receiving antenna RX, the phase angle shift shown in Fig. 14 occurs on the return path of the signal received by the receiving antennas RX1_3, RX2_2, and RX2_3.

[0088] That is, for each virtual antenna V, a relative phase angle occurs between the received signals, which is the sum of the phase angle shift on the outbound path due to the Y-direction position of the corresponding transmitting antenna TX and the phase angle shift on the return path due to the Y-direction position of the receiving antenna RX.

[0089] In the case of a direct path, as shown in Fig. 15, the relative phase angles of the virtual antennas V of the mismatched pair are the same. Therefore, when the phase difference between the virtual antennas V of the mismatched pair is calculated in the process of compensating for the phase error between the circuits 3 and 4, this relative phase angle is canceled out. Therefore, there is no substantial effect on the calculation of the phase error between the circuits 3 and 4. Note that even when the signal passes through a path that reflects at the reflection point Pc on both the outbound and inbound paths, the relative phase angles of the virtual antennas V of the mismatched pair are the same.

[0090] However, when transmission and reception occur via a triangular path, the relative phase angle affects the compensation process. For example, in the case of the first triangular path, for the receiving antenna RX, as shown in Figure 16, a phase angle shift -dsinφ with respect to the receiving antennas RX1_1, RX1_2, and RX2_1 occurs on the return path of the signal received by the receiving antennas RX1_3, RX2_2, and RX2_3. Note that the phase angle occurring on the outgoing path of the signal is the same as in Figure 13.

[0091] 17, the relative phase angles between the virtual antennas V of a mismatched pair are mismatched due to the difference in the Y-direction positions of the transmitting antenna TX and the receiving antenna RX. In other words, when a phase difference is calculated between the virtual antennas V of a mismatched pair in the phase error compensation process, the difference between these relative phase angles is also included in the phase difference between the circuits. This causes a decrease in accuracy in calculating the phase error between the circuits.

[0092] 18, for the second triangular path, a phase angle shift of -d sinφ occurs in the outbound path of the signal transmitted from transmitting antenna TX2_1 with respect to transmitting antenna TX1_1. Similarly, a phase angle shift of -2d sinφ occurs in the outbound path of the signal transmitted from transmitting antenna TX2_2. And a phase angle shift of -3d sinφ occurs in the outbound path of the signal transmitted from transmitting antenna TX1_2.

[0093] Therefore, as in the case of the first triangular path, the relative phase angles between the virtual antennas V of the mismatched pair are mismatched (see FIG. 19 ). Therefore, in any case of the triangular path, the difference in the Y-direction positions of the transmitting antenna TX and the receiving antenna RX can result in a decrease in the accuracy of the calculation of the phase error between the circuits 3 and 4. Note that the above description deals with the generation of triangular paths due to road surface reflections. However, objects other than the road surface, such as a reflective object (e.g., a tunnel ceiling) present in the Y-direction relative to the radar device 1, can also be a cause of path mismatches.

[0094] On the other hand, in the radar device 1 of the first embodiment, even when transmission and reception occur via a triangular path, the relative phase differences between the virtual antennas V of the mismatched pair are substantially the same.

[0095] For example, in the case of the first triangular path, as shown in Fig. 20, for the transmitting antenna TX, a phase angle shift of 2d sin θ occurs for the transmitting antennas TX1_1 and TX2_1 on the outbound path of the signals transmitted from the transmitting antennas TX1_2 and TX2_2. As for the receiving antenna RX, as shown in Fig. 21, a phase angle shift of -d sin φ occurs for the receiving antennas RX1_1, RX1_2, and RX2_1 on the return path of the signals received by the receiving antennas RX1_3, RX2_2, and RX2_3.

[0096] In the first embodiment, in each mismatched pair of a non-overlapping group, the Y-direction positions of the transmitting antennas TX and the receiving antennas RX overlap. Therefore, no deviation in the relative phase angle occurs due to differences in the Y-direction positions of the transmitting antennas TX on the outbound signal path. Similarly, no phase difference occurs due to differences in the Y-direction positions of the receiving antennas RX on the inbound signal path. Therefore, the relative phase angles of each virtual antenna V in the mismatched pairs of a non-overlapping group substantially match, as shown in FIG. 22 .

