MIMO radar signal processing device, its receiving signal processing device and a method for determining the propagation mode of a received signal vector

Abstract

A MIMO radar signal processing device has: a plurality of matched filter groups (1211-121 M ) to which received signals from a plurality of receiving antennas (21-2 M ) and transmission signals from a plurality of transmission signal generating sections (1111-111 N ) are respectively input, and which output matched filter outputs that become vector elements of a received signal vector; a tentative angle measurement section (122) that assumes the matched filter outputs from the plurality of matched filter groups (1211-121 M ) to be direct propagation mode received signals, and that calculates tentative angle measurement values for a received signal vector of interest; and a bidirectional angle measurement section (123) that acquires bidirectional angle measurement values for the received signal vector of interest based on the matched filter outputs from the plurality of matched filter groups (1211-121 M ) and the tentative angle measurement values calculated by the tentative angle measurement section (122).

Description

Technical Field

[0001] The present invention relates to a MIMO (Multiple Input Multiple Output) radar signal processing apparatus that outputs different transmitted signals to multiple transmitting antennas, receives received signals from multiple receiving antennas, obtains a bidirectional angle measurement value of the received signal vector of interest based on the input received signals, which is composed of the sending angle and the arrival angle, and captures the reflected wave of the transmitted wave sent from the transmitting antenna reaching an object as the arriving wave. Background Technology

[0002] In addition to the direct propagation mode, where the path of the incoming wave from the MIMO radar device to the object (outgoing path) and the path of the reflected wave from the object to the MIMO radar device (return path) are consistent, there is also a multipath propagation mode where the outgoing path and the return path are inconsistent.

[0003] Therefore, in the MIMO radar signal processing unit of the MIMO radar device, it is necessary to determine whether the received signal is in direct propagation mode or multipath propagation mode.

[0004] Patent Document 1 shows a signal processing apparatus that determines whether the estimated direction of arrival is correct based on the difference between the received signal from the antenna and the estimated received signal, i.e., the residual signal, and suppresses false detection of objects. The estimated received signal is calculated based on the estimated direction of arrival of the radio wave calculated from the received signals from multiple antennas.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-186973 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, in the signal processing device shown in Patent Document 1, the arrival angle of the incoming wave is used to calculate and estimate the received signal. However, it is not possible to accurately grasp the propagation environment sensed by the MIMO radar device, i.e., the propagation environment within the electromagnetic wave illumination range. Therefore, it is desirable to be able to determine the direct propagation mode with higher accuracy.

[0010] The present invention was made in view of the above circumstances, and its object is to obtain, for example, a MIMO radar signal processing device that can determine with higher accuracy which propagation mode is the direct propagation mode or the multipath propagation mode, and obtain bidirectional angle measurement values ​​that can be used in the propagation mode determination.

[0011] Methods for solving problems

[0012] The MIMO radar signal processing apparatus of the present invention comprises: multiple transmit signal generation units, each generating a different transmit signal and outputting the generated transmit signal to a corresponding transmit antenna; multiple matched filter banks, each receiving a receive signal from a receive antenna and a transmit signal from the multiple transmit signal generation units, and outputting a matched filter output as a vector element of the receive signal vector, wherein the receive signal from the receive antenna corresponds to a multiple receive antenna that captures the reflected wave from the transmit antenna that is reflected by an object as an incoming wave; a provisional angle measurement unit, which assumes the matched filter output from the multiple matched filter banks to be a receive signal based on the direct propagation mode of the incoming wave that is directly propagated by the transmit wave reflected by the object, and obtains a provisional angle measurement value for the receive signal vector of interest corresponding to the range Doppler cell given by the target detection processing; and a bidirectional angle measurement unit, which obtains a bidirectional angle measurement value consisting of the send-out angle and the arrival angle for the receive signal vector of interest based on the matched filter output from the multiple matched filter banks and the provisional angle measurement value calculated by the provisional angle measurement unit.

[0013] Invention Effects

[0014] According to the present invention, a bidirectional angle measurement value consisting of the sending angle and the arrival angle of the received signal vector of interest is obtained. Therefore, when the bidirectional angle measurement value is used, for example, to determine which propagation mode is direct propagation mode or multipath propagation mode, the propagation mode can be determined with higher accuracy, and the propagation environment sensed by the MIMO radar device can be grasped in more detail. Attached Figure Description

[0015] Figure 1 This is an overall structural diagram showing the MIMO radar device of Embodiment 1.

[0016] Figure 2 This is a diagram showing the multipath propagation waves of different objects A and B, which are reflected once each and for a total of twice, within the radio wave illumination range of the MIMO radar device.

[0017] Figure 3 This is a flowchart illustrating the operation of the receiving signal processing device, specifically the method for determining the propagation mode of the received signal vector. Detailed Implementation

[0018] Implementation Method 1

[0019] according to Figure 1 The MIMO radar device of Embodiment 1 will be described.

[0020] The MIMO radar device has multiple transmitting antennas 1, namely the first transmitting antenna 11 to the Nth transmitting antenna 1. N Multiple receiving antennas 2, namely the first receiving antenna 21 to the Mth receiving antenna 2 M And MIMO radar signal processing device 100.

[0021] N and M are natural numbers greater than 2.

[0022] The MIMO radar signal processing device 100 includes a transmitting signal processing device 110 and a receiving signal processing device 120.

[0023] The transmitting signal processing apparatus 110 has a plurality of transmitting signal generation units 111, namely the first transmitting signal generation unit 1111 to the Nth transmitting signal generation unit 111. N .

[0024] The receiving signal processing device 120 has multiple matched filter groups 121, namely the first matched filter group 1211 to the Mth matched filter group 121. M Provisional angle measuring unit 122, bidirectional angle measuring unit 123, and propagation mode discrimination unit 124.

[0025] Transmitting antenna 11 to the Nth transmitting antenna 1 N They respectively receive signals from the corresponding first to Nth transmission signal generation units 1111. N The transmitted signal is converted into a transmitted wave and then emitted as a radiant, distinct transmitted waves TW1 to TW2. N .

[0026] Transmitting antenna 11 to the Nth transmitting antenna 1 N They are arranged in a straight line at certain intervals.

[0027] From the first transmitting antenna 11 to the Nth transmitting antenna 1 N The first transmitted wave TW1 to the Nth transmitted wave TW1 were sent. N It refers to transmitted waves based on mutually orthogonal signals (orthogonal signals). Orthogonality means, for example, that they will not interfere with each other due to differences in time, phase, frequency, symbol, etc.

[0028] Furthermore, in the following explanation, to avoid confusion, unless otherwise specified, the first transmitting antenna 11 to the Nth transmitting antenna 1 will be referred to as such. N and the first transmitted wave TW1 to the Nth transmitted wave TW N The following explanation will focus on transmitting antenna 1 and transmitting wave TW.

[0029] First transmitting signal generation unit 1111 to Nth transmitting signal generation unit 111 NRespectively connected to the first transmitting antenna 11 to the Nth transmitting antenna 1 N Correspondingly, different transmission signals are generated for each signal, and the generated transmission signals are output to the corresponding transmission antenna 1.

