CN116990799A - Target azimuth angle and pitch angle measuring method, device and storage medium - Google Patents

Abstract

The invention discloses a target azimuth angle and pitch angle measuring method, a device and a storage medium, wherein the method comprises the following steps: driving a plurality of antennas of the radar to transmit radio frequency signals to a target and receive echo signals; carrying out wave beam forming operation on echo signals of two transmitting antennas with the same height to obtain an azimuth angle set; obtaining a corresponding complex matrix according to echo signals of subarrays with different positions in the pitching dimension, and performing beam forming operation on the complex matrix to obtain a second complex vector; and carrying out beam forming operation on each second complex vector to obtain an azimuth angle-pitch angle combination pair corresponding to the target. The technical scheme provided by the invention can solve the technical problem that the resolution capability of the radar to measure the target azimuth angle and the pitch angle is low because the number of channels corresponding to the antenna is small when the cascade of the radio frequency chips of the radar system is small in the prior art.

Description

Target azimuth angle and pitch angle measuring method, device and storage medium

Technical Field

The present invention relates to the field of radar technologies, and in particular, to a method and apparatus for measuring azimuth angle and pitch angle of a target, and a storage medium.

Background

In a radar system, when the position information and the motion state of a target are detected, the position of the target can be determined through radio frequency signals transmitted by the radar and received echo signals, specifically, the azimuth angle and the pitch angle of the target can be obtained, and then the information such as the speed, the number and the direction of the target can be obtained. In a radar system, the working frequency band of the millimeter wave radar is lower than that of a laser radar, the measurement accuracy is not influenced by light and weather, and the millimeter wave radar is more and more widely applied to various scenes for measuring the target position, and plays an irreplaceable role.

In the prior art, the current 4D millimeter wave radar generally uses a scheme of cascading four Radio Frequency (RF) chips, and an antenna array formed by the four RF chips has 12 transmitting channels and 16 receiving channels, so that a sparse area array can be formed, and the antenna array has higher resolution capability when carrying out two-dimensional resolution of azimuth and pitching on a measurement target. However, for low-cost radars, there are fewer cascades, for example, for a scheme of cascade connection of two radio frequency chips, the antenna array is composed of only 6 transmitting channels and 8 receiving channels, and since the number of channels corresponding to the two cascades of radars is small, the high resolution capability of the four cascades of radars is difficult to achieve when the two-dimensional resolution of azimuth and pitching is performed on a measurement target. Therefore, in order to improve the measurement accuracy of the radar, it is necessary to design an antenna array reasonably and optimize a signal processing algorithm.

Disclosure of Invention

The invention provides a target azimuth angle and pitch angle measuring method, device and storage medium, and aims to effectively solve the technical problem that in the prior art, when the cascade of radio frequency chips of a radar system is less, the number of channels corresponding to an antenna is less, so that the resolution capability of the radar is lower when the target azimuth angle and pitch angle are measured.

According to an aspect of the present invention, there is provided a target azimuth and elevation angle measurement method for a MIMO radar having a plurality of transmitting antennas and a plurality of receiving antennas, the plurality of transmitting antennas and the plurality of receiving antennas constituting a channel array including a plurality of array elements, and the channel array including a plurality of sub-arrays each of which is constituted by an array element corresponding to the same transmitting antenna, the method comprising:

driving the plurality of transmitting antennas to each transmit radio frequency signals to at least one target and driving the plurality of receiving antennas to receive echo signals from the at least one target, wherein the plurality of transmitting antennas comprise two transmitting antennas positioned at the same height, and the horizontal spacing of other transmitting antennas in the plurality of transmitting antennas is smaller than the horizontal spacing of the two transmitting antennas positioned at the same height;

Performing a beam forming operation of a preset first form on a first complex vector determined by echo signals associated with the two transmitting antennas positioned at the same height to obtain an azimuth angle set;

selecting a preset number of subarrays with different pitching dimension positions in the subarrays to obtain a complex matrix determined by echo signals corresponding to the selected subarrays, and carrying out a preset second form of beam forming operation on the complex matrix to obtain a plurality of second complex vectors;

and performing the beamforming operation of the first form on each second complex vector to obtain a plurality of azimuth-elevation angle combination pairs which are in one-to-one correspondence with the at least one target.

Further, the plurality of receiving antennas are located at the same height and the side lobe of the corresponding antenna array pattern is not greater than-5 dB.

Further, the transmitting antennas except for the two transmitting antennas positioned at the same height in the plurality of transmitting antennas meet the minimum redundancy array requirement in the pitching dimension and are uniformly distributed in the azimuth dimension.

Further, the plurality of subarrays of the plurality of transmitting antennas have uniform beamwidths in the azimuth dimension.

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

For each echo signal associated with the two transmitting antennas located at the same elevation, constructing a corresponding complex number based on amplitude and phase information in the echo signal;

and constructing the first complex vector by taking the complex number corresponding to each echo signal as a vector element.

Further, the performing a beamforming operation of a preset first form on a first complex vector determined by echo signals associated with the two transmitting antennas located at the same height to obtain an azimuth angle set further includes:

and according to the first form, carrying out beam forming operation on the first complex vector according to a first covariance matrix corresponding to the first complex vector and a corresponding receiving antenna array azimuth dimension guide vector expression so as to obtain the azimuth angle set.

Further, according to the first form, performing beamforming operation on the first complex vector according to a first covariance matrix corresponding to the first complex vector and a corresponding receiving antenna array azimuth dimension steering vector expression to obtain the azimuth set includes:

calculating a first covariance matrix corresponding to the first complex vector according to the following formula:

wherein X represents the first complex vector, X ^H Represents the conjugate transpose of the first complex vector,representing a first covariance matrix corresponding to the first complex vector;

calculating the azimuth set according to:

wherein θ _azi (n) represents the azimuth set comprising n azimuth angles,represents the corresponding azimuth dimension angle, a (θ) _azi ) Represents the direction vector expression of the receiving antenna array azimuth dimension corresponding to the first complex vector, a (theta) _azi ) ^H Represents a (θ) _azi ) Conjugate transpose of->Representing a first covariance matrix corresponding to the first complex vector;

wherein, the first complex vector corresponds to the receiving antenna array azimuth dimension guiding vector expression a _azi The specific expression of (n) is as follows:

wherein d _azi (N) represents the azimuth dimension spacing vector, X of the receiving antenna corresponding to the first complex vector _base -an azimuth dimension baseline representing the receiving antenna, -a _azi The azimuth dimension incident angle is represented, N represents the number of receiving antennas, and lambda represents the wavelength of the radio frequency signal.

Further, the selecting a preset number of subarrays with different pitch-dimension positions in the plurality of subarrays to obtain the complex matrix determined by the echo signals corresponding to the selected subarrays includes:

for each echo signal corresponding to the selected subarray, constructing a corresponding complex number based on amplitude and phase information in the echo signal;

And constructing the complex matrix by taking the complex number corresponding to each echo signal as a vector element.