[0097] Furthermore, when transmission and reception via the second triangular path occurs, for the transmitting antenna TX, a phase angle shift of -2d sin φ occurs for the transmitting antennas TX1_1 and TX2_1 on the outbound path of the signal transmitted from the transmitting antennas TX1_2 and TX2_2, as shown in Fig. 23. For the receiving antenna RX, a phase angle shift of 2d sin θ occurs for the receiving antennas RX1_1, RX1_2, and RX2_1 on the return path of the signal received by the receiving antennas RX1_3, RX2_2, and RX2_3, as shown in Fig. 24.

[0098] However, as with the first triangular path, since the Y-direction positions of the transmitting antennas TX and the receiving antennas RX in the mismatched pair overlap, the relative phase angles of each virtual antenna V in the mismatched pair are substantially the same, as shown in FIG. 25 .

[0099] That is, regardless of which triangular path is used for transmission or reception, the relative phase angle caused by the triangular path is cancelled out when the phase difference between the mismatched pair of virtual antennas V is calculated in the compensation process. Therefore, the influence of the relative phase angle on the calculation of the phase error between circuits 3 and 4 is substantially avoided.

[0100] According to the first embodiment, the corresponding transmitting antennas TX and corresponding receiving antennas RX of a mismatched pair are arranged to overlap in the vertical direction, so that the radar device 1 can suppress a decrease in the accuracy of estimating the phase error caused by mismatched paths due to reflectors other than the target in the vertical direction, such as a road surface.

[0101] Furthermore, according to the first embodiment, when the target distance is within the allowable distance range, the compensation process is executed. Therefore, when the influence of the mismatch path is small, the phase error can be compensated. Therefore, the influence of the mismatch path can be further reduced, and the deterioration of the estimation accuracy of the phase error can be further suppressed.

[0102] Second Embodiment As shown in Figures 26 and 27, the second embodiment is a modification of the first embodiment. In the radar device 1 of the second embodiment, the number of transmitting antennas TX and receiving antennas RX, and the number of transmitting circuits 3 and receiving circuits 4 are the same as those in the first embodiment. The correspondence between the transmitting antennas TX and the transmitting circuits 3 and the correspondence between the receiving antennas RX and the receiving circuits 4 are also the same as those in the first embodiment. In the second embodiment, the transmitting antennas TX and the receiving antennas RX are arranged one-dimensionally. Here, "arranged one-dimensionally" means arranged so as to be aligned along one reference direction. In this embodiment, the antennas TX and RX are arranged side by side in the X direction.

[0103] More specifically, as shown in Fig. 26, transmitting antennas TX1_1, TX1_2, TX2_1, and TX2_2 are arranged in this order from one side to the other in the X direction, which is the reference direction. Transmitting antennas TX1_1 and TX1_2 are arranged with a distance of 6d between them. Transmitting antennas TX1_2 and TX2_1 are arranged with a distance of 4d between them. Furthermore, transmitting antennas TX2_1 and TX2_2 are arranged with a distance of 6d between them.

[0104] Furthermore, the receiving antennas RX1_1, RX1_2, RX2_1, RX2_2, RX1_3, and RX2_3 are arranged in this order from one side to the other in the reference direction at an interval d.

[0105] As in the first embodiment, 24 virtual antennas V are virtually formed. In this embodiment, for the transmitting antenna TX1_1, the virtual antennas V virtually formed for the receiving antennas RX1_1, RX1_2, RX2_1, RX1_3, RX2_2, and RX2_3 are designated as virtual antennas V1, V2, V3, V4, V5, and V6, in that order. Furthermore, for the transmitting antenna TX1_2, the virtual antennas V virtually formed for each receiving antenna RX are designated as virtual antennas V7, V8, V9, V10, V11, and V12, in the order of the receiving antennas RX. Furthermore, the virtual antennas V virtually formed for the transmitting antenna TX2_1 are designated as virtual antennas V13, V14, V15, V16, V17, and V18, in the same order. Similarly, virtual antennas V assumed for the transmitting antenna TX2_2 are virtual antennas V19, V20, V21, V22, V23, and V24.

