Target azimuth and elevation angle measurement method and device, and storage medium

Abstract

The application discloses a target azimuth and elevation angle measurement method and device and a storage medium, wherein the method comprises: driving multiple antennas of a radar to emit radio frequency signals to a target and receive echo signals; performing beamforming operation on the echo signals of two transmitting antennas at the same height to obtain an azimuth angle set; obtaining a corresponding complex matrix from the echo signals of subarrays with different positions in the elevation direction, and performing beamforming operation on the complex matrix to obtain a second complex vector; and performing beamforming operation on each second complex vector to obtain a target corresponding azimuth-elevation angle combination pair. The technical scheme provided by the application can solve the technical problem in the prior art that when the number of cascaded radio frequency chips of a radar system is small, the number of channels corresponding to the antennas is small, and the resolution capability of the radar for measuring the target azimuth and elevation angles is low.

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 target azimuth and elevation angles. 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 current technologies, most 4D millimeter-wave radars use a cascaded configuration of four radio frequency (RF) chips, forming an antenna array with 12 transmit channels and 16 receive channels. This allows for a relatively sparse array, providing high resolution for azimuth and elevation measurements of the target. However, low-cost radars may employ fewer cascaded configurations. For example, a cascaded configuration of two RF chips results in an antenna array with only six transmit channels and eight receive channels. Due to the limited number of channels in a two-chip cascaded radar, it is difficult to achieve the high resolution of a four-chip cascaded radar when performing azimuth and elevation measurements. Therefore, to improve radar measurement accuracy, it is necessary to design the antenna array appropriately and optimize the signal processing algorithm. Summary of the Invention

[0004] This invention provides a method, apparatus, and storage medium for measuring target azimuth and elevation angles, aiming to effectively solve the technical problem in the prior art where the number of channels corresponding to the antenna is small when the cascaded radio frequency chips of the radar system are few, resulting in low resolution when the radar measures the target azimuth and elevation angles.

[0005] According to one aspect of the present invention, a method for measuring target azimuth and elevation angles is provided 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, and the channel array includes multiple subarrays, each of the subarrays being composed of array elements corresponding to the same transmitting antenna, characterized in that the method includes:

[0006] The plurality of transmitting antennas are each driven to transmit radio frequency signals toward at least one target and the plurality of receiving antennas are driven to receive echo signals from the at least one target, wherein the plurality of transmitting antennas includes two transmitting antennas located at the same height, and the horizontal spacing between the other transmitting antennas in the plurality of transmitting antennas is smaller than the horizontal spacing between the two transmitting antennas located at the same height;

[0007] A preset first form of beamforming operation is performed on a first complex vector determined by the echo signals associated with the two transmitting antennas located at the same altitude to obtain an azimuth angle set;

[0008] Select a preset number of subarrays with different pitch positions from the plurality of subarrays to obtain a complex matrix determined by the echo signal corresponding to the selected subarrays, and perform a preset second form of beamforming operation on the complex matrix to obtain a plurality of second complex vectors.

[0009] For each of the second complex vectors, the first form of beamforming operation is performed to obtain multiple azimuth-elevation combination pairs that correspond one-to-one with the at least one target.

[0010] Furthermore, the plurality of receiving antennas are located at the same height and the sidelobes of the corresponding antenna array pattern are no greater than -5dB.

[0011] Furthermore, among the plurality of transmitting antennas, except for the two transmitting antennas located at the same altitude, the transmitting antennas satisfy the minimum redundancy array requirement in the elevation dimension and are uniformly distributed in the azimuth dimension.

[0012] Furthermore, the multiple subarrays of the multiple transmitting antennas have the same azimuth beamwidth.

[0013] Further, the step of performing a preset first-form beamforming operation on a first complex vector determined by the echo signals associated with the two transmitting antennas at the same altitude to obtain an azimuth angle set includes:

[0014] For each echo signal associated with the two transmitting antennas located at the same height, a corresponding complex number is constructed based on the amplitude and phase information in the echo signal;

[0015] The first complex vector is constructed by using the complex number corresponding to each echo signal as a vector element.

[0016] Furthermore, the step of performing a preset first-form beamforming operation on the first complex vector determined by the echo signals associated with the two transmitting antennas located at the same altitude to obtain the azimuth angle set further includes:

[0017] According to the first form, beamforming is performed on the first complex vector based on the first covariance matrix corresponding to the first complex vector and the corresponding azimuth steering vector expression of the receiving antenna array to obtain the azimuth angle set.

[0018] Further, the step of performing beamforming on the first complex vector according to the first form, based on the first covariance matrix corresponding to the first complex vector and the corresponding azimuth steering vector expression of the receiving antenna array, to obtain the azimuth angle set includes:

[0019] The first covariance matrix corresponding to the first complex vector is calculated according to the following formula:

[0020] ,

[0021] Where X represents the first complex vector. This represents the conjugate transpose of the first complex vector. 1 represents the first covariance matrix corresponding to the first complex vector;

[0022] The set of azimuth angles is calculated according to the following formula:

[0023] ,

[0024] in, This represents the set of azimuth angles containing n azimuth angles. This indicates the azimuth angle corresponding to the maximum value of the expression it points to. This represents the expression for the azimuth-dimensional steering vector of the receiving antenna array corresponding to the first complex vector. express The conjugate transpose of . 1 represents the first covariance matrix corresponding to the first complex vector;

[0025] Wherein, the first complex vector corresponds to the azimuth-dimensional steering vector expression of the receiving antenna array. The specific expression is as follows:

[0026] ,

[0027] ,

[0028] in, This represents the azimuth spacing vector of the receiving antenna corresponding to the first complex vector. This indicates the azimuth baseline of the receiving antenna. Indicates the azimuth angle of incidence, and N represents the number of receiving antennas. This indicates the wavelength of the radio frequency signal.

[0029] Further, the step of selecting a predetermined number of subarrays with different pitch positions from the plurality of subarrays to obtain the complex matrix determined by the echo signal corresponding to the selected subarray includes:

[0030] For each echo signal corresponding to the selected subarray, a corresponding complex number is constructed based on the amplitude and phase information in the echo signal;

[0031] The complex matrix is ​​constructed by using the complex number corresponding to each echo signal as a vector element.

[0032] Furthermore, the step of performing a preset second-form beamforming operation on the complex matrix to obtain multiple second complex vectors includes:

[0033] For each azimuth angle in the set of azimuth angles, perform the following operation:

[0034] The weighted vector corresponding to the azimuth angle is calculated based on the azimuth angle, the wavelength of the radio frequency signal, and the azimuth dimension spacing of the receiving antennas corresponding to the complex matrix.

[0035] The second complex vector corresponding to the azimuth angle is calculated based on the weighted vector and the complex matrix.

