Receiving device and radar device

Abstract

To allow a decrease in system gain to be suppressed even when multiple beams are formed and subarray signals (or element signals) cannot be directly acquired, causing gaps between beams.SOLUTION: According to a receiving device of the embodiment, in a receiving system, received signals Rxn(N≥n≥1) from N(N≥2) beams with any directional direction, partially overlapped M(M≥2) beams, and Wn×Rxn multiplied by a complex weight Wn so that the amplitude and phase are equal in a predetermined direction θm(M≥m≥1) within the overlapping angle interval are used to obtain outputs of L(L>N) Σ (sum) beams to detect a target, and monopulse angle measurement is performed for the target detection cell using the Σ beam and Δ (difference) beam before synthesis.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present embodiment relates to a receiving device and a radar device. [Background technology]

[0002] In receivers and radar devices that use subarrays to form beams using DBF (Digital Beam Forming), the spacing between subarrays is large, so there are restrictions on the direction in which beamforming can be performed using DBF between subarrays.

[0003] For this reason, when using a subarray of Ns (Ns>1) elements, both the antenna aperture and the observation space are divided into Ns parts, each divided aperture corresponds to a divided observation space, and the phase shifter of the subarray of each divided aperture directs the beam toward the center of each divided space, so that multiple beams are formed by DBF only within that divided range.

[0004] However, in the above-mentioned method of forming multiple beams using DBF only within the divided range, gaps between beams occur between the divided spaces, resulting in a reduction in system gain. Furthermore, even within each divided space, if there are restrictions on the number of beams due to processing scale restrictions, gaps between beams will also result in a reduction in system gain. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] DBF (Digital Beam Forming): Yoshida, 'Revised Radar Technology', Institute of Electronics, Information and Communication Engineers, pp.289-291 (1996) [Non-patent document 2] CFAR (Constant False Alarm Rate): Yoshida, 'Revised Radar Technology', Institute of Electronics, Information and Communication Engineers, pp.87-89 (1996) [Non-patent document 3] Monopulse Angle Measurement: Yoshida, 'Revised Radar Technology', Institute of Electronics, Information and Communication Engineers, pp.260-264 (1996) [Non-patent document 4] Extended Array (KR Product Array): Wing-Kin Ma, 'DOA Estimation of Quasi-Stationary Signals With Less Sensors Than Sources and Unknown Spatial Noise Covariance: A Khatri-Rao Subspace Approach', IEEE Trans. Signal Process., vol.58, no.4, pp.2168-2180, April(2010) [Non-patent document 5] Taylor distribution: Yoshida, 'Revised Radar Technology', Institute of Electronics, Information and Communication Engineers, pp.134-135 (1996) [Non-patent document 6] Pulse compression: Ouchi, 'Fundamentals of Synthetic Aperture Radar for Remote Sensing', Tokyo Denki University Press, pp.131-149 (2003) Summary of the Invention [Problem to be solved by the invention]

[0006] The objective of this embodiment is to provide a receiving device and a radar device that can suppress a decrease in system gain even when multiple beams are formed, subarray signals (or element signals) cannot be directly acquired, and gaps occur between beams. [Means for solving the problem]

[0007] In order to solve the above problems, the receiving device of the first embodiment uses, in its receiving system, received signals Rxn (N ≧ n ≧ 1) from N (N ≧ 2) beams with arbitrary pointing directions, M (M ≧ 2) partially overlapped beams, and Wn × Rxn multiplied by a complex weight Wn so that the amplitude and phase are equal in a predetermined direction θm (M ≧ m ≧ 1) within the overlapping angle interval, to obtain the output of L (L > N) Σ (sum) beams to detect the target, and performs monopulse angle measurement for the target detection cell using the Σ beam and Δ (difference) beam before synthesis (gap beam formation using arbitrary multi-beams).

[0008] In other words, with the receiving device having the above configuration, in the receiving system, N beam signals having any direction of direction are used to obtain and detect a composite beam signal having any direction of direction, and further, monopulse angle measurement can be performed using the original monopulse beam so as not to be affected by factors such as the broadening of the beam width due to the composite beam.