[0106] Because the transmitting antennas TX1_1 and TX1_2 are arranged at an interval of 6d, the virtual antenna V assumed for transmitting antenna TX1_1 is at a virtual position relatively shifted by 6d from the virtual antenna V assumed for transmitting antenna TX1_2. Furthermore, the transmitting antennas TX1_2 and TX2_1 are arranged at an interval of 4d. Therefore, the virtual antenna V assumed for transmitting antenna TX1_2 is at a virtual position relatively shifted by 4d from the virtual antenna V assumed for transmitting antenna TX2_1. Furthermore, the transmitting antennas TX2_1 and TX2_2 are arranged at an interval of 6d. Therefore, the virtual antenna V assumed for transmitting antenna TX2_1 is at a virtual position relatively shifted by 6d from the virtual antenna V assumed for transmitting antenna TX2_2.

[0107] Therefore, with such an arrangement of antennas TX and RX, there are two pairs of virtual antennas V whose virtual positions overlap, as shown in Figure 27. Note that in Figure 27, each virtual antenna V is shown shifted in the vertical direction of the paper, but in reality, each virtual antenna V is assumed to have its virtual position on a virtual line VL extending in the X direction. That is, virtual antennas V that are located at the same horizontal position in Figure 27 are pairs of virtual antennas V whose virtual positions overlap. Specifically, (V11, V13) and (V12, V14) are pairs of virtual antennas V whose virtual positions overlap. Both of these pairs are mismatched pairs. Furthermore, these two pairs are non-overlapping groups.

[0108] In this embodiment, all transmitting antennas TX are arranged to overlap in the Y direction, and all receiving antennas RX are arranged to overlap in the Y direction. That is, all mismatched pairs included in a non-overlapping group also have corresponding transmitting antennas TX and corresponding receiving antennas RX arranged to overlap in the Y direction. The reception processing unit 62 performs compensation processing based on received signals that can be acquired from at least two pairs of virtual antennas V from these pairs.

[0109] In the second embodiment, the transmitting antennas TX and the receiving antennas RX are both arranged one-dimensionally in the X direction, which makes it possible to more reliably achieve both compensation accuracy and spatial resolution in the X direction than when the same number of antennas are arranged two-dimensionally.

[0110] 28 to 32, the third embodiment is a modification of the second embodiment. In the fourth embodiment, the number of transmitting antennas TX and receiving antennas RX, and the number of transmitting circuits 3 and receiving circuits 4 are the same as those in the second embodiment. Furthermore, the correspondence between each transmitting antenna TX and each transmitting circuit 3, and the correspondence between each receiving antenna RX and each receiving circuit 4 are also the same as those in the second embodiment.

[0111] In the radar device 1 of the third embodiment, at least one transmitting antenna TX has a wiring length different from that of the other transmitting antennas TX. In the example shown in Fig. 28, the wiring Wt2 of the transmitting antenna TX1_2 connected to the first transmitting circuit 3_1 is longer than the wiring Wt1 of the other transmitting antennas TX. Furthermore, the wiring lengths of the respective wirings Wr of the receiving antennas RX are all substantially the same.

[0112] When antennas with different wiring lengths exist, the transmitting antenna TX and the receiving antenna RX are arranged so that the number of mismatched pairs in a non-overlapping group, which is a set of virtual antennas V whose combinations of transmitting circuits 3 and receiving circuits 4 do not overlap with other sets, among a set of virtual antenna sets whose virtual positions overlap among the group of virtual antennas V assumed for each transmitting antenna TX and whose combinations of transmitting circuits 3 and receiving circuits 4 do not match, is at least Ns + Nr - 2 sets.

[0113] The transmitting antennas TX and receiving antennas RX are arranged so as to include at least one different wiring length pair, which is a pair of virtual antennas whose virtual positions overlap and whose wiring lengths do not match. Furthermore, the transmitting antennas TX and receiving antennas RX are arranged so that the total number of belonging pairs, which is a pair of virtual antennas V belonging to at least one of the mismatched pairs and the different wiring length pairs in the non-overlapping group, is at least Ns+Nr-1 pairs.

[0114] As shown in Figure 29, transmitting antennas TX1_1, TX1_2, TX2_1, and TX2_2 are arranged in this order from one side to the other in the X direction. The transmitting antennas TX1_1 and TX1_2 are arranged with a distance of 6d between them. The transmitting antennas TX1_2 and TX2_1 are arranged with a distance of 3d between them. The transmitting antennas TX2_1 and TX2_2 are arranged with a distance of 6d between them. The arrangement of the receiving antennas RX is the same as in the second embodiment.

