Target azimuth measurement method and device, and storage medium

Abstract

The application discloses a target azimuth measurement method and device and a storage medium, and is used for a MIMO radar. The method comprises the following steps: driving a transmitting antenna to transmit two radio frequency signals with different center frequencies and receiving a return signal; obtaining a first complex vector according to a complex matrix corresponding to the return signal; calculating a second-order cumulative quantity matrix according to the first complex vector, and obtaining an array element distance matrix according to the position of a receiving array element; converting the array element distance matrix into an array element index vector, and vectorizing the second-order cumulative quantity matrix to obtain a second complex vector; and determining the azimuth of a target to be measured based on the array element index vector and the second complex vector. The technical scheme provided by the application can solve the technical problem in the prior art that the scattering intensity of a detection point on a target to be measured randomly changes when a millimeter wave radar measures the azimuth of the target, the target return phase wave is distorted, the angle glint phenomenon is caused, and the angle measurement error is caused.

Description

Technical Field

[0001] This invention relates to the field of radar technology, and in particular to a method, apparatus and storage medium for measuring the azimuth angle of a target. Background Technology

[0002] In radar systems, when detecting the position and motion of a target, the target's location can be determined by the radio frequency signals emitted by the radar and the echo signals received. Specifically, the target's azimuth and elevation angles can be obtained, and information such as the target's speed, quantity, and direction can be derived. Millimeter-wave radar operates at lower frequencies than lidar, and its measurement accuracy is unaffected by light and weather conditions. It is increasingly widely used in various scenarios for measuring target positions, playing an irreplaceable role.

[0003] In existing technologies, millimeter-wave radar suffers from angular scintillation when resolving the azimuth parameters of a target, making stable and accurate resolution difficult, especially noticeable in single-shot scenarios. When millimeter-wave radar measures a target, the scattering intensity at different detection points on the target varies and changes constantly. Correspondingly, the relative phase between the radar and the detection point also changes randomly, causing distortion in the wavefront of the target echo reflected back to the radar. The tilt and random oscillation of the wavefront on the receiving antenna aperture plane inevitably lead to angular measurement errors, i.e., angular scintillation, reducing the radar's measurement accuracy. Summary of the Invention

[0004] This invention provides a target azimuth angle measurement method, device, and storage medium, aiming to effectively solve the technical problem in the prior art where, when measuring the target azimuth angle, the random variation of the scattering intensity at the detection point on the target causes phase wave distortion of the target echo, resulting in angular scintillation and leading to angular measurement errors.

[0005] According to one aspect of the present invention, a target azimuth measurement method is disclosed for a MIMO radar, the MIMO radar having multiple transmitting antennas and multiple receiving antennas, the multiple transmitting antennas and the multiple receiving antennas constituting a channel array including multiple array elements, characterized in that the method includes:

[0006] Each of the transmitting antennas is driven to transmit a first radio frequency signal and a second radio frequency signal with different center frequencies to the target under test, and the plurality of receiving antennas are driven to receive a plurality of first echo signals corresponding to each of the first radio frequency signals and a plurality of second echo signals corresponding to each of the second radio frequency signals fed back by the target under test;

[0007] An echo signal complex matrix is ​​obtained based on the plurality of first echo signals and the plurality of second echo signals, and the average value of the elements corresponding to the same receiving antenna in the echo signal complex matrix is ​​calculated to obtain a first complex vector;

[0008] The second-order cumulant matrix corresponding to the channel array is calculated based on the first complex vector, and the array element distance matrix is ​​obtained based on the position of the receiving array elements corresponding to the plurality of receiving antennas.

[0009] The array element distance matrix is ​​converted into an array element index vector according to a preset rule, and the second-order cumulant matrix is ​​vectorized based on the array element index vector to obtain a second complex vector.

[0010] The azimuth of the target under test is determined based on the array element index vector and the second complex vector.

[0011] Furthermore, the beamwidths of the plurality of receiving antennas are consistent.

[0012] Furthermore, the array elements of the multiple transmitting antennas are located at different positions.

[0013] Further, obtaining the echo signal complex matrix based on the plurality of first echo signals and the plurality of second echo signals includes:

[0014] The plurality of first echo signals and the plurality of second echo signals are grouped according to the transmitting antenna;

[0015] For each echo signal group, construct a corresponding complex number based on the amplitude and phase information of each echo signal in the echo signal group, and use each complex number as an element to form the complex number column vector corresponding to the echo signal group;

[0016] The complex matrix of the echo signal is formed by the complex column vectors corresponding to all echo signal groups.

[0017] Further, the step of averaging the elements corresponding to the same receiving antenna in the complex matrix of the echo signal to obtain the first complex vector includes:

[0018] For each of the receiving antennas, calculate the average value of all complex elements in the complex matrix of the echo signal corresponding to that receiving antenna;

[0019] The average value corresponding to each of the receiving antennas is used as a vector element to form the first complex vector.

[0020] Further, the step of calculating the second-order cumulant matrix corresponding to the channel array based on the first complex vector includes:

[0021] The second-order cumulant matrix is ​​calculated according to the following formula:

[0022] R = ZZ H ,

[0023] Where Z represents the first complex vector, Z H Let R represent the conjugate transpose of the first complex vector, and let R represent the second-order cumulant matrix.

[0024] Further, obtaining the array element distance matrix based on the receiving array element positions corresponding to the plurality of receiving antennas includes:

[0025] Obtain the positions of the receiving array elements corresponding to the plurality of receiving antennas, and use the position of the receiving array element corresponding to each receiving antenna as a vector element to form an array element position vector;

[0026] The array element distance matrix is ​​constructed based on the array element position vector.

[0027] Further, constructing the array element distance matrix based on the array element position vector includes:

[0028] The element distance matrix is ​​calculated according to the following formula:

[0029] I = Array - Array T ,

[0030] Wherein, Array represents the array element position vector, Array T I represents the transpose of the element position vector, and I represents the element distance matrix.

[0031] Further, the step of converting the array element distance matrix into an array element index vector according to a preset rule includes:

[0032] The matrix elements in the array element distance matrix are sorted in a preset order, and elements with the same value in the sorted element sequence are merged into one element to form the array element index vector.

[0033] Further, the step of vectorizing the second-order cumulant matrix based on the array element index vector to obtain the second complex vector includes:

[0034] (1) For each vector element in the array element index vector, perform the following steps:

[0035] In the array element index vector, determine the vector index corresponding to the vector element, and in the array element distance matrix, determine at least one matrix row and column index corresponding to the vector element;

[0036] In the second-order cumulant matrix, determine at least one matrix element at a position that corresponds one-to-one with the row and column indices of the at least one matrix;

[0037] The average value of the average vector is obtained by averaging the elements of the at least one matrix.