[0030] That is, the first transmission signal generation unit 1111 generates a first transmission signal and outputs the first transmission signal to the corresponding first transmission antenna 11; the second transmission signal generation unit 1112 generates a second transmission signal and outputs the second transmission signal to the corresponding second transmission antenna 12; the Nth transmission signal generation unit 111... N Generate the Nth transmitted signal and output the Nth transmitted signal to the corresponding Nth transmitted antenna 1. N The first to the Nth transmitted signals are orthogonal to each other.

[0031] In addition, the first transmission signal generation unit 1111 to the Nth transmission signal generation unit 111 N The transmitted signals are respectively output to the first matched filter group 1211 to the Mth matched filter group 121. M .

[0032] First transmitting signal generation unit 1111 to Nth transmitting signal generation unit 111 N This is a known signal generation unit; detailed descriptions are omitted.

[0033] Furthermore, in the following description, to avoid confusion, unless otherwise specified, the first transmitting signal generation unit 1111 to the Nth transmitting signal generation unit 111 will be referred to as such. N The signal generation unit 111 will be described in detail.

[0034] First receiving antenna 21 to Mth receiving antenna 2 M They are arranged in a straight line at certain intervals.

[0035] First receiving antenna 21 to Mth receiving antenna 2 M The transmitted waves TW sent from multiple transmitting antennas 1 are reflected from the object and respectively taken as different arriving waves RW1 to RW1. M Come and capture the upcoming waves RW1~RW M Converted into a received signal, and output to the corresponding first matched filter group 1211 to the Mth matched filter group 121 M .

[0036] Furthermore, in the following explanation, to avoid confusion, unless otherwise specified, the first receiving antenna 21 to the Mth receiving antenna 2 will be referred to as such. M The following explanation will focus on receiving antenna 2.

[0037] Matched filter bank 1211 to Mth matched filter bank 121 M Respectively connected to the first receiving antenna 21 to the Mth receiving antenna 2 M Configure accordingly.

[0038] Matched filter bank 1211 to Mth matched filter bank 121 M The received signal is input from the corresponding receiving antenna 2 and the transmitted signal is input from the multiple transmitting signal generation units 111.

[0039] Matched filter bank 1211 to Mth matched filter bank 121 M Each is composed of a matched filter, and the transmitted signals from multiple transmitted signal generation units 111 are used as copies of the matched filters to obtain N matched filter outputs.

[0040] That is, through M received signals and N transmitted signals, from the first matched filter group 1211 to the Mth matched filter group 121 M The outputs of M×N matched filters are obtained, which are M×N virtual received signals.

[0041] In other words, the first matched filter group 1211 to the Mth matched filter group 121 M This is equivalent to converting the incoming wave obtained by M×N virtual receiving antennas configured at the same intervals as the multiple transmitting antennas 1 into a received signal and outputting the received signal.

[0042] From the first matched filter bank 1211 to the Mth matched filter bank 121 M The output of the matched filter becomes a vector element of the received signal vector in the virtual received signal obtained from the incoming wave by M×N virtual receiving antennas.

[0043] The received signal vectors that correspond to the specified range Doppler cells, i.e., the range Doppler cells given by the target detection process, in these received signal vectors become the received signal vectors of interest, x(i).

[0044] That is, 1 to N S The received signal vector in the i-th snapshot of the snapshot used for target detection processing becomes the received signal vector of interest x(i) for each virtual receiving antenna. where i is 1 to N. S Snapshot number. N S It is a natural number greater than 2.

[0045] Matched filter bank 1211 to Mth matched filter bank 121 MIt can perform operations using any of the following methods: TDMA (Time Division Multiple Access), CDMA (Code Division Multiple Access), DDMA (Doppler Division Multiple Access), or FDMA (Frequency Division Multiple Access).

[0046] However, it is not limited to the specific methods mentioned above; other methods may also be used.

[0047] Matched filter bank 1211 to Mth matched filter bank 121 M These are known matched filter banks; detailed descriptions are omitted.

[0048] Furthermore, in the following explanation, to avoid complexity, unless otherwise specified, the first matched filter group 1211 to the Mth matched filter group 121 are referred to as such. M The following explanation is given for matched filter bank 121.

[0049] Furthermore, the received signal vector x(i) of interest also exists in all M×N virtual receiving antennas. However, in the following explanation, to avoid complexity, we will focus on one received signal vector x(i) of interest. However, the same approach applies to the other received signal vectors x(i) of interest.

[0050] Before explaining the feature points in Embodiment 1 of the receiving signal processing apparatus 120, namely the provisional angle measuring unit 122, the bidirectional angle measuring unit 123, and the propagation mode discrimination unit 124, the receiving signal vector x(i) of interest will be explained.

[0051] First, such as Figure 2 As shown, the received signal vector x(i) of interest for the multipath propagation mode is explained when there are different objects A and B within the radio wave illumination range of the MIMO radar device and the receiving antenna 2 captures the multipath propagation wave as the incoming wave.

[0052] In addition, the radio wave illumination range of the MIMO radar device is the propagation environment sensed by the MIMO radar device.

[0053] Let the propagation angle from object A to object B be (u A ,u B (where u) A ≠u B The propagation angle from object B to object A will be set as (u). B ,uA (where u) A ≠u B When, due to the reversibility of propagation, such as Figure 2 As shown by the arrow, there are two multipath propagation paths in both directions when objects A and B are reflected once each: the first multipath propagation path based on TW(1)→MW(1)→RW(1) and the second multipath propagation path based on TW(2)→MW(2)→RW(2).

[0054] Here, the propagation angle is correlated with the azimuth or elevation angle in the plane.

[0055] Of course, the propagation angle can also be an angle within space determined by the azimuth and elevation angles.

[0056] In the following explanation, we will assume that the propagation angle is correlated with the angle in the plane using azimuth or elevation angle. However, the same applies when the propagation angle is set as an angle in space determined by azimuth and elevation angle.

[0057] The first multipath propagation path TW(1)→MW(1)→RW(1) is a counterclockwise multipath propagation path from the MIMO radar device, where the transmitted wave TW is reflected by object A, and the reflected wave is reflected by object B and becomes the incoming wave RW, reaching the MIMO radar device.

[0058] The second multipath propagation path TW(2)→MW(2)→RW(2) is a clockwise multipath propagation path from the MIMO radar device, where the transmitted wave TW is reflected by object B, and the reflected wave is reflected by object A and becomes the incoming wave RW.

[0059] Furthermore, as a multipath propagation path, the explanation focuses on the case where the object is reflected twice. However, the explanation also applies when the object is reflected three or more times.

[0060] In the first multipath propagation path, the propagation angle u A This becomes the delivery angle (DOD: Direction-of-Departure), the propagation angle u. B Becoming the direction of arrival (DOA), in the second multipath propagation path, the propagation angle u B Become the sending angle, the propagation angle u A Become the arrival corner.

[0061] The signal vector x(i) that we are interested in at this time becomes Equation (1).