Further, the performing a beamforming operation of a preset second form on the complex matrix to obtain a plurality of second complex vectors includes:

performing the following for each azimuth in the set of azimuths:

calculating a weight vector corresponding to the azimuth based on the azimuth, the wavelength of the radio frequency signal and the azimuth dimension distance of the receiving antenna corresponding to the complex matrix;

and calculating the second complex vector corresponding to the azimuth according to the weighted vector and the complex matrix.

Further, the performing a beamforming operation of a preset second form on the complex matrix to obtain a plurality of second complex vectors further includes:

for each azimuth in the azimuth set, calculating the weighting vector corresponding to the azimuth according to the following formula:

wherein w represents the weighting vector corresponding to the azimuth angle, d _azi An azimuth dimension space vector X representing the receiving antenna corresponding to the complex matrix _base An azimuth dimension base line, θ, representing the receiving antenna corresponding to the complex matrix _n Representing the azimuth angle, λ representing the wavelength of the radio frequency signal;

For each azimuth in the azimuth set, calculating the second complex vector corresponding to the azimuth according to the following formula:

Y(k)＝w ^T M(k,:),k＝1,2,…m，

wherein Y (k) represents the kth element, w, in the second complex vector corresponding to the azimuth angle ^T Representing the transpose of the weighting vector w corresponding to the azimuth, M (k: a) representing the acquisition of the complex matrix MAll columns of the kth row, m, are the total number of selected subarrays.

Further, said performing said first form of beamforming operation for each of said second complex vectors to obtain a plurality of azimuth-elevation combinations in one-to-one correspondence with said at least one target comprises:

performing the following operations for each of the second complex vectors:

calculating a second covariance matrix corresponding to the second complex vector according to the second complex vector;

and according to the first form, carrying out wave beam forming operation on the second complex vector according to a second covariance matrix corresponding to the second complex vector and a corresponding receiving antenna array pitching dimension guide vector expression so as to obtain a plurality of azimuth angle-pitch angle combinations corresponding to the at least one target one by one.

Further, for each second complex vector, calculating a second covariance matrix corresponding to the second complex vector according to the second complex vector, and performing beamforming operation on the second complex vector according to the second covariance matrix corresponding to the second complex vector and a corresponding receiving antenna array pitch dimension steering vector expression according to the first form to obtain a plurality of azimuth-elevation angle combinations corresponding to the at least one target one to one, where the beamforming operation includes:

Performing the following operations for each of the second complex vectors:

calculating a second covariance matrix corresponding to the second complex vector according to the following formula:

wherein Y represents the second complex vector, Y ^H Represents the conjugate transpose of the second complex vector Y,representing a second covariance matrix corresponding to the second complex vector;

calculating a set of pitch angles associated with azimuth angles in the set of azimuth angles corresponding to the second complex vector to form at least one azimuth-pitch angle combination according to:

wherein θ _ele (l) Representing a set of pitch angles consisting of i pitch angles associated with azimuth angles in said set of azimuth angles corresponding to the second complex vector,represents the corresponding pitch dimension angle, a (θ) _ele ) A (theta) represents a receiving antenna array pitch dimension vector expression corresponding to the second complex vector _ele ) ^H Represents a (θ) _ele ) Conjugate transpose of->A second covariance matrix corresponding to the second complex vector is represented, and at least one azimuth-elevation angle combination formed by beamforming for the second complex vector is represented as follows:

wherein θ _n Representing the azimuth angle, θ, corresponding to the second complex vector _group Representing a set of azimuth-elevation angle combinations, θ, formed by the second complex vector _ele (1),…,θ _ele (l) Representing the azimuth angle theta _n Corresponding l pitch angles;

wherein, the second complex vector corresponds to the receiving antenna array pitching dimension guiding vector expression a _ele The specific expression of (n) is as follows:

wherein d _ele Representing pitch dimension spacing vectors, Z, of adjacent receive antennas _base Represents a tilt dimension baseline, θ, of the receiving antenna _ele The angle of incidence in the pitch dimension is represented, N represents the number of receiving antennas, and lambda represents the wavelength of the radio frequency signal.

Further, for each second complex vector, calculating a second covariance matrix corresponding to the second complex vector according to the second complex vector, and performing beamforming operation on the second complex vector according to the second covariance matrix corresponding to the second complex vector and a corresponding receiving antenna array pitch dimension steering vector expression according to the first form to obtain a plurality of azimuth-elevation angle combinations corresponding to the at least one target one to one, where the beamforming operation includes:

combining a total set of azimuth-elevation angle combinations formed by all second complex vectors into a plurality of azimuth-elevation angle combinations in one-to-one correspondence with the at least one target, wherein the total set is represented by:

wherein θ _angle Representing the total set, θ _group 1，…，θ _group n represents the set of azimuth-elevation angle combinations formed by the respective second complex vectors.

According to another aspect of the present invention, there is also provided a target azimuth and elevation angle measuring device for a MIMO radar having a plurality of transmitting antennas and a plurality of receiving antennas, the plurality of transmitting antennas and the plurality of receiving antennas constituting a channel array including a plurality of array elements, and the channel array including a plurality of sub-arrays each of which is constituted by an array element corresponding to the same transmitting antenna, the device comprising:

a radio frequency signal transmitting unit, configured to drive the plurality of transmitting antennas to each transmit a radio frequency signal to at least one target and drive the plurality of receiving antennas to receive echo signals from the at least one target, where the plurality of transmitting antennas include two transmitting antennas located at the same height, and a horizontal pitch of other transmitting antennas in the plurality of transmitting antennas is smaller than a horizontal pitch of the two transmitting antennas located at the same height;

an azimuth angle set determining unit, configured to perform a beamforming operation of a preset first form on a first complex vector determined by echo signals associated with the two transmitting antennas located at the same height to obtain a first azimuth angle set;

The complex vector determining unit is used for selecting a preset number of subarrays with different pitching dimension positions in the subarrays to obtain a complex matrix determined by echo signals corresponding to the selected subarrays, and carrying out a preset second form of beam forming operation on the complex matrix to obtain a plurality of second complex vectors;

and the azimuth angle-pitch angle combination generating unit is used for carrying out the beamforming operation of the first form on each second complex vector so as to obtain a plurality of azimuth angle-pitch angle combinations which are in one-to-one correspondence with the at least one target.

According to another aspect of the invention, the storage medium has stored therein a plurality of instructions adapted to be loaded by a processor to perform any of the target azimuth and pitch angle measurement methods described above.

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

in the technical scheme disclosed by the invention, when the array is designed, the heights of the two transmitting antennas with the largest distance in the azimuth dimension are kept consistent, so that the pitch angles of targets corresponding to the two transmitting antennas are consistent, and the pitch distances of other transmitting antennas are different. In algorithm design, a plurality of azimuth angle sets under different azimuth angles under the same pitch angle are obtained through echo signals of two transmitting antennas with the same height, then a plurality of pitch angles corresponding to different azimuth angles are obtained through echo signals of transmitting antennas with different pitch intervals, and further an azimuth angle-pitch angle combination pair is obtained. In the invention, the resolution capability of the radar on azimuth angle and pitch angle is improved by specially designing the array and optimizing the algorithm, so that the radar has better measurement accuracy.

