Method for target angle estimation based on sparse reconstruction machine phase scanning radar space-time joint

Abstract

The application discloses a target angle estimation method based on sparse reconstruction machine phase scanning radar space-time joint, and the implementation steps are as follows: a two-dimensional absolute coordinate system is established; the echo signal of a to-be-detected target of a machine phase scanning radar antenna array in the two-dimensional absolute coordinate system is converted into space-time joint data; a sparse reconstruction algorithm is adopted to convert the sparse representation of the space-time joint data into a sparse space spectrum, so that the angle estimation value of the target is obtained. The target angle estimation method designed by the application can fully exert the advantages of the multi-channel of the machine phase scanning radar in a noise environment, can ensure low operation amount, and can greatly improve the accuracy and stability of the target angle estimation.

Description

Technical Field

[0001] This invention belongs to the field of radar technology, and more specifically relates to a target angle estimation method based on sparse reconstruction and joint space-time data in radar signal processing technology. This invention can be applied to mechanically scanned radar systems, using a sparse reconstruction algorithm on joint space-time data to achieve effective target angle estimation. Background Technology

[0002] Unlike phased array radars with fixed antenna arrays, mechanically scanned phased array radars achieve full airspace coverage through the mechanical rotation of the array, while also being able to manipulate the radar beam to track targets. Therefore, mechanically scanned phased array radars have the advantage of being able to detect targets in any direction using the normal beam of the array, without the antenna gain and detection accuracy loss caused by beam broadening. By reducing the number of antenna arrays, mechanically scanned phased array radars significantly reduce system costs, overcome the limitation of mechanically scanned radars having only one channel, and expand the scanning angle range of phased array radars. In recent years, this type of radar has received widespread attention.

[0003] Wan Cheng et al., in their paper "A Method for Estimating the Azimuth Angle of Key Targets Based on Mechanically Scanned Phased Array Radar" (Shipborne Electronic Countermeasures, 2021, 8, 44-4), proposed a method for estimating the azimuth angle of key targets using mechanically scanned phased array radar. The method involves using a one-dimensional phased array radar with simultaneous mechanical and azimuth electronic scanning. Digital multi-beam technology allows for the formation of multiple receiving beams in different azimuth ranges to cover a larger surveillance area. Accurate tracking of key targets requires consideration not only of the radar's rotational characteristics but also of the fact that the beam shape of the phased array radar varies in each azimuth. Therefore, a polynomial fitting method is first used to accurately model each beam in different azimuths, and then an amplitude comparison method is applied to estimate the azimuth angle of the key target under radar array rotation conditions. While this method can estimate the target angle, it still has two shortcomings: firstly, the angle estimation is based on the angle measurement mode of mechanically scanned radar, making it unsuitable for multi-channel scenarios with mechanically scanned phased array radar. Secondly, estimating the angle of a single target only can lead to the loss of other targets. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the existing technologies by proposing a target angle estimation method based on sparse reconfiguration mechanical phase-scanning radar with joint space-time operation. This method aims to solve the problem that existing technologies can only perform beam velocity scanning on key areas and only estimate the angle of a single target, resulting in the loss of other targets.

[0005] To achieve the above objectives, the present invention converts the spatial data of array elements received by multiple pulses from a mechanically scanned radar antenna into spatiotemporally concatenated data according to the receiving order. This data exhibits a regular change in the angle of the target relative to the antenna normal direction, resulting from the rotation of the random phase-scanned radar antenna array around the origin. Based on this change, a spatiotemporal joint basis vector is used to fit the spatiotemporal joint data, thereby achieving angle measurement by the mechanically scanned radar. This solves the problem that existing technologies are limited to the angle measurement mode of mechanically scanned radar. Furthermore, when estimating the target angle, after obtaining the target Doppler frequency, the present invention uses a sparse reconstruction algorithm to convert the spatiotemporal joint data into a sparse spatial spectrum, obtaining the spatial distribution of the target. The algorithm also strongly suppresses the sidelobes of the spatial spectrum, enabling clear sparse spatial spectral peaks of multiple targets when estimating their angles, thus solving the problem that existing technologies can only detect one target at a time.