[0038] (2) Take all the average vector values ​​as vector elements to form the second complex vector, wherein the position of each average vector value in the second complex vector is the position indicated by the vector index corresponding to the average vector value.

[0039] Further, determining the azimuth angle of the target based on the array element index vector and the second complex vector includes:

[0040] (1) Perform the following operations for each predicted azimuth angle within the predicted angle range:

[0041] Beamforming is performed on the second complex vector based on the array element index vector, the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal and the estimated azimuth angle to obtain a spatial spectrum corresponding to the estimated azimuth angle.

[0042] (2) Determine the azimuth associated with the target based on the spatial spectrum corresponding to each of the estimated azimuth angles.

[0043] Further, the step of beamforming the second complex vector based on the array element index vector and the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal and the estimated azimuth angle for each estimated azimuth angle within the estimated angle range to obtain the spatial spectrum corresponding to the estimated azimuth angle includes:

[0044] The array steering vector corresponding to the estimated azimuth angle is calculated based on the array element index vector, the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal, and the estimated azimuth angle; and the spatial spectrum corresponding to the estimated azimuth angle is calculated based on the array steering vector and the second complex vector.

[0045] Further, the step of calculating the array steering vector corresponding to each estimated azimuth angle based on the array element index vector, the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal, and the estimated azimuth angle, and calculating the spatial spectrum corresponding to the estimated azimuth angle based on the array steering vector and the second complex vector includes:

[0046] The array steering vector corresponding to the estimated azimuth angle is calculated using the following formula:

[0047]

[0048] Where W represents the array steering vector corresponding to the estimated azimuth angle, and I vec X represents the element index vector. baseThe azimuth baseline of the plurality of receiving antennas is represented, θ represents the estimated azimuth angle, and λ represents the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal.

[0049] The spatial spectrum corresponding to the estimated azimuth angle is calculated using the following formula:

[0050] Y = w T X,

[0051] Where Y represents the spatial spectrum corresponding to the estimated azimuth angle, w T X represents the transpose of the array guide vector, and X represents the second complex vector.

[0052] Furthermore, the estimated angle range is -90° to 90°.

[0053] Further, determining the azimuth angle associated with the target based on the spatial spectrum corresponding to each estimated azimuth angle includes:

[0054] A modulo operation is performed on each of the spatial spectra to obtain multiple amplitude spectra. The peak amplitude spectrum among the multiple amplitude spectra is determined, and the estimated azimuth angle corresponding to the peak amplitude spectrum is determined as the azimuth angle associated with the target to be measured.

[0055] According to another aspect of the present invention, the present invention also provides a target azimuth angle measuring device for a MIMO radar, the MIMO radar having multiple transmitting antennas and multiple receiving antennas, the multiple transmitting antennas and the multiple receiving antennas constituting a channel array including multiple array elements. The device is characterized in that it comprises:

[0056] The signal transmitting and receiving unit is used to drive each of the transmitting antennas to transmit a first radio frequency signal and a second radio frequency signal with different center frequencies to the target under test, and to drive the plurality of receiving antennas to receive a plurality of first echo signals corresponding to each of the first radio frequency signals and a plurality of second echo signals corresponding to each of the second radio frequency signals fed back by the target under test.

[0057] The first complex vector calculation unit is used to obtain an echo signal complex matrix based on the plurality of first echo signals and the plurality of second echo signals, and to calculate the average of the elements in the echo signal complex matrix corresponding to the same receiving antenna to obtain a first complex vector.

[0058] The matrix calculation unit is used to calculate the second-order cumulant matrix corresponding to the channel array based on the first complex vector, and to obtain the array element distance matrix based on the receiving array element positions corresponding to the plurality of receiving antennas.

[0059] The second complex vector calculation unit is used to convert the array element distance matrix into an array element index vector according to a preset rule, and to vectorize the second-order cumulant matrix based on the array element index vector to obtain the second complex vector.

[0060] An azimuth angle determination unit is used to determine the azimuth angle of the target under test based on the array element index vector and the second complex vector.

[0061] According to another aspect of the invention, the invention also provides a storage medium storing a plurality of instructions adapted to be loaded by a processor to execute any of the target azimuth measurement methods described above.

[0062] Through one or more embodiments of the above embodiments of the present invention, at least the following technical effects can be achieved:

[0063] In the technical solution disclosed in this invention, the echo signals returned from the target by radio frequency signals corresponding to different center frequencies are obtained. The average value of the echo signal corresponding to each transmitting antenna is calculated and correlated with the array element position of the receiving antenna. The signal processing algorithm is optimized to obtain a spatial spectrum. The azimuth angle of the target is determined based on the estimated azimuth angle corresponding to the peak position of the amplitude spectrum of the spatial spectrum. Compared with existing technologies, the peak value of the amplitude spectrum in this solution is more pronounced, significantly higher than other peaks, and the frequency of peak occurrence is higher. Therefore, the target azimuth angle measurement method disclosed in this application not only possesses a certain super-resolution capability but also improves the measurement accuracy. That is, it not only makes it easier to distinguish the azimuth angle of the target but also achieves higher resolution, thereby improving the radar's detection performance. Attached Figure Description

[0064] The technical solution and other beneficial effects of the present invention will become apparent from the following detailed description of specific embodiments of the invention, in conjunction with the accompanying drawings.

[0065] Figure 1 A flowchart illustrating the steps of a target azimuth measurement method provided in an embodiment of the present invention;

[0066] Figure 2 A schematic diagram of a radar radio frequency signal waveform provided in an embodiment of the present invention;

[0067] Figure 3 A schematic diagram of an antenna array provided in an embodiment of the present invention;

[0068] Figure 4 This is a schematic diagram of the amplitude spectrum corresponding to a spatial spectrum provided in an embodiment of the present invention;

[0069] Figure 5 This is a schematic diagram of a target azimuth angle measuring device provided in an embodiment of the present invention. Detailed Implementation

[0070] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0071] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, the character " / " in this document, unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0072] Figure 1 The diagram shows a flowchart of a target azimuth measurement method provided by an embodiment of the present invention. According to one aspect of the present invention, a target azimuth measurement method is disclosed for use in a MIMO radar. The MIMO radar has multiple transmitting antennas and multiple receiving antennas, which constitute a channel array including multiple array elements. The method is characterized by comprising:

[0073] Step 101: Drive each of the transmitting antennas to transmit a first radio frequency signal and a second radio frequency signal with different center frequencies to the target under test, and drive the plurality of receiving antennas to receive a plurality of first echo signals corresponding to each of the first radio frequency signals and a plurality of second echo signals corresponding to each of the second radio frequency signals fed back by the target under test;

[0074] Step 102: Obtain an echo signal complex matrix based on the plurality of first echo signals and the plurality of second echo signals, and calculate the mean of the elements in the echo signal complex matrix corresponding to the same receiving antenna to obtain a first complex vector;

[0075] Step 103: Calculate the second-order cumulant matrix corresponding to the channel array based on the first complex vector, and obtain the array element distance matrix based on the receiving array element positions corresponding to the multiple receiving antennas;

[0076] Step 104: Convert the array element distance matrix into an array element index vector according to a preset rule, and vectorize the second-order cumulant matrix based on the array element index vector to obtain a second complex vector;

[0077] Step 105: Determine the azimuth of the target under test based on the array element index vector and the second complex vector.