[0036] Furthermore, the step of performing a preset second-form beamforming operation on the complex matrix to obtain multiple second complex vectors further includes:

[0037] For each azimuth angle in the set of azimuth angles, the weighted vector corresponding to that azimuth angle is calculated according to the following formula:

[0038] ,

[0039] in, This represents the weighted vector corresponding to the azimuth angle. This represents the azimuth spacing vector of the receiving antennas corresponding to the complex matrix. This represents the azimuth baseline of the receiving antenna corresponding to the complex matrix. This indicates the azimuth angle. Indicates the wavelength of the radio frequency signal;

[0040] For each azimuth angle in the set of azimuth angles, the second complex vector corresponding to that azimuth angle is calculated according to the following formula:

[0041] ,

[0042] in, This represents the k-th element in the second complex vector corresponding to the azimuth angle. This represents the weighted vector corresponding to the azimuth angle. transpose, Indicates taking the complex matrix The k-th row of the array contains all columns, and m is the total number of the selected subarrays.

[0043] Further, the step of performing the first form of beamforming operation on each of the second complex vectors to obtain multiple azimuth-elevation angle combinations corresponding one-to-one with the at least one target includes:

[0044] For each of the second complex vectors, perform the following operation:

[0045] Calculate the second covariance matrix corresponding to the second complex vector;

[0046] According to the first form, beamforming is performed on the second complex vector based on the second covariance matrix corresponding to the second complex vector and the corresponding pitch dimension steering vector expression of the receiving antenna array to obtain multiple azimuth-elevation angle combinations that correspond one-to-one with the at least one target.

[0047] Further, for each second complex vector, calculating the second covariance matrix corresponding to the second complex vector, and performing beamforming on the second complex vector according to the first form based on the second covariance matrix corresponding to the second complex vector and the corresponding receiving antenna array elevation dimension steering vector expression to obtain multiple azimuth-elevation angle combinations corresponding one-to-one with the at least one target includes:

[0048] For each of the second complex vectors, perform the following operation:

[0049] The second covariance matrix corresponding to the second complex vector is calculated according to the following formula:

[0050]

[0051] Where Y represents the second complex vector, This represents the conjugate transpose of the second complex vector Y. 2 represents the second covariance matrix corresponding to the second complex vector;

[0052] The set of elevation angles associated with the azimuth angles in the set of azimuth angles corresponding to the second complex vector is calculated according to the following formula to form at least one azimuth-elevation angle combination:

[0053] ,

[0054] in, Indicates by The set of pitch angles formed by the pitch angles associated with the azimuth angles in the set of azimuth angles corresponding to the second complex vector. This indicates the pitch angle corresponding to the maximum value of the expression it points to. This represents the expression for the elevation dimension steering vector of the receiving antenna array corresponding to the second complex vector. express The conjugate transpose of . 2 represents the second covariance matrix corresponding to the second complex vector, and at least one azimuth-elevation angle combination formed by beamforming on the second complex vector is expressed as follows:

[0055] ,

[0056] in, This represents the azimuth angle corresponding to the second complex vector. This represents the set of azimuth-elevation angle combinations formed by the second complex vector. Indicates the azimuth angle corresponding One pitch angle;

[0057] Wherein, the second complex vector corresponds to the elevation dimension steering vector expression of the receiving antenna array. The specific expression is as follows:

[0058] ,

[0059] in, This represents the elevation dimension spacing vector between adjacent receiving antennas. This represents the elevation baseline of the receiving antenna. The angle of incidence is represented by the elevation dimension, and N represents the number of receiving antennas. This indicates the wavelength of the radio frequency signal.

[0060] Further, for each second complex vector, calculating the second covariance matrix corresponding to the second complex vector, and performing beamforming on the second complex vector according to the first form based on the second covariance matrix corresponding to the second complex vector and the corresponding receiving antenna array elevation dimension steering vector expression to obtain multiple azimuth-elevation angle combinations corresponding one-to-one with the at least one target includes:

[0061] The total set of azimuth-elevation angle combinations formed by all the second complex vectors is taken as a plurality of azimuth-elevation angle combinations corresponding one-to-one with the at least one target, wherein the total set is represented by the following formula:

[0062] ,

[0063] in, Represents the total set, This represents the set of azimuth-elevation angle combinations formed by each of the second complex vectors.

[0064] According to another aspect of the present invention, the present invention also provides a target azimuth and elevation 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, and the channel array including multiple subarrays, each of the subarrays being composed of array elements corresponding to the same transmitting antenna, characterized in that the device comprises:

[0065] A radio frequency signal transmitting unit is used to drive the plurality of transmitting antennas to transmit radio frequency signals to at least one target and to drive the plurality of receiving antennas to receive echo signals from the at least one target, wherein the plurality of transmitting antennas includes two transmitting antennas located at the same height, and the horizontal spacing between the other transmitting antennas in the plurality of transmitting antennas is smaller than the horizontal spacing between the two transmitting antennas located at the same height.

[0066] An azimuth set determination unit is used to perform a preset first form of beamforming operation on a first complex vector determined by the echo signals associated with the two transmitting antennas located at the same altitude to obtain a first azimuth set;

[0067] The complex vector determination unit is used to select a preset number of subarrays with different pitch dimension positions from the plurality of subarrays to obtain a complex matrix determined by the echo signal corresponding to the selected subarray, and to perform a preset second form of beamforming operation on the complex matrix to obtain a plurality of second complex vectors.

[0068] An azimuth-elevation combination generation unit is used to perform the first form of beamforming operation on each of the second complex vectors to obtain multiple azimuth-elevation combinations that correspond one-to-one with the at least one target.

[0069] According to another aspect of the invention, the storage medium stores a plurality of instructions adapted to be loaded by a processor to perform any of the target azimuth and elevation angle measurement methods as described above.

[0070] Through one or more embodiments of the above embodiments of the present invention, at least the following technical effects can be achieved:

[0071] In the technical solution disclosed in this invention, during array design, the two transmitting antennas with the largest azimuth distance maintain the same height, thus the target elevation angles corresponding to these two transmitting antennas are the same, while the elevation distances of the other transmitting antennas are different. In the algorithm design, multiple azimuth angle sets at different azimuths under the same elevation angle are first obtained through the echo signals from the two transmitting antennas with the same height. Then, multiple elevation angles corresponding to different azimuths are obtained through the echo signals from the transmitting antennas with different elevation distances, thereby obtaining azimuth-elevation angle combinations. In this invention, through special array design and algorithm optimization, the radar's ability to resolve azimuth and elevation angles is improved, thereby giving the radar better measurement accuracy. Attached Figure Description

[0072] 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.

[0073] Figure 1 A flowchart illustrating the steps of a method for measuring the azimuth and elevation angles of a target, provided in an embodiment of the present invention;

[0074] Figure 2 An antenna array radiation pattern provided in an embodiment of the present invention;

[0075] Figure 3 This is a schematic diagram of an antenna array provided in Embodiment 1 of the present invention;

[0076] Figure 4 This is a schematic diagram of a target azimuth and elevation angle measuring device provided in an embodiment of the present invention. Detailed Implementation

[0077] 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.