[0006] To achieve the above objectives, the technical solution adopted by the invention includes the following steps:

[0007] Step 1: Establish a two-dimensional absolute coordinate system;

[0008] Step 2: Convert the received target echo signal from the two-dimensional absolute coordinate system phase-scanned radar antenna array into space-time joint data;

[0009] Step 3: Use the sparse reconstruction algorithm to transform the sparse representation of the spatiotemporal joint data into a sparse spatial spectrum to obtain the angle estimate of the target.

[0010] Compared with the prior art, the present invention has the following advantages:

[0011] First, because this invention fully utilizes the spatial and temporal information of mechanically scanned radar when detecting targets, and constructs spatiotemporally linked data, the data dimensionality is greatly reduced and the computational complexity is very low. This overcomes the shortcomings of existing technologies that are limited to the angle measurement mode of mechanically scanned radar. As a result, this invention can give full play to the advantages of the multi-channel of mechanically scanned radar, reduce the time cost of target angle measurement, and enhance the application value of this invention in engineering.

[0012] Secondly, because the present invention uses a sparse reconstruction algorithm to transform spatiotemporal joint data into a sparse spatial spectrum when estimating the target angle, it overcomes the shortcomings of existing technologies that can only detect one target. This enables the present invention to accurately estimate the angle value of the target while tracking multiple targets, thereby improving the accuracy of target angle estimation and obtaining more robust performance. Attached Figure Description

[0013] Figure 1 This is a flowchart of the present invention;

[0014] Figure 2This is a schematic diagram of the operation of a phase-scanning radar in an embodiment of the present invention, wherein... Figure 2 (a) is a schematic diagram of the mechanically scanned radar operating in the absolute coordinate system, and (b) is the first... The state of each pulse, 2(c) is the final working state of the mechanically scanned radar;

[0015] Figure 3 This is a simulation diagram of the present invention, wherein, Figure 3 (a) is the sparse space spectrum of the angle estimation of a single target in the simulation experiment of this invention. Figure 3 (b) is the sparse spatial spectrum of the estimated angles of two targets with the same Doppler frequency but different angles in the simulation experiment of this invention. Figure 3 (c) is the sparse space spectrum of the estimated angles of two targets with different Doppler frequencies and angles in the simulation experiment of this invention. Figure 3 (d) is the sparse space spectrum of the target angle estimation in the simulation experiment of this invention, where three targets have different angles, two of which have the same Doppler frequency. Figure 3 (e) is a graph showing the trend of the root mean square error of the target angle estimation with the detection signal-to-noise ratio for three targets with different angles, two of which have the same Doppler frequency, in the simulation experiment of this invention. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0017] Reference Figure 1 The implementation steps of the embodiments of the present invention will be described in further detail below.

[0018] Step 1, establish a two-dimensional absolute coordinate system as follows:

[0019] The first step is to establish a two-dimensional absolute coordinate system. , The horizontal axis represents the absolute coordinate system. The vertical axis represents the absolute coordinate system. Represents the origin of the absolute coordinate system;

[0020] The second step involves using the origin of the absolute coordinate system as the fulcrum for the mechanically scanned radar, and rotating the radar antenna array clockwise at a uniform speed around the origin. angle, The value of is equal to the beamwidth in the normal direction of the mechanically scanned radar antenna array.

[0021] The phase-scanning radar antenna array of the present invention can be selected with any array structure.

[0022] In this embodiment of the invention, the array structure selected is an equidistant linear array. (Refer to...) Figure 2(a) The process of receiving spatial signals from the equidistant linear array structure of the mechanically scanned radar according to an embodiment of the present invention is further described.