Drawings

The technical solution and other advantageous effects of the present invention will be made apparent by the following detailed description of the specific embodiments of the present invention with reference to the accompanying drawings.

FIG. 1 is a flow chart of steps of a method for measuring a target azimuth angle and a pitch angle according to an embodiment of the present invention;

fig. 2 is a diagram of an antenna array according to an embodiment of the present invention;

fig. 3 is a schematic diagram of an antenna array according to a first embodiment of the present invention;

fig. 4 is a schematic structural diagram of a target azimuth and pitch angle measurement device according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention.

In the description of the present invention, it should be noted that, unless explicitly specified and defined otherwise, the term "and/or" herein is merely an association relationship describing associated objects, and means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone. The character "/" herein generally indicates that the associated object is an "or" relationship unless otherwise specified.

Fig. 1 is a flowchart illustrating steps of a target azimuth and pitch angle measurement method according to an embodiment of the present invention, and according to an aspect of the present invention, there is provided a target azimuth and pitch angle measurement method for a MIMO radar, where the MIMO radar has a plurality of transmitting antennas and a plurality of receiving antennas, the plurality of transmitting antennas and the plurality of receiving antennas form a channel array including a plurality of array elements, and the channel array includes a plurality of sub-arrays, each of the sub-arrays is formed by array elements corresponding to the same transmitting antenna, and the target azimuth and pitch angle measurement method includes:

step 101: driving the plurality of transmitting antennas to each transmit radio frequency signals to at least one target and driving the plurality of receiving antennas to receive echo signals from the at least one target, wherein the plurality of transmitting antennas comprise two transmitting antennas positioned at the same height, and the horizontal spacing of other transmitting antennas in the plurality of transmitting antennas is smaller than the horizontal spacing of the two transmitting antennas positioned at the same height;

step 102: performing a beam forming operation of a preset first form on a first complex vector determined by echo signals associated with the two transmitting antennas positioned at the same height to obtain an azimuth angle set;

Step 103: selecting a preset number of subarrays with different pitching dimension positions in the subarrays to obtain a complex matrix determined by echo signals corresponding to the selected subarrays, and carrying out a preset second form of beam forming operation on the complex matrix to obtain a plurality of second complex vectors;

step 104: and performing the beamforming operation of the first form on each second complex vector to obtain a plurality of azimuth-elevation angle combination pairs which are in one-to-one correspondence with the at least one target.

The technical scheme disclosed by the invention can be used for the radar with two cascaded radio frequency chips, is provided with 6 transmitting antennas and 8 receiving antennas, and is provided with 48 channels correspondingly, and particularly relates to an array design and an angle resolution algorithm, so that the measurement accuracy of the radar can be improved.

The radar system detects the azimuth angle and the pitch angle of the target by using the transmitted pulse signals and the corresponding echo signals, specifically, the transmitting antenna transmits the pulse signals to the target, the echo signals are returned after the pulse signals reach the target to be detected, the radar system acquires the echo signals returned by the target, and the current position, the motion state and the like of the target are calculated according to the amplitude, the phase, the wavelength and other information of the echo signals.

The radar may be a MIMO (Multiple-Input Multiple-Output) radar, where MIMO technology refers to using Multiple transmitting antennas and receiving antennas at a transmitting end and a receiving end, respectively, so that signals are transmitted on Multiple channels, thereby improving communication quality. The system can fully utilize space resources, realize multiple transmission and multiple reception through a plurality of antennas, and can doubly improve the system channel capacity under the condition of not increasing frequency spectrum resources and antenna transmitting power.

In a MIMO radar system, the antennas include a plurality of transmitting antennas and a plurality of receiving antennas, wherein a channel corresponds between any one of the transmitting antennas and any one of the receiving antennas. And a transmitting antenna corresponds to a plurality of receiving antennas, and accordingly, a channel array is formed between the transmitting antenna and the receiving antennas, wherein each channel is a subarray of the channel array, and the subarrays are formed by array elements corresponding to the same transmitting antenna.

The above steps 101 to 104 are specifically described below.

In the step 101, the plurality of transmitting antennas are 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, wherein the plurality of transmitting antennas include two transmitting antennas located at the same height, and a horizontal pitch of other transmitting antennas in the plurality of transmitting antennas is smaller than a horizontal pitch of the two transmitting antennas located at the same height.

The target to be measured of the radar may be a vehicle, a pedestrian in a moving state, or a stationary object, for example. In this solution, the layout of the transmitting antennas of the radar has a special design, and in all the transmitting antennas, the heights of the two transmitting antennas are the same, and in all the transmitting antennas, the distance between the two transmitting antennas with the same height is the largest relative to the distance between the other two pairs of transmitting antennas. For example, when the transmitting antennas are all arranged on a straight line, the two antennas with the same height may be the two antennas at the two ends.

When the radar needs to measure the azimuth angle and the pitch angle of the target, a plurality of transmitting antennas in the radar transmit radio frequency signals to the target, and after the radio frequency signals reach the target, the signals are reflected back by the target, and the receiving antennas receive the returned echo signals.

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

Illustratively, there are two transmit antennas in the antenna array that are the same height, and thus, the target azimuth angle is different, but the elevation angle is the same, relative to the two transmit antennas. After the echo signals of all the antennas are acquired, the echo signals of the two transmitting antennas with the same height are acquired first, and signal data are acquired in the echo signals to form a first complex vector. In order to correlate the first complex vector with the azimuth angle, carrying out a first form of beam forming operation on the first complex vector, and obtaining azimuth angle sets corresponding to the two transmitting antennas with the same height after signal processing, wherein the azimuth angle sets are a plurality of arrival angles of echo signals in azimuth directions. The beamforming algorithm corresponding to the first form is an adaptive beamforming algorithm.

In step 103, a preset number of subarrays with different pitch-dimension positions are selected to obtain a complex matrix determined by echo signals corresponding to the selected subarrays, and a preset second form of beamforming operation is performed on the complex matrix to obtain a plurality of second complex vectors.

For example, after echo signals of two transmitting antennas with the same height are processed, any one of the two transmitting antennas is selected, and all or part of other transmitting antennas are simultaneously selected, wherein the pitch dimension positions of the selected transmitting antennas are different from each other. The number of the subarrays is preset, and the subarrays corresponding to all the transmitting antennas except the two transmitting antennas with the same height can be included, or only part of subarrays can be selected, and the subarrays can be flexibly set according to actual conditions. After the echo signals of all the selected subarrays are acquired, determining a complex matrix according to all the selected echo signals. In order to correlate the complex matrix with the azimuth angles, a second form of beamforming operation is performed on the complex matrix, specifically, after an azimuth angle set is obtained, the pitch angle of the target under 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, each azimuth angle corresponds to a second complex vector after the signal processing, and all azimuth angles correspond to a plurality of second complex vectors. Among them, the second form of beamforming operation uses a digital beamforming (Digital beamforming, DBF) algorithm.

In step 104, the beamforming operation of the first form is performed for each of the second complex vectors to obtain a plurality of azimuth-elevation angle combination pairs corresponding to the at least one target one to one.