[0078] This invention discloses a target azimuth angle measurement method for MIMO radar, wherein the MIMO radar has multiple transmitting antennas and multiple receiving antennas, and the multiple transmitting antennas and the multiple receiving antennas constitute a channel array including multiple array elements.

[0079] Radar systems use transmitted pulse signals and corresponding echo signals to detect the azimuth and elevation angles of a target. Specifically, the transmitting antenna sends a pulse signal to the target, and when the pulse signal reaches the target, it returns an echo signal. The radar system acquires the echo signal returned by the target and calculates the target's current position and motion state based on information such as the amplitude, phase, and wavelength of the echo signal.

[0080] MIMO (Multiple-Input Multiple-Output) radar technology refers to the use of multiple transmit and receive antennas at both the transmitting and receiving ends, enabling signal transmission across multiple channels and thus improving communication quality. It makes full use of space resources, achieving multiple transmissions and receptions through multiple antennas, and can significantly increase system channel capacity without increasing spectrum resources or antenna transmission power.

[0081] In a MIMO radar system, the antenna includes multiple transmitting antennas and multiple receiving antennas. Each transmitting antenna corresponds to a channel with each receiving antenna. One transmitting antenna corresponds to multiple receiving antennas, and correspondingly, the transmitting antenna and the multiple receiving antennas form a channel array. Each channel is a subarray of the channel array, and the multiple subarrays are composed of array elements corresponding to the same transmitting antenna.

[0082] The following is a detailed description of steps 101 to 105 above.

[0083] In step 101 above, each of the transmitting antennas is driven to transmit a first radio frequency signal and a second radio frequency signal with different center frequencies to the target under test, and the plurality of receiving antennas are driven to receive a plurality of first echo signals corresponding to each of the first radio frequency signals and a plurality of second echo signals corresponding to each of the second radio frequency signals fed back by the target under test.

[0084] For example, Figure 2 The figure shown is a radar radio frequency signal waveform diagram provided in an embodiment of the present invention. The waveform of the first radio frequency signal is as follows: Figure 2 Waveform A in the diagram, the waveform of the second radio frequency signal is... Figure 2Waveform B in the diagram has a different center frequency than waveform A, while other parameters remain the same. Specifically, the parameters of the radio frequency signal include pulse amplitude, pulse rise time, pulse fall time, pulse width, and duty cycle. The two radio frequency signals have a fixed frequency difference at their center frequencies, and their wavelengths are very similar. Superimposing signals with different center frequencies has a decorrelation effect.

[0085] The transmitting antenna transmits a first radio frequency (RF) signal and a second RF signal to the target under test. After the RF signals reach the target, they are reflected back by the target, and the receiving antenna receives the echo signals. Based on the phase and amplitude information corresponding to the echo signals, the distance and motion state of the target can be estimated. The first RF signal corresponds to the first echo signal, and the second RF signal corresponds to the second echo signal.

[0086] In step 102 above, an echo signal complex matrix is ​​obtained based on the plurality of first echo signals and the plurality of second echo signals, and the average value of the elements in the echo signal complex matrix corresponding to the same receiving antenna is calculated to obtain a first complex vector.

[0087] For example, a MIMO radar has multiple transmit antennas and multiple receive antennas. For the received echo signals, firstly, the echo signals from two pulse signals are combined into a complex matrix. For instance, a radar with two cascaded radio frequency chips... Figure 3 This is a schematic diagram of an antenna array provided in an embodiment of the present invention. In this array design, the radar has 6 transmitting antennas and 8 receiving antennas, corresponding to 48 channels. Accordingly, for the first pulse signal, the receiving antennas will receive 48 echo signals, one transmitting antenna corresponds to 8 echo signals, and the 6 receiving antennas correspond to 6 sets of signals. Similarly, for the second pulse signal, the receiving antennas will also receive 48 echo signals, one transmitting antenna corresponds to 8 echo signals, and the 6 receiving antennas correspond to 6 sets of signals. The two pulse signals correspond to 96 echo signals, and each transmitting antenna corresponds to 12 sets of echo signals. These 96 echo signals are combined into an 8*12 echo signal complex matrix.

[0088] The first complex vector is obtained by averaging the elements corresponding to the same receiving antenna in the complex matrix of the echo signal. Averaging the echo signal uses a space-time equivalence method. For example, 12 sets of signals are equivalent to 12 snapshots, where 6 sets are generated by waveform A and the other 6 sets by waveform B. Waveforms A and B have a temporal sequence, and the 6 sets of waveforms A or B, due to their different spatial positions in the array, are equivalent to different receiving times in the subarray. This equivalence can be simply referred to as "space-time joint". For an 8*12 complex matrix of the echo signal, 8 corresponds to 8 receiving antennas, and 12 corresponds to two pulse signals transmitted by 6 transmitting antennas. For each transmitting antenna, the elements corresponding to the 12 echo signals are averaged, that is, the elements of each row of the complex matrix of the echo signal are averaged to obtain an 8*1 first complex vector.

[0089] In step 103 above, the second-order cumulant matrix corresponding to the channel array is calculated based on the first complex vector, and the array element distance matrix is ​​obtained based on the receiving array element positions corresponding to the plurality of receiving antennas.

[0090] For example, the first complex vector is processed to obtain a second-order cumulant matrix based on the first complex vector and its conjugate transpose. The positions of the receiving elements corresponding to the radar's receiving antennas are obtained, and a position vector is constructed from this position vector. Then, an element distance matrix is ​​generated based on the position vector. The elements in this element distance matrix correspond to the distance between every two transmitting antennas among the multiple transmitting antennas. The element distance matrix and the second-order cumulant matrix are matrices with the same number of rows and columns, and the elements of the two matrices can correspond one-to-one.

[0091] In step 104 above, the array element distance matrix is ​​converted into an array element index vector according to a preset rule, and the second-order cumulant matrix is ​​vectorized based on the array element index vector to obtain a second complex vector.