[0023] The center point of the equidistant linear array structure of the mechanically scanned radar antenna array in this embodiment of the invention coincides with the origin of its corresponding absolute coordinate system. The mechanically scanned radar antenna array along... Figure 2 The arrow in (a) rotates clockwise around the origin at a constant speed. angle. Figure 2 In (a), dashed lines 2, 3, and the dashed circle represent the absolute coordinate system. Figure 2 The dashed line in (a) represents the initial state of operation of a mechanically scanned radar with an equidistant linear array structure. The dashed line 1 in 2(a) represents the direction of the normal direction of the mechanically scanned radar antenna array in the absolute coordinate system during the initial state of operation. This represents the angle value of the normal direction of the phase-scanning radar antenna array in the absolute coordinate system under the initial state of operation. Figure 2 (a) The dashed line 1 in the middle represents the first... The direction of a target in the absolute coordinate system. Figure 2 (a) Representing the The angle value of each target in the absolute coordinate system. Figure 2 (a) The first phase of operation of the phase-scanned radar The angle value of a target relative to the normal direction of the machine-scanned radar antenna array. Figure 2 The solid line in (a) represents the final operating state of a mechanically scanned radar with an equidistant linear array structure. The solid line 1 in (a) represents the direction of the normal to the mechanically scanned radar antenna array in the absolute coordinate system during the final operating state. Figure 2 (a) This represents the angle value of the normal direction of the mechanically scanned radar antenna array in the absolute coordinate system in the final state of operation. In the initial state of operation, all targets are located near the normal direction of the mechanically scanned radar antenna array, the number of array elements is 14, and the element spacing is 0.57 times the carrier wavelength, receiving the target echo signal.

[0024] Step 2: Convert the received target echo signal from the two-dimensional absolute coordinate system phase-scanned radar antenna array into space-time joint data.

[0025] The echo signal of the target under test is as follows:

[0026] ;

[0027] in, This indicates that the mechanically scanned radar antenna array is in the... Each pulse received contains all the targets to be measured. echo signal, This indicates the total number of elements in the mechanically scanned radar antenna array. , This indicates that the mechanically scanned radar antenna array rotates clockwise around the radar fulcrum. The total number of pulses at the angle, The value of approximation integer values, This indicates the angle by which the mechanically scanned radar antenna array rotates clockwise around the radar pivot point within two adjacent pulses. This indicates that the mechanically scanned radar antenna array is in the... The total number of all targets under test received by each pulse. Indicates the serial number of the target to be tested. Indicates the first The target to be tested is in the first The angle between each pulse and the array normal direction is The guide vector, , Indicates the first pulse. The angle value of the target in the absolute coordinate system. This represents the angle value in the absolute coordinate system corresponding to the normal direction of the phase-scanned radar antenna array at the moment of the first pulse. Indicates the first The target to be tested is in the first The complex envelope of a pulse, , Indicates the first pulse. The complexity of a target to be tested. Represented by natural constant Index-based operations. The symbol representing the imaginary unit. Indicates the first The Doppler frequency of the target object to be measured Indicates the pulse repetition period. express noise vector, Represents the noise vector The row number, its value is equal to .

[0028] Reference Figure 2 (b) A further detailed description is given of the target echo signal received from the phase-scanned radar antenna array in a two-dimensional absolute coordinate system. Figure 2 In (b), the solid line 1 represents a mechanically scanned radar antenna array with an equidistant linear array structure in the [missing information - likely a specific configuration or step]. Position at the time of each pulse Figure 2 In (b), the dashed line 5 represents the position of the mechanically scanned radar antenna array with an equidistant linear array structure in the initial state of operation of the mechanically scanned radar. Figure 2 In (b), the dashed line 1 represents the first... The normal direction of the phase-scanned radar antenna array during each pulse is in the direction of the absolute coordinate system. Figure 2 (b) Representing the The angle value of the normal direction of the phase-scanned radar antenna array in the absolute coordinate system during each pulse. Figure 2 (b) The dashed line 4 represents the 4th rank. The direction of a target in the absolute coordinate system. Figure 2 (b) Representing the The angle value of each target in the absolute coordinate system. Figure 2 (b) Representing the The pulse number is... The angle value of a target relative to the normal direction of the machine-scanned radar antenna array. Figure 2 (b) Representing the The target to be tested is in the first... The angle between each pulse and the array normal direction is The guide vector. Figure 2 (b) Representative phased-scan radar passed through The angle value through which each pulse rotates around the origin.