[0062]

[0063] In equation (1), i is 1 to N. S The snapshot number, s(i) is the complex amplitude of the reflected signal, n(i) is the receiver noise vector, and a MIMO (u A ,u B ) is the sending angle u in the first multipath propagation path. A and the angle of arrival u B The corresponding virtual array steering vector, a MIMO (u B ,u A ) is the sending angle u in the second multipath propagation path. B and the angle of arrival u A The corresponding virtual array steering vector, b(u A ,u B ) is related to the propagation angle (u) A ,u B The corresponding multipath guidance vector.

[0064] Virtual array steering vector a MIMO (u A ,u B The guiding vector a from the transmitting array T (u A ) and receiver array steering vector a R (u B The Kronecker product is given by the virtual array steering vector a. MIMO (u B ,u A The guiding vector a from the transmitting array T (u B ) and receiver array steering vector a R (u A The Kronecker product of is given by the following equation (2).

[0065]

[0066]

[0067] When considering equation (2) above, the multipath steering vector b(u) in equation (1) above... A ,u B It is represented by the following formula (3).

[0068]

[0069] Furthermore, according to equation (3) above, it can be seen that, with the propagation angle (u) B ,u A The corresponding multipath guidance vector b(u) B ,uA ) and the propagation angle (u) A ,u B The corresponding multipath guidance vector b(u) A ,u B If they are equal, then equation (4) holds true.

[0070] b(u B u A )=b(u A u B (4)

[0071] On the other hand, we focus on the correlation matrix R in the received signal vector x(i). XX It is represented by the following formula (5).

[0072]

[0073] In equation (5), P S It is the reflected signal power, σ 2 It is the receiver noise power, R AB R is the autocorrelation matrix of the multipath propagating wave in the first multipath propagation path. BA It is the autocorrelation matrix of the multipath propagation wave in the second multipath propagation path.

[0074] Autocorrelation matrix R AB and autocorrelation matrix R BA It is represented by the following formula (6).

[0075] R AB =p s a MIMO (u A u B )a MIMO H (u A u B )

[0076] R BA =p s a MIMO (u B u A )a MIMO H (u B u A )…(6)

[0077] The item on the right side of equation (5) shown in (7) below is the cross-correlation matrix generated by the coherence of the multipath propagation waves in the first and second multipath propagation paths.

[0078]

[0079] The cross-correlation matrix shown in (7) above is represented by the following equation (8).

[0080]

[0081] That is, as shown in equation (8) above, the cross-correlation matrix shown in (7) above is the sum of the correlation matrix in the first multipath propagation path affected by the second multipath propagation path and the correlation matrix in the second multipath propagation path affected by the first multipath propagation path.

[0082] Next, the received signal vector x(i) of the direct propagation mode, which is consistent with the path (outbound path) of the transmitted wave TW from the MIMO radar device to object A and the path (loop) of the reflected wave RW from object A to the MIMO radar device, will be explained.

[0083] In the direct propagation mode, the transmit angle u in the transmitted wave is the received signal vector x(i) of interest. A and the arrival angle u in the arriving wave A Since they are the same, they are represented by the following formula (9).

[0084] x(i)=a MIMO (u A u A )s(i)+n(i)…(9)

[0085] Therefore, the correlation matrix R based on the received signal vector x(i) of the direct propagation wave is... XX It is represented by the following formula (10).

[0086]

[0087] In equation (10), R AA It is the autocorrelation matrix of the direct propagation wave in the direct propagation path of object A, and is represented by the following equation (11).

[0088] R AA =p s a MIMO (u A u A )a MIMO H (u A u A )…(11)

[0089] The autocorrelation matrix R of the direct propagation wave in the direct propagation mode is such that the path (outgoing path) of the transmitted wave TW from the MIMO radar device to object B and the path (loop) of the reflected wave RW from object B to the MIMO radar device are consistent. BBIt is expressed in the same way as the above formula (11).

[0090] Next, the provisional angle measuring unit 122, the bidirectional angle measuring unit 123, and the propagation mode discrimination unit 124 in the receiving signal processing device 120 will be described.

[0091] The provisional angle measurement unit 122 calculates a provisional angle measurement value for the received signal vector x(i) corresponding to the range Doppler cell given by the target detection processing, based on the received signal of the M×N virtual receiving antennas, which is assumed to be the output of the matched filter for the multiple matched filter banks 121.

[0092] The provisional angle measurement unit 122 calculates provisional angle measurement values ​​for the received signal vector x(i) of interest, respectively, based on the matched filter outputs for the M×N virtual receiving antennas input from the multiple matched filter banks 121, as follows.

[0093] That is, regarding the provisional angle measurement unit 122, the provisional angle measurement value for each received signal vector x(i) of interest is calculated, and the azimuth spectrum Ptentative(u) of the beamforming method shown in the following equation (12) is obtained, and the angle u corresponding to the maximum value of the azimuth spectrum Ptentative(u) is obtained. tV The angle u of the maximum value tV Set as a provisional angle measurement value.

[0094] In summary, in equation (12), the sending angle and the arrival angle that constitute the bidirectional angle measurement value of the signal vector x(i) of interest are assumed to be the same propagation angle u. The assumed propagation angle u is used as a variable to calculate the azimuth spectrum Ptentative(u). The propagation angle u at which the azimuth spectrum Ptentative(u) reaches its maximum value is taken as the provisional angle measurement value u. tV .

[0095]

[0096] According to equation (12), the azimuth spectrum Ptentative(u) depends on the virtual array steering vector a corresponding to the directly propagating wave. MIMO (u,u) depends on the propagation angle (u,u).

[0097] In addition, in equation (12), u is the scanning angle representing the sending angle and the arriving angle.

[0098] When the output of the matched filter from the matched filter bank 121, which is input to the provisional angle measuring unit 122, is the received signal of the direct propagation wave about object A, the correlation matrix R is based on the received signal vector x(i) of interest from the direct propagation wave. XX It is represented by the above formula (10).

[0099] Therefore, in the provisional angle measurement unit 122, the propagation angle u is used as a variable to calculate the azimuth spectrum Ptentative(u). The propagation angle u at which the azimuth spectrum Ptentative(u) shows its maximum value is considered as the sending angle u in the direct propagation wave for object A. A and the angle of arrival u A .

[0100] As a result, the provisional angle measuring unit 122 is able to obtain what is considered the output angle u. A and the angle of arrival u A Provisional angle measurement value u tV .

[0101] Furthermore, when the output of the matched filter from the matched filter bank 121, which is input to the provisional angle measuring unit 122, is the received signal of the direct propagation wave about object B, the correlation matrix R based on the received signal vector x(i) of interest from the direct propagation wave... XX It is expressed in the same way as the above formula (10).

[0102] Therefore, in the provisional angle measurement unit 122, the propagation angle u is used as a variable to calculate the azimuth spectrum Ptentative(u). The propagation angle u at which the azimuth spectrum Ptentative(u) shows its maximum value is considered as the sending angle u in the direct propagation wave for object B. B and the angle of arrival u B .

[0103] As a result, the provisional angle measuring unit 122 is able to obtain what is considered the output angle u. B and the angle of arrival u B Provisional angle measurement value u tV .