[0009] Furthermore, in the receiving system of the receiving device according to the second embodiment, received signals Rxn (N ≧ n ≧ 1) from N (N ≧ 2) beams with arbitrary pointing directions, partially overlapped M (M ≧ 2) beams, and Wn × Rxn obtained by multiplying the received signals by a complex weight Wn so that they have equal amplitude and equal phase in an orthogonal direction θm (M ≧ m ≧ 1) in the observation space within the overlapping angle section, generate output signals of L (L > 1) orthogonal beams, perform inverse FFT on L orthogonal beam axes for each cell of the received signal, generate L element signals for each received signal cell, form Ld (Ld > 1) beams for detection and detect the target, then perform extended (KR product) array processing on the target detection cells, form a Σ (sum) beam and a Δ (difference) beam to measure the angle of the monopulse (orthogonal beam formation by arbitrary multi-beams and extended array).

[0010] That is, with the receiving device having the above configuration, in the receiving system, N beam signals having any direction of direction are used to form orthogonal beams, element signals are obtained by inverse FFT, a detection beam is formed and detected, and then a beam signal having any direction of direction with high resolution in the angle axis is obtained by extended array processing, thereby enabling target detection and monopulse angle measurement.

[0011] In addition, in the radar device according to the third embodiment, the transmitting system forms a beam that covers the entire observation space, and the receiving system forms a total of N multi-beams using Ns (Ns>1) sets of subarrays with different directivity directions, each of which covers the observation space divided into Ns ways, and the receiving device according to the first or second embodiment obtains L beam signals (dense multi-beam formation using a SIMO-configured subarray DBF).

[0012] That is, with the radar device having the above configuration, transmission covers the entire observation space, thereby eliminating the influence of isolation between divided observation spaces for reception, and reception uses multiple beams with different beam scanning directions by the subarray phase shifters, thereby reducing the influence of gain reduction due to inter-beam gaps, enabling detection and monopulse angle measurement. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram showing the configuration of a receiving system of a receiving device according to the first embodiment. [Figure 2] FIG. 2 is a conceptual diagram showing the configuration of Ns divided sub-arrays used in the antenna of the receiving system of the receiving device shown in FIG. [Figure 3] FIG. 3 is a block diagram showing the configuration of the receiving modules and receiving power supply circuits that constitute the subarray shown in FIG. [Figure 4] FIG. 4 is a conceptual diagram showing how the antenna aperture is divided into Ns portions and each divided aperture is assigned to a space division unit in the first embodiment. [Figure 5]FIG. 5 is a waveform diagram showing how a synthesized Σ beam is formed from the received Σ beams in each subarray and how monopulse angle measurement is performed in the first embodiment. [Figure 6] FIG. 6 is a waveform diagram showing how a composite beam is formed to fill the gap between beams and a beam with a large SN is selected to perform target detection in the first embodiment. [Figure 7] FIG. 7 is a waveform diagram showing the process of monopulse angle measurement in the first embodiment. [Figure 8] FIG. 8 is a block diagram showing the configuration of a receiving system of a receiving device according to the second embodiment. [Figure 9] FIG. 9 is a waveform diagram showing how orthogonal beams are formed in directions spaced equally apart on the sin θ axis by orthogonal beam forming and subarray signals are obtained by inverse Fourier transform in the second embodiment. [Figure 10] FIG. 10 is a conceptual diagram showing how all element signals are generated by performing an inverse Fourier transform on the outputs of time-division orthogonal multi-beams formed in a divided two-dimensional observation space in the second embodiment. [Figure 11] FIG. 11 is a conceptual diagram showing the processing state when the KR product array processing of the virtual array and the real array is used as an extended array in the second embodiment. [Figure 12] FIG. 12 is a block diagram showing the configuration of a transmission system and a reception system of a radar device according to the third embodiment. [Figure 13] FIG. 13 is a block diagram showing a system of the transceiver modules, the transmission power feeding circuit, and the reception power feeding circuit that constitute the subarray shown in FIG. 12 in the third embodiment. [Figure 14] FIG. 14 is a conceptual diagram showing how the antenna aperture is divided into Ns portions and each divided aperture is assigned to a space division unit in the third embodiment. [Figure 15] FIG. 15 is a diagram showing a three-dimensional coordinate system indicating the calculated position of a target in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments will be described with reference to the drawings.

[0015] (First embodiment) The configuration of the first embodiment will be described with reference to FIGS.

