A radar multi-domain agile waveform design method and its sparse recovery processing method

Abstract

The present invention relates to the field of radar agile waves, and specifically to a radar multi-domain agile waveform design method and a sparse recovery processing method thereof, which perform multi-domain agility based on inter-pulse repetition frequency, operating carrier frequency and transmitting antenna sequence; the radar multi-domain agile waveform sparse recovery processing method utilizes sparse prior information of targets in the scene to be observed to accurately reconstruct target parameters; through the scheme of the present invention, the radar anti-interference capability is effectively improved, the radar electromagnetic compatibility potential is enhanced, the range resolution, velocity resolution, angle resolution and velocity deambiguation performance of the waveform are improved, the underdetermined estimation problem caused by undersampling of the agile waveform is solved, the high sidelobe phenomenon caused by traditional matching processing methods is avoided, and high-precision estimation of target parameters can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of radar agile waves, and in particular to a radar multi-domain agile waveform design method and a sparse recovery processing method thereof. Background Art

[0002] Agile waveforms are an effective way to improve radar anti-interference and enhance radar detection capabilities. Compared to traditional radar fixed-parameter waveforms, agile waveforms reduce the probability of interception of effective radar signals and improve radar anti-interference capabilities by nonlinearly modulating waveform parameters in dimensions such as operating carrier frequency, signal coding, and polarization. Furthermore, the increased degrees of observation freedom provided by waveform parameter agility lays the foundation for high-resolution radar detection. However, current research on radar agile waveforms has largely remained focused on single-domain agility, resulting in low waveform degrees of freedom and room for improvement in anti-interference capabilities and detection performance.

[0003] For the coherent processing of agile waveforms, the traditional matched filtering method has low computational complexity and stable calculation results. However, due to the multi-domain agility, the echo signal has random data missing in each dimension. The matched filtering method will cause underdetermined estimation problems and high sidelobes, that is, random fluctuations of noise-like sidelobes (pseudo-peaks) appear in the estimated spectrum. When the amplitude of the pseudo-peak is large, it may be mistaken for a small target and cause false alarms, or it may also mask other weak targets. Summary of the Invention

[0004] Aiming at the problems of low degree of freedom, anti-interference capability and detection performance of the current agile joint waveform, a radar multi-domain agile waveform design method and a sparse recovery processing method thereof are provided to improve target detection performance and suppress sidelobes.

[0005] To solve the above technical problems, the present invention provides a radar multi-domain agile waveform design method, which constructs a multi-domain agile waveform coding mode with inter-pulse repetition frequency coding, working carrier frequency coding, and transmitting antenna sequence coding. The required waveform parameters are designed according to the target scene detection requirements, and the echo signal is obtained through the multi-domain agile waveform coding mode.

[0006] Among them, the inter-pulse repetition frequency coding is constructed and the repetition frequency jitter parameters are designed according to the speed measurement range required by the target scene. The following steps are used: Based on the classic pulse radar waveform, the starting time of each pulse is randomly jittered before and after the fixed pulse repetition interval, and the interval between two adjacent pulses after the inter-pulse repetition frequency is set to T l , Define the undersampling factor as The number of time domain undersampling points is N = Lγ, and the maximum unambiguous speed of the waveform after repetition frequency jitter is the maximum unambiguous speed determined by ξ; it is required that two adjacent pulses do not overlap in time, and the design is based on the above criteria and ξ;

[0007] Where T is the fixed pulse repetition interval; is the time control code word of the lth pulse, and Within the value range, it obeys independent and identical distribution; ξ is the minimum time jitter interval; L is the number of pulses; γ is the wavelength; T l is the interval between two adjacent pulses;

[0008] Constructing pulse working carrier frequency coding and designing carrier frequency agility parameters according to the distance resolution required by the target scene include: setting the working carrier frequency of the first pulse to f l , The maximum value of is M, and the resolution of fine range image is The pulse bandwidth is required to be greater than the minimum frequency modulation interval and is designed according to the above standards. with Δf;