[0104] On the other hand, when the matched filter output from the matched filter bank 121 input to the provisional angle measuring unit 122 is a received signal for a multipath propagating wave, the correlation matrix R based on the received signal vector x(i) of interest for the multipath propagating wave is... XX It is represented by the above formula (5).

[0105] In the provisional angle measurement unit 122, the propagation angle u is used as a variable to calculate the azimuth spectrum Ptentative(u), and the propagation angle u at which the azimuth spectrum Ptentative(u) shows its maximum value is obtained as the provisional angle measurement value u. tV .

[0106] However, the provisional angle measurement value u obtained here tV It is impossible to estimate the send-out angle and arrival angle for the RW of the arriving wave based on multipath propagation.

[0107] That is, when the output of the matched filter from the matched filter bank 121 is the received signal for a multipath propagating wave, compared with the maximum value of the azimuth spectrum Ptentative(u) obtained by the propagation angle (u,u), the value obtained by the propagation angle (u) is lower. A ,u B ) or (u B ,u A (where u) A ≠u B The maximum value of the azimuth spectrum Ptentative(u) obtained is relatively large.

[0108] Therefore, when the output of the matched filter from the matched filter bank 121 is based on the arrival wave RW of the multipath propagation wave, the output angle u cannot be obtained from the maximum value of the azimuth spectrum Ptentative(u). A or u B and the angle of arrival u B or u A .

[0109] Furthermore, when there are multiple azimuth spectra Ptentative(u) showing maxima in the azimuth spectrum Ptentative(u) obtained by using the propagation angle u as a variable, the provisional angle measurement unit 122 obtains the propagation angle u for each of the multiple azimuth spectra Ptentative(u) showing maxima as a provisional angle measurement value u. tV .

[0110] That is, when there are multiple azimuth spectra Ptentative(u) showing multiple maxima, the provisional angle measurement unit 122 obtains multiple provisional angle measurement values ​​u corresponding to the multiple maxima. tV .

[0111] Furthermore, in the example above, the provisional angle measuring unit 122 obtains the provisional angle value u, which is assumed to be a directly propagating wave, by beamforming. tV However, the provisional angular measurement value u, which is assumed to be the arrival wave RW as a directly propagating wave, can also be obtained through the MUSIC (Multiple Signal Classification) method or the ESPRIT (Estimation of Signal Parameters via Rotational Invariance Techniques) method. tV .

[0112] The bidirectional angle measuring unit 123 measures the angle based on the outputs of the matched filters from the multiple matched filter banks 121 and the provisional angle measuring value u calculated by the provisional angle measuring unit 122. tVCalculate the bidirectional angle measurement value consisting of the sending angle and the arrival angle for the received signal vector x(i) of interest.

[0113] That is, in the following formula (13), the provisional angle measurement value u calculated by the provisional angle measurement unit 122 is used. tV Let u be the angle of arrival for the received signal vector x(i) of interest. B This will be used to calculate the output angle u. A The azimuth spectrum P is obtained by using the propagation angle u as a variable. D (u), the azimuth spectrum P D (u) The propagation angle u that becomes the maximum value bi Let the output angle be u. A .

[0114] u bi =argmaxP D (u)

[0115]

[0116] According to equation (13), the azimuth spectrum P D (u) depends on the virtual array steering vector a MIMO (u,u tV ), depends on the propagation angle (u,u) tV ).

[0117] In addition, in equation (13), u is the scanning angle representing the output angle.

[0118] As a result, the bidirectional angle measuring unit 123 obtains the transmission angle u for the received signal vector of interest x(i). A To make the azimuth spectrum P D (u) The propagation angle u that becomes the maximum value bi And the angle u B The provisional angle measurement value u calculated by the provisional angle measurement unit 122 tV The bidirectional angle measurement value.

[0119] In the above description, the output angle is set to u. A Set the arrival angle as u B An explanation has been given, but even if the output angle is set to u... B Set the arrival angle as u A It can also obtain bidirectional angle measurement values ​​in exactly the same way.

[0120] In summary, regardless of the transmission angle and arrival angle of the incoming wave toward the virtual receiving antenna, the bidirectional angle measuring unit 123 can obtain the transmission angle u relative to the respective received signal vector x(i) of interest in the virtual receiving antenna. bi The arrival angle is u tV The bidirectional angle measurement value.

[0121] Furthermore, the provisional angle measurement values ​​obtained by the provisional angle measurement unit 122 correspond to multiple maxima as multiple provisional angle measurement values ​​u. tV When present, the bidirectional angle measuring unit 123 will measure multiple provisional angle values ​​u. tV As arrival angle u B This will be used to calculate the output angle u. A The azimuth spectrum P is obtained by using the propagation angle u as a variable. D (u), the azimuth spectrum P D (u) The propagation angle u that becomes the maximum value bi Let the output angle be u. A .

[0122] Then, the bidirectional angle measuring unit 123 calculates multiple provisional angle values ​​u. tV and for multiple provisional angle measurement values ​​u tV The propagation angle u bi The difference between each | u bi -u tV |, obtain the difference |u bi -u tV | Indicates the propagation angle u of the minimum value bi Let the output angle be u. A And the provisional angle measurement value u tV Let the arrival angle be u. B The focus is on the bidirectional angle measurement values ​​in the received signal vector x(i).

[0123] The propagation mode discrimination unit 124 determines whether the propagation mode of the received signal vector x(i) for which the bidirectional angle measurement value is obtained by the bidirectional angle measurement unit 123 is the direct propagation mode or the multipath propagation mode, and outputs the discrimination result.

[0124] The propagation mode discrimination unit 124 calculates the output angle u that constitutes the bidirectional angle measurement value obtained by the bidirectional angle measurement unit 123. bi and the angle of arrival u tV The difference |u bi -u tV |, the difference |u bi -u tV | Compare with the threshold th.

[0125] Furthermore, the provisional angle measurement values ​​obtained by the provisional angle measurement unit 122 correspond to multiple maxima as multiple provisional angle measurement values ​​u. tV And multiple provisional angle measurement values ​​u exist and are obtained through the bidirectional angle measuring unit 123. tV and for multiple provisional angle measurement values ​​u tV The propagation angle u bi The difference between each | u bi -utV The difference between the minimum values ​​is shown in |u|. bi -u tV In the case of |, the propagation mode discrimination unit 124 determines the output angle u obtained by the bidirectional angle measuring unit 123. bi and the angle of arrival u tV The minimum difference |u bi -u tV | Compare with the threshold th.

[0126] The propagation mode discriminant unit 124 is in the difference |u bi -u tV When | is below the threshold th, the propagation mode in the received signal vector x(i) is determined to be the direct propagation mode, and the output is a determination result of the direct propagation mode.

[0127] difference|u bi -u tV |Below the threshold th means the delivery angle u bi and the angle of arrival u tV Approximate or identical means that the propagation mode of the received signal vector x(i) is a direct propagation mode in which the path (outbound path) of the transmitted wave TW from the MIMO radar device to the object and the path (loop) of the reflected wave RW from the object to the MIMO radar device are the same.