[0016] Fig. 1 is a block diagram showing the configuration of a receiving system of a receiving device according to the first embodiment. Fig. 2 is a conceptual diagram showing the configuration of Ns-divided subarrays used in an antenna of the receiving system of the receiving device shown in Fig. 1, and Fig. 3 is a block diagram showing the configuration of a receiving module and a receiving power feeding circuit that constitute the subarrays shown in Fig. 2.

[0017] In the receiving system shown in Fig. 1, radar reflected signals are received by Ns receiving subarrays (1 to Ns) 161 to 16Ns that make up the receiving antenna shown in Fig. 2. Here, as shown in Fig. 3, each receiving subarray includes antenna elements 61 to 6i, ..., 6n, ..., 6Ns, and the respective received signals are low-noise amplified by receiving modules 71 to 7Ns that include LNAs (Low Noise Amplifications) and phase shifters, etc., and the signals are phase-aligned and combined and output by a receiving power supply circuit 8R.

[0018] The received signals obtained by each receiving subarray 161-16Ns are frequency-converted to baseband by frequency converters 171-17Ns and then converted to digital signals by AD converters 181-18Ns. Next, a DBFΣ beam former 19 forms a Σ (sum) beam from the radar signals of the digital beams (hereinafter referred to as DBF (Digital Beam Forming)) between the subarrays of each system, and an arbitrary beam is synthesized by a beam combiner 20. After that, a signal processor 21 performs signal processing for target detection, a CFAR detector 22 performs target detection processing using CFAR (Constant False Alarm Rate), and an AZ / EL monopulse angle finder 23 forms a Δ (difference) beam for each AZ angle and EL angle, and performs monopulse angle measurement by combining this with the received Σ beam data output from the Σ beam former 19. The angle measurement result is output as the target observation value.

[0019] The signal processing in the receiving device having the above configuration will be described with reference to FIGS.

[0020] Figure 4 is a conceptual diagram showing how the antenna aperture is divided into Ns portions and each divided aperture is assigned to a spatial division unit; Figure 5(a) shows how a composite Σ beam is formed from the received Σ beams in each subarray; Figure 5(b) is a waveform diagram showing how monopulse angle measurement is performed; Figure 6(a) shows how a composite beam that fills the gap between beams is formed; Figure 6(b) is a waveform diagram showing how a beam with a large SN is selected to detect a target; Figure 7(a) shows the relationship between Σ beams and Δ beams; and Figure 7(b) is a waveform diagram showing the processing of monopulse angle measurement.

[0021] In the receiving system shown in FIG. 1, each subarray signal is frequency-converted by the frequency converters of the analog receiving processors 171-17Ns and converted to a digital signal by the AD converters 181-18Ns. Next, a receiving beam is formed by the DBF Σ beam former 19. This beamforming process is shown in FIG. 4. Because subarrays have a larger antenna aperture length than element antennas, their beamwidths are narrower, resulting in a narrower observation range for each subarray. Therefore, to observe a wider observation range, the total number of antenna elements is divided into a number equal to the number of subarray elements Ns. If the number of elements in each division unit of the antenna is M, each division unit contains M / Ns subarrays. A receiving beam is formed from these subarrays using DBF (Non-Patent Document 1). In this case, because the divided observation space has the beam patterns (responses) of the subarrays, the system gain is likely to decrease between the divided spaces. Furthermore, if the number of beams in a divided space is limited due to the DBF processing scale, the system gain may also decrease between beams.

[0022] Therefore, in this embodiment, to reduce the effect of this, a combined Σ beam that reduces the effect of gain reduction is formed using the formed receive beam (original beam). Specifically, as shown in Fig. 5(a), receive Σ beams on both sides of the direction in which gain reduction occurs are used, and complex weights that align the amplitude and phase in the direction in which the beam is formed are multiplied by the Δ beams on both sides of the Σ beam to combine them, as shown in Fig. 5(b).

[0023]

number

[0024] This makes it possible to synthesize beams that fill the gaps between beams. Since the target direction is unknown before detection, if there are many points of gain reduction due to gaps between the original beams as shown in Figure 6(a), a synthesized beam that fills the gaps is formed in advance as shown in Figure 6(b), and a beam with a large SN ratio is selected for detection.