[0078] 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.

[0079] Figure 1The diagram shows a flowchart of the target azimuth and elevation angle measurement method provided in an embodiment of the present invention. According to one aspect of the present invention, a target azimuth and elevation angle measurement method is provided for a MIMO radar. The MIMO radar has multiple transmitting antennas and multiple receiving antennas. The multiple transmitting antennas and the multiple receiving antennas constitute a channel array including multiple array elements, and the channel array includes multiple subarrays. Each subarray is composed of array elements corresponding to the same transmitting antenna. The target azimuth and elevation angle measurement method includes:

[0080] Step 101: Drive the plurality of transmitting antennas to transmit radio frequency signals toward at least one target and drive the plurality of receiving antennas to receive echo signals from the at least one target, wherein the plurality of transmitting antennas includes two transmitting antennas located at the same height, and the horizontal spacing between the other transmitting antennas in the plurality of transmitting antennas is smaller than the horizontal spacing between the two transmitting antennas located at the same height;

[0081] Step 102: Perform a preset first form of beamforming operation on the first complex vector determined by the echo signals associated with the two transmitting antennas at the same altitude to obtain an azimuth angle set;

[0082] Step 103: Select a preset number of subarrays with different pitch positions from the plurality of subarrays to obtain a complex matrix determined by the echo signal corresponding to the selected subarray, and perform a preset second form of beamforming operation on the complex matrix to obtain a plurality of second complex vectors.

[0083] Step 104: Perform beamforming operation of the first form on each of the second complex vectors to obtain multiple azimuth-elevation combination pairs corresponding one-to-one with the at least one target.

[0084] The technical solution disclosed in this invention can be used in radar with two cascaded radio frequency chips, which has 6 transmitting antennas and 8 receiving antennas, corresponding to 48 channels. Specifically, it involves array design and angle resolution algorithm, which can improve the measurement accuracy of radar.

[0085] 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.

[0086] Among them, the radar can be MIMO (Multiple-Input Multiple-Output) radar. MIMO technology refers to the use of multiple transmit antennas and receive antennas at the transmitting and receiving ends, respectively, so that the signal is transmitted on multiple channels, thereby improving communication quality. It can make full use of space resources and achieve multiple transmissions and receptions through multiple antennas, thereby increasing the system channel capacity many times over without increasing spectrum resources and antenna transmission power.

[0087] 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.

[0088] The following is a detailed description of steps 101 to 104 above.

[0089] In step 101 above, the plurality of transmitting antennas are each driven to transmit radio frequency signals to at least one target and the plurality of receiving antennas are driven to receive echo signals from the at least one target. The plurality of transmitting antennas includes two transmitting antennas located at the same height, and the horizontal spacing between the other transmitting antennas in the plurality of transmitting antennas is smaller than the horizontal spacing between the two transmitting antennas located at the same height.

[0090] For example, the target of the radar can be a moving vehicle or pedestrian, or a stationary object. In this scheme, the radar's transmitting antennas are specially designed. Among all the transmitting antennas, two are at the same height. Furthermore, the distance between these two antennas at the same height is the largest relative to the distance between the other two pairs of transmitting antennas. For instance, when all the transmitting antennas are arranged in a straight line, these two antennas at the same height can be the two antennas at the very ends.

[0091] When the radar needs to measure the azimuth and elevation angles of a target, multiple transmitting antennas in the radar transmit radio frequency signals to the target. When the radio frequency signals reach the target, the signals are reflected back by the target, and the receiving antenna receives the echo signals.

[0092] In step 102 above, a preset first form of beamforming operation is performed on the first complex vector determined by the echo signals associated with the two transmitting antennas located at the same altitude to obtain an azimuth angle set.

[0093] For example, the antenna array has two transmitting antennas at the same height. Therefore, the target azimuth angle is different relative to these two transmitting antennas, but the elevation angle is the same. After acquiring the echo signals from all antennas, the echo signals from the two transmitting antennas at the same height are acquired first. Signal data is extracted from the echo signals to form a first complex vector. To correlate the first complex vector with the azimuth angle, a first form of beamforming operation is performed on the first complex vector. After signal processing, a set of azimuth angles corresponding to the two transmitting antennas at the same height is obtained. The set of azimuth angles represents multiple angles of arrival of the echo signal in the azimuth direction. The beamforming algorithm corresponding to the first form is an adaptive beamforming algorithm.

[0094] In step 103 above, a preset number of subarrays with different pitch positions are selected from the plurality of subarrays to obtain a complex matrix determined by the echo signal corresponding to the selected subarray, and a preset second form of beamforming operation is performed on the complex matrix to obtain a plurality of second complex vectors.

[0095] For example, after processing the echo signals from two transmitting antennas at the same height, one of these two transmitting antennas is selected, and simultaneously all or some of the other transmitting antennas are selected, wherein the elevation dimensions of the selected transmitting antennas are different from each other. The number of subarrays is a preset number, which can include subarrays corresponding to all transmitting antennas except the two at the same height, or only some subarrays can be selected, depending on the actual situation. After obtaining the echo signals from all selected subarrays, a complex matrix is ​​determined based on all the selected echo signals. To associate the complex matrix with the azimuth angles, a second form of beamforming operation is first performed on the complex matrix. Specifically, after obtaining the azimuth angle set, the elevation angle of the target at different azimuth angles needs to be calculated. Signal processing is performed based on each azimuth angle in the azimuth angle set and the complex matrix. After signal processing, each azimuth angle corresponds to a second complex vector, and all azimuth angles correspond to multiple second complex vectors. The second form of beamforming operation uses a digital beamforming (DBF) algorithm.

[0096] In step 104 above, the first form of beamforming operation is performed on each of the second complex vectors to obtain multiple azimuth-elevation angle combinations that correspond one-to-one with the at least one target.

[0097] For example, after obtaining the second complex vector corresponding to each azimuth angle and the elevation angle, a first form of beamforming operation is performed on each second complex vector to obtain the final azimuth-elevation angle combination pair.

[0098] In the technical solution disclosed in this invention, during array design, the two transmitting antennas with the largest azimuth distance maintain the same height, thus the target elevation angles corresponding to these two transmitting antennas are the same, while the elevation distances of the other transmitting antennas are different. In the algorithm design, multiple azimuth angle sets at different azimuths under the same elevation angle are first obtained through the echo signals from the two transmitting antennas with the same height. Then, multiple elevation angles corresponding to different azimuths are obtained through the echo signals from the transmitting antennas with different elevation distances, thereby obtaining azimuth-elevation angle combinations. In this invention, through special array design and algorithm optimization, the radar's ability to resolve azimuth and elevation angles is improved, thereby giving the radar better measurement accuracy.

[0099] Furthermore, the plurality of receiving antennas are located at the same height and the sidelobes of the corresponding antenna array pattern are no greater than -5dB.