[0128] On the other hand, the propagation mode discriminant 124 is in the difference |u bi -u tV When the threshold th is exceeded, the propagation mode of the received signal vector x(i) is determined to be the multipath propagation mode, and the output is the determination result of the multipath propagation mode.

[0129] difference|u bi -u tV |Exceeding the threshold th means that at the sending angle u bi With the arrival angle u tV The existence of a difference means that the propagation mode of the received signal vector x(i) is a multipath propagation path where the path and return of the propagating wave are inconsistent.

[0130] The provisional angle measuring unit 122, bidirectional angle measuring unit 123, and propagation mode discrimination unit 124 are configured by a microcomputer containing memory such as CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory).

[0131] Next, use Figure 3The operation of MIMO radar signal processing devices, especially receiving signal processing devices, is explained, focusing on the propagation mode discrimination method of the received signal vector x(i).

[0132] The incoming wave RW captured by multiple receiving antennas 2 is converted into a received signal by the multiple receiving antennas 2, and the converted received signal is input to multiple matched filter groups 121 corresponding to the multiple receiving antennas 2 respectively.

[0133] Each matched filter bank 121 outputs a number of matched filter outputs equal to the number of input transmitted signals, using received signals from the corresponding receiving antenna 2 and transmitted signals from multiple transmitting signal generation units 111.

[0134] As shown in step ST1, the provisional angle measurement unit 122, which is input to the outputs of the matched filters from the multiple matched filter banks 121, calculates a provisional angle measurement value u for the received signal vector of interest x(i) for each matched filter output. tV .

[0135] Obtain the provisional angle measurement value u tV The propagation angle u, which is the maximum value of the azimuth spectrum Ptentative(u) shown in equation (12), is obtained.

[0136] Next, as shown in step ST2, the matched filter output, which is input from the output of the multiple matched filter banks 121, and receives the provisional angle measurement value u calculated by the provisional angle measurement unit 122, is processed. tV The bidirectional angle measurement unit 123 calculates the bidirectional angle measurement value of the received signal vector x(i) of interest for each matched filter output.

[0137] The bidirectional angle measuring unit 123 sets the arrival angle that constitutes the bidirectional angle measuring value as the provisional angle measuring value u calculated by the provisional angle measuring unit 122. tV The sending angle that constitutes the bidirectional angle measurement value is set as the azimuth spectrum P shown in the above formula (13). D (u) The propagation angle u that becomes the maximum value bi Obtain bidirectional angle measurement values ​​(u bi ,u tV ).

[0138] Next, as shown in step ST3, the propagation mode discrimination unit 124 calculates the output angle u of the bidirectional angle measurement value of the received signal vector x(i) of interest calculated by the bidirectional angle measurement unit 123 for each matched filter output. bi and the angle of arrival u tV The difference |u bi -u tV |, the difference |u bi -u tV | Compare with the threshold th.

[0139] As shown in step ST4, the propagation mode discrimination unit 124 determines the propagation mode of the received signal vector x(i) based on the comparison result.

[0140] The propagation mode discriminant unit 124 is in the difference |u bi -u tV When | is below the threshold th, the output is a discrimination result such as direct propagation mode, in the difference |u bi -u tV When the threshold th is exceeded, the output is a judgment result of multi-path propagation mode.

[0141] On the other hand, in step ST1, when there are multiple azimuth spectra Ptentative(u) showing maximum points in the azimuth spectrum Ptentative(u) obtained by the provisional angle measuring unit 122, steps ST1 to ST2 are as follows.

[0142] In step ST1, the provisional angle measuring unit 122 obtains the propagation angle u of the azimuth spectrum Ptentative(u) for each of the multiple points showing a maximum as a provisional angle measuring value u. tV .

[0143] In step ST2, the bidirectional angle measuring unit 123 measures the multiple provisional angle values ​​u obtained by the provisional angle measuring unit 122. tV As arrival angle u B Obtain the azimuth spectrum P D (u) The propagation angle u that becomes the maximum value bi As the sending angle u A .

[0144] Then, the bidirectional angle measuring unit 123 calculates multiple provisional angle values ​​u. tV and for multiple provisional angle measurement values ​​u tV The propagation angle u bi The difference between each | u bi -u tV |

[0145] The bidirectional angle measuring unit 123 obtains the difference |u to be calculated. bi -u tV | Indicates the propagation angle u of the minimum value bi Let the output angle be u. A And the provisional angle measurement value u tV Let the arrival angle be u. B The focus is on the bidirectional angle measurement values ​​in the received signal vector x(i).

[0146] In step ST3, the propagation mode discrimination unit 124 outputs the bidirectional angle u that constitutes the bidirectional angle value of the received signal vector x(i) of interest obtained by the bidirectional angle measurement unit 123 for each matched filter output. bi and the angle of arrival u tV The difference |u bi -u tV | Compare with the threshold th.

[0147] As described above, the MIMO radar signal processing apparatus of Embodiment 1 includes: a provisional angle measurement unit 122, which takes the matched filter outputs from multiple matched filter banks 121 as a received signal assuming a direct propagation mode based on the received wave RW, which is directly propagated by the transmitted wave TW after being reflected by an object, and calculates a provisional angle measurement value u for the received signal vector x(i) of interest corresponding to the range Doppler cell given by the target detection processing. tV ; and a bidirectional angle measuring unit 123, which calculates a provisional angle value u based on the matched filter outputs from multiple matched filter banks 121 and the provisional angle measuring unit 122. tV To obtain the value of the received signal vector x(i) based on the sending angle u bi and the angle of arrival u tV The bidirectional angle measurement values ​​constituted can, for example, be used to determine which propagation mode is in the direct propagation mode or the multipath propagation mode.

[0148] That is, the received signal vector x(i) obtained by the bidirectional angle measuring unit 123 is obtained from the sending angle u bi and the angle of arrival u tV When the bidirectional angle measurement values ​​are used to determine the propagation mode, they can accurately determine whether the propagation mode of the received signal vector x(i) is the direct propagation mode or the multipath propagation mode, and can gain a more detailed understanding of the propagation environment sensed by the MIMO radar device.

[0149] Furthermore, the MIMO radar signal processing apparatus of Embodiment 1 also includes a propagation mode discrimination unit 124, which determines the propagation mode based on the bidirectional angle measurement values ​​(u) obtained by the bidirectional angle measurement unit 123. bi ,u tV The system can determine with high accuracy whether the propagation mode of the received signal vector x(i) is the direct propagation mode or the multipath propagation mode, thus enabling a more detailed understanding of the propagation environment sensed by the MIMO radar device.

[0150] Implementation Method 2

[0151] The MIMO radar device of Embodiment 2 will be described.

[0152] The MIMO radar device of Embodiment 2 differs from the MIMO radar device of Embodiment 1 in that the bidirectional angle measuring section 123 is different, but the other structures are the same or identical to those of the MIMO radar device of Embodiment 1.

[0153] Therefore, the provisional angle measuring unit 122, the bidirectional angle measuring unit 123, and the propagation mode discrimination unit 124 will be described below.