[0092] For example, the elements in the element distance matrix correspond to the distances between different elements. The elements of the element distance matrix and the second-order cumulant matrix are in one-to-one correspondence; the distance between every two antennas corresponds to the element in the echo signal. The element distance matrix is ​​converted into an element index vector according to a preset rule. Elements in the element index vector can be associated with elements of the element distance matrix, and thus with elements in the second-order cumulant matrix. Therefore, the second-order cumulant matrix can be vectorized based on the element index vector to obtain a second complex vector.

[0093] In step 105 above, the azimuth angle of the target to be measured is determined based on the array element index vector and the second complex vector.

[0094] For example, data processing is performed on the array element index vector and the second complex vector based on a specific beamforming algorithm, and the azimuth of the target to be measured is determined according to the spatial spectrum direction finding method.

[0095] In the technical solution disclosed in this invention, the echo signals returned from the target by radio frequency signals corresponding to different center frequencies are obtained. The average value of the echo signal corresponding to each transmitting antenna is calculated and correlated with the array element position of the receiving antenna. The signal processing algorithm is optimized to obtain a spatial spectrum. The azimuth angle of the target is determined based on the estimated azimuth angle corresponding to the peak position of the amplitude spectrum of the spatial spectrum. Compared with existing technologies, the peak value of the amplitude spectrum in this solution is more pronounced, significantly higher than other peaks, and the frequency of peak occurrence is higher. Therefore, the target azimuth angle measurement method disclosed in this application not only possesses a certain super-resolution capability but also improves the measurement accuracy. That is, it not only makes it easier to distinguish the azimuth angle of the target but also achieves higher resolution, thereby improving the radar's detection performance.

[0096] Furthermore, the beamwidths of the plurality of receiving antennas are consistent.

[0097] For example, beamwidth, also known as half-power beamwidth, is one of the parameters describing antenna performance, referring to an antenna mode or beam angle. In this scheme, the beamwidth of the radio frequency signal is the same in multiple sub-arrays composed of multiple receiving antennas.

[0098] Furthermore, the array elements of the multiple transmitting antennas are located at different positions.

[0099] For example, when designing an array, it is required that multiple transmission channels be located in different spatial positions, that is, the array elements of multiple transmission antennas are located in different positions.

[0100] Further, in step 102 above, obtaining the echo signal complex matrix based on the plurality of first echo signals and the plurality of second echo signals includes:

[0101] The plurality of first echo signals and the plurality of second echo signals are grouped according to the transmitting antenna;

[0102] For each echo signal group, construct a corresponding complex number based on the amplitude and phase information of each echo signal in the echo signal group, and use each complex number as an element to form the complex number column vector corresponding to the echo signal group;

[0103] The complex matrix of the echo signal is formed by the complex column vectors corresponding to all echo signal groups.

[0104] For example, all received echo signals are grouped; specifically, multiple first echo signals and multiple second echo signals are grouped according to the transmitting antenna. Each transmitting antenna corresponds to a complex vector consisting of multiple echo signals.

[0105] Specifically, for each echo signal group, the amplitude and phase information of each echo signal in the echo signal group are obtained, and a corresponding complex number is constructed based on the amplitude and phase of the signal. Multiple echo signals correspond to multiple complex numbers, and each complex number is used as an element to form the complex number column vector corresponding to the echo signal group.

[0106] Construct a complex matrix of echo signals from the complex column vectors corresponding to all echo signal groups from multiple transmitting antennas.

[0107] Further, in step 102 above, the step of averaging the elements corresponding to the same receiving antenna in the complex matrix of the echo signal to obtain the first complex vector includes:

[0108] For each of the receiving antennas, calculate the average value of all complex elements in the complex matrix of the echo signal corresponding to that receiving antenna;

[0109] The average value corresponding to each of the receiving antennas is used as a vector element to form the first complex vector.

[0110] For example, a first complex vector is calculated from the complex matrix of the echo signals. Each column vector in the complex matrix of the echo signals represents multiple echo signals corresponding to a transmitting antenna. The complex numbers corresponding to these multiple echo signals are averaged to obtain a complex number. Each of the multiple transmitting antennas corresponds to a complex number, and the multiple complex numbers of the multiple transmitting antennas are combined to construct a first complex vector.

[0111] Further, in step 103 above, calculating the second-order cumulant matrix corresponding to the channel array based on the first complex vector includes:

[0112] The second-order cumulant matrix is ​​calculated according to the following formula:

[0113] R = ZZ H ,

[0114] Where Z represents the first complex vector. H Let R represent the conjugate transpose of the first complex vector, and let R represent the second-order cumulant matrix.

[0115] For example, a second-order cumulant matrix is ​​obtained from the second-order cumulant matrix and its conjugate transpose, with the same number of row vectors and column vectors.

[0116] Further, in step 103 above, obtaining the array element distance matrix based on the receiving array element positions corresponding to the plurality of receiving antennas includes:

[0117] Obtain the positions of the receiving array elements corresponding to the plurality of receiving antennas, and use the position of the receiving array element corresponding to each receiving antenna as a vector element to form an array element position vector;

[0118] The array element distance matrix is ​​constructed based on the array element position vector.

[0119] For example, in the array design, both the transmitting antenna and the receiving antenna have corresponding array element positions. The data related to the position of the receiving array element are used to form an array element position vector. Then, the array element distance matrix is ​​obtained based on the array element position vector and its transpose, with each element corresponding to the distance between the two transmitting antennas.

[0120] Further, in step 103 above, constructing the array element distance matrix based on the array element position vector includes:

[0121] The element distance matrix is ​​calculated according to the following formula:

[0122] I = Array - Array T ,

[0123] Wherein, Array represents the array element position vector, Array T I represents the transpose of the element position vector, and I represents the element distance matrix.

[0124] For example, the element distance matrix representing the distance between every two antennas is obtained from the element position vector and its transpose.

[0125] Further, in step 104 above, converting the array element distance matrix into an array element index vector according to a preset rule includes:

[0126] The matrix elements in the array element distance matrix are sorted in a preset order, and elements with the same value in the sorted element sequence are merged into one element to form the array element index vector.

[0127] For example, all matrix elements in the element distance matrix are grouped into a column vector. The elements in this column vector can be sorted according to a preset order, such as sorting from smallest to largest or from largest to smallest. After sorting, multiple matrix elements with the same number may appear. These multiple identical elements are merged into one element. After sorting and merging, an element index vector is obtained. The number of elements in this element index vector is less than the number of matrix elements in the element distance matrix.

[0128] Further, in step 104 above, the step of vectorizing the second-order cumulant matrix based on the array element index vector to obtain the second complex vector includes:

[0129] (1) For each vector element in the array element index vector, perform the following steps:

[0130] In the array element index vector, determine the vector index corresponding to the vector element, and in the array element distance matrix, determine at least one matrix row and column index corresponding to the vector element;

[0131] In the second-order cumulant matrix, determine at least one matrix element at a position that corresponds one-to-one with the row and column indices of the at least one matrix;

[0132] The average value of the average vector is obtained by averaging the elements of the at least one matrix.