[0025] That is, in this embodiment, the original beams obtained by the beam combiner 20 and the selected composite beam are used in the signal processor 21 to perform signal processing such as FFT to improve the system gain, and then the CFAR detector 22 detects the target using CFAR (Non-Patent Document 2) or the like, and extracts the detected cells. At this time, if a target is detected using the original beams, the AZ / EL monopulse angle measurer 23 directly performs monopulse angle measurement (Non-Patent Document 3). If a target is detected using the composite beam, the original beam with the higher SN is used to perform AZ / EL monopulse angle measurement.

[0026] There is also a method of using a synthesized Σ beam and a Δ beam, but since the synthesized beam tends to have a wider beam width even if the SN improves, the original beam is often better for improving angle measurement accuracy.

[0027] Monopulse angle measurement can be formulated as follows: This is a method of measuring angle using the Σ beam and Δ beam shown in Figure 7(a) by calculating the error voltage ε shown in the following equation and using a previously acquired error voltage table. Figure 7(b) shows the state of the error voltage.

[0028]

number

[0029] As described above, the receiving device according to this embodiment uses received signals Rxn (N ≥ n ≥ 1) from N (N ≥ 2) beams with any direction of direction, and partially overlaps M (M ≥ 2) beams, multiplying them by complex weights Wn to achieve equal amplitude and equal phase in a predetermined direction θm within the overlapping angle interval to obtain and detect L (L > M) Σ beam outputs using Wn × Rxn, and performs monopulse angle measurement for the detection cell using the Σ beam and Δ beam before combining. In this way, N beam signals with any direction of direction are used to obtain a combined beam signal in any direction of direction, allowing for target detection. Furthermore, monopulse angle measurement can be performed using the original monopulse beam without being affected by beam width broadening due to the combined beam.

[0030] (Second embodiment) The configuration of the second embodiment will be described with reference to FIGS.

[0031] Fig. 8 is a block diagram showing the configuration of a receiving system of a receiving device according to a second embodiment. Figs. 9(a) to 9(f) are waveform diagrams showing how orthogonal beams are formed in equally spaced directions on the sinθ axis by orthogonal beam forming, and how subarray signals are obtained by inverse Fourier transform. Fig. 10 is a conceptual diagram showing how all element signals are generated by inverse Fourier transforming the outputs of time-division orthogonal multibeams formed in a divided two-dimensional observation space. Fig. 11 is a conceptual diagram showing how KR product array processing of a virtual array and a real array is used as an extended array.

[0032] In the first embodiment, a method of combining beams to fill gaps between beams was described. In this case, if you want to form a beam in an arbitrary direction, there are restrictions because it depends on the original beam direction. In this embodiment, we will explain how to deal with this. First, in this embodiment, we will assume that the beam configuration is the same as in Figure 4 and that beams are formed within each division unit.

[0033] In the receiving system shown in Figure 8, the received signals obtained by Ns receiving subarrays (1 to Ns) 161 to 16Ns are converted to baseband by frequency converters 171 to 17Ns, converted to digital signals by AD converters 181 to 18Ns, and output to DBFΣ beam former 19.

[0034] The DBFΣ beamformer 19 is the same as in the first embodiment. In this embodiment, an orthogonal beamformer 24 forms an orthogonal beam from the Σ beam signals formed by the DBFΣ beamformer 19, a subarray signal generator 25 generates subarray signals from the orthogonal beam signals, and a receive beam is formed by a beamformer 26. A signal processor 21 performs signal processing for target detection, and a CFAR detector 22 performs target detection processing using CFAR. Next, a KR product processor 27 performs KR product array processing of the virtual array and the real array, a monopulse beamformer 28 forms difference beams for the AZ angle and the EL angle for monopulse angle measurement, and an AZ / EL monopulse angle finder 23 performs monopulse angle measurement for the AZ angle and the EL angle, and the angle measurement results are output as target observation values.

[0035] The signal processing performed by the receiving device having the above configuration will be described with reference to FIGS.

[0036] In the first embodiment, beams are synthesized so as to fill the gaps between beams by beam synthesis, but in this embodiment, orthogonal beams are formed in directions spaced equally apart on the sin θ axis by orthogonal beam formation using a similar method. This is shown in Figure 9.