[0100] For example, in the array design of a radar antenna, for the transmitting antennas, the azimuth spacing of all transmitting antennas is different in the azimuth dimension; in the elevation dimension, the two transmitting antennas with the largest spacing have the same elevation spacing, and the elevation spacing of the other transmitting antennas is different, even from the elevation spacing of the two transmitting antennas with the same elevation spacing. For the receiving antennas, the azimuth spacing of the receiving antennas is different in the azimuth dimension, but the elevation spacing of the receiving antennas remains consistent, that is, multiple receiving antennas are located at the same height, and the sidelobes of the corresponding antenna array pattern are no greater than -5dB. Figure 2 The image shown is an antenna array radiation pattern provided by an embodiment of the present invention, such as... Figure 2 As shown, in the antenna array pattern, only the main lobe is greater than -5dB, while the side lobes are not greater than -5dB.

[0101] Furthermore, among the plurality of transmitting antennas, except for the two transmitting antennas located at the same altitude, the transmitting antennas satisfy the minimum redundancy array requirement in the elevation dimension and are uniformly distributed in the azimuth dimension.

[0102] For example, in order to improve the measurement accuracy of radar, for the array design of transmitting antennas, the distance between two transmitting antennas of the same height is maximized in the elevation dimension. Apart from the two transmitting antennas of the same height, other transmitting antennas can be located between the two transmitting antennas of the same height. In order to meet the minimum redundancy array requirement in the elevation dimension, the other transmitting antennas need to be evenly distributed in the azimuth dimension, or the distance between adjacent transmitting antennas is not much different from each other.

[0103] Furthermore, the multiple subarrays of the multiple transmitting antennas have the same azimuth beamwidth.

[0104] For example, beamwidth is one of the parameters describing antenna performance, also known as half-power beamwidth, which refers to an antenna mode or beam angle. In this scheme, in multiple sub-arrays composed of multiple transmit antennas, the RF signal has the same beamwidth in the azimuth dimension.

[0105] Further, in step 102 above, the step of performing a preset first form of beamforming operation on the first complex vector determined by the echo signals associated with the two transmitting antennas located at the same altitude to obtain the azimuth angle set includes:

[0106] For each echo signal associated with the two transmitting antennas located at the same height, a corresponding complex number is constructed based on the amplitude and phase information in the echo signal;

[0107] The first complex vector is constructed by using the complex number corresponding to each echo signal as a vector element.

[0108] For example, firstly, signal processing is performed on the echo signals of transmitting antennas located at the same height. The amplitude and phase of the signal are obtained from the echo signals of different subarrays of the channel array of the transmitting antenna. Complex numbers are constructed based on the amplitude and phase. Each transmitting antenna corresponds to multiple subarrays, and multiple subarrays correspond to multiple complex numbers. Multiple complex numbers are used as vector elements of a first complex vector to construct a first complex vector corresponding to a transmitting antenna.

[0109] Furthermore, in step 102 above, the step of performing a preset first form of beamforming operation on the first complex vector determined by the echo signals associated with the two transmitting antennas located at the same altitude to obtain the azimuth angle set further includes:

[0110] According to the first form, beamforming is performed on the first complex vector based on the first covariance matrix corresponding to the first complex vector and the corresponding azimuth steering vector expression of the receiving antenna array to obtain the azimuth angle set.

[0111] For example, firstly, the corresponding first covariance matrix and azimuth steering vector expression are calculated based on the first complex vector. Then, beamforming is performed using a first form, which is the Bartlett beamformer adaptive beamforming algorithm. The Bartlett beamformer beamforming algorithm is used to operate on the first covariance matrix and the azimuth steering vector expression to obtain the azimuth angle set.

[0112] Further, the step of performing beamforming on the first complex vector according to the first form, based on the first covariance matrix corresponding to the first complex vector and the corresponding azimuth steering vector expression of the receiving antenna array, to obtain the azimuth angle set includes:

[0113] The first covariance matrix corresponding to the first complex vector is calculated according to the following formula:

[0114] ,

[0115] Where X represents the first complex vector. This represents the conjugate transpose of the first complex vector. 1 represents the first covariance matrix corresponding to the first complex vector;

[0116] The set of azimuth angles is calculated according to the following formula:

[0117] ,

[0118] in, This represents the set of azimuth angles containing n azimuth angles. This indicates the azimuth angle corresponding to the maximum value of the expression it points to. This represents the expression for the azimuth-dimensional steering vector of the receiving antenna array corresponding to the first complex vector. express The conjugate transpose of . 1 represents the first covariance matrix corresponding to the first complex vector;

[0119] Wherein, the first complex vector corresponds to the azimuth-dimensional steering vector expression of the receiving antenna array. The specific expression is as follows:

[0120] ,

[0121] ,

[0122] in, This represents the azimuth spacing vector of the receiving antenna corresponding to the first complex vector. This indicates the azimuth baseline of the receiving antenna. Indicates the azimuth angle of incidence, and N represents the number of receiving antennas. This indicates the wavelength of the radio frequency signal.

[0123] For example, the first covariance matrix is ​​obtained first from the first complex vector and its conjugate transpose. Then, the array azimuth steering vector expression is obtained from the first complex vector and the corresponding azimuth spacing vector of the receiving antenna. Finally, the azimuth angle set is obtained from the first covariance matrix and the array azimuth steering vector expression.

[0124] Further, in step 103 above, selecting a preset number of subarrays with different pitch positions from the plurality of subarrays to obtain the complex matrix determined by the echo signal corresponding to the selected subarray includes:

[0125] For each echo signal corresponding to the selected subarray, a corresponding complex number is constructed based on the amplitude and phase information in the echo signal;

[0126] The complex matrix is ​​constructed by using the complex number corresponding to each echo signal as a vector element.

[0127] For example, signal processing is first performed on the echo signals of the selected transmitting antennas at different elevation positions to obtain the signal amplitude and phase from the echo signals of different subarrays of the channel array of the transmitting antenna. Complex numbers are constructed based on the amplitude and phase. Each transmitting antenna corresponds to multiple subarrays, and multiple subarrays correspond to multiple complex numbers. These multiple complex numbers are used as vector elements to construct a complex matrix corresponding to multiple transmitting antennas.

[0128] Further, in step 103 above, the step of performing a preset second-form beamforming operation on the complex matrix to obtain multiple second complex vectors includes:

[0129] For each azimuth angle in the set of azimuth angles, perform the following operation:

[0130] The weighted vector corresponding to the azimuth angle is calculated based on the azimuth angle, the wavelength of the radio frequency signal, and the azimuth dimension spacing of the receiving antennas corresponding to the complex matrix.

[0131] The second complex vector corresponding to the azimuth angle is calculated based on the weighted vector and the complex matrix.

[0132] For example, for each azimuth angle in the azimuth angle set, the weighted vector of the corresponding receiving antenna under that azimuth angle is calculated, and then the second complex vector is calculated.