[0029] Reference Figure 2 (c) A further detailed description is given of the target echo signal received from the phase-scanned radar antenna array in a two-dimensional absolute coordinate system. Figure 2 In (c), the solid line 1 represents the position of a mechanically scanned phased array radar antenna array with an equidistant linear array structure in its final operating state. Figure 2 In (c), the dashed line 4 represents the position of the mechanically scanned radar antenna array with an equidistant linear array structure in the initial state of operation of the mechanically scanned radar. Figure 2 In (c), the dashed line 1 represents the direction of the normal to the phase-scanned radar antenna array in the absolute coordinate system when the array is in its final operating state. Figure 2 (c) This represents the angle value of the normal direction of the phase-scanned radar antenna array in the absolute coordinate system when the array is in its final working state. Figure 2 (c) The dashed line at the midpoint 5 represents the first... The direction of a target in the absolute coordinate system. Figure 2 (c) Representing the The angle value of each target in the absolute coordinate system. Figure 2 (c) The final state of the representative phase-scanned radar antenna array The angle value of a target relative to the normal direction of the machine-scanned radar antenna array. Figure 2 (c) This represents the angle that the phase-scanning radar antenna array rotates around the origin from the initial state of the phase-scanning radar to the final state of the phase-scanning radar. Figure 2 (c) Representing the The angle of the target object relative to the normal direction of the array at the final operating state of the mechanically scanned radar antenna array is: The guide vector.

[0030] The spatiotemporal joint data is obtained by the following transformation:

[0031] ;

[0032] in, This represents the signal received from a mechanically scanned radar antenna array in a two-dimensional absolute coordinate system, containing all targets to be measured. The secondary target echo signal is converted into space-time combined data according to the receiving order. , This indicates that the mechanically scanned radar antenna array is in the... Each pulse received contains all the targets to be measured. echo signal, This indicates the transpose operation.

[0033] Step 3: Use the sparse reconstruction algorithm to transform the sparse representation of the spatiotemporal joint data into a sparse spatial spectrum to obtain the angle estimate of the target.

[0034] The sparse representation of the spatiotemporal joint data is as follows:

[0035] ;

[0036] in, Represents the spatiotemporal joint data in sparse space 3D vector The value is equal to , The value is equal to , express A dictionary matrix of dimension 1. express sparse space spectrum, The value is equal to , The value is equal to , , , ;

[0037] The dictionary matrix , , , In absolute coordinate system The number of angular grids equally spaced within the space. This represents the total number of non-repeating frequency values ​​among all the Doppler frequencies of the target obtained by the mechanically scanned radar during the target detection process; Represents the space-time joint basis vector in the dictionary matrix; , , Indicates the first The angle grid at the first angle is... The angle between each pulse and the array normal direction is The guide vector, Indicates the first The angle grid at the first angle is... The angle value relative to the normal direction of the mechanically scanned radar antenna for each pulse. , Indicates the first The angle values ​​of each angle grid in the absolute coordinate system. This represents the first of all Doppler frequencies of the target to be measured. One non-repeating frequency value.

[0038] The sparse reconstruction algorithm refers to using convex optimization tools to solve the following equation to obtain the sparse space spectrum:

[0039] ;

[0040] in, This indicates the operation of finding the minimum value. This represents the 2-norm operation. Represents the regularization parameter. Take a norm operation.

[0041] The angle estimate of the target is obtained by the following formula:

[0042] ;

[0043] in, This represents the estimated angle of the target obtained from the sparse spatial spectrum. , This indicates the operation of searching for all local maxima greater than -20dB and obtaining the corresponding angle values. This represents the logarithm operation with base 10. This indicates a modulo operation. Represents the first in the sparse space spectrum One element, , The value is equal to , This represents the maximum element modulus among all element moduli in the sparse space spectrum. , This indicates the operation of taking the maximum value.

[0044] The effects of this invention will be further explained below with reference to simulation experiments:

[0045] 1. Simulation experimental conditions.