[0037] First, the orthogonal beam former 24 forms the orthogonal multibeams shown in Fig. 9(b) from the signals b1, b2, ..., bN1 / P, ..., bNs of an arbitrary multibeam (Σ beam) shown in Fig. 9(a) formed by the DBFΣ beam former 19. The subarray signal generator 25 generates subarray signals (amplitude, phase) shown in Fig. 9(c) from the orthogonal beam signals. The beam former 26 forms a composite beam for detection (receive beam). The signal processor 21 performs signal processing for target detection. The CFAR detector 22 performs target detection processing using CFAR. Next, the KR product processor 27 performs KR product array processing of the virtual array and real array shown in Fig. 9(e). The monopulse beam former 28 forms Σ beams and Δ beams for the AZ angle and EL angle for monopulse angle measurement shown in Fig. 9(f). The AZ / EL monopulse angle measurer 23 performs monopulse angle measurement for each AZ angle and EL angle, and outputs the angle measurement results as target observation values.

[0038] In other words, once an orthogonal beam is created, a subarray signal can be obtained by performing an inverse Fourier transform on it.

[0039]

number

[0040] The weight Wpn for beam direction control can be expressed by the following equation:

[0041]

number

[0042]

number

[0043] In Figure 9(c), for simplicity, the angle axis is shown as one-dimensional. In the two-dimensional case, however, as shown in Figure 10, by forming a time-division orthogonal multi-beam for the divided observation space (sinθ axis) and performing an inverse Fourier transform, all element signals are generated for each divided observation space.

[0044] By using this subarray signal, any beam can be formed within the divided aperture range, so that multiple beams with few gaps between beams can be formed, enabling target detection with a high system gain.

[0045] Once target detection cells can be extracted, extended (KR product) array processing can be applied. KR product array processing can be applied even before target detection, but in the case of multiple targets, false detections may occur due to the multiplication process. To suppress this effect, it is more appropriate to detect targets and extract range-Doppler cells, and then apply KR product array processing to a single target.

[0046] Next, the part that performs KR product array processing (Non-Patent Document 4) will be formulated. First, if an input signal including an observation direction θ is expressed as X(θ), the following equation is obtained.

[0047]

number

[0048] Next, the source signal Xin is used to perform KR product array processing as extended array processing.

[0049]

number

[0050] When the leftmost and topmost elements are vectorized, the following equation is obtained.

[0051]

number

[0052] This Xkr can be used as the element signal Xn of the new extended array to form a receive beam. The state of the data in this extended array is shown in Figure 11.

[0053] In the monopulse beam former 28, the elements of equation (10) are multiplied by Taylor weights (Non-Patent Document 5) or the like as weights for reducing side lobes, and then multiplied by complex weights for beam pointing direction control, and then summed using DBF (Digital Beam Forming, Non-Patent Document 3), resulting in the following equation:

[0054]

number

[0055] The complex weight Wpn for beam pointing direction control can be expressed by the following equation:

[0056]

number

[0057] In the case of a Δ beam, the aperture in Wn of equation (11) is divided into two parts, and each part is assigned a + and a - sign.

[0058] As described above, the radar device according to the second embodiment generates output signals of L (L>1) orthogonal beams in the reception system using received signals Rxn (N≧n≧1) from N (N≧2) beams having any directionality, partially overlapped M (M≧2) beams, and Wn×Rxn obtained by multiplying the received signals by complex weight Wn so that they have equal amplitude and equal phase in the orthogonal direction θm (M≧m≧1) in the observation space within the overlap angle section, performs inverse FFT on L orthogonal beam axes for each cell of the received signals, generates L element signals for each received signal cell, forms Ld (Ld>1) beams for detection, and detects the target. After that, it performs extended (KR product) array processing on the target detection cells, forms Σ beams and Δ beams, and performs monopulse angle measurement.

[0059] That is, in the receiving system, orthogonal beams are formed using N beam signals with any direction of direction, element signals are obtained by inverse FFT, a detection beam is formed and detected, and then a beam signal with any direction of direction with high resolution of the angle axis is obtained by expanded array processing, enabling target detection and monopulse angle measurement. In this way, since monopulse beams of Σ and Δ can be formed, an expanded array with a KR product array can be used to measure angles with high precision using high-resolution beams.

[0060] (Third embodiment) The configuration of the third embodiment will be described with reference to FIGS.

[0061] Fig. 12 is a block diagram showing the configuration of a radar device according to a third embodiment, where (a) is a block diagram showing the configuration of a transmission system and (b) is a block diagram showing the configuration of a reception system. Also, Fig. 13 is a block diagram showing the systems of the transmission / reception modules, transmission power feed circuits, and reception power feed circuits that make up the subarray shown in Fig. 12. Fig. 14 is a conceptual diagram showing how the antenna aperture is divided into Ns portions and how each divided aperture is assigned to a space division unit. Fig. 15 is a diagram showing a three-dimensional coordinate system that shows the calculated position of a target.