Illustratively, after obtaining second complex vectors corresponding to each azimuth and associated with the elevation, a first form of beamforming operation is performed on each second complex vector to obtain a final azimuth-elevation combination pair, wherein.

Detailed Description

In the technical scheme disclosed by the invention, when the array is designed, the heights of the two transmitting antennas with the largest distance in the azimuth dimension are kept consistent, so that the pitch angles of targets corresponding to the two transmitting antennas are consistent, and the pitch distances of other transmitting antennas are different. In algorithm design, a plurality of azimuth angle sets under different azimuth angles under the same pitch angle are obtained through echo signals of two transmitting antennas with the same height, then a plurality of pitch angles corresponding to different azimuth angles are obtained through echo signals of transmitting antennas with different pitch intervals, and further an azimuth angle-pitch angle combination pair is obtained. In the invention, the resolution capability of the radar on azimuth angle and pitch angle is improved by specially designing the array and optimizing the algorithm, so that the radar has better measurement accuracy.

Further, the plurality of receiving antennas are located at the same height and the side lobe of the corresponding antenna array pattern is not greater than-5 dB.

Illustratively, in an array design of antennas of a radar, azimuth pitches of all the transmitting antennas are different in azimuth dimensions for the transmitting antennas; in the pitch dimension, the pitch pitches of the two transmitting antennas with the largest pitch are the same, in addition, the pitch pitches of the other transmitting antennas are different, and the pitch pitches of the other transmitting antennas are different from the pitch pitches of the two transmitting antennas with the same pitch. For the receiving antennas, in the azimuth dimension, the azimuth intervals of the receiving antennas are different, but the pitch intervals of the receiving antennas are kept consistent, namely, a plurality of receiving antennas are positioned at the same height, the side lobe of the corresponding antenna array directional diagram is not more than-5 dB, fig. 2 shows an antenna array directional diagram provided by the embodiment of the invention, and only the main lobe is more than-5 dB and the side lobe is not more than-5 dB in the antenna array directional diagram as shown in fig. 2.

Further, the transmitting antennas except for the two transmitting antennas positioned at the same height in the plurality of transmitting antennas meet the minimum redundancy array requirement in the pitching dimension and are uniformly distributed in the azimuth dimension.

For example, in order to improve the measurement accuracy of the radar, for the array design of the transmitting antennas, the spacing between the two transmitting antennas having the same height is the largest in the pitch dimension, other transmitting antennas may be located between the two transmitting antennas having the same height in addition to the two transmitting antennas having the same height, and in order to satisfy the minimum redundancy array requirement in the pitch dimension, the other transmitting antennas need to be uniformly distributed in the azimuth dimension, or the spacing between the adjacent transmitting antennas is not much different from each other.

Further, the plurality of subarrays of the plurality of transmitting antennas have uniform beamwidths in the azimuth dimension.

Illustratively, beam width is one of the parameters describing antenna performance, also known as half-power beam bandwidth, referring to one antenna pattern or beam angle. In this scheme, in a plurality of subarrays formed by a plurality of transmitting antennas, the beam width of the radio frequency signals in the azimuth dimension is the same.

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

For each echo signal associated with the two transmitting antennas located at the same elevation, constructing a corresponding complex number based on amplitude and phase information in the echo signal;

and constructing the first complex vector by taking the complex number corresponding to each echo signal as a vector element.

In an exemplary embodiment, first, echo signals of transmitting antennas located at the same height are subjected to signal processing, amplitudes of signals and phases of signals are obtained from echo signals of different subarrays of a channel array of the transmitting antennas, complex numbers are constructed according to the amplitudes and phases, each transmitting antenna corresponds to a plurality of subarrays, the plurality of subarrays corresponds to the plurality of complex numbers, and the plurality of complex numbers are used as vector elements of a first complex vector to construct the first complex vector corresponding to one transmitting antenna.

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

and according to the first form, carrying out beam forming operation on the first complex vector according to a first covariance matrix corresponding to the first complex vector and a corresponding receiving antenna array azimuth dimension guide vector expression so as to obtain the azimuth angle set.

Illustratively, a corresponding first covariance matrix and azimuth-dimensional steering vector expression are first calculated from the first complex vector. Beamforming is then performed in a first form, which is an adaptive beamforming algorithm (Bartlett beamformer), and the first covariance matrix and the azimuth-dimension steering vector expression are computed in a Bartlett beamformer beamforming algorithm to obtain an azimuth set.

Further, according to the first form, performing beamforming operation on the first complex vector according to a first covariance matrix corresponding to the first complex vector and a corresponding receiving antenna array azimuth dimension steering vector expression to obtain the azimuth set includes:

calculating a first covariance matrix corresponding to the first complex vector according to the following formula:

wherein X represents the first complex vector, X ^H Represents the conjugate transpose of the first complex vector,representing a first covariance matrix corresponding to the first complex vector;

calculating the azimuth set according to:

wherein θ _azi (n) represents the azimuth set comprising n azimuth angles,represents the corresponding azimuth dimension angle, a (θ) _azi ) Represents the direction vector expression of the receiving antenna array azimuth dimension corresponding to the first complex vector, a (theta) _azi ) ^H Represents a (θ) _azi ) Conjugate transpose of->Representing a first covariance matrix corresponding to the first complex vector;

wherein, the first complex vector corresponds to the receiving antenna array azimuth dimension guiding vector expression a _azi The specific expression of (n) is as follows:

wherein d _azi (N) represents the azimuth dimension spacing vector, X of the receiving antenna corresponding to the first complex vector _base -an azimuth dimension baseline representing the receiving antenna, -a _azi The azimuth dimension incident angle is represented, N represents the number of receiving antennas, and lambda represents the wavelength of the radio frequency signal.

Illustratively, the first covariance matrix is first obtained from the first complex vector and the conjugate transpose of the first complex vector. And then obtaining an array azimuth dimension guide vector expression according to the first complex vector and the azimuth dimension spacing vector of the corresponding receiving antenna. And finally, obtaining an azimuth angle set according to the first covariance matrix and the array azimuth dimension guide vector expression.

Further, in step 103, the selecting a preset number of subarrays with different pitch positions in the plurality of subarrays to obtain the complex matrix determined by the echo signals corresponding to the selected subarrays includes:

For each echo signal corresponding to the selected subarray, constructing a corresponding complex number based on amplitude and phase information in the echo signal;

and constructing the complex matrix by taking the complex number corresponding to each echo signal as a vector element.

Illustratively, first, echo signals of selected transmitting antennas with different pitch dimension positions are subjected to signal processing, and the amplitude of the signals and the phase of the signals are obtained from the echo signals of different subarrays of a channel array of the transmitting antennas. And constructing complex numbers according to the amplitude and the phase, wherein each transmitting antenna corresponds to a plurality of subarrays, the subarrays correspond to a plurality of complex numbers, and the complex numbers are used as vector elements to construct complex matrixes corresponding to the transmitting antennas.

Further, in step 103, performing a beamforming operation of a preset second form on the complex matrix to obtain a plurality of second complex vectors includes:

performing the following for each azimuth in the set of azimuths:

calculating a weight vector corresponding to the azimuth based on the azimuth, the wavelength of the radio frequency signal and the azimuth dimension distance of the receiving antenna corresponding to the complex matrix;

and calculating the second complex vector corresponding to the azimuth according to the weighted vector and the complex matrix.