[0046] The simulation experiment of this invention was conducted with an Intel(R) Core(TM) i9-13900HX CPU@5.40GHz and 64G of memory.

[0047] The software platform for the simulation experiment of this invention is: Windows 11 operating system and MATLAB R2023a.

[0048] 2. Simulation Content and Result Analysis

[0049] The simulation experiments of this invention were conducted using the method of this invention, and a total of five simulation experiments were carried out in a Gaussian white noise environment.

[0050] Simulation Experiment 1 is a simulation of angle estimation for a single target, specifically, a single-pulse beamforming experiment using the method of this invention in a Gaussian white noise environment, with a signal-to-noise ratio of [value missing] after beamforming with 14 elements. The sparse spatial spectrum of the single target angle estimation is shown in the following figure. Figure 3 The curve shown in (a).

[0051] The mechanically scanned radar antenna array used in simulation experiment 1 of this invention is an equidistant linear array with the phase reference point at the array center. The total number of array elements is 14, the element spacing is 0.57 times the carrier wavelength, and the beamwidth in the normal direction of the mechanically scanned radar antenna array is... The angle by which the mechanically scanned radar antenna array rotates clockwise around the radar pivot point within two adjacent pulses is [value missing]. Mechanically scanned radar pulse repetition period Mechanically scanned radar pulse repetition frequency carrier wavelength m, element spacing The angle of the target in the absolute coordinate system is The Doppler frequency of the target is The target's complex amplitude is 1, and the mechanically scanned radar antenna array rotates clockwise around the radar's pivot point. The total number of pulses is 89.

[0052] Simulation Experiment 2 simulates the angle estimation of two targets with different angles but the same Doppler frequency. Specifically, it simulates the signal-to-noise ratio of a single pulse beamformer with 14 elements in a noisy environment, achieved using the method of this invention. The sparse spatial spectrum of the target angle estimation for two targets with different angles but the same Doppler frequency is shown in the figure. Figure 3 The curve shown in (b).

[0053] The angle of the first target in the absolute coordinate system used in simulation experiment 2 is... The Doppler frequency of the first target is The angle of the second target in the absolute coordinate system is The Doppler frequency of the second target is The complex amplitude of both targets is 1, and other parameters are the same as in simulation experiment 1.

[0054] Simulation Experiment 3 simulates the angle estimation of two targets with different angles and Doppler frequencies. Specifically, it simulates the signal-to-noise ratio of a single pulse beamformer with 14 elements in a noisy environment, achieved using the method of this invention. The sparse spatial spectrum of the target angle estimates at two different angles and different Doppler frequencies is plotted as follows: Figure 3 The two curves shown in (c).

[0055] The angle of the first target in the absolute coordinate system used in simulation experiment 3 is... The Doppler frequency of the first target is The angle of the second target in the absolute coordinate system is The Doppler frequency of the second target is The complex amplitude of both targets is 1, and other parameters are the same as in simulation experiment 1.

[0056] Simulation Experiment 4 simulates the angle estimation of three targets with different angles, two of which have the same Doppler frequency. Specifically, it simulates the signal-to-noise ratio of a single-pulse beamformer with 14 elements in a noisy environment after beamforming using the method of this invention. The sparse spatial spectrum of target angle estimates for three targets with different angles, two of which have the same Doppler frequency, is plotted as follows: Figure 3 The two curves shown in (d).

[0057] The angle of the first target in the absolute coordinate system used in simulation experiment 4 is... The Doppler frequency of the first target is The angle of the second target in the absolute coordinate system is The Doppler frequency of the second target is The angle of the third target in the absolute coordinate system is The Doppler frequency of the third target is The complex amplitude of all three targets is 1, and other parameters are the same as in simulation experiment 1.

[0058] Simulation Experiment 5 simulates the root mean square error of angle estimation for three targets with different angles, two of which have the same Doppler frequency. Specifically, it simulates the signal-to-noise ratio range of a single pulse beamformer with 14 elements in a noisy environment after beamforming using the method of this invention. The root mean square error of the target angle estimation for three targets with different angles, two of which have the same Doppler frequency, is plotted as a function of the signal-to-noise ratio. Figure 3 The curve shown in (d).