[0133] Furthermore, in step 104 above, the step of performing a preset second-form beamforming operation on the complex matrix to obtain multiple second complex vectors further includes:

[0134] For each azimuth angle in the set of azimuth angles, the weighted vector corresponding to that azimuth angle is calculated according to the following formula:

[0135] ,

[0136] in, This represents the weighted vector corresponding to the azimuth angle. This represents the azimuth spacing vector of the receiving antennas corresponding to the complex matrix. This represents the azimuth baseline of the receiving antenna corresponding to the complex matrix. This indicates the azimuth angle. Indicates the wavelength of the radio frequency signal;

[0137] For each azimuth angle in the set of azimuth angles, the second complex vector corresponding to that azimuth angle is calculated according to the following formula:

[0138] ,

[0139] in, This represents the k-th element in the second complex vector corresponding to the azimuth angle. This represents the weighted vector corresponding to the azimuth angle. transpose, Indicates taking the complex matrix The k-th row of the array contains all columns, and m is the total number of the selected subarrays.

[0140] For example, the second form of beamforming operation uses a digital beamforming (DBF) algorithm.

[0141] Further, in step 105 above, performing the first form of beamforming operation on each of the second complex vectors to obtain multiple azimuth-elevation angle combinations corresponding one-to-one with the at least one target includes:

[0142] For each of the second complex vectors, perform the following operation:

[0143] Calculate the second covariance matrix corresponding to the second complex vector;

[0144] According to the first form, beamforming is performed on the second complex vector based on the second covariance matrix corresponding to the second complex vector and the corresponding pitch dimension steering vector expression of the receiving antenna array to obtain multiple azimuth-elevation angle combinations that correspond one-to-one with the at least one target.

[0145] For example, firstly, the corresponding second covariance matrix and pitch-dimensional steering vector expression are calculated based on the second complex vector. Then, beamforming is performed using a first form, where the beamforming algorithm corresponding to the first form is an adaptive beamforming algorithm. The Bartlett beamformer beamforming algorithm is used to calculate the second covariance matrix and azimuth-dimensional steering vector expression to obtain multiple azimuth-elevation angle combinations.

[0146] Further, for each second complex vector, calculating the second covariance matrix corresponding to the second complex vector, and performing beamforming on the second complex vector according to the first form based on the second covariance matrix corresponding to the second complex vector and the corresponding receiving antenna array elevation dimension steering vector expression to obtain multiple azimuth-elevation angle combinations corresponding one-to-one with the at least one target includes:

[0147] For each of the second complex vectors, perform the following operation:

[0148] The second covariance matrix corresponding to the second complex vector is calculated according to the following formula:

[0149]

[0150] Where Y represents the second complex vector, This represents the conjugate transpose of the second complex vector Y. 2 represents the second covariance matrix corresponding to the second complex vector;

[0151] The set of elevation angles associated with the azimuth angles in the set of azimuth angles corresponding to the second complex vector is calculated according to the following formula to form at least one azimuth-elevation angle combination:

[0152] ,

[0153] in, Indicates by The set of pitch angles formed by the pitch angles associated with the azimuth angles in the set of azimuth angles corresponding to the second complex vector. This indicates the pitch angle corresponding to the maximum value of the expression it points to. This represents the expression for the elevation dimension steering vector of the receiving antenna array corresponding to the second complex vector. express The conjugate transpose of . 2 represents the second covariance matrix corresponding to the second complex vector, and at least one azimuth-elevation angle combination formed by beamforming on the second complex vector is expressed as follows:

[0154] ,

[0155] in, This represents the azimuth angle corresponding to the second complex vector. This represents the set of azimuth-elevation angle combinations formed by the second complex vector. Indicates the azimuth angle corresponding One pitch angle;

[0156] Wherein, the second complex vector corresponds to the elevation dimension steering vector expression of the receiving antenna array. The specific expression is as follows:

[0157] ,

[0158] in, This represents the elevation-dimensional spacing vector between adjacent receiving antennas. This represents the elevation baseline of the receiving antenna. The angle of incidence is represented by the elevation dimension, and N represents the number of receiving antennas. This indicates the wavelength of the radio frequency signal.

[0159] For example, the second covariance matrix is ​​first obtained from the second complex vector and its conjugate transpose. Then, the array elevation steering vector expression is obtained from the second complex vector and the corresponding elevation spacing vector of the receiving antenna. Finally, the Bartlett beamformer beamforming algorithm is used to perform beamforming operations on the second covariance matrix and the azimuth steering vector expression to obtain multiple azimuth-elevation angle combinations.

[0160] Further, for each second complex vector, calculating the second covariance matrix corresponding to the second complex vector, and performing beamforming on the second complex vector according to the first form based on the second covariance matrix corresponding to the second complex vector and the corresponding receiving antenna array elevation dimension steering vector expression to obtain multiple azimuth-elevation angle combinations corresponding one-to-one with the at least one target includes:

[0161] The total set of azimuth-elevation angle combinations formed by all the second complex vectors is taken as a plurality of azimuth-elevation angle combinations corresponding one-to-one with the at least one target, wherein the total set is represented by the following formula:

[0162] ,

[0163] in, Represents the total set, This represents the set of azimuth-elevation angle combinations formed by each of the second complex vectors.

[0164] For example, each azimuth-elevation pair in the set of azimuth-elevation combinations includes an azimuth angle and an elevation angle, and the n azimuth angles correspond to n pairs of azimuth-elevation angles respectively.

[0165] Example 1

[0166] In Example 1, the radar uses a cascaded two radio frequency chips, with 6 transmitting antennas and 8 receiving antennas, corresponding to 48 channels.

[0167] In the array design, the first and sixth antennas have the same height. The array designs are shown in Tables 1 and 2, where Table 1 shows a transmit channel (Rx) array design and Table 2 shows a receive channel (Tx) array design. In these figures, Xbase represents the azimuth baseline, i.e., the unit of azimuth spacing, and Zbase represents the elevation baseline, i.e., the unit of elevation spacing, where Xbase = 2.1e-3; Zbase = 5.7e-3.

[0168] Table 1. Transmit Channel (Rx) Array Design

[0169] Launch channel elevation spacing / Zbase -5 -7 -10 -13 -14 -5

[0170] Table 2 Receive Channel (Tx) Array Design

[0171] Receive channel pitch spacing / Zbase 0 0 0 0 0 0 0 0

[0172] Figure 3 The diagram shown is a schematic of an antenna array provided in Embodiment 1. Figure 3 In this array, there are 48 channels corresponding to 6 transmitting antennas and 8 receiving antennas. The first and sixth antennas have the same height. The eight subarrays corresponding to the first antenna are arrays [1-8], and the eight subarrays corresponding to the sixth antenna are arrays [41-48].