Illustratively, for each azimuth in the set of azimuths, a weight vector for the corresponding receiving antenna at that azimuth is calculated, and a second complex vector is calculated.

Further, in the step 104, the performing a beamforming operation of a preset second form on the complex matrix to obtain a plurality of second complex vectors further includes:

for each azimuth in the azimuth set, calculating the weighting vector corresponding to the azimuth according to the following formula:

wherein w represents the weighting vector corresponding to the azimuth angle, d _azi An azimuth dimension space vector X representing the receiving antenna corresponding to the complex matrix _base An azimuth dimension base line, θ, representing the receiving antenna corresponding to the complex matrix _n Representing the azimuth angle, λ representing the wavelength of the radio frequency signal;

for each azimuth in the azimuth set, calculating the second complex vector corresponding to the azimuth according to the following formula:

Y(k)＝w ^T M(k,:),k＝1,2,…m，

wherein Y (k) represents the kth element, w, in the second complex vector corresponding to the azimuth angle ^T Representing the transpose of the weighting vector w corresponding to the azimuth, M (k: i) representing taking all columns of the kth row in the complex matrix M, M being the total number of selected subarrays.

Illustratively, the second form of beamforming operation uses a digital beamforming (Digital beamforming, DBF) algorithm.

Further, in the step 105, the performing the beamforming operation of the first form for each of the second complex vectors to obtain a plurality of azimuth-elevation angle combinations corresponding to the at least one target one-to-one includes:

performing the following operations for each of the second complex vectors:

calculating a second covariance matrix corresponding to the second complex vector according to the second complex vector;

and according to the first form, carrying out wave beam forming operation on the second complex vector according to a second covariance matrix corresponding to the second complex vector and a corresponding receiving antenna array pitching dimension guide vector expression so as to obtain a plurality of azimuth angle-pitch angle combinations corresponding to the at least one target one by one.

Illustratively, a corresponding second covariance matrix and pitch-dimension-oriented vector expression are first calculated from the second complex vector. And then carrying out beamforming operation through a first form, wherein the beamforming algorithm corresponding to the first form is an adaptive beamforming algorithm, and carrying out operation on the second covariance matrix and the azimuth dimension guide vector expression through a Bartlett beamformer beamforming algorithm so as to obtain a plurality of azimuth-pitch angle combinations.

Further, for each second complex vector, calculating a second covariance matrix corresponding to the second complex vector according to the second complex vector, and performing beamforming operation on the second complex vector according to the second covariance matrix corresponding to the second complex vector and a corresponding receiving antenna array pitch dimension steering vector expression according to the first form to obtain a plurality of azimuth-elevation angle combinations corresponding to the at least one target one to one, where the beamforming operation includes:

performing the following operations for each of the second complex vectors:

calculating a second covariance matrix corresponding to the second complex vector according to the following formula:

wherein Y represents the second complex vector, Y ^H Represents the conjugate transpose of the second complex vector Y,representing a second covariance matrix corresponding to the second complex vector;

calculating a set of pitch angles associated with azimuth angles in the set of azimuth angles corresponding to the second complex vector to form at least one azimuth-pitch angle combination according to:

wherein θ _ele (l) Representing a set of pitch angles consisting of i pitch angles associated with azimuth angles in said set of azimuth angles corresponding to the second complex vector,represents the corresponding pitch dimension angle, a (θ) _ele ) A (theta) represents a receiving antenna array pitch dimension vector expression corresponding to the second complex vector _ele ) ^H Represents a (θ) _ele ) Conjugate transpose of->A second covariance matrix corresponding to the second complex vector is represented, and at least one azimuth-elevation angle combination formed by beamforming for the second complex vector is represented as follows:

wherein θ _n Representing the azimuth angle, θ, corresponding to the second complex vector _group Representing a set of azimuth-elevation angle combinations, θ, formed by the second complex vector _ele (1),…,θ _ele (l) Representing the azimuth angle theta _n Corresponding l pitch angles;

wherein, the second complex vector corresponds to the receiving antenna array pitching dimension guiding vector expression a _ele The specific expression of (N) is as follows:

wherein d _ele Representing pitch dimension spacing vectors, Z, of adjacent receive antennas _base Represents a tilt dimension baseline, θ, of the receiving antenna _ele The angle of incidence in the pitch dimension is represented, N represents the number of receiving antennas, and lambda represents the wavelength of the radio frequency signal.

Illustratively, the second covariance matrix is first obtained from the second complex vector and a conjugate transpose of the second complex vector. And then obtaining an array pitch dimension guide vector expression according to the second complex vector and the pitch dimension distance vector of the corresponding receiving antenna. And finally, carrying out beamforming operation on the second covariance matrix and the azimuth dimension guide vector expression by using a Bartlett beamformer beamforming algorithm so as to obtain a plurality of azimuth-pitch angle combinations.

Further, for each second complex vector, calculating a second covariance matrix corresponding to the second complex vector according to the second complex vector, and performing beamforming operation on the second complex vector according to the second covariance matrix corresponding to the second complex vector and a corresponding receiving antenna array pitch dimension steering vector expression according to the first form to obtain a plurality of azimuth-elevation angle combinations corresponding to the at least one target one to one, where the beamforming operation includes:

combining a total set of azimuth-elevation angle combinations formed by all second complex vectors into a plurality of azimuth-elevation angle combinations in one-to-one correspondence with the at least one target, wherein the total set is represented by:

wherein θ _angle Representing the total set, θ _group 1，…，θ _group n represents the set of azimuth-elevation angle combinations formed by the respective second complex vectors.

Illustratively, each azimuth-pitch pair in the set of azimuth-pitch combinations includes an azimuth and a pitch, the n azimuths corresponding to the n azimuth-pitch angles, respectively.

Example 1

In the first embodiment, the radar adopts a scheme of cascading two radio frequency chips, and the radar has 6 transmitting antennas, 8 receiving antennas and 48 channels.

In the array design, the 1 st antenna and the 6 th antenna have the same height. The array designs are shown in tables 1 and 2, wherein table 1 is a transmit channel (Rx) array design and table 2 is a receive channel (Tx) array design. In the figure, xbase denotes an azimuth dimension baseline, i.e., a unit of azimuth pitch, zbase denotes a pitch dimension baseline, which is a unit of pitch, where xbase=2.1e-3; zbase=5.7e-3.

TABLE 1 emission channel (Rx) array design

Transmission channel azimuth spacing/Xbase	-9	-3	3	9	14	16
							Pitch spacing of transmit channels/Zbase	-5	-7	-10	-13	-14	-5

TABLE 2 receive channel (Tx) array design

Fig. 3 is a schematic diagram of an antenna array according to a first embodiment, in fig. 3, 48 channels are corresponding to 6 transmitting antennas and 8 receiving antennas. The heights of the 1 st antenna and the 6 th antenna are the same, 8 subarrays corresponding to the 1 st antenna are arrays [1-8], and 8 subarrays corresponding to the 6 th antenna are arrays [41-48].