[0009] Among them, f0 is the initial carrier frequency; is the frequency control codeword of the lth pulse, which obeys independent and identical distribution within the value range; Δf is the minimum frequency hopping interval; M is the number of carrier frequency agility points, M is given by Determine; c is the speed of light;

[0010] Construct pulse transmitting antenna sequence coding and design spatial agility parameters according to the side angle accuracy of the target scene. The parameters include: based on the time division multiplexing MIMO equally spaced linear array system, the transmitting antenna transmits according to the sequence number, and the path difference between two adjacent pulses caused by the transmitting antenna is d l , The angular resolution is The angular resolution is determined by H; the number of transmitting and receiving antennas is determined based on the above criteria;

[0011] where d t is the distance between adjacent transmitting antennas; is the spatial control codeword, The value range is independent and identically distributed; θ is the azimuth; H is the number of virtual channels defined, that is, the product of the number of transmitting antennas and receiving antennas; where d r represents the distance between adjacent receiving antennas; λ represents the wavelength.

[0012] Furthermore, the multi-domain agile waveform coding mode is jointly implemented. According to the designed coding mode, there are I receiving array elements. After down-mixing and ignoring the high-order phase terms, the echo signal of the i-th receiving array element obtained by the l-th pulse of the point target in the multi-domain agile waveform coding mode can be expressed as:

[0013]

[0014] Where α(t) represents the baseband signal; t represents the fast time; R0, v, and θ represent the distance, speed, and azimuth angle of the target, respectively; t l represents the starting time of the first pulse; c is the speed of light; f l is the operating carrier frequency of the first pulse; d l is the path difference between two adjacent pulses caused by the transmitting antenna; d r represents the distance between adjacent receiving antennas.

[0015] A radar multi-domain agile waveform sparse recovery processing method based on a radar multi-domain agile waveform design method includes the following steps:

[0016] S1. Designing a selection matrix according to the multi-domain agile waveform coding mode, and multiplying the selection matrix with the Fourier basis matrix to obtain an observation matrix;

[0017] S2. According to the number of targets in the target scene, select the corresponding sparsity, input the echo signal and the measurement matrix into the subspace tracking algorithm for sparse recovery, and obtain the distance, speed, and angle information of the target.

[0018] Furthermore, in step S1, a sparse recovery processing method is used to accurately reconstruct the target parameters using the sparse prior information of the target in the scene to be observed. The abstract formula is:

[0019] y=Bx

[0020] Among them, y is the echo signal; x is the spectrum to be estimated, which is a column vector; B is the observation matrix;

[0021] The measurement matrix B=ΦΨ, where Φ is a selection matrix, and the elements in the selection matrix take values ​​from 0 or 1; Ψ is a Fourier basis matrix;

[0022] The Fourier basis matrix is:

[0023]

[0024] Where E = e -j2π / NMH The three-dimensional Fourier basis matrices of the multi-domain agile waveform coding are Kronecker products to form Ψ, and the number of rows and columns of the Fourier basis matrix of the multi-domain agile waveform coding are N, M, and H respectively.

[0025] Substituting B = ΦΨ, we can obtain the relationship between the echo signal and the spectrum to be estimated:

[0026] y=ΦΨx=Bx

[0027] Furthermore, in step S2, a subspace tracking algorithm is used to perform sparse recovery processing, and the steps are as follows:

[0028] S201. Input K, B, and y, where K is the target sparsity, i.e., the maximum index number;

[0029] S202. Find Γ (0) ={In B H The indices of the K elements with the largest absolute values ​​in y};

[0030] S203, let Bt0 = {Γ (0) The corresponding K column of B};

[0031] S204, let the residual r (0) =y-Bt0x0;

[0032] Among them, x0 is the least squares solution:

[0033] S205, set the initial value q=0;

[0034] S206, start loop, q=q+1;

[0035] S207, Γ (q) ={In B H r (q-1) The indices of the K elements with the largest absolute values ​​in};