[0115] As in the second embodiment, 24 virtual antennas V are virtually formed. For each of the virtual antennas V1 to V24, the corresponding transmitting antenna TX and receiving antenna RX are the same as in the first embodiment.

[0116] Because the transmitting antennas TX1_1 and TX1_2 are spaced apart by 6d, the virtual antenna V assumed for transmitting antenna TX1_1 is located at a virtual position that is relatively shifted by 6d from the virtual antenna V assumed for transmitting antenna TX1_2. Furthermore, because the transmitting antennas TX1_2 and TX2_1 are spaced apart by 3d, the virtual antenna V assumed for transmitting antenna TX1_2 is located at a virtual position that is relatively shifted by 3d from the virtual antenna V assumed for transmitting antenna TX2_1. Furthermore, because the transmitting antennas TX2_1 and TX2_2 are spaced apart by 6d, the virtual antenna V assumed for transmitting antenna TX2_1 is located at a virtual position that is relatively shifted by 6d from the virtual antenna V assumed for transmitting antenna TX2_2.

[0117] Therefore, in such an arrangement of antennas TX and RX, there are three pairs of virtual antennas V whose virtual positions overlap, as shown in Fig. 30. Specifically, (V10, V13), (V11, V14), and (V12, V15) are the pairs of virtual antennas V whose virtual positions overlap, respectively.

[0118] The above three sets are a set of mismatched pairs in which the combinations of the transmitter circuits 3 and the receiver circuits 4 do not match among the virtual antennas V. Furthermore, these three sets are a non-overlapping group in which the combination patterns of the transmitter circuits 3 and the receiver circuits 4 do not overlap. Therefore, this antenna arrangement satisfies the condition that there are at least Ns+Nr-2 sets of mismatched pairs constituting a non-overlapping group.

[0119] Furthermore, these three pairs are each different wiring length pairs. That is, the wiring lengths of virtual antennas V10, V11, and V12 are longer than the wiring lengths of virtual antennas V13, V14, and V15. Therefore, the number of different wiring length pairs in this antenna arrangement is three, which satisfies the condition of at least one pair. As a result, this antenna arrangement has three associated pairs, which satisfies the condition of at least Ns + Nr - 1 pairs.

[0120] In this embodiment, all the transmitting antennas TX are arranged to overlap in the Y direction, and all the receiving antennas RX are arranged to overlap in the Y direction. Therefore, in all the mismatched pairs included in the belonging pair, the corresponding transmitting antennas TX and corresponding receiving antennas RX are also arranged to overlap in the Y direction.

[0121] In this case, in the processes of S80 and S90, the control unit 6 further calculates a phase error and an amplitude error according to the wiring length difference of the virtual antenna V. Here, the wiring length of the virtual antenna V means the sum of the wiring length from the transmitting antenna TX corresponding to the virtual antenna V to the transmitting circuit 3 and the wiring length from the corresponding receiving antenna RX to the receiving circuit 4. Here, only the wiring Wt2 is longer than the wiring Wt1, and all the wirings Wr of the receiving antenna RX are substantially the same length, so the wiring length of the virtual antenna V assumed for the transmitting antenna TX1_2 is longer than the wiring lengths of the virtual antennas V assumed for the transmitting antennas TX other than the transmitting antenna TX1_2.

[0122] Generally, as shown in FIG. 31 , the phase error due to the wiring length difference for each virtual antenna V increases linearly according to the wiring length difference relative to a reference wiring length Lo (e.g., the shortest wiring length). That is, the phase error relative to the wiring length difference is a value obtained by multiplying the wiring length difference by K. Here, the slope K, which correlates with the magnitude of the phase error relative to the wiring length difference, is a temperature parameter that changes with temperature. That is, if the wiring length LA of the virtual antenna V assumed for the transmitting antenna TX1_2 in this embodiment is taken as LA, the slope K can be calculated from the wiring length difference LA-Lo. In this case, the reference wiring length Lo is the wiring length of the virtual antenna V assumed for the transmitting antennas TX other than the transmitting antenna TX1_2.