The steps of measuring the azimuth and pitch angles of the target are as follows:

the antenna comprises 6 transmitting antennas for transmitting radio frequency signals, 8 receiving antennas for receiving echo signals, 48 subarrays are formed between the transmitting antennas and the receiving antennas, and each subarray corresponds to one echo signal.

Echo signals corresponding to 8 subarrays [1-8] of the 1 st antenna and echo signals corresponding to 6 subarrays [41-48] of the 6 th antenna are obtained. The 16 subarrays of the two transmitting antennas correspond to 16 complex numbers, each complex number comprises amplitude information and phase information of an echo signal, and a first complex vector formed by the 16 complex numbers is a group of complex vectors of 16 x 1.

And carrying out beamforming operation corresponding to the adaptive beamforming algorithm (Bartlett beamformer) on the first complex vector so as to obtain an azimuth angle set consisting of n azimuth angles.

A group of subarrays are arbitrarily selected from the subarrays [1-8] and the subarrays [41-48], and then 32 subarrays [9-16], [17-24 ], [25-32], [33-40] corresponding to other 4 transmitting antennas with different pitch intervals form a complex matrix M of 5*8, for example, the complex matrix can be a complex matrix formed by [1-8], [9-16], [17-24 ], [25-32], [33-40] or a complex matrix formed by [9-16], [17-24 ], [25-32], [33-40] and [41-48 ].

For each of the n azimuth angles, performing a beamforming operation corresponding to a digital beamforming (Digital beamforming, DBF) algorithm on the complex matrix at the azimuth angle to obtain a second complex vector.

And performing a beamforming operation corresponding to the adaptive beamforming algorithm (Bartlett beamformer) on the second complex vector to obtain an azimuth-elevation angle combination pair under the azimuth angle.

Multiple azimuth-pitch angle combinations are constructed from corresponding pairs of so-called azimuth-pitch angle combinations of the n pitch angles.

In the invention, the resolution capability of the radar on azimuth angle and pitch angle is improved by specially designing the array and optimizing the algorithm, so that the radar has better measurement accuracy.

Based on the same inventive concept as the target azimuth and pitch angle measurement method of the present embodiment, the present embodiment provides a target azimuth and pitch angle measurement device for a MIMO radar, where the MIMO radar has a plurality of transmitting antennas and a plurality of receiving antennas, the plurality of transmitting antennas and the plurality of receiving antennas form a channel array including a plurality of array elements, and the channel array includes a plurality of sub-arrays, each of the sub-arrays is formed by an array element corresponding to the same transmitting antenna, please refer to fig. 2, and the device includes:

a radio frequency signal transmitting unit 201, configured to drive the plurality of transmitting antennas to each transmit a radio frequency signal to at least one target and drive the plurality of receiving antennas to receive echo signals from the at least one target, where the plurality of transmitting antennas include two transmitting antennas located at the same height, and a horizontal pitch of other transmitting antennas in the plurality of transmitting antennas is smaller than a horizontal pitch of the two transmitting antennas located at the same height;

an azimuth angle set determining unit 202, configured to perform a beamforming operation of a preset first form on a first complex vector determined by echo signals associated with the two transmitting antennas located at the same height to obtain a first azimuth angle set;

A complex vector determining unit 203, configured to select a preset number of subarrays with different pitch-dimensional positions in the plurality of subarrays, so as to obtain a complex matrix determined by echo signals 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;

an azimuth-elevation angle combination generating unit 204, configured to perform the beamforming operation of the first form for each of the second complex vectors to obtain a plurality of azimuth-elevation angle combinations corresponding to the at least one target one by one.

Further, the plurality of receiving antennas are located at the same height and the side lobe of the corresponding antenna array pattern is not greater than-5 dB.

Further, the transmitting antennas except for the two transmitting antennas positioned at the same height in the plurality of transmitting antennas meet the minimum redundancy array requirement in the pitching dimension and are uniformly distributed in the azimuth dimension.

Further, the plurality of subarrays of the plurality of transmitting antennas have uniform beamwidths in the azimuth dimension.

Further, the azimuth set determining unit 202 is further configured to:

for each echo signal associated with the two transmitting antennas located at the same elevation, constructing a corresponding complex number based on amplitude and phase information in the echo signal;

And constructing the first complex vector by taking the complex number corresponding to each echo signal as a vector element.

Further, the azimuth set determining unit 202 is further configured to:

and according to the first form, carrying out beam forming operation on the first complex vector according to a first covariance matrix corresponding to the first complex vector and a corresponding receiving antenna array azimuth dimension guide vector expression so as to obtain the azimuth angle set.

Further, the azimuth set determining unit 202 is further configured to:

calculating a first covariance matrix corresponding to the first complex vector according to the following formula:

wherein X represents the first complex vector, X ^H Represents the conjugate transpose of the first complex vector,representing a first covariance matrix corresponding to the first complex vector;

calculating the azimuth set according to:

wherein θ _azi (n) represents the azimuth set comprising n azimuth angles,represents the corresponding azimuth dimension angle, a (θ) _azi ) Represents the direction vector expression of the receiving antenna array azimuth dimension corresponding to the first complex vector, a (theta) _azi ) ^H Represents a (θ) _azi ) Conjugate transpose of->Representing a first covariance matrix corresponding to the first complex vector;

Wherein, the first complex vector corresponds to the receiving antenna array azimuth dimension guiding vector expression a _azi The specific expression of (n) is as follows:

wherein d _azi (N) represents the azimuth dimension spacing vector, X of the receiving antenna corresponding to the first complex vector _base -an azimuth dimension baseline representing the receiving antenna, -a _azi The azimuth dimension incident angle is represented, N represents the number of receiving antennas, and lambda represents the wavelength of the radio frequency signal.

Further, the complex vector determining unit 203 is further configured to:

for each echo signal corresponding to the selected subarray, constructing a corresponding complex number based on amplitude and phase information in the echo signal;

and constructing the complex matrix by taking the complex number corresponding to each echo signal as a vector element.

Further, the complex vector determining unit 203 is further configured to:

performing the following for each azimuth in the set of azimuths:

calculating a weight vector corresponding to the azimuth based on the azimuth, the wavelength of the radio frequency signal and the azimuth dimension distance of the receiving antenna corresponding to the complex matrix;

and calculating the second complex vector corresponding to the azimuth according to the weighted vector and the complex matrix.

Further, the complex vector determining unit 203 is further configured to:

For each azimuth in the azimuth set, calculating the weighting vector corresponding to the azimuth according to the following formula:

wherein w represents the weighting vector corresponding to the azimuth angle, d _azi An azimuth dimension space vector X representing the receiving antenna corresponding to the complex matrix _base Representing the corresponding receiving antenna of the complex matrixAzimuth dimension baseline, θ _n Representing the azimuth angle, λ representing the wavelength of the radio frequency signal;

for each azimuth in the azimuth set, calculating the second complex vector corresponding to the azimuth according to the following formula:

Y(k)＝w ^T M(k,:),k＝1,2,…m，

wherein Y (k) represents the kth element, w, in the second complex vector corresponding to the azimuth angle ^T Representing the transpose of the weighting vector w corresponding to the azimuth, M (k: i) representing taking all columns of the kth row in the complex matrix M, M being the total number of selected subarrays.