[0173] The steps for measuring the azimuth and elevation angles of a target are as follows:

[0174] Six transmitting antennas transmit radio frequency signals, and eight receiving antennas receive echo signals. The transmitting and receiving antennas form 48 subarrays, with each subarray corresponding to one echo signal.

[0175] The echo signals of the 1st antenna corresponding to the 8 subarrays [1-8] and the 6th antenna corresponding to the 6 subarrays [41-48] are obtained. The 16 subarrays of the two transmitting antennas correspond to 16 complex numbers. Each complex number includes the amplitude and phase information of the echo signal. The first complex vector constructed by the 16 complex numbers is a set of 16*1 complex vectors.

[0176] The first complex vector is subjected to beamforming operation corresponding to the adaptive beamforming algorithm (Bartlett beamformer) to obtain an azimuth angle set consisting of n azimuth angles.

[0177] Choose any one of the subarrays [1-8] and [41-48], and then combine it with the 32 subarrays [9-16], [17-24], [25-32], and [33-40] corresponding to the other four transmitting antennas with different elevation spacing to form a 5*8 complex matrix M. For example, the complex matrix can be a complex matrix composed of [1-8], [9-16], [17-24], [25-32], and [33-40], or a complex matrix composed of [9-16], [17-24], [25-32], [33-40], and [41-48].

[0178] For each of the n azimuth angles, under that azimuth angle, the complex matrix is ​​subjected to beamforming operation corresponding to the Digital Beamforming (DBF) algorithm to obtain the second complex vector.

[0179] The second complex vector is subjected to beamforming operation corresponding to the adaptive beamforming algorithm (Bartlett beamformer) to obtain the azimuth-elevation combination pair at that azimuth angle.

[0180] Construct multiple azimuth-pitch combinations based on all the azimuth-pitch combinations corresponding to the n pitch angles.

[0181] In this invention, by specially designing the array and optimizing the algorithm, the radar's ability to resolve azimuth and elevation angles is improved, thereby giving the radar better measurement accuracy.

[0182] Based on the same inventive concept as the target azimuth and elevation angle measurement method of the present invention, the present invention provides a target azimuth and elevation angle measurement device for a MIMO radar. The MIMO radar has multiple transmitting antennas and multiple receiving antennas. The multiple transmitting antennas and the multiple receiving antennas constitute a channel array including multiple array elements, and the channel array includes multiple subarrays. Each subarray is composed of array elements corresponding to the same transmitting antenna. Please refer to [reference needed]. Figure 2 The device is characterized in that it comprises:

[0183] Radio frequency signal transmitting unit 201 is used to drive the plurality of transmitting antennas to transmit radio frequency signals to at least one target and to drive the plurality of receiving antennas to receive echo signals from the at least one target, wherein the plurality of transmitting antennas includes two transmitting antennas located at the same height, and the horizontal spacing between the other transmitting antennas in the plurality of transmitting antennas is smaller than the horizontal spacing between the two transmitting antennas located at the same height.

[0184] Azimuth set determination unit 202 is used to perform a preset first form of beamforming operation on a first complex vector determined by the echo signals associated with the two transmitting antennas located at the same height to obtain a first azimuth set;

[0185] The complex vector determination unit 203 is used to select a preset number of subarrays with different pitch positions among the plurality of subarrays to obtain a complex matrix determined by the echo signal corresponding to the selected subarray, and to perform a preset second form of beamforming operation on the complex matrix to obtain a plurality of second complex vectors.

[0186] The azimuth-elevation combination generation unit 204 is used to perform the first form of beamforming operation on each of the second complex vectors to obtain multiple azimuth-elevation combinations that correspond one-to-one with the at least one target.

[0187] Furthermore, the plurality of receiving antennas are located at the same height and the sidelobes of the corresponding antenna array pattern are no greater than -5dB.

[0188] Furthermore, among the plurality of transmitting antennas, except for the two transmitting antennas located at the same altitude, the transmitting antennas satisfy the minimum redundancy array requirement in the elevation dimension and are uniformly distributed in the azimuth dimension.

[0189] Furthermore, the multiple subarrays of the multiple transmitting antennas have the same azimuth beamwidth.

[0190] Furthermore, the azimuth set determination unit 202 is also used for:

[0191] For each echo signal associated with the two transmitting antennas located at the same height, a corresponding complex number is constructed based on the amplitude and phase information in the echo signal;

[0192] The first complex vector is constructed by using the complex number corresponding to each echo signal as a vector element.

[0193] Furthermore, the azimuth set determination unit 202 is also used for:

[0194] According to the first form, beamforming is performed on the first complex vector based on the first covariance matrix corresponding to the first complex vector and the corresponding azimuth steering vector expression of the receiving antenna array to obtain the azimuth angle set.

[0195] Furthermore, the azimuth set determination unit 202 is also used for:

[0196] The first covariance matrix corresponding to the first complex vector is calculated according to the following formula:

[0197] ,

[0198] Where X represents the first complex vector. This represents the conjugate transpose of the first complex vector. 1 represents the first covariance matrix corresponding to the first complex vector;

[0199] The set of azimuth angles is calculated according to the following formula:

[0200] ,

[0201] in, This represents the set of azimuth angles containing n azimuth angles. This indicates the azimuth angle corresponding to the maximum value of the expression it points to. This represents the expression for the azimuth-dimensional steering vector of the receiving antenna array corresponding to the first complex vector. express The conjugate transpose of . 1 represents the first covariance matrix corresponding to the first complex vector;

[0202] Wherein, the first complex vector corresponds to the azimuth-dimensional steering vector expression of the receiving antenna array. The specific expression is as follows:

[0203] ,

[0204] ,

[0205] in, This represents the azimuth spacing vector of the receiving antenna corresponding to the first complex vector. This indicates the azimuth baseline of the receiving antenna. Indicates the azimuth angle of incidence, and N represents the number of receiving antennas. This indicates the wavelength of the radio frequency signal.

[0206] Furthermore, the complex vector determination unit 203 is also used for:

[0207] For each echo signal corresponding to the selected subarray, a corresponding complex number is constructed based on the amplitude and phase information in the echo signal;

[0208] The complex matrix is ​​constructed by using the complex number corresponding to each echo signal as a vector element.

[0209] Furthermore, the complex vector determination unit 203 is also used for:

[0210] For each azimuth angle in the set of azimuth angles, perform the following operation:

[0211] The weighted vector corresponding to the azimuth angle is calculated based on the azimuth angle, the wavelength of the radio frequency signal, and the azimuth dimension spacing of the receiving antennas corresponding to the complex matrix.

[0212] The second complex vector corresponding to the azimuth angle is calculated based on the weighted vector and the complex matrix.