[0123] Here, the difference in wiring length in the virtual antenna V assumed for the pair of the transmitting antenna TXa_b and the receiving antenna RXi_j is expressed as L ａｂｉｊ (where a, b, i, and j are natural numbers). The compensation unit 64 uses three pairs, (V10, V13), (V11, V14), and (V12, V15), as belonging pairs, as shown in FIG. 32. The wiring length difference L ａｂｉｊ The phase error caused by ａｂｉｊ Then, the phase difference θ of the peak for (V10, V13) Ｖ１０ -θ Ｖ１３ is the phase difference θ of the peaks related to equation (15), (V11, V14) Ｖ１１ -θ Ｖ１４ is the phase difference θ of the peaks related to equation (16), (V12, V15) Ｖ１２ -θ Ｖ１５ can be defined by the relationship shown in Equation (17).

[0124] Here, the phase error e ａｂｉｊ To, L ａｂｉｊ When substituted for K, the above formulas (15) to (17) can be transformed into the following formulas (18) to (20).

[0125] When this is converted into a matrix format, the phase difference and relative phase error of each pair satisfy the relationship expressed by the following equation (21).

[0126] The term on the left side of the above-mentioned equation (21) is a phase difference vector Y3 between the overlapping virtual antennas V. The first term on the right side of the equation (21) is a coefficient matrix A3, and the second term is a phase error vector X3. The phase difference vector Y3 can be calculated from the phase of the peak in each beat signal. The coefficient matrix A3 is a constant matrix. Therefore, the equation (21) can be expressed as e ｔｘ２ , e ｒｘ２ , K as unknowns. That is, the compensation unit 64 calculates e ｔｘ２ , e ｒｘ２ , K are acquired as the relative phase error of the second transmitting circuit 3_2 with respect to the first transmitting circuit 3_1, the relative phase error of the second receiving circuit 4_2 with respect to the first receiving circuit 4_1, and the relative phase error according to the wiring length difference.

[0127] In the amplitude compensation process, similarly to the phase compensation process, the compensator 64 defines, for each set of virtual antennas V corresponding to the associated pair, a linear equation based on the amplitude difference of the peaks of the beat signals, with the amplitude error between the transmitting circuits 3 and the receiving circuits 4 as unknowns. The compensator 64 obtains the solution of this linear equation as the amplitude error.

[0128] The amplitude error due to the difference in wiring length from the reference wiring length Lo increases linearly with the difference in wiring length from the reference wiring length, similar to the phase error. The increase in the amplitude error due to the difference in wiring length changes with temperature. That is, the amplitude error due to the difference in wiring length is the value obtained by multiplying the difference in wiring length by the temperature parameter α.

[0129] Wiring length difference L ａｂｉｊ The amplitude error caused by G ａｂｉｊ Then, the amplitude difference A of the peak for (V10, V13) Ｖ１０ -A Ｖ１３ is the amplitude difference A of the peaks related to equation (22), (V11, V14) Ｖ１１ -A Ｖ１４ is the amplitude difference A of the peaks related to equation (23), (V12, V15) Ｖ１２ -A Ｖ１５ can be defined by the relationship shown in equation (24).

[0130] Here, the amplitude error G ａｂｉｊ To, L ａｂｉｊ When substituted with α, the above formulas (22) to (24) can be transformed into the following formulas (25) to (27).

[0131] When Equations (25) to (27) are converted into a matrix format, the amplitude difference and relative amplitude error of each pair satisfy the relationship expressed by Equation (28) below.

[0132] The term on the left side of Equation (28) is an amplitude difference vector Y4 between the overlapping virtual antennas V. The first term on the right side of Equation (28) is a coefficient matrix A4, and the second term is an amplitude error vector X2. The amplitude difference vector Y4 can be obtained from the amplitude of the peak in each beat signal, and the coefficient matrix A4 is a constant matrix. That is, the compensator 64 calculates G as a solution of Equation (28). ｔｘ２ , G ｒｘ２ , α are acquired as the relative amplitude error of the second transmission circuit 3_2 relative to the first transmission circuit 3_1, the relative amplitude error of the second reception circuit 4_2 relative to the first reception circuit 4_1, and the relative amplitude error due to the wiring length.

[0133] According to this third embodiment, at least one of a phase difference and an amplitude difference between different transmitter circuits, at least one of a phase difference and an amplitude difference between different receiver circuits, and at least one of a phase difference and an amplitude difference corresponding to a difference in wiring length between virtual antennas can be compensated for based on a comparison result between the received signals of at least Ns+Nr-1 pairs belonging to the virtual antennas. Therefore, it is possible to compensate for errors between different transmitter circuits and errors due to differences in wiring length, in addition to errors between different receiver circuits. Furthermore, by arranging at least one of the transmitter antennas and the receiver antennas at uneven intervals, the aperture length of the virtual antenna can be larger than when the antennas are arranged at equal intervals. Therefore, it is possible to achieve both compensation accuracy and spatial resolution.