[0133] (2) Take all the average vector values ​​as vector elements to form the second complex vector, wherein the position of each average vector value in the second complex vector is the position indicated by the vector index corresponding to the average vector value.

[0134] For example, using each vector element in the element index vector as an index, the second-order cumulant matrix is ​​vectorized to obtain a second complex vector. Specifically, the vectorization of the second-order cumulant matrix corresponds to two steps. In the first step, based on the vector elements in the element index vector, one or more corresponding matrix elements are found in the element distance matrix. Then, based on these one or more matrix elements, one or more matrix elements are found in the second-order cumulant matrix. If there are multiple matrix elements, their average is calculated to obtain an average vector value. In the second step, the obtained average vector value is placed into the second complex vector, and the position of this average vector value in the second complex vector is the same as the position of the corresponding vector element in the element index vector, that is, the vector indices of the two numbers are consistent.

[0135] Further, in step 105 above, determining the azimuth angle of the target based on the array element index vector and the second complex vector includes:

[0136] (1) Perform the following operations for each predicted azimuth angle within the predicted angle range:

[0137] Beamforming is performed on the second complex vector based on the array element index vector, the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal and the estimated azimuth angle to obtain a spatial spectrum corresponding to the estimated azimuth angle.

[0138] (2) Determine the azimuth associated with the target based on the spatial spectrum corresponding to each of the estimated azimuth angles.

[0139] For example, a spatial spectrum is used to measure the azimuth of the target. Specifically, a range of estimated angles is set, and all angles within the range are traversed according to a preset angle interval to calculate the spatial spectrum corresponding to each estimated azimuth. After obtaining all the spatial spectra corresponding to all estimated azimuths, the azimuth of the target can be determined based on the spatial spectrum.

[0140] Further, in step 105 above, the step of beamforming the second complex vector based on the array element index vector and the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal and the estimated azimuth angle for each estimated azimuth angle within the estimated angle range to obtain the spatial spectrum corresponding to the estimated azimuth angle includes:

[0141] The array steering vector corresponding to the estimated azimuth angle is calculated based on the array element index vector, the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal, and the estimated azimuth angle; and the spatial spectrum corresponding to the estimated azimuth angle is calculated based on the array steering vector and the second complex vector.

[0142] For example, the second complex vector is used as the input signal for beamforming operation. The beamforming operation is performed by a digital beamforming (DBF) algorithm. First, the array steering vector is calculated based on the array element index vector, the radio frequency signal and the estimated azimuth angle. Then, the spatial spectrum corresponding to the estimated azimuth angle is calculated based on the array steering vector and the second complex vector.

[0143] Further, in step 105 above, the step of calculating the array steering vector corresponding to the estimated azimuth angle based on the array element index vector, the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal and the estimated azimuth angle for each estimated azimuth angle, and calculating the spatial spectrum corresponding to the estimated azimuth angle based on the array steering vector and the second complex vector includes:

[0144] The array steering vector corresponding to the estimated azimuth angle is calculated using the following formula:

[0145]

[0146] Where W represents the array steering vector corresponding to the estimated azimuth angle, and I vec X represents the element index vector. base The azimuth baseline of the plurality of receiving antennas is represented, θ represents the estimated azimuth angle, and λ represents the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal.

[0147] The spatial spectrum corresponding to the estimated azimuth angle is calculated using the following formula:

[0148] Y = w T X,

[0149] Where Y represents the spatial spectrum corresponding to the estimated azimuth angle, w T X represents the transpose of the array guide vector, and X represents the second complex vector.

[0150] For example, data processing is performed according to a digital beamforming algorithm to obtain the spatial spectrum corresponding to the estimated azimuth angle.

[0151] Furthermore, the estimated angle range is -90° to 90°.

[0152] For example, the azimuth angle range is -90° to 90°, and correspondingly, the estimated angle range is -90° to 90°. Within this range, to improve radar measurement accuracy, the angle difference between two adjacent estimated azimuth angles is reduced, resulting in more estimated azimuth angles.

[0153] Further, in step 105 above, determining the azimuth angle associated with the target based on the spatial spectrum corresponding to each estimated azimuth angle includes:

[0154] A modulo operation is performed on each of the spatial spectra to obtain multiple amplitude spectra. The peak amplitude spectrum among the multiple amplitude spectra is determined, and the estimated azimuth angle corresponding to the peak amplitude spectrum is determined as the azimuth angle associated with the target to be measured.

[0155] For example, after obtaining the spatial spectrum corresponding to each estimated azimuth angle, in order to intuitively identify the azimuth angle, a modulus operation is performed on the spatial spectrum. Each spatial spectrum corresponds to an amplitude spectrum, and all amplitude spectra are combined to form a peak diagram. Figure 4 An amplitude spectrum corresponding to a spatial spectrum is provided in an embodiment of the present invention, such as... Figure 4 As shown, amplitude spectrum 1 is the amplitude spectrum corresponding to the spatial spectrum obtained after conventional DBF processing in the prior art, and amplitude spectrum 2 is the amplitude spectrum corresponding to the spatial spectrum obtained after DBF processing using the method of this application. Obviously, the amplitude height of amplitude spectrum 2 is only half that of amplitude spectrum 1. The predicted azimuth angle of the target corresponding to the peak position is more obvious in amplitude spectrum 2 than in amplitude spectrum 1, and the peaks appear more frequently. Therefore, the target azimuth angle measurement method disclosed in this application not only has a certain super-resolution capability, but also improves the measurement accuracy. That is, it can not only more easily distinguish the azimuth angle of the target, but also has higher resolution, thus improving the radar detection performance.

[0156] Example 1

[0157] The target azimuth angle measurement method of the present invention is described below according to Embodiment 1. In this embodiment, the radar is a radar with two cascaded radio frequency chips, and the radio frequency signal waveform of the radar is as follows. Figure 2 As shown, the antenna array is as follows Figure 3 As shown, the radar system has 6 transmitting antennas and 8 receiving antennas, corresponding to 48 channels.

[0158] For the first pulse signal, the receiving antenna will receive 48 echo signals, with one transmitting antenna corresponding to 8 echo signals and 6 receiving antennas corresponding to 6 sets of signals. Similarly, for the second pulse signal, the receiving antenna will also receive 48 echo signals, with one transmitting antenna corresponding to 8 echo signals and 6 receiving antennas corresponding to 6 sets of signals. The two pulse signals correspond to 96 echo signals, with each transmitting antenna corresponding to 12 sets of echo signals. These 96 echo signals are then combined to form an 8*12 complex echo signal matrix. Figure 2 Waveform 1 shown is in Figure 3 The echo signal generated on the array is denoted as Z1, and waveform 2 is... Figure 3 The echo signal generated on the array is denoted as Z2, which is a complex vector of size 48×1.