[0062] In this embodiment, a case will be described in which a transmitting antenna and a receiving antenna are shared, and a transmitting beam and a receiving beam can be formed.

[0063] 12(a), a signal generator 11 generates a transmission seed signal, a modulator 12 generates a modulated signal, a frequency converter 13 converts this into a high-frequency signal, pulse-modulates it 14, and inputs it to each subarray 15. In the transmission system of each subarray, as shown in Fig. 13, the signal is distributed to each transceiver module 41, ..., 4i, ..., 4n, ..., 4Ns by the subarray's transmission feed circuit 5T, phase-controlled by a phase shifter, amplified by a high-output amplifier, and transmitted from antenna elements 31, ..., 3i, ..., 3n, ..., 3Ns via a circulator. In addition, in the receiving system of each subarray, the received signals input from the antenna elements 31, ..., 3i, ..., 3n, ..., 3Ns are passed through a circulator and amplified by a low-noise amplifier in each transmitting / receiving module 41, ..., 4i, ..., 4n, ..., 4Ns, and then phase-controlled by a phase shifter, combined by the receiving power supply circuit 5R, and output as a receiving subarray signal.

[0064] 12(b), the configuration of Ns-system receiving subarrays (1 to Ns) 161 to 16Ns, frequency converters 171 to 17Ns, AD converters 181 to 18Ns, and the DBFΣ beam former 19 and subsequent components is the same as in the second embodiment, with an orthogonal beam former 24 forming an orthogonal beam from the Σ beam signals formed by the DBFΣ beam former 19, a subarray signal generator 25 generating subarray signals from the orthogonal beam signals, and a receiving beam being formed by a beam former 26, a signal processor 21 performing signal processing for target detection, and a CFAR detector 22 performing target detection processing using CFAR. Subsequently, a KR product processor 27 performs KR product array processing of the virtual array and the real array, a monopulse beam former 28 forming difference beams for the AZ angle and the EL angle for monopulse angle measurement, an AZ / EL monopulse angle measurer 23 performing monopulse angle measurement for the AZ angle and the EL angle, and outputting the angle measurement results as target observation values.

[0065] The signal processing in the radar device having the above configuration will be described with reference to FIGS.

[0066] First, in the transmission system shown in Figure 12(a), a transmission seed signal is generated by a signal generator 11, a modulated signal is generated by a modulator 12, this is converted to a high-frequency signal by a frequency converter 13, pulse-modulated by a pulse modulator 14, and input to each subarray 15. The system for each subarray is shown in Figure 13. The signal is distributed to each transceiver module by the subarray's transmission feed circuit 41, phase-controlled by a phase shifter, amplified by a high-output amplifier, and transmitted from the antenna element via a circulator. The received signal input from the antenna element is amplified by a low-noise amplifier via a circulator, phase-controlled by a phase shifter, and then combined by a receiving feed circuit 42 and output as a receiving subarray signal.

[0067] The received signals of each subarray 161 to 16Nn are processed in the same manner as in the second embodiment by the receiving system shown in Fig. 12(b). In the case of a pulse-compressed signal, the pulse is compressed by range compression (Non-Patent Document 6), and then converted to the Doppler axis by slow-time axis FFT processing, to obtain range-Doppler cell signals (RD data) for each of the N (N≧2) channel subarrays. The receiving system shown in Fig. 12(b) has the same configuration as in the second embodiment, but it can also be implemented with the same configuration as in the first embodiment.

[0068] In a transmitting subarray, if transmission is performed for each divided observation space as in reception, isolation is required due to the different frequencies and codes between the divided spaces, and if the isolation is insufficient, the problem arises that beams from adjacent divided spaces cannot be combined.

[0069] Therefore, in this embodiment, all subarrays are used to form a beam that covers the entire observation space by phase control. For example, a phase control method can be used to spoil the transmitted beam shape from a pencil beam by adding a quadratic phase to the aperture axis, thereby widening the beam width.

[0070]

number

[0071] By outputting the observation value using the angle measurement value and the distance measurement value obtained using the detection range cell, the three-dimensional coordinates (X, Y, Z) of the target shown in FIG. 15 can be calculated.