[0134] (Fourth Embodiment) As shown in Figures 33 and 34, the fourth embodiment is a modification of the third embodiment. In the fifth embodiment, the number and arrangement of the transmitting antennas TX and receiving antennas RX are the same as in the third embodiment. However, in the fourth embodiment, as in the third embodiment, the wiring Wt2 of the transmitting antenna TX1_2 connected to the first transmitting circuit 3_1 is longer than the wiring Wt1 of the other transmitting antennas TX. Furthermore, the wiring lengths of the respective wirings Wr of the receiving antennas RX are all substantially the same. In this case, a virtual antenna V shown in Figure 34 is virtually formed for the arrangement shown in Figure 33.

[0135] 34, of the seven mismatched pairs, (V5, V8), (V9, V20), and (V12, V23) are different wiring length pairs. Therefore, the possible belonging pairs are, for example, the non-overlapping groups (V3, V14) and (V6, V17) and the different wiring length pair (V9, V20), for a total of three pairs, which satisfy the condition of Ns+Nr-1 or more pairs. Therefore, the reception processing unit 62 performs compensation processing based on the reception results of the above three pairs.

[0136] (Other Embodiments) Although multiple embodiments have been described above, the present disclosure should not be construed as being limited to those embodiments, and can be applied to various embodiments and combinations within the scope that does not deviate from the gist of the present disclosure.

[0137] In a modified example, the Y direction may be horizontal and the X direction may be vertical, in which case the radar device 1 can avoid the occurrence of a phase difference due to a triangular path caused by a reflecting object other than the target in the horizontal direction, such as a guardrail, and improve the accuracy of phase compensation.

[0138] In a variant, both the transmitting antennas TX and the receiving antennas RX may be arranged at non-equidistant intervals.

[0139] In a modified example, the dedicated computer constituting the control unit 6 may be a sensor management ECU that comprehensively controls multiple types of sensors mounted on the vehicle. The dedicated computer constituting the control unit 6 may be an integration ECU that integrates vehicle driving control. The dedicated computer constituting the control unit 6 may be a determination ECU that determines driving tasks in vehicle driving control. The dedicated computer constituting the control unit 6 may be a monitoring ECU that monitors vehicle driving control. The dedicated computer constituting the control unit 6 may be an evaluation ECU that evaluates vehicle driving control. The dedicated computer constituting the control unit 6 may be a navigation ECU that navigates the vehicle's driving route. The dedicated computer constituting the control unit 6 may be a locator ECU that estimates the vehicle's own state quantity. The dedicated computer constituting the control unit 6 may be an actuator ECU that controls the vehicle's driving actuators. The dedicated computer constituting the control unit may be an HCU (Human Machine Interface (HMI) Control Unit) that controls information presentation in the vehicle. The dedicated computer constituting the control unit 6 may be a computer outside the vehicle, for example, an external center or mobile terminal that can communicate with the vehicle.

[0140] In a modified example, the mobile body to which the radar device 1 is applied may be, for example, an autonomous robot that can transport luggage or collect information by autonomous driving or remote driving. Examples of the autonomous robot include an autonomous vehicle.