[0159] The first complex vector is obtained by averaging the elements corresponding to the same receiving antenna in the complex matrix of the echo signal. For example, for an 8*12 complex matrix of the echo signal, 8 corresponds to 8 receiving antennas, and 12 corresponds to two pulse signals transmitted by 6 transmitting antennas. For each transmitting antenna, the elements corresponding to the 12 echo signals are averaged, that is, the elements of each row of the complex matrix of the echo signal are averaged to obtain an 8*1 first complex vector. The 48 channels of signals in Z1 and Z2 are divided into 6 groups according to different transmitting channels, resulting in a total of 12 groups of signals denoted as X. X is an 8*12 complex matrix of the echo signal, where 8 represents the number of receiving channels and 12 represents the 12 groups of signals. The 12 groups of signals in X are averaged according to the same receiving array element to obtain a first complex vector Z of size 8*1.

[0160] The azimuth resolution algorithm is based on second-order cumulants and the DBF digital beamforming algorithm, where the second-order cumulants R of the array are represented as follows:

[0161] R 8×8 =ZZ H Z H This indicates taking the conjugate transpose of Z.

[0162] Let Array be the array element position vector of size 1x8, and let I be the array element distance matrix corresponding to Array in the second-order space. The array element distance matrix I is calculated as follows:

[0163] I 8×8 =Array-Array T,

[0164] Taking the receiving subarrays 1-8 as an example, assume their element position vector Array = [1,3,6,8,14,20,26,29]. T The matrix elements of the array element distance matrix I can be represented by Table 1 as follows:

[0165] Table 1. Matrix element table of the array element distance matrix

[0166] 0 -2 -5 -7 -13 -19 -25 -28 2 0 -3 -5 -11 -17 -23 -26 5 3 0 -2 -8 -14 -20 -23 7 5 2 0 -6 -12 -18 -21 13 11 8 6 0 -6 -12 -15 19 17 14 12 6 0 -6 -9 25 23 20 18 12 6 0 -3 28 26 23 21 15 9 3 0

[0167] The second-order accumulator R is vectorized to form the second complex vector X. The specific steps are as follows:

[0168] (1) Merge the positions of identical elements in the element distance matrix I, and sort them in ascending order to obtain the matrix vector index I. vec .

[0169] (2) Index the matrix vector I vec Using the smallest or largest number as the first index, find its corresponding row and column in the element distance matrix I, extract the complex signal of the corresponding row and column in the second-order cumulant R, and fill it into the first index position of the second complex vector X. When multiple minimum values ​​exist, extract multiple matrix elements of the second-order cumulant R according to the rows and columns corresponding to all minimum values ​​in the element distance matrix I, average the multiple matrix elements, and fill them into the first index position of the second complex vector X.

[0170] (3) Take the matrix vector index I according to the same steps as in step (2). vec The average value of the matrix vector corresponding to the second smallest or second largest value in the second-order cumulant R is used to fill the second index of the second complex vector X with the average value of the matrix vector.

[0171] (4) Following the methods in steps (1) and (2), index the matrix vector I. vec The numbers in the matrix are arranged in ascending order. Rows and columns are found in the distance matrix I, and multiple matrix elements in the second-order cumulant R are indexed according to these rows and columns, and then sequentially filled into the second complex vector X. The final second complex vector X has a magnitude equal to that of I. vec The vectors have the same size.

[0172] (5) Using the second complex vector X as the input signal, perform DBF. For each estimated azimuth angle, calculate the array steering vector W corresponding to the estimated azimuth angle, and calculate the spatial spectrum Y corresponding to the estimated azimuth angle based on the array steering vector W and the second complex vector X:

[0173] The array steering vector W corresponding to the estimated azimuth angle is calculated using the following formula:

[0174]

[0175] Where W represents the array steering vector corresponding to the estimated azimuth angle, and I vec X represents the element index vector. base The baseline represents the azimuth dimension of multiple receiving antennas, θ represents the estimated azimuth angle, and λ represents the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal.

[0176] The spatial spectrum Y corresponding to the estimated azimuth angle is calculated using the following formula:

[0177] Y = w T X,

[0178] Where Y represents the spatial spectrum corresponding to the estimated azimuth angle, w T X represents the transpose of the array guide vector, and X represents the second complex vector.

[0179] (6) Perform a modulo operation on each spatial spectrum to obtain multiple amplitude spectra, determine the peak amplitude spectrum among the multiple amplitude spectra, and determine the estimated azimuth angle corresponding to the peak amplitude spectrum as the azimuth angle associated with the target to be measured.

[0180] The amplitude spectrum corresponding to the spatial spectrum is as follows Figure 4 As shown, amplitude spectrum 1 is the amplitude spectrum corresponding to the spatial spectrum obtained after DBF processing using the existing technology, and amplitude spectrum 2 is the amplitude spectrum corresponding to the spatial spectrum obtained after DBF processing using the method of this application. The target azimuth angle measurement method disclosed in this application not only has a certain super-resolution capability, but also improves the measurement accuracy. That is, it can not only more easily distinguish the azimuth angle of the target, but also has higher resolution, thereby improving the detection performance of the radar.

[0181] Based on the same inventive concept as the target azimuth angle measurement method of the present invention, the present invention provides a target azimuth angle measurement device for MIMO radar. The MIMO radar has multiple transmitting antennas and multiple receiving antennas, which constitute a channel array including multiple array elements. The device is characterized in that... (Please refer to...) Figure 5 The device includes:

[0182] The signal transmitting and receiving unit 201 is used to drive each of the transmitting antennas to transmit a first radio frequency signal and a second radio frequency signal with different center frequencies to the target under test, and to drive the plurality of receiving antennas to receive a plurality of first echo signals corresponding to each of the first radio frequency signals and a plurality of second echo signals corresponding to each of the second radio frequency signals fed back by the target under test.

[0183] The first complex vector calculation unit 202 is used to obtain an echo signal complex matrix based on the plurality of first echo signals and the plurality of second echo signals, and to calculate the average of the elements in the echo signal complex matrix corresponding to the same receiving antenna to obtain a first complex vector.

[0184] The matrix calculation unit 203 is used to calculate the second-order cumulant matrix corresponding to the channel array based on the first complex vector, and to obtain the array element distance matrix based on the receiving array element positions corresponding to the plurality of receiving antennas.

[0185] The second complex vector calculation unit 204 is used to convert the array element distance matrix into an array element index vector according to a preset rule, and to vectorize the second-order cumulant matrix based on the array element index vector to obtain a second complex vector.

[0186] The azimuth angle determination unit 205 is used to determine the azimuth angle of the target under test based on the array element index vector and the second complex vector.