Further, the azimuth-elevation angle combination generating unit 204 is further configured to:

performing the following operations for each of the second complex vectors:

calculating a second covariance matrix corresponding to the second complex vector according to the second complex vector;

and according to the first form, carrying out wave beam forming operation on the second complex vector according to a second covariance matrix corresponding to the second complex vector and a corresponding receiving antenna array pitching dimension guide vector expression so as to obtain a plurality of azimuth angle-pitch angle combinations corresponding to the at least one target one by one.

Further, the azimuth-elevation angle combination generating unit 204 is further configured to:

performing the following operations for each of the second complex vectors:

calculating a second covariance matrix corresponding to the second complex vector according to the following formula:

wherein Y represents the second complex vector, Y ^H Represents the conjugate transpose of the second complex vector Y,representing a second covariance matrix corresponding to the second complex vector;

calculating a set of pitch angles associated with azimuth angles in the set of azimuth angles corresponding to the second complex vector to form at least one azimuth-pitch angle combination according to:

wherein θ _ele (l) Representing a set of pitch angles consisting of i pitch angles associated with azimuth angles in said set of azimuth angles corresponding to the second complex vector,represents the corresponding pitch dimension angle, a (θ) _ele ) A (theta) represents a receiving antenna array pitch dimension vector expression corresponding to the second complex vector _ele ) ^H Represents a (θ) _ele ) Conjugate transpose of->A second covariance matrix corresponding to the second complex vector is represented, and at least one azimuth-elevation angle combination formed by beamforming for the second complex vector is represented as follows:

wherein θ _n Representing the azimuth angle, θ, corresponding to the second complex vector _group Representing a set of azimuth-elevation angle combinations, θ, formed by the second complex vector _ele (1),…,θ _ele (l) Representing the azimuth angle theta _n Corresponding l pitch angles;

wherein, the second complex vector corresponds to the receiving antenna array pitching dimension guiding vector expression a _ele The specific expression of (n) is as follows:

wherein d _ele Representing pitch dimension spacing vectors, Z, of adjacent receive antennas _base Represents a tilt dimension baseline, θ, of the receiving antenna _ele The angle of incidence in the pitch dimension is represented, N represents the number of receiving antennas, and lambda represents the wavelength of the radio frequency signal.

Further, the azimuth-elevation angle combination generating unit 204 is further configured to:

combining a total set of azimuth-elevation angle combinations formed by all second complex vectors into a plurality of azimuth-elevation angle combinations in one-to-one correspondence with the at least one target, wherein the total set is represented by:

wherein θ _angle Representing the total set, θ _group 1，…，θ _group n represents the set of azimuth-elevation angle combinations formed by the respective second complex vectors.

In addition, other aspects and implementation details of the target azimuth angle and pitch angle measuring device are the same as or similar to those of the target azimuth angle and pitch angle measuring method described above, and are not described herein again.

According to another aspect of the invention there is also provided a storage medium having stored therein a plurality of instructions adapted to be loaded by a processor to perform any of the target azimuth and elevation measurement methods as described above.

In summary, although the present invention has been described in terms of the preferred embodiments, the preferred embodiments are not limited to the above embodiments, and various modifications and changes can be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention is defined by the appended claims.

Claims (15)

1. A target azimuth and elevation angle measurement method for a MIMO radar having a plurality of transmitting antennas and a plurality of receiving antennas, the plurality of transmitting antennas and the plurality of receiving antennas constituting a channel array including a plurality of array elements, and the channel array including a plurality of sub-arrays each of which is constituted by an array element corresponding to the same transmitting antenna, the method comprising:

driving the plurality of transmitting antennas to each transmit radio frequency signals to at least one target and driving the plurality of receiving antennas to receive echo signals from the at least one target, wherein the plurality of transmitting antennas comprise two transmitting antennas positioned at the same height, and the horizontal spacing of other transmitting antennas in the plurality of transmitting antennas is smaller than the horizontal spacing of the two transmitting antennas positioned at the same height;

Performing a beam forming operation of a preset first form on a first complex vector determined by echo signals associated with the two transmitting antennas positioned at the same height to obtain an azimuth angle set;

selecting a preset number of subarrays with different pitching dimension positions in the subarrays to obtain a complex matrix determined by echo signals corresponding to the selected subarrays, and carrying out a preset second form of beam forming operation on the complex matrix to obtain a plurality of second complex vectors;

and performing the beamforming operation of the first form on each second complex vector to obtain a plurality of azimuth-elevation angle combination pairs which are in one-to-one correspondence with the at least one target.

2. The method of claim 1, wherein the plurality of receive antennas are located at the same elevation and the corresponding antenna array pattern has a side lobe of no more than-5 dB.

3. The method of claim 2, wherein the transmitting antennas of the plurality of transmitting antennas except for the two transmitting antennas located at the same height satisfy a minimum redundancy array requirement in a pitch dimension and are uniformly distributed in an azimuth dimension.

4. The method of claim 3, wherein the plurality of subarrays of the plurality of transmit antennas are uniform in azimuth dimension beamwidth.

5. The method of claim 1, wherein performing a pre-set first form of beamforming operation for a first complex vector determined from echo signals associated with the two co-located transmit antennas to obtain an azimuth set comprises:

for each echo signal associated with the two transmitting antennas located at the same elevation, constructing a corresponding complex number based on amplitude and phase information in the echo signal;

and constructing the first complex vector by taking the complex number corresponding to each echo signal as a vector element.

6. The method of claim 5, wherein performing a pre-set first form of beamforming operation for a first complex vector determined from echo signals associated with the two co-located transmit antennas to obtain an azimuth set further comprises:

and according to the first form, carrying out beam forming operation on the first complex vector according to a first covariance matrix corresponding to the first complex vector and a corresponding receiving antenna array azimuth dimension guide vector expression so as to obtain the azimuth angle set.

7. The method of claim 6, wherein said beamforming the first complex vector according to the first version based on a first covariance matrix corresponding to the first complex vector and a corresponding receive antenna array azimuth dimension steering vector expression to obtain the set of azimuth angles comprises:

Calculating a first covariance matrix corresponding to the first complex vector according to the following formula:

wherein X represents the first complex vector, X ^H Represents the conjugate transpose of the first complex vector,representing a first covariance matrix corresponding to the first complex vector;

calculating the azimuth set according to:

wherein θ _azi (n) represents the azimuth set comprising n azimuth angles,represents the corresponding azimuth dimension angle, a (θ) _azi ) Represents the direction vector expression of the receiving antenna array azimuth dimension corresponding to the first complex vector, a (theta) _azi ) ^H Represents a (θ) _azi ) Conjugate transpose of->Representing a first covariance matrix corresponding to the first complex vector;

wherein, the first complex vector corresponds to the receiving antenna array azimuth dimension guiding vector expression a _azi The specific expression of (n) is as follows:

wherein d _azi (N) represents the azimuth dimension spacing vector, X of the receiving antenna corresponding to the first complex vector _base -an azimuth dimension baseline representing the receiving antenna, -a _azi The azimuth dimension incident angle is represented, N represents the number of receiving antennas, and lambda represents the wavelength of the radio frequency signal.