[0141] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, with the subsequent clause alternatively referring to the preceding clause. Furthermore, some clauses may be described in a multiple dependent form, with the subsequent clause referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0142] (Technical Idea 1) A radio communication system comprising: a plurality of transmitting antennas (TX) and a plurality of receiving antennas (RX); Ns transmitting circuits (3) connected to the corresponding transmitting antennas and outputting transmitting signals; Nr receiving circuits (4) connected to the corresponding receiving antennas and acquiring receiving signals; and a control unit (6) outputting sensing data correlated with the receiving signals, wherein Ns and Nr are integers of 2 or more, and at least one of the plurality of transmitting antennas and the plurality of receiving antennas is arranged at unequal intervals, and a plurality of virtual antennas (V) are virtually formed for each of the transmitting antennas according to a phase difference of the receiving signals between the receiving antennas, and for mismatched pairs, which are pairs of virtual antennas among the multiple virtual antennas whose assumed virtual positions overlap and whose combinations of the transmitting circuits and the receiving circuits corresponding to the virtual antennas do not match among the virtual antennas, assuming a group of mismatched pairs whose combination patterns of the transmitting circuits and the receiving circuits do not overlap with each other, the mismatched pairs are arranged so that at least Ns+Nr-2 pairs of the mismatched pairs are included in the group, and for at least Ns+Nr-2 pairs of the mismatched pairs in the group, the corresponding transmitting antennas and receiving antennas are arranged so that they are positioned to overlap in a specific direction, and the control unit outputs the sensing data in which phase errors between different transmitting circuits and different receiving circuits are compensated in correlation with a comparison result of the received signals between the virtual antennas in at least Ns+Nr-2 pairs of the mismatched pairs.

[0143] (Technical Idea 2) A radio communication system comprising: a plurality of transmitting antennas (TX) and a plurality of receiving antennas (RX); Ns transmitting circuits (3) connected by wiring to the corresponding transmitting antennas and outputting transmitting signals; Nr receiving circuits (4) connected by wiring to the corresponding receiving antennas and acquiring receiving signals; and a control unit (6) outputting sensing data correlated with the receiving signals, wherein Ns and Nr are integers of 2 or more, and at least one of the plurality of transmitting antennas and the plurality of receiving antennas is arranged at unequal intervals, and a plurality of virtual antennas (V) are virtually formed for each transmitting antenna according to a phase difference of the receiving signals between the receiving antennas for the plurality of receiving antennas, and for mismatched pairs, which are pairs of virtual antennas whose assumed virtual positions overlap among the plurality of virtual antennas and whose combinations of the transmitting circuit and the receiving circuit corresponding to the virtual antennas do not match among the virtual antennas, the control unit is arranged so that, assuming a group of mismatched pairs whose combination patterns of the transmitting circuit and the receiving circuit do not overlap with each other, the group includes at least Ns+Nr-2 pairs of the mismatched pairs, and the pair of virtual antennas whose virtual positions overlap among the plurality of virtual antennas and whose wiring lengths do not match include at least one different wiring length pair, and the control unit is arranged so that the total number of belonging pairs, which are pairs of virtual antennas belonging to at least one of the mismatched pairs and the different wiring length pairs included in the group, is at least Ns+Nr-1 pairs, and the control unit is arranged so that, for the belonging pairs, the corresponding transmitting antennas and the corresponding receiving antennas are positioned to overlap in a specific direction, and a radar device that outputs the sensing data in which the phase error corresponding to the difference in wiring length between the virtual antennas, the phase error between the different transmitting circuits, and the phase error between the different receiving circuits are compensated in correlation with a comparison result of the received signals between the virtual antennas in at least Ns+Nr-1 sets of the belonging pairs.

[0144] (Technical Concept 3) The radar device according to Technical Concept 1 or 2, wherein the specific direction is a vertical direction.

[0145] (Technical Concept 4) The radar device according to Technical Concept 1 or 2, wherein the specific direction is a horizontal direction.

[0146] (Technical Idea 5) The radar device according to any one of Technical Ideas 1 to 4, wherein the control unit compensates for the phase error when the estimated distance to the detection target is within an allowable distance range.

[0147] (Technical Idea 6) A radar device according to any one of Technical Ideas 1 to 5, wherein the control unit outputs the sensing data in which the phase error has been compensated by further utilizing the comparison result of the received signals between the virtual antennas in the mismatched pair in which the combination pattern of the transmitting circuit and the receiving circuit overlaps with the mismatched pair in the group.

[0148] (Technical Idea 7) A radar device according to any one of Technical Ideas 1 to 5, further comprising a temperature sensor (5) for detecting the temperature of the transmitting circuit and the receiving circuit, wherein the control unit determines whether the received signal is effective for compensating for the phase error, and if it is determined that the received signal is not effective for compensating for the phase error, outputs the sensing data in which the phase error has been compensated in correlation with the temperature of the transmitting circuit and the receiving circuit.