[0187] Furthermore, the beamwidths of the plurality of receiving antennas are consistent.

[0188] Furthermore, the array elements of the multiple transmitting antennas are located at different positions.

[0189] Furthermore, the first complex vector calculation unit 202 is also used for:

[0190] The plurality of first echo signals and the plurality of second echo signals are grouped according to the transmitting antenna;

[0191] For each echo signal group, construct a corresponding complex number based on the amplitude and phase information of each echo signal in the echo signal group, and use each complex number as an element to form the complex number column vector corresponding to the echo signal group;

[0192] The complex matrix of the echo signal is formed by the complex column vectors corresponding to all echo signal groups.

[0193] Furthermore, the first complex vector calculation unit 202 is also used for:

[0194] For each of the receiving antennas, calculate the average value of all complex elements in the complex matrix of the echo signal corresponding to that receiving antenna;

[0195] The average value corresponding to each of the receiving antennas is used as a vector element to form the first complex vector.

[0196] Furthermore, the matrix calculation unit 203 is also used for:

[0197] The second-order cumulant matrix is ​​calculated according to the following formula:

[0198] R = ZZ H ,

[0199] Where Z represents the first complex vector, Z H Let R represent the conjugate transpose of the first complex vector, and let R represent the second-order cumulant matrix.

[0200] Furthermore, the matrix calculation unit 203 is also used for:

[0201] Obtain the positions of the receiving array elements corresponding to the plurality of receiving antennas, and use the position of the receiving array element corresponding to each receiving antenna as a vector element to form an array element position vector;

[0202] The array element distance matrix is ​​constructed based on the array element position vector.

[0203] Furthermore, the matrix calculation unit 203 is also used for:

[0204] The element distance matrix is ​​calculated according to the following formula:

[0205] I = Array - Array T ,

[0206] Wherein, Array represents the array element position vector, Array T I represents the transpose of the element position vector, and I represents the element distance matrix.

[0207] Furthermore, the second complex vector calculation unit 204 is also used for:

[0208] The matrix elements in the array element distance matrix are sorted in a preset order, and elements with the same value in the sorted element sequence are merged into one element to form the array element index vector.

[0209] Furthermore, the second complex vector calculation unit 204 is also used for:

[0210] (1) For each vector element in the array element index vector, perform the following steps:

[0211] In the array element index vector, determine the vector index corresponding to the vector element, and in the array element distance matrix, determine at least one matrix row and column index corresponding to the vector element;

[0212] In the second-order cumulant matrix, determine at least one matrix element at a position that corresponds one-to-one with the row and column indices of the at least one matrix;

[0213] The average value of the average vector is obtained by averaging the elements of the at least one matrix.

[0214] (2) Take all the average vector values ​​as vector elements to form the second complex vector, wherein the position of each average vector value in the second complex vector is the position indicated by the vector index corresponding to the average vector value.

[0215] Furthermore, the azimuth angle determination unit 205 is also used for:

[0216] (1) Perform the following operations for each predicted azimuth angle within the predicted angle range:

[0217] Beamforming is performed on the second complex vector based on the array element index vector, the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal and the estimated azimuth angle to obtain a spatial spectrum corresponding to the estimated azimuth angle.

[0218] (2) Determine the azimuth associated with the target based on the spatial spectrum corresponding to each of the estimated azimuth angles.

[0219] Furthermore, the azimuth angle determination unit 205 is also used for:

[0220] The array steering vector corresponding to the estimated azimuth angle is calculated based on the array element index vector, the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal, and the estimated azimuth angle; and the spatial spectrum corresponding to the estimated azimuth angle is calculated based on the array steering vector and the second complex vector.

[0221] Furthermore, the azimuth angle determination unit 205 is also used for:

[0222] The array steering vector corresponding to the estimated azimuth angle is calculated using the following formula:

[0223]

[0224] Where W represents the array steering vector corresponding to the estimated azimuth angle, and I vec X represents the element index vector. base The azimuth baseline of the plurality of receiving antennas is represented, θ represents the estimated azimuth angle, and λ represents the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal.

[0225] The spatial spectrum corresponding to the estimated azimuth angle is calculated using the following formula:

[0226] Y = w T X,

[0227] Where Y represents the spatial spectrum corresponding to the estimated azimuth angle, w T X represents the transpose of the array guide vector, and X represents the second complex vector.

[0228] Furthermore, the estimated angle range is -90° to 90°.

[0229] Furthermore, the azimuth angle determination unit 205 is also used for:

[0230] A modulo operation is performed on each of the spatial spectra to obtain multiple amplitude spectra. The peak amplitude spectrum among the multiple amplitude spectra is determined, and the estimated azimuth angle corresponding to the peak amplitude spectrum is determined as the azimuth angle associated with the target to be measured.

[0231] Furthermore, other aspects and implementation details of the target azimuth angle measuring device are the same as or similar to the target azimuth angle measuring method described above, and will not be repeated here.

[0232] According to another aspect of the present invention, the present invention also provides a storage medium storing a plurality of instructions adapted to be loaded by a processor to execute any of the target azimuth measurement methods described above.

[0233] In summary, although the present invention has been disclosed above with reference to preferred embodiments, the above preferred embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A target azimuth measurement method for a MIMO radar, wherein the MIMO radar has multiple transmitting antennas and multiple receiving antennas, the multiple transmitting antennas and the multiple receiving antennas constituting a channel array including multiple array elements, characterized in that, The method includes: Each of the transmitting antennas is driven to transmit a first radio frequency signal and a second radio frequency signal with different center frequencies to the target under test, and the plurality of receiving antennas are driven to receive a plurality of first echo signals corresponding to each of the first radio frequency signals and a plurality of second echo signals corresponding to each of the second radio frequency signals fed back by the target under test; An echo signal complex matrix is ​​obtained based on the plurality of first echo signals and the plurality of second echo signals, and the average value of the elements corresponding to the same receiving antenna in the echo signal complex matrix is ​​calculated to obtain a first complex vector; The second-order cumulant matrix corresponding to the channel array is calculated based on the first complex vector, and the array element distance matrix is ​​obtained based on the receiving array element positions corresponding to the multiple receiving antennas. The array element distance matrix is ​​converted into an array element index vector according to a preset rule, and the second-order cumulant matrix is ​​vectorized based on the array element index vector to obtain a second complex vector. The azimuth of the target under test is determined based on the array element index vector and the second complex vector.

2. The method as described in claim 1, characterized in that, The beamwidths of the multiple receiving antennas are consistent.

3. The method as described in claim 2, characterized in that, The array elements of the multiple transmitting antennas are located at different positions.