[0154] In the following formula (14), the bidirectional angle measuring unit 123 measures the provisional angle value u calculated by the provisional angle measuring unit 122. tV Let u be the output angle for the received signal vector x(i) of interest. A This will be used to calculate the arrival angle u. B The azimuth spectrum P is obtained by using the propagation angle u as a variable. A (u), the azimuth spectrum P A (u) The propagation angle u that becomes the maximum value bi Let the arrival angle be u. B .

[0155] u bi =argmaxP A (u)

[0156]

[0157] According to equation (14), the azimuth spectrum P A (u) depends on the virtual array steering vector a MIMO (u tV ,u), depends on the propagation angle (u) tV ,u).

[0158] In addition, in equation (14), u is the scanning angle representing the arrival angle.

[0159] As a result, the bidirectional angle measuring unit 123 obtains the transmission angle u for the received signal vector of interest x(i). A The provisional angle measurement value u calculated by the provisional angle measurement unit 122 tV And the angle u B To make the azimuth spectrum P A (u) The propagation angle u that becomes the maximum value bi The bidirectional angle measurement value.

[0160] In the above description, the output angle is set to u. A Set the arrival angle as u B An explanation has been given, but even if the output angle is set to u... B Set the arrival angle as u AIt can also obtain bidirectional angle measurement values ​​in exactly the same way.

[0161] In summary, regardless of the transmission angle and arrival angle of the incoming wave toward the virtual receiving antenna, the bidirectional angle measuring unit 123 can obtain the transmission angle u for each of the received signal vectors of interest x(i) of the virtual receiving antenna. tV The arrival angle is u bi The bidirectional angle measurement value.

[0162] The propagation mode discrimination unit 124 calculates the output angle u that constitutes the bidirectional angle measurement value obtained by the bidirectional angle measurement unit 123. tV and the angle of arrival u bi The difference |u tV -u bi |, the difference |u tV -u bi | Compare with the threshold th.

[0163] The propagation mode discriminant unit 124 is in the difference |u tV -u bi When | is below the threshold th, the propagation mode of the received signal vector x(i) is determined to be the direct propagation mode, and the output is a determination result of the direct propagation mode.

[0164] On the other hand, the propagation mode discriminant 124 is in the difference |u tV -u bi When the threshold th is exceeded, the propagation mode of the received signal vector x(i) is determined to be the multipath propagation mode, and the output is the determination result of the multipath propagation mode.

[0165] Furthermore, when there are multiple azimuth spectra Ptentative(u) showing maximum points in the azimuth spectrum Ptentative(u) obtained by the provisional angle measuring unit 122, the provisional angle measuring unit 122, the bidirectional angle measuring unit 123, and the propagation mode discrimination unit 124 operate as follows.

[0166] That is, the provisional angle measuring unit 122 obtains the propagation angle u of the azimuth spectrum Ptentative(u) for multiple points showing maxima as the provisional angle measuring value u. tV .

[0167] The bidirectional angle measuring unit 123 measures multiple provisional angle values ​​u obtained by the provisional angle measuring unit 122. tV Each is used as the sending angle u A , azimuth spectrum P D (u) The propagation angle u that becomes the maximum value bi Let the arrival angle be u. B .

[0168] Then, the bidirectional angle measuring unit 123 calculates multiple provisional angle values ​​u.tV and for multiple provisional angle measurement values ​​u tV The propagation angle u bi The difference between each | u tV -u bi |

[0169] The bidirectional angle measuring unit 123 acquires the provisional angle measurement value u. tV Let the output angle be u. A And the difference |u tV -u bi | Indicates the propagation angle u of the minimum value bi Let the arrival angle be u. B The focus is on the bidirectional angle measurement value of the received signal vector x(i).

[0170] The propagation mode discrimination unit 124 transmits the bidirectional angle u that constitutes the bidirectional angle value of the received signal vector x(i) obtained by the bidirectional angle measurement unit 123. tV and the angle of arrival u bi The difference |u tV -u bi | Compare with the threshold th.

[0171] The MIMO radar signal processing device of Embodiment 2 also has the same effect as the MIMO radar signal processing device of Embodiment 1.

[0172] Implementation Method 3

[0173] The MIMO radar device of Embodiment 3 will be described.

[0174] The MIMO radar device of Embodiment 3 differs from the MIMO radar device of Embodiment 1 in that the bidirectional angle measuring section 123 is different, but the other structures are the same or identical to those of the MIMO radar device of Embodiment 1.

[0175] Therefore, the provisional angle measuring unit 122, the bidirectional angle measuring unit 123, and the propagation mode discrimination unit 124 will be described below.

[0176] In the above formula (13), similar to Embodiment 1, the bidirectional angle measuring unit 123 calculates the provisional angle value u by the provisional angle measuring unit 122. tV Let u be the angle of arrival for the received signal vector x(i) of interest. B This will be used to calculate the output angle u. A The azimuth spectrum P is obtained by using the propagation angle u as a variable. D (u), obtain the azimuth spectrum P D (u) The propagation angle u that becomes the maximum value bi Let the output angle be u. A The first provisional bidirectional angle measurement value (u) bi ,utV Furthermore, in the above formula (14), similarly to embodiment 2, the bidirectional angle measuring unit 123 calculates the provisional angle value u by the provisional angle measuring unit 122. tV Let u be the output angle for the received signal vector x(i) of interest. A This will be used to calculate the arrival angle u. B The azimuth spectrum P is obtained by using the propagation angle u as a variable. A (u), obtain the azimuth spectrum P A (u) The propagation angle u that becomes the maximum value bi Let the arrival angle be u. B The second provisional bidirectional angle measurement value (u) tV ,u bi ).

[0177] The bidirectional angle measuring unit 123 sets the first provisional bidirectional angle measuring value (u) bi ,u tV ) azimuth spectrum P D (u) and the second provisional bidirectional angle measurement value (u) tV ,u bi ) azimuth spectrum P A (u) is compared, and the first provisional bidirectional angle measurement value (u) is used. bi ,u tV ) and the second provisional bidirectional angle measurement value (u tV ,u bi Any provisional bidirectional angle measurement value in () is set as the bidirectional angle measurement value.

[0178] That is, the bidirectional angle measuring unit 123 in the azimuth spectrum P D (u) Comparison of azimuth spectrum P A When (u) is large, select the first provisional bidirectional angle measurement value (u). bi ,u tV As a bidirectional angular measurement value, in the azimuth spectrum P A (u) Comparison of azimuth spectrum P D When (u) is large, select the second provisional bidirectional angle measurement value (u). tV ,u bi () as a bidirectional angle measurement value.

[0179] In the above description, the output angle is set to u. A Set the arrival angle as u B An explanation has been given, but even if the output angle is set to u... B Set the arrival angle as u A It can also obtain bidirectional angle measurement values ​​in exactly the same way.

[0180] The propagation mode discrimination unit 124 selects the first provisional bidirectional angle measurement value (u). bi ,u tVWhen used as a bidirectional angle measurement value, the output angle u constituting the bidirectional angle measurement value obtained by the bidirectional angle measurement unit 123 is calculated in the same manner as in Embodiment 1. bi and the angle of arrival u tV The difference |u bi -u tV |, the difference |u bi -u tV | Compare with the threshold th.