[0072]

number

[0073] As described above, the radar device according to the third embodiment can suppress degradation due to gaps in the observation space by applying the techniques of the first and second embodiments. That is, the transmitting side forms a beam that covers the entire observation space, and the receiving side forms a total of N multibeams using Ns (Ns>1) sets of subarrays with different directivity directions so as to cover each of the Ns divided observation spaces, and L beam signals are obtained using the receiving device according to the first or second embodiment. By covering the entire observation space during transmission, the influence of isolation between the divided observation spaces during reception is eliminated, and then, during reception, the influence of gain reduction due to gaps between beams is reduced using multibeams with different beam scanning directions by the phase shifters of the subarrays, enabling detection and monopulse angle measurement to be performed.

[0074] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0075] 11...signal generator, 12...modulator, 13...frequency converter, 14...pulse modulator, 15...transmitting antenna, 161-16Ns...subarray, 171-17Ns...frequency converter, 181-18Ns...AD converter, 19...DBFΣ beam former, 20...beam combiner, 21...signal processor, 22...CFAR detector, 23...AZ / EL monopulse angle finder, 24...orthogonal beam former, 25...subarray signal generator, 26...beam former, 27...KR product processor, 28...monopulse beam former.

Claims

1. In the receiving system, the received signal Rxn (N ≥ n ≥ 1) from N (N ≥ 2) beams with any directional orientation, the partially overlapped M (M ≥ 2) beams, and the received signal Wn × Rxn multiplied by a complex weight Wn to have equal amplitude and equal phase in a predetermined direction θm (M ≥ m ≥ 1) within the overlap angle section are used to obtain the output of L (L > N) Σ (sum) beams to detect the target, and perform monopulse angle measurement for the target detection cell using the Σ beam before synthesis and the Δ (difference) beam. Receiving device.

2. In the receiving system, received signals Rxn (N ≥ n ≥ 1) from N (N ≥ 2) beams with any directionality, partially overlapped M (M ≥ 2) beams, and Wn × Rxn multiplied by complex weight Wn so that they have equal amplitude and equal phase in the orthogonal direction θm (M ≥ m ≥ 1) in the observation space within the overlap angle section are used to generate output signals for L (L > 1) orthogonal beams, and for each cell of the received signal, an inverse FFT is performed on L orthogonal beam axes to generate L element signals for each received signal cell, and Ld (Ld > 1) beams for detection are formed to detect the target, and then extended array processing is performed on the target detection cells, and a Σ (sum) beam and a Δ (difference) beam are formed to measure the monopulse angle. Receiving device.

3. The transmitting system forms a beam that covers the entire observation space, and the receiving system forms a total of N multi-beams using Ns (Ns>1) sets of sub-arrays with different directivity directions, each of which covers the observation space divided into Ns ways; The receiving system uses received signals Rxn (N ≥ n ≥ 1) from N (N ≥ 2) beams with any directional orientation, M (M ≥ 2) partially overlapped beams, and Wn × Rxn multiplied by complex weight Wn so that the amplitude and phase are equal in a predetermined direction θm (M ≥ m ≥ 1) within the overlap angle interval, to obtain outputs from L (L > N) Σ (sum) beams to detect the target, and performs monopulse angle measurement for the target detection cell using the Σ beam and Δ (difference) beam before synthesis. Radar equipment.

4. The transmitting system forms a beam that covers the entire observation space, and the receiving system forms a total of N multi-beams using Ns (Ns>1) sets of sub-arrays with different directivity directions, each of which covers the observation space divided into Ns ways; The receiving system generates output signals of L (L > 1) orthogonal beams using received signals Rxn (N ≥ n ≥ 1) from N (N ≥ 2) beams with arbitrary directionality, partially overlapped M (M ≥ 2) beams, and Wn × Rxn obtained by multiplying complex weights Wn so that the amplitudes and phases are equal in the orthogonal direction θm (M ≥ m ≥ 1) in the observation space within the overlap angle range, performs inverse FFT on L orthogonal beam axes for each cell of the received signal, generates L element signals for each received signal cell, forms Ld (Ld > 1) beams for detection, detects the target, and then performs extended array processing on the target detection cells, forms a Σ (sum) beam and a Δ (difference) beam, and performs monopulse angle measurement. Radar equipment.

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