4. The method as described in claim 3, characterized in that, The step of obtaining the echo signal complex matrix based on the plurality of first echo signals and the plurality of second echo signals includes: The plurality of first echo signals and the plurality of second echo signals are grouped according to the transmitting antenna; For each echo signal group, construct a corresponding complex number based on the amplitude and phase information of each echo signal in the echo signal group, and use each complex number as an element to form the complex number column vector corresponding to the echo signal group; The complex matrix of the echo signal is formed by the complex column vectors corresponding to all echo signal groups.

5. The method as described in claim 4, characterized in that, The step of averaging the elements corresponding to the same receiving antenna in the complex matrix of the echo signal to obtain the first complex vector includes: For each of the receiving antennas, calculate the average value of all complex elements in the complex matrix of the echo signal corresponding to that receiving antenna; The average value corresponding to each of the receiving antennas is used as a vector element to form the first complex vector.

6. The method as described in claim 5, characterized in that, The step of calculating the second-order cumulant matrix corresponding to the channel array based on the first complex vector includes: The second-order cumulant matrix is ​​calculated according to the following formula: R=ZZ H , Where Z represents the first complex vector, Z H Let R represent the conjugate transpose of the first complex vector, and let R represent the second-order cumulant matrix.

7. The method as described in claim 6, characterized in that, The step of obtaining the array element distance matrix based on the positions of the receiving array elements corresponding to the plurality of receiving antennas includes: Obtain the positions of the receiving array elements corresponding to the plurality of receiving antennas, and use the position of the receiving array element corresponding to each receiving antenna as a vector element to form an array element position vector; The array element distance matrix is ​​constructed based on the array element position vector.

8. The method as described in claim 7, characterized in that, The step of constructing the array element distance matrix based on the array element position vector includes: The element distance matrix is ​​calculated according to the following formula: I=Array-Array T , Wherein, Array represents the array element position vector, Array T I represents the transpose of the element position vector, and I represents the element distance matrix.

9. The method as described in claim 8, characterized in that, The step of converting the array element distance matrix into an array element index vector according to a preset rule includes: The matrix elements in the array element distance matrix are sorted in a preset order, and elements with the same value in the sorted element sequence are merged into one element to form the array element index vector.

10. The method as described in claim 9, characterized in that, The step of vectorizing the second-order cumulant matrix based on the array element index vector to obtain the second complex vector includes: (1) For each vector element in the array element index vector, perform the following steps: In the array element index vector, determine the vector index corresponding to the vector element, and in the array element distance matrix, determine at least one matrix row and column index corresponding to the vector element; In the second-order cumulant matrix, determine at least one matrix element at a position that corresponds one-to-one with the row and column indices of the at least one matrix; The average value of the average vector is obtained by averaging the elements of the at least one matrix. (2) Take all the average vector values ​​as vector elements to form the second complex vector, wherein the position of each average vector value in the second complex vector is the position indicated by the vector index corresponding to the average vector value.

11. The method as described in claim 10, characterized in that, Determining the azimuth angle of the target based on the array element index vector and the second complex vector includes: (1) Perform the following operations for each predicted azimuth angle within the predicted angle range: Beamforming is performed on the second complex vector based on the array element index vector, the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal and the estimated azimuth angle to obtain a spatial spectrum corresponding to the estimated azimuth angle. (2) Determine the azimuth associated with the target based on the spatial spectrum corresponding to each of the estimated azimuth angles.

12. The method as described in claim 11, characterized in that, The step of beamforming the second complex vector based on the array element index vector and the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal and the estimated azimuth angle for each estimated azimuth angle within the estimated angle range to obtain the spatial spectrum corresponding to the estimated azimuth angle includes: The array steering vector corresponding to the estimated azimuth angle is calculated based on the array element index vector, the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal, and the estimated azimuth angle; and the spatial spectrum corresponding to the estimated azimuth angle is calculated based on the array steering vector and the second complex vector.

13. The method as described in claim 12, characterized in that, The step of calculating the array steering vector corresponding to each estimated azimuth angle based on the array element index vector, the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal, and the estimated azimuth angle, and calculating the spatial spectrum corresponding to the estimated azimuth angle based on the array steering vector and the second complex vector includes: The array steering vector corresponding to the estimated azimuth angle is calculated using the following formula: Where W represents the array steering vector corresponding to the estimated azimuth angle, and I vec X represents the element index vector. base The azimuth baseline of the plurality of receiving antennas is represented, θ represents the estimated azimuth angle, and λ represents the wavelength of the first radio frequency signal or the wavelength of the second radio frequency signal. The spatial spectrum corresponding to the estimated azimuth angle is calculated using the following formula: Y=w T X, Where Y represents the spatial spectrum corresponding to the estimated azimuth angle, w T X represents the transpose of the array guide vector, and X represents the second complex vector.

14. The method as described in claim 13, characterized in that, The estimated angle range is -90° to 90°.

15. The method as described in claim 14, characterized in that, The step of determining the azimuth associated with the target based on the spatial spectrum corresponding to each estimated azimuth includes: A modulo operation is performed on each of the spatial spectra to obtain multiple amplitude spectra. The peak amplitude spectrum among the multiple amplitude spectra is determined, and the estimated azimuth angle corresponding to the peak amplitude spectrum is determined as the azimuth angle associated with the target to be measured.

16. A target azimuth angle measuring device for use in a MIMO radar, the MIMO radar having multiple transmitting antennas and multiple receiving antennas, the multiple transmitting antennas and the multiple receiving antennas constituting a channel array including multiple array elements, characterized in that... The device includes: The signal transmitting and receiving unit is used to drive each of the transmitting antennas to transmit a first radio frequency signal and a second radio frequency signal with different center frequencies to the target under test, and to drive the plurality of receiving antennas to receive a plurality of first echo signals corresponding to each of the first radio frequency signals and a plurality of second echo signals corresponding to each of the second radio frequency signals fed back by the target under test. The first complex vector calculation unit is used to obtain an echo signal complex matrix based on the plurality of first echo signals and the plurality of second echo signals, and to calculate the average of the elements in the echo signal complex matrix corresponding to the same receiving antenna to obtain a first complex vector. The matrix calculation unit is used to calculate the second-order cumulant matrix corresponding to the channel array based on the first complex vector, and to obtain the array element distance matrix based on the receiving array element positions corresponding to the plurality of receiving antennas. The second complex vector calculation unit is used to convert the array element distance matrix into an array element index vector according to a preset rule, and to vectorize the second-order cumulant matrix based on the array element index vector to obtain the second complex vector. An azimuth angle determination unit is used to determine the azimuth angle of the target under test based on the array element index vector and the second complex vector.

17. A storage medium, characterized in that, The storage medium stores a plurality of instructions, which are adapted to be loaded by a processor to execute the target azimuth measurement method as described in any one of claims 1 to 15.

Images