[0181] The propagation mode discriminant unit 124 is in the difference |u bi -u tV When | is below the threshold th, the propagation mode of the received signal vector x(i) is determined to be the direct propagation mode, and the output is a determination result of the direct propagation mode.

[0182] On the other hand, the propagation mode discriminant 124 is in the difference |u bi -u tV When the threshold th is exceeded, the propagation mode of the received signal vector x(i) is determined to be the multipath propagation mode, and the output is the determination result of the multipath propagation mode.

[0183] In addition, when selecting the second provisional bidirectional angle measurement value (u) tV ,u bi When used as a bidirectional angle measurement value, similar to Embodiment 2, the output angle u constituting the bidirectional angle measurement value obtained by the bidirectional angle measurement unit 123 is calculated. tV and the angle of arrival u bi The difference |u tV -u bi |, the difference |u tV -u bi | Compare with the threshold th.

[0184] The propagation mode discriminant unit 124 is in the difference |u tV -u bi When | is below the threshold th, the propagation mode of the received signal vector x(i) is determined to be the direct propagation mode, and the output is a determination result of the direct propagation mode.

[0185] On the other hand, the propagation mode discriminant 124 is in the difference |u tV -u bi When the threshold th is exceeded, the propagation mode of the received signal vector x(i) is determined to be the multipath propagation mode, and the output is the determination result of the multipath propagation mode.

[0186] Furthermore, when there are multiple azimuth spectra Ptentative(u) showing maximum points in the azimuth spectrum Ptentative(u) obtained by the provisional angle measuring unit 122, the provisional angle measuring unit 122, the bidirectional angle measuring unit 123, and the propagation mode discrimination unit 124 operate as follows.

[0187] That is, the provisional angle measuring unit 122 obtains the propagation angle u of the azimuth spectrum Ptentative(u) for multiple points showing maxima as the provisional angle measuring value u. tV .

[0188] The bidirectional angle measuring unit 123 measures multiple provisional angle values ​​u obtained by the provisional angle measuring unit 122. tV As arrival angle u B , azimuth spectrum P D (u) The propagation angle u that becomes the maximum value bi Let the output angle be u. A .

[0189] Then, the bidirectional angle measuring unit 123 calculates multiple provisional angle values ​​u. tV and for multiple provisional angle measurement values ​​u tV The propagation angle u bi The difference between each | u bi -u tV |

[0190] The bidirectional angle measuring unit 123 acquires the provisional angle measurement value u. tV Let the arrival angle be u. B And the difference |u bi -u tV | Indicates the propagation angle u of the minimum value bi Let the output angle be u. A The first provisional bidirectional angle measurement value (u) of the received signal vector x(i) is of interest. bi ,u tV ).

[0191] Furthermore, the bidirectional angle measuring unit 123 measures the multiple provisional angle values ​​u obtained by the provisional angle measuring unit 122. tV Each is used as the sending angle u A , azimuth spectrum P A (u) The propagation angle u that becomes the maximum value bi Let the arrival angle be u. B .

[0192] Then, the bidirectional angle measuring unit 123 calculates multiple provisional angle values ​​u. tV and for multiple provisional angle measurement values ​​u tV The propagation angle u bi The difference between each | u tV -u bi |

[0193] The bidirectional angle measuring unit 123 acquires the provisional angle measurement value u. tV Let the output angle be u. A And the difference |u tV -u bi | Indicates the propagation angle u of the minimum value bi Let the arrival angle be u. B The second provisional bidirectional angle measurement value (u) of the received signal vector x(i) is of interest. tV ,u bi ).

[0194] The bidirectional angle measuring unit 123 sets the first provisional bidirectional angle measuring value (u) bi ,u tV ) azimuth spectrum P D (u) and the second provisional bidirectional angle measurement value (u) tV ,u bi ) azimuth spectrum P A (u) is compared, and the provisional two-way angle measurement value with the larger azimuth spectrum is set as the two-way angle measurement value of the received signal vector x(i) of interest.

[0195] The propagation mode discrimination unit 124 compares the difference between the sending angle and the arriving angle of the bidirectional angle measurement value that constitutes the interest reception signal vector x(i) obtained by the bidirectional angle measurement unit 123 with the threshold th.

[0196] The MIMO radar signal processing device of Embodiment 3 also has the same effect as the MIMO radar signal processing device of Embodiment 1.

[0197] Furthermore, the bidirectional angle measuring unit 123 obtains the first provisional bidirectional angle measuring value (u). bi ,u tV ) and the second provisional bidirectional angle measurement value (u tV ,u bi By setting any provisional bidirectional angle measurement value as a bidirectional angle measurement value, it is possible to determine with higher accuracy whether the propagation mode of the received signal vector x(i) is the direct propagation mode or the multipath propagation mode.

[0198] Furthermore, it is possible to modify any structural element in each embodiment or omit any structural element in each embodiment.

[0199] Industrial availability

[0200] The MIMO radar signal processing device of the present invention can be applied to radar devices for monitoring flying objects, aircraft, marine radar devices, ship surveillance radar devices, vehicle-mounted radar devices, infrastructure radar devices, etc.

[0201] Label Explanation

[0202] 11~1 N : Transmitting antenna 1 to transmitting antenna N; 21 to 2 M : 1st to Mth receiving antennas; 100: MIMO radar signal processing device; 110: Transmit signal processing device; 1111 to 111 N 120: First to Nth transmit signal generation units; 1211 to 12121 (receive signal processing device) M 122: Matched filter bank 1 to M; 123: Provisional angle measurement unit; 124: Propagation mode discrimination unit.

Claims

1. A MIMO radar signal processing device, the MIMO radar signal processing device comprising: Multiple signal generation units generate different transmission signals for each other and output the generated transmission signals to the corresponding transmission antennas; Multiple matched filter banks are respectively input to the received signal from the receiving antenna and the transmitted signal from the multiple transmitted signal generation units. The transmitted signal from the multiple transmitted signal generation units is used as a copy of the matched filter, and the output is the matched filter output, which becomes the vector element of the received signal vector. The received signal from the receiving antenna corresponds to a plurality of receiving antennas that capture the reflected wave from the transmitted wave sent by the transmitting antenna as the incoming wave after it reaches the object. The provisional angle measurement unit takes the matched filter output from the plurality of matched filter banks as a received signal based on the direct propagation mode of the incoming wave, which is the direct propagation of the transmitted wave after being reflected by the object, and obtains a provisional angle measurement value for the received signal vector of interest corresponding to the range Doppler unit given by the target detection processing. The bidirectional angle measurement unit obtains a bidirectional angle measurement value consisting of the sending angle and the arriving angle for the received signal vector of interest, based on the matched filter outputs from the plurality of matched filter banks and the provisional angle measurement value calculated by the provisional angle measurement unit. as well as The propagation mode discrimination unit determines, based on the bidirectional angle measurement value, whether the propagation mode of the received signal vector of interest obtained by the bidirectional angle measurement unit is a direct propagation mode or a multipath propagation mode, in which the path of the transmitted wave to the object and the path of the reflected wave from the object to the MIMO radar signal processing device are inconsistent.