8. The method of claim 7, wherein selecting a predetermined number of subarrays of the plurality of subarrays that differ in pitch dimension position to obtain the complex matrix determined by echo signals corresponding to the selected subarrays comprises:

For each echo signal corresponding to the selected subarray, constructing a corresponding complex number based on amplitude and phase information in the echo signal;

and constructing the complex matrix by taking the complex number corresponding to each echo signal as a vector element.

9. The method of claim 8, wherein performing a preset second form of beamforming operation on the complex matrix to obtain a plurality of second complex vectors comprises:

performing the following for each azimuth in the set of azimuths:

calculating a weight vector corresponding to the azimuth based on the azimuth, the wavelength of the radio frequency signal and the azimuth dimension distance of the receiving antenna corresponding to the complex matrix;

and calculating the second complex vector corresponding to the azimuth according to the weighted vector and the complex matrix.

10. The method of claim 9, wherein performing a preset second form of beamforming operation on the complex matrix to obtain a plurality of second complex vectors further comprises:

for each azimuth in the azimuth set, calculating the weighting vector corresponding to the azimuth according to the following formula:

wherein w represents the weighting vector corresponding to the azimuth angle, d _azi An azimuth dimension space vector X representing the receiving antenna corresponding to the complex matrix _base An azimuth dimension base line, θ, representing the receiving antenna corresponding to the complex matrix _n Representing the azimuth angle, λ representing the wavelength of the radio frequency signal;

for each azimuth in the azimuth set, calculating the second complex vector corresponding to the azimuth according to the following formula:

Y(k)＝w ^T M(k,:),k＝1,2,...m，

wherein Y (k) represents the kth element, w, in the second complex vector corresponding to the azimuth angle ^T Representing the transpose of the weighting vector w corresponding to the azimuth, M (k: i) representing taking all columns of the kth row in the complex matrix M, M being the total number of selected subarrays.

11. The method of claim 10, wherein said performing the beamforming operation of the first form for each of the second complex vectors to obtain a plurality of azimuth-elevation angle combinations that correspond one-to-one to the at least one target comprises:

performing the following operations for each of the second complex vectors:

calculating a second covariance matrix corresponding to the second complex vector according to the second complex vector;

and according to the first form, carrying out wave beam forming operation on the second complex vector according to a second covariance matrix corresponding to the second complex vector and a corresponding receiving antenna array pitching dimension guide vector expression so as to obtain a plurality of azimuth angle-pitch angle combinations corresponding to the at least one target one by one.

12. The method of claim 11, wherein for each of the second complex vectors, calculating a second covariance matrix corresponding to the second complex vector from the second complex vector, and in accordance with the first form, beamforming the second complex vector from the second covariance matrix corresponding to the second complex vector and the corresponding receive antenna array elevation dimension steering vector expression to obtain a plurality of azimuth-elevation angle combinations that are one-to-one corresponding to the at least one target comprises:

performing the following operations for each of the second complex vectors:

calculating a second covariance matrix corresponding to the second complex vector according to the following formula:

wherein Y represents the second complex vector, Y ^H Represents the conjugate transpose of the second complex vector Y,representing a second covariance matrix corresponding to the second complex vector;

calculating a set of pitch angles associated with azimuth angles in the set of azimuth angles corresponding to the second complex vector to form at least one azimuth-pitch angle combination according to:

wherein θ _ele (l) Representing a set of pitch angles consisting of i pitch angles associated with azimuth angles in said set of azimuth angles corresponding to the second complex vector, Represents the corresponding pitch dimension angle, a (θ) _ele ) A (theta) represents a receiving antenna array pitch dimension vector expression corresponding to the second complex vector _ele ) ^H Represents a (θ) _ele ) Conjugate transpose of->A second covariance matrix corresponding to the second complex vector is represented, and at least one azimuth-elevation angle combination formed by beamforming for the second complex vector is represented as follows:

wherein θ _n Representing the azimuth angle, θ, corresponding to the second complex vector _group Representing a set of azimuth-elevation angle combinations, θ, formed by the second complex vector _ele (1),…,θ _ele (l) Representing the azimuth angle theta _n Corresponding l pitch angles;

wherein, the second complex vector corresponds to the receiving antenna array pitching dimension guiding vector expression a _ele The specific expression of (n) is as follows:

wherein d _ele Representing pitch dimension spacing vectors, Z, of adjacent receive antennas _base Represents a tilt dimension baseline, θ, of the receiving antenna _ele The angle of incidence in the pitch dimension is represented, N represents the number of receiving antennas, and lambda represents the wavelength of the radio frequency signal.

13. The method of claim 12, wherein for each of the second complex vectors, calculating a second covariance matrix corresponding to the second complex vector from the second complex vector, and in accordance with the first form, beamforming the second complex vector from the second covariance matrix corresponding to the second complex vector and the corresponding receive antenna array elevation dimension steering vector expression to obtain a plurality of azimuth-elevation angle combinations that are one-to-one corresponding to the at least one target comprises:

Combining a total set of azimuth-elevation angle combinations formed by all second complex vectors into a plurality of azimuth-elevation angle combinations in one-to-one correspondence with the at least one target, wherein the total set is represented by:

wherein θ _angle Representing the total set, θ _group 1，…，θ _group n represents the set of azimuth-elevation angle combinations formed by the respective second complex vectors.

14. A measurement device for target azimuth and elevation angle for a MIMO radar having a plurality of transmitting antennas and a plurality of receiving antennas, the plurality of transmitting antennas and the plurality of receiving antennas constituting a channel array comprising a plurality of array elements, and the channel array comprising a plurality of sub-arrays, each of the sub-arrays being constituted by array elements corresponding to the same transmitting antenna, the device comprising:

a radio frequency signal transmitting unit, configured to drive the plurality of transmitting antennas to each transmit a radio frequency signal to at least one target and drive the plurality of receiving antennas to receive echo signals from the at least one target, where the plurality of transmitting antennas include two transmitting antennas located at the same height, and a horizontal pitch of other transmitting antennas in the plurality of transmitting antennas is smaller than a horizontal pitch of the two transmitting antennas located at the same height;

An azimuth angle set determining unit, configured to perform a beamforming operation of a preset first form on a first complex vector determined by echo signals associated with the two transmitting antennas located at the same height to obtain a first azimuth angle set;

the complex vector determining unit is used for selecting a preset number of subarrays with different pitching dimension positions in the subarrays to obtain a complex matrix determined by echo signals corresponding to the selected subarrays, and carrying out a preset second form of beam forming operation on the complex matrix to obtain a plurality of second complex vectors;

and the azimuth angle-pitch angle combination generating unit is used for carrying out the beamforming operation of the first form on each second complex vector so as to obtain a plurality of azimuth angle-pitch angle combinations which are in one-to-one correspondence with the at least one target.

15. A storage medium having stored therein a plurality of instructions adapted to be loaded by a processor to perform the target azimuth and pitch angle measurement method of any one of claims 1 to 13.