[0213] Furthermore, the complex vector determination unit 203 is also used for:

[0214] For each azimuth angle in the set of azimuth angles, the weighted vector corresponding to that azimuth angle is calculated according to the following formula:

[0215] ,

[0216] in, This represents the weighted vector corresponding to the azimuth angle. This represents the azimuth spacing vector of the receiving antennas corresponding to the complex matrix. This represents the azimuth baseline of the receiving antenna corresponding to the complex matrix. This indicates the azimuth angle. Indicates the wavelength of the radio frequency signal;

[0217] For each azimuth angle in the set of azimuth angles, the second complex vector corresponding to that azimuth angle is calculated according to the following formula:

[0218] ,

[0219] in, This represents the k-th element in the second complex vector corresponding to the azimuth angle. This represents the weighted vector corresponding to the azimuth angle. transpose, Indicates taking the complex matrix The k-th row of the array contains all columns, and m is the total number of the selected subarrays.

[0220] Furthermore, the azimuth-elevation angle combination generation unit 204 is also used for:

[0221] For each of the second complex vectors, perform the following operation:

[0222] Calculate the second covariance matrix corresponding to the second complex vector;

[0223] According to the first form, beamforming is performed on the second complex vector based on the second covariance matrix corresponding to the second complex vector and the corresponding pitch dimension steering vector expression of the receiving antenna array to obtain multiple azimuth-elevation angle combinations that correspond one-to-one with the at least one target.

[0224] Furthermore, the azimuth-elevation angle combination generation unit 204 is also used for:

[0225] For each of the second complex vectors, perform the following operation:

[0226] The second covariance matrix corresponding to the second complex vector is calculated according to the following formula:

[0227]

[0228] Where Y represents the second complex vector, This represents the conjugate transpose of the second complex vector Y. 2 represents the second covariance matrix corresponding to the second complex vector;

[0229] The set of elevation angles associated with the azimuth angles in the set of azimuth angles corresponding to the second complex vector is calculated according to the following formula to form at least one azimuth-elevation angle combination:

[0230] ,

[0231] in, Indicates by The set of pitch angles formed by the pitch angles associated with the azimuth angles in the set of azimuth angles corresponding to the second complex vector. This indicates the pitch angle corresponding to the maximum value of the expression it points to. This represents the expression for the elevation dimension steering vector of the receiving antenna array corresponding to the second complex vector. express The conjugate transpose of . 2 represents the second covariance matrix corresponding to the second complex vector, and at least one azimuth-elevation angle combination formed by beamforming on the second complex vector is expressed as follows:

[0232] ,

[0233] in, This represents the azimuth angle corresponding to the second complex vector. This represents the set of azimuth-elevation angle combinations formed by the second complex vector. Indicates the azimuth angle corresponding One pitch angle;

[0234] Wherein, the second complex vector corresponds to the elevation dimension steering vector expression of the receiving antenna array. The specific expression is as follows:

[0235] ,

[0236] in, This represents the elevation-dimensional spacing vector between adjacent receiving antennas. This represents the elevation baseline of the receiving antenna. The angle of incidence is represented by the elevation dimension, and N represents the number of receiving antennas. This indicates the wavelength of the radio frequency signal.

[0237] Furthermore, the azimuth-elevation angle combination generation unit 204 is also used for:

[0238] The total set of azimuth-elevation angle combinations formed by all the second complex vectors is taken as a plurality of azimuth-elevation angle combinations corresponding one-to-one with the at least one target, wherein the total set is represented by the following formula:

[0239] ,

[0240] in, Represents the total set, This represents the set of azimuth-elevation angle combinations formed by each of the second complex vectors.

[0241] Furthermore, other aspects and implementation details of the target azimuth and elevation angle measuring device are the same as or similar to the target azimuth and elevation angle measuring methods described above, and will not be repeated here.

[0242] 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 and elevation angle measurement methods as described above.

[0243] 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 method for measuring target azimuth and elevation angles, used in 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, and the channel array including multiple subarrays, each of the subarrays being composed of array elements corresponding to the same transmitting antenna, characterized in that... The method includes: The plurality of transmitting antennas are each driven to transmit radio frequency signals toward at least one target and the plurality of receiving antennas are driven to receive echo signals from the at least one target, wherein the plurality of transmitting antennas includes two transmitting antennas located at the same height, and the horizontal spacing between the other transmitting antennas in the plurality of transmitting antennas is smaller than the horizontal spacing between the two transmitting antennas located at the same height; A preset first form of beamforming operation is performed on a first complex vector determined by the echo signals associated with the two transmitting antennas located at the same altitude to obtain an azimuth angle set; Select a preset number of subarrays with different pitch positions from the plurality of subarrays to obtain a complex matrix determined by the echo signal corresponding to the selected subarrays, and perform a preset second form of beamforming operation on the complex matrix to obtain a plurality of second complex vectors. For each of the second complex vectors, the first form of beamforming operation is performed to obtain multiple azimuth-elevation angle combinations that correspond one-to-one with the at least one target. According to the first form, beamforming is performed on the first complex vector based on the first covariance matrix corresponding to the first complex vector and the corresponding azimuth steering vector expression of the receiving antenna array to obtain the azimuth angle set, including: The first covariance matrix corresponding to the first complex vector is calculated according to the following formula: ， Where X represents the first complex vector. This represents the conjugate transpose of the first complex vector. 1 represents the first covariance matrix corresponding to the first complex vector; The set of azimuth angles is calculated according to the following formula: ， in, This represents the set of azimuth angles containing n azimuth angles. This indicates the azimuth angle corresponding to the maximum value of the expression it points to. This represents the expression for the azimuth-dimensional steering vector of the receiving antenna array corresponding to the first complex vector. express The conjugate transpose of . 1 represents the first covariance matrix corresponding to the first complex vector; Wherein, the first complex vector corresponds to the azimuth-dimensional steering vector expression of the receiving antenna array. The specific expression is as follows: ， ， in, This represents the azimuth spacing vector of the receiving antenna corresponding to the first complex vector. This indicates the azimuth baseline of the receiving antenna. Indicates the azimuth angle of incidence, and N represents the number of receiving antennas. Indicates the wavelength of the radio frequency signal; The step of performing a pre-defined second-form beamforming operation on the complex matrix to obtain multiple second complex vectors further includes: For each azimuth angle in the set of azimuth angles, the weighted vector corresponding to that azimuth angle is calculated according to the following formula: ， in, This represents the weighted vector corresponding to the azimuth angle. This represents the azimuth spacing vector of the receiving antennas corresponding to the complex matrix. This represents the azimuth baseline of the receiving antenna corresponding to the complex matrix. This indicates the azimuth angle. Indicates the wavelength of the radio frequency signal; For each azimuth angle in the set of azimuth angles, the second complex vector corresponding to that azimuth angle is calculated according to the following formula: ， in, This represents the k-th element in the second complex vector corresponding to the azimuth angle. This represents the weighted vector corresponding to the azimuth angle. transpose, Represents taking a complex matrix The k-th row and all columns in the array, where m is the total number of the selected subarrays; For each of the second complex vectors, a second covariance matrix corresponding to the second complex vector is calculated. Then, according to the first form, beamforming is performed on the second complex vector based on the second covariance matrix and the corresponding elevation steering vector expression of the receiving antenna array to obtain multiple azimuth-elevation angle combinations corresponding one-to-one with the at least one target, including: The total set of azimuth-elevation angle combinations formed by all the second complex vectors is taken as a plurality of azimuth-elevation angle combinations corresponding one-to-one with the at least one target, wherein the total set is represented by the following formula: ， in, Represents the total set, This represents the set of azimuth-elevation angle combinations formed by each of the second complex vectors.