[0059] The angle of the first target in the absolute coordinate system used in simulation experiment 5 is... The Doppler frequency of the first target is The angle of the second target in the absolute coordinate system is The Doppler frequency of the second target is The angle of the third target in the absolute coordinate system is The Doppler frequency of the third target is The complex amplitudes of the three targets are all 1, and the signal-to-noise ratio range after beamforming of the single pulse and 14 elements is [value missing]. The number of Monte Carlo experiments was 1000, and other parameters were the same as those in simulation experiment 1.

[0060] The following is combined Figure 2 The simulation diagrams further illustrate the effects of the present invention.

[0061] Figure 3 (a) The horizontal axis represents the scanning angle range, and the vertical axis represents the amplitude, with the unit being dB. Figure 3 In (a), the solid line represents the sparse space spectrum of a target. From Figure 3 As can be seen in (a), the peaks of the sparse space spectrum are sharp, and the angle values ​​corresponding to the peaks can be clearly obtained, indicating that the target angle estimation method of the present invention has stable performance.

[0062] Figure 3 (b) The horizontal axis represents the scanning angle range, and the vertical axis represents the amplitude, with the unit being dB. Figure 3 The solid line in (b) represents the sparse spatial spectrum of two targets with different angles but the same Doppler frequency. From Figure 3 As can be seen in (b), when there are two or more targets with the same Doppler frequency, the peak of the sparse space spectrum is sharp, and the angle value corresponding to the peak can be clearly obtained. Furthermore, the region between the peaks is obviously concave, indicating that the target angle estimation method of the present invention has stable performance.

[0063] Figure 3 (c) The horizontal axis represents the scanning angle range, and the vertical axis represents the amplitude, with the unit being dB. Figure 3 In (c), the solid line represents the sparse spatial spectrum of a target with a Doppler frequency of 170 Hz, and the dashed line represents the sparse spatial spectrum of a target with a Doppler frequency of 70 Hz. From... Figure 3 As can be seen in (c), when there are two or more targets with different Doppler frequencies, the peak of the sparse space spectrum is sharp, and the angle value corresponding to the peak can be clearly obtained, indicating that the target angle estimation method of the present invention has stable performance.

[0064] Figure 3 (d) The horizontal axis represents the scanning angle range, and the vertical axis represents the amplitude, with the unit being dB. Figure 3 In (c), the solid line represents the sparse spatial spectrum of the target with a Doppler frequency of 170 Hz, and the dashed line represents the sparse spatial spectrum of the target with a Doppler frequency of 70 Hz. From... Figure 3 As can be seen from (d), the peaks of the sparse space spectrum are sharp, and the angle values ​​corresponding to the peaks can be clearly obtained, indicating that the target angle estimation method of the present invention has stable performance.

[0065] Figure 3 (e) The horizontal axis represents the detection signal-to-noise ratio in dB, and the vertical axis represents the root mean square error. Figure 3 The solid line in (d) represents the relationship between the root mean square error of multi-target angle estimation and the signal-to-noise ratio obtained using the method proposed in this invention. From... Figure 3 (e) It can be seen that as the signal-to-noise ratio increases, the root mean square error of angle measurement tends to zero. For example... Figure 3 (d) It can be seen that the target angle estimation method of the present invention has accurate angle measurement performance.