Claims

1. A radio communication system comprising: a plurality of transmitting antennas (TX) and a plurality of receiving antennas (RX); Ns transmitting circuits (3) connected to the corresponding transmitting antennas and outputting transmitting signals; Nr receiving circuits (4) connected to the corresponding receiving antennas and acquiring receiving signals; and a control unit (6) outputting sensing data correlated with the receiving signals, wherein Ns and Nr are integers of 2 or more; at least one of the plurality of transmitting antennas and the plurality of receiving antennas is arranged at unequal intervals, and a plurality of virtual antennas (V) are virtually formed for each of the transmitting antennas according to the phase difference of the receiving signals between the receiving antennas; and for mismatched pairs, which are pairs of virtual antennas among the multiple virtual antennas whose assumed virtual positions overlap and whose combinations of the transmitting circuits and the receiving circuits corresponding to the virtual antennas do not match among the virtual antennas, assuming a group of mismatched pairs whose combination patterns of the transmitting circuits and the receiving circuits do not overlap with each other, the mismatched pairs are arranged so that at least Ns+Nr-2 pairs of the mismatched pairs are included in the group, and for at least Ns+Nr-2 pairs of the mismatched pairs in the group, the corresponding transmitting antennas and receiving antennas are arranged so that they are positioned to overlap in a specific direction, and the control unit outputs the sensing data in which phase errors between different transmitting circuits and different receiving circuits are compensated in correlation with a comparison result of the received signals between the virtual antennas in at least Ns+Nr-2 pairs of the mismatched pairs.

2. A system comprising: a plurality of transmitting antennas (TX) and a plurality of receiving antennas (RX); Ns transmitting circuits (3) connected to the corresponding transmitting antennas by wiring and outputting transmitting signals; Nr receiving circuits (4) connected to the corresponding receiving antennas by wiring and acquiring receiving signals; and a control unit (6) outputting sensing data correlated with the receiving signals, wherein Ns and Nr are each an integer of 2 or more; at least one of the plurality of transmitting antennas and the plurality of receiving antennas is arranged at unequal intervals, and a plurality of virtual antennas (V) are virtually formed for each transmitting antenna according to the phase difference of the receiving signals between the receiving antennas for the plurality of receiving antennas; and for mismatched pairs, which are pairs of virtual antennas whose assumed virtual positions overlap among the plurality of virtual antennas and whose combinations of the transmitting circuit and the receiving circuit corresponding to the virtual antennas do not match among the virtual antennas, the control unit is arranged so that, assuming a group of mismatched pairs whose combination patterns of the transmitting circuit and the receiving circuit do not overlap with each other, the group includes at least Ns+Nr-2 pairs of the mismatched pairs, and the pair of virtual antennas whose virtual positions overlap among the plurality of virtual antennas and whose wiring lengths do not match include at least one different wiring length pair, and the control unit is arranged so that the total number of belonging pairs, which are pairs of virtual antennas belonging to at least one of the mismatched pairs and the different wiring length pairs included in the group, is at least Ns+Nr-1 pairs, and the control unit is arranged so that, for the belonging pairs, the corresponding transmitting antennas and the corresponding receiving antennas are positioned to overlap in a specific direction, and a radar device that outputs the sensing data in which the phase error corresponding to the difference in wiring length between the virtual antennas, the phase error between the different transmitting circuits, and the phase error between the different receiving circuits are compensated in correlation with a comparison result of the received signals between the virtual antennas in at least Ns+Nr-1 sets of the belonging pairs.

3. A radar device according to claim 1 or claim 2, wherein the specific direction is a vertical direction.

4. A radar device according to claim 1 or claim 2, wherein the specific direction is a horizontal direction.

5. The radar device according to claim 1 or 2, wherein the control unit compensates for the phase error when the estimated distance to the detection target is within an allowable distance range.

6. The radar device according to claim 1 or 2, wherein the control unit further utilizes the comparison result of the received signals between the virtual antennas in the mismatched pair whose combination pattern of the transmitting circuit and the receiving circuit overlaps with that of the mismatched pair in the group, to output the sensing data in which the phase error has been compensated.

7. A radar device as described in claim 1 or claim 2, further comprising a temperature sensor (5) for detecting the temperature of the transmitting circuit and the receiving circuit, wherein the control unit determines whether the received signal is effective for compensating for the phase error, and if it is determined that the received signal is not effective for compensating for the phase error, outputs the sensing data in which the phase error has been compensated in correlation with the temperature of the transmitting circuit and the receiving circuit.

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