2. The MIMO radar signal processing device according to claim 1, wherein, The provisional angle measurement value obtained by the provisional angle measurement unit is obtained in the following manner: the sending angle and the arrival angle of the bidirectional angle measurement value constituting the received signal vector of interest are set to the same propagation angle, and the propagation angle that shows the maximum value of the azimuth spectrum obtained by using the propagation angle as a variable is obtained as the provisional angle measurement value.

3. The MIMO radar signal processing apparatus according to claim 1 or 2, wherein, The bidirectional angle measurement value in the bidirectional angle measurement unit is obtained in the following manner: the provisional angle measurement value calculated by the provisional angle measurement unit is set as the output angle of the bidirectional angle measurement value constituting the received signal vector of interest, and the arrival angle of the bidirectional angle measurement value constituting the received signal vector of interest is obtained.

4. The MIMO radar signal processing apparatus according to claim 1 or 2, wherein, The bidirectional angle measurement value in the bidirectional angle measurement unit is obtained in the following manner: the provisional angle measurement value calculated by the provisional angle measurement unit is set as the arrival angle of the bidirectional angle measurement value constituting the target received signal vector, and the sending angle of the bidirectional angle measurement value constituting the target received signal vector is obtained.

5. The MIMO radar signal processing apparatus according to claim 1 or 2, wherein, The bidirectional angle measurement value in the bidirectional angle measurement unit is obtained in the following manner: either a first provisional bidirectional angle measurement value or a second provisional bidirectional angle measurement value is set as the bidirectional angle measurement value. The first provisional bidirectional angle measurement value is obtained by setting the provisional angle measurement value calculated by the provisional angle measurement unit as the output angle of the bidirectional angle measurement value constituting the received signal vector of interest, and obtaining the arrival angle of the bidirectional angle measurement value constituting the received signal vector of interest. The second provisional bidirectional angle measurement value is obtained by setting the provisional angle measurement value calculated by the provisional angle measurement unit as the arrival angle of the bidirectional angle measurement value constituting the received signal vector of interest, and obtaining the output angle of the bidirectional angle measurement value constituting the received signal vector of interest.

6. The MIMO radar signal processing apparatus according to claim 1, wherein, The provisional angle measurement value obtained by the provisional angle measurement unit is obtained in the following manner: the sending angle and the arrival angle of the bidirectional angle measurement value constituting the received signal vector of interest are set to the same propagation angle, and the propagation angle that shows the maximum value of the azimuth spectrum obtained by using the propagation angle as a variable is obtained as the provisional angle measurement value. The bidirectional angle measurement values ​​in the bidirectional angle measurement unit are obtained in the following manner: when there are multiple provisional angle measurement values ​​obtained by the provisional angle measurement unit, the multiple provisional angle measurement values ​​are respectively set as the other side of the sending angle and the arriving angle of the bidirectional angle measurement values ​​constituting the target received signal vector, and the difference between the sending angle and the arriving angle is calculated. The sending angle and the arriving angle that show the smallest difference between the calculated sending angle and the arriving angle are obtained as the sending angle and the arriving angle of the bidirectional angle measurement values ​​constituting the target received signal vector.

7. The MIMO radar signal processing apparatus according to claim 1, wherein, The propagation mode discrimination unit discriminates the propagation mode in the following manner: it compares the difference between the sending angle and the arriving angle that constitute the bidirectional angle measurement value obtained by the bidirectional angle measurement unit with a threshold. When the difference is below the threshold, it is discriminated as a direct propagation mode. When the difference exceeds the threshold, it is discriminated as a multipath propagation mode.

8. A receiving signal processing device for a MIMO radar signal processing apparatus, the receiving signal processing device of the MIMO radar signal processing apparatus comprising: Multiple matched filter banks are respectively input to received signals from a receiving antenna and transmitted signals from multiple transmitted signal generation units that output transmitted signals to a transmitting antenna. The transmitted signals from the multiple transmitted signal generation units are used as copies of the matched filters, and the output is the matched filter output, which becomes the vector elements of the received signal vector. The received signal from the receiving antenna corresponds to a plurality of receiving antennas that capture the reflected wave from the transmitted wave sent by the transmitting antenna as the incoming wave after it reaches the object. The provisional angle measurement unit takes the matched filter output from the plurality of matched filter banks as a received signal based on the direct propagation mode of the incoming wave, which is the direct propagation of the transmitted wave after being reflected by the object, and obtains a provisional angle measurement value for the received signal vector of interest corresponding to the range Doppler unit given by the target detection processing. The bidirectional angle measurement unit obtains a bidirectional angle measurement value consisting of the sending angle and the arriving angle for the received signal vector of interest, based on the matched filter outputs from the plurality of matched filter banks and the provisional angle measurement value calculated by the provisional angle measurement unit. as well as The propagation mode discrimination unit determines, based on the bidirectional angle measurement value, whether the propagation mode of the received signal vector of interest obtained by the bidirectional angle measurement unit is a direct propagation mode or a multipath propagation mode, in which the path of the transmitted wave to the object and the path of the reflected wave from the object to the MIMO radar signal processing device are inconsistent.

9. A propagation mode discrimination method focusing on the received signal vector, wherein, The method for determining the propagation mode of the received signal vector has the following steps: Multiple signal generation units generate different transmission signals and output the generated transmission signals to the corresponding transmission antennas; Multiple matched filter banks are respectively input with received signals from receiving antennas and transmitted signals from multiple transmitting signal generation units. The transmitted signals from the multiple transmitting signal generation units are used as copies of the matched filters, and the output is the matched filter output, which is the vector element of the received signal vector. The received signals from the receiving antennas correspond to the multiple receiving antennas that capture the reflected waves from the transmitted waves sent by the transmitting antennas as the incoming waves. The provisional angle measurement unit assumes the output of the matched filter from the plurality of matched filter banks to be the received signal based on the direct propagation mode of the incoming wave, which is the direct propagation of the transmitted wave after being reflected by the object, and obtains a provisional angle measurement value for the received signal vector of interest corresponding to the range Doppler unit given by the target detection processing. The bidirectional angle measurement unit sets the provisional angle measurement value calculated by the provisional angle measurement unit as one of the transmission angle and arrival angle of the bidirectional angle measurement value constituting the received signal vector of interest, calculates the other propagation angle among the transmission angle and the arrival angle, and obtains the bidirectional angle measurement value through the provisional angle measurement value and the calculated propagation angle; and The propagation mode discrimination unit compares the difference between the sending angle and the arriving angle of the bidirectional angle measurement values ​​obtained by the bidirectional angle measurement unit with a threshold. When the difference is below the threshold, it is determined to be a direct propagation mode. When the difference exceeds the threshold, it is determined to be a multipath propagation mode. In the multipath propagation mode, the path of the transmitted wave to the object and the path of the reflected wave from the object to the MIMO radar signal processing device are inconsistent.

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