2. The method as described in claim 1, characterized in that, The multiple receiving antennas are located at the same height and the sidelobes of the corresponding antenna array pattern are no greater than -5dB.

3. The method as described in claim 2, characterized in that, Of the plurality of transmitting antennas, all except the two transmitting antennas located at the same altitude meet the minimum redundancy array requirement in the elevation dimension and are uniformly distributed in the azimuth dimension.

4. The method as described in claim 3, characterized in that, The multiple subarrays of the multiple transmitting antennas have the same azimuth beamwidth.

5. The method as described in claim 1, characterized in that, The step of performing a preset first-form beamforming operation on a first complex vector determined by the echo signals associated with the two transmitting antennas at the same altitude to obtain an azimuth angle set includes: For each echo signal associated with the two transmitting antennas located at the same height, a corresponding complex number is constructed based on the amplitude and phase information in the echo signal; The first complex vector is constructed by using the complex number corresponding to each echo signal as a vector element.

6. The method as described in claim 5, characterized in that, The step of performing a preset first-form beamforming operation on a first complex vector determined by the echo signals associated with the two transmitting antennas at the same altitude to obtain an azimuth angle set further includes: According to the first form, beamforming is performed on the first complex vector based on the first covariance matrix corresponding to the first complex vector and the corresponding azimuth steering vector expression of the receiving antenna array to obtain the azimuth angle set.

7. The method as described in claim 6, characterized in that, The step of selecting a predetermined number of subarrays with different elevation positions from the plurality of subarrays to obtain the complex matrix determined by the echo signal corresponding to the selected subarrays includes: For each echo signal corresponding to the selected subarray, a corresponding complex number is constructed based on the amplitude and phase information in the echo signal; The complex matrix is ​​constructed by using the complex number corresponding to each echo signal as a vector element.

8. The method as described in claim 7, characterized in that, The step of performing a pre-defined second-form beamforming operation on the complex matrix to obtain multiple second complex vectors includes: For each azimuth angle in the set of azimuth angles, perform the following operation: The weighted vector corresponding to the azimuth angle is calculated based on the azimuth angle, the wavelength of the radio frequency signal, and the azimuth dimension spacing of the receiving antennas corresponding to the complex matrix. The second complex vector corresponding to the azimuth angle is calculated based on the weighted vector and the complex matrix.

9. The method as described in claim 8, characterized in that, The step of performing the first form of beamforming operation on each of the second complex vectors to obtain multiple azimuth-elevation angle combinations corresponding one-to-one with the at least one target includes: For each of the second complex vectors, perform the following operation: Calculate the second covariance matrix corresponding to the second complex vector; According to the first form, beamforming is performed on the second complex vector based on the second covariance matrix corresponding to the second complex vector and the corresponding pitch dimension steering vector expression of the receiving antenna array to obtain multiple azimuth-elevation angle combinations that correspond one-to-one with the at least one target.

10. The method as described in claim 9, characterized in that, For each of the second complex vectors, the step of calculating the second covariance matrix corresponding to the second complex vector, and performing beamforming on the second complex vector according to the first form, based on the second covariance matrix corresponding to the second complex vector and the corresponding pitch-dimensional steering vector expression of the receiving antenna array, to obtain multiple azimuth-elevation angle combinations corresponding one-to-one with the at least one target, includes: For each of the second complex vectors, perform the following operation: The second covariance matrix corresponding to the second complex vector is calculated according to the following formula: Where Y represents the second complex vector, This represents the conjugate transpose of the second complex vector Y. 2 represents the second covariance matrix corresponding to the second complex vector; The set of elevation angles associated with the azimuth angles in the set of azimuth angles corresponding to the second complex vector is calculated according to the following formula to form at least one azimuth-elevation angle combination: ， in, Indicated by The set of pitch angles formed by the pitch angles associated with the azimuth angles in the set of azimuth angles corresponding to the second complex vector. This indicates the pitch angle corresponding to the maximum value of the expression it points to. This represents the expression for the elevation dimension steering vector of the receiving antenna array corresponding to the second complex vector. express The conjugate transpose of . 2 represents the second covariance matrix corresponding to the second complex vector, and at least one azimuth-elevation angle combination formed by beamforming on the second complex vector is expressed as follows: ， in, This represents the azimuth angle corresponding to the second complex vector. This represents the set of azimuth-elevation angle combinations formed by the second complex vector. Indicates the azimuth angle corresponding One pitch angle; Wherein, the second complex vector corresponds to the elevation dimension steering vector expression of the receiving antenna array. The specific expression is as follows: ， in, This represents the elevation-dimensional spacing vector between adjacent receiving antennas. This represents the elevation baseline of the receiving antenna. The angle of incidence is represented by the elevation dimension, and N represents the number of receiving antennas. This indicates the wavelength of the radio frequency signal.

11. A device for measuring the azimuth and elevation angles of a target, used 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, and the channel array including multiple subarrays, each of the subarrays consisting of array elements corresponding to the same transmitting antenna, characterized in that, The device implements the target azimuth and elevation angle measurement method as described in claim 1, and the device comprises: A radio frequency signal transmitting unit is used to drive the plurality of transmitting antennas to transmit radio frequency signals to at least one target and to drive the plurality of receiving antennas to receive echo signals from the at least one target, wherein the plurality of transmitting antennas includes two transmitting antennas located at the same height, and the horizontal spacing between the other transmitting antennas in the plurality of transmitting antennas is smaller than the horizontal spacing between the two transmitting antennas located at the same height. An azimuth set determination unit is used to perform a preset first form of beamforming operation on a first complex vector determined by the echo signals associated with the two transmitting antennas located at the same altitude to obtain a first azimuth set; The complex vector determination unit is used to select a preset number of subarrays with different pitch dimension positions from the plurality of subarrays to obtain a complex matrix determined by the echo signal corresponding to the selected subarray, and to perform a preset second form of beamforming operation on the complex matrix to obtain a plurality of second complex vectors. An azimuth-elevation combination generation unit is used to perform the first form of beamforming operation on each of the second complex vectors to obtain multiple azimuth-elevation combinations that correspond one-to-one with the at least one target.

12. A storage medium, characterized in that, The storage medium stores a plurality of instructions adapted to be loaded by a processor to execute the target azimuth and elevation angle measurement method as described in any one of claims 1 to 10.

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