Claims

1. A target angle estimation method based on sparse reconfiguration mechanical phase-scanning radar with joint space-time operation, characterized in that, The steps of this method include the following: Step 1: Establish a two-dimensional absolute coordinate system. The steps are as follows: The first step is to establish a two-dimensional absolute coordinate system. , The horizontal axis represents the absolute coordinate system. The vertical axis represents the absolute coordinate system. Represents the origin of the absolute coordinate system; The second step involves using the origin of the absolute coordinate system as the fulcrum for the mechanically scanned radar, and rotating the radar antenna array clockwise at a uniform speed around the origin. angle, The value of is equal to the beamwidth in the normal direction of the mechanically scanned radar antenna array; Step 2: Convert the received target echo signal from the two-dimensional absolute coordinate system phase-scanned radar antenna array into space-time joint data; The echo signal of the target under test is as follows: ； in, This indicates that the mechanically scanned radar antenna array is in the... Each pulse received contains all the targets to be measured. echo signal, This indicates the total number of elements in the mechanically scanned radar antenna array. , This indicates that the mechanically scanned radar antenna array rotates clockwise around the radar fulcrum. The total number of pulses at the angle, The value of approximation integer values, This indicates the angle by which the mechanically scanned radar antenna array rotates clockwise around the radar pivot point within two adjacent pulses. This indicates that the mechanically scanned radar antenna array is in the... The total number of all targets under test received by each pulse. Indicates the serial number of the target to be tested. Indicates the first The target to be tested is in the first The angle between each pulse and the array normal direction is The guide vector, , Indicates the first pulse. The angle value of the target in the absolute coordinate system. This represents the angle value in the absolute coordinate system corresponding to the normal direction of the phase-scanned radar antenna array at the moment of the first pulse. Indicates the first The target to be tested is in the first The complex envelope of a pulse, , Indicates the first pulse. The complexity of the target to be tested, Represented by natural constant Index-based operations. The symbol representing the imaginary unit. Indicates the first The Doppler frequency of the target object to be measured Indicates the pulse repetition period. express noise vector, Represents the noise vector The row number, its value is equal to ; The spatiotemporal joint data is obtained by the following transformation: ； in, This represents the signal received from a mechanically scanned radar antenna array in a two-dimensional absolute coordinate system, containing all targets to be measured. The secondary target echo signal is converted into space-time combined data according to the receiving order. , This indicates that the mechanically scanned radar antenna array is in the... Each pulse received contains all the targets to be measured. echo signal, Indicates the transpose operation; Step 3: Using a sparse reconstruction algorithm, the sparse representation of the spatiotemporal joint data is transformed into a sparse spatial spectrum to obtain the target's angle estimate. The sparse expression for the spatiotemporal joint data is as follows: ； in, Represents the spatiotemporal joint data in sparse space 3D vector The value is equal to , The value is equal to , express A dictionary matrix of dimension 1. express sparse space spectrum, The value is equal to , The value is equal to , , , ; The dictionary matrix , , , In absolute coordinate system The number of angular grids equally spaced within the space. This represents the total number of non-repeating frequency values ​​among all the Doppler frequencies of the target obtained by the mechanically scanned radar during the target detection process; Represents the space-time joint basis vector in the dictionary matrix; , , Indicates the first The angle grid at the first angle is... The angle between each pulse and the array normal direction is The guide vector, Indicates the first The angle grid at the first angle is... The angle value relative to the normal direction of the mechanically scanned radar antenna for each pulse. , Indicates the first The angle values ​​of each angle grid in the absolute coordinate system. This represents the first of all Doppler frequencies of the target to be measured. One non-repeating frequency value.

2. The target angle estimation method based on sparse reconstruction mechanical phase-scanning radar space-time joint method according to claim 1, characterized in that, The sparse reconstruction algorithm mentioned in step 3 refers to using convex optimization tools to solve the following equation to obtain the sparse space spectrum: ； in, This indicates the operation of finding the minimum value. This represents the 2-norm operation. Represents the regularization parameter. Take a norm operation.

3. The target angle estimation method based on sparse reconstruction mechanical phase-scanning radar space-time joint method according to claim 1, characterized in that, The target angle estimate mentioned in step 3 is obtained by the following formula: ； in, This represents the estimated angle of the target obtained from the sparse spatial spectrum. , This indicates the operation of searching for all local maxima greater than -20dB and obtaining the corresponding angle values. This represents the logarithm operation with base 10. This indicates a modulo operation. Represents the first in the sparse space spectrum One element, , The value is equal to , This represents the maximum element modulus among all element moduli in the sparse space spectrum. , This indicates the operation of taking the maximum value.

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