[0036] S208, Bt q ={Γ (q) The corresponding K column of B};

[0037] S209, solve using the least squares method:

[0038] S210, residual r (q) =y-Bt q x q ;

[0039] S211, when ‖r (q) ‖2>‖r (q-1) ‖2, end the loop;

[0040] S212, output x q , the x q is the vector to be estimated, x q It is expanded into three two-dimensional matrices, namely speed-high-resolution distance dimension, speed-angle dimension, and angle-high-resolution distance dimension. The distance, speed, and angle of the target can be determined by the peak value.

[0041] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0042] (1) The present invention designs a multi-domain agile waveform coding mode, which further improves the randomness of the waveform, reduces the probability of radar signal being intercepted, and thus improves the radar's anti-interference capability and enhances the radar's electromagnetic compatibility potential; at the same time, through the freedom of random agile decoupling of inter-pulse repetition coding-transmitting antenna sequence coding and inter-pulse repetition coding-operating carrier frequency coding, the waveform's distance resolution, velocity resolution, angle resolution and velocity deambiguation performance can also be effectively improved.

[0043] (2) The present invention is based on the multi-domain parameters of inter-pulse repetition coding-working carrier frequency coding-transmitting antenna sequence coding. After the high resolution of the agile waveform, the target spatial distribution presents a sparse characteristic. The subspace tracking algorithm is used to restore the incomplete data set of inter-pulse repetition coding-working carrier frequency coding-transmitting antenna sequence coding, solve the underdetermined estimation problem caused by undersampling of the agile waveform, avoid the high sidelobe phenomenon caused by the traditional matching processing method; and can achieve high-precision estimation of the target parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0045] Figure 2 This is a schematic diagram of the classic pulse radar waveform;

[0046] Figure 3 is a joint coding diagram of a multi-domain agile waveform of the present invention;

[0047] Figure 4 It is a schematic diagram of the selection matrix of the present invention;

[0048] Figure 5 This is a schematic diagram of the traditional velocity-high-resolution distance dimension matched filtering results;

[0049] Figure 6 This is a schematic diagram of the speed-high resolution distance dimension sparse recovery result of the present invention;

[0050] Figure 7 This is a schematic diagram of the traditional velocity-angle dimension matched filtering results;

[0051] Figure 8 This is a schematic diagram of the velocity-angle dimension sparse recovery result of the present invention;

[0052] Figure 9 This is a schematic diagram of the traditional angle-high resolution distance dimension matched filtering results;

[0053] Figure 10 This is a schematic diagram of the angle-high-resolution distance dimension sparse recovery results of the present invention. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0055] The present invention designs a random agility mode based on the three-dimensional combination of inter-pulse repetition coding, working carrier frequency coding, and transmitting antenna sequence coding of MIMO radar to increase the waveform freedom, improve the anti-interference ability and detection performance; and based on the sparse recovery idea, adopts the subspace tracking algorithm to recover the missing sampling information and solve the underdetermined estimation problem in traditional processing.

[0056] The technical idea of ​​the invention is: first, construct a multi-domain agile coded transmission mode, and design waveform parameters according to the target scene to establish a signal model; based on the processing idea of ​​sparse recovery, construct an observation matrix corresponding to the echo signal; use the sparse prior information of the target in the scene to be observed, and adopt the subspace tracking algorithm to complete the accurate reconstruction of the target parameters, so as to achieve the purpose of suppressing sidelobes, improving target detection performance and avoiding interference.

[0057] The present invention provides a radar multi-domain agile waveform design method, constructs a multi-domain agile waveform coding mode of inter-pulse repetition coding, working carrier frequency coding and transmitting antenna sequence coding, designs the required waveform parameters according to the target scene detection requirements, and obtains the echo signal through the multi-domain agile waveform coding mode.

[0058] Specifically, the inter-pulse repetition frequency coding is constructed and the repetition frequency jitter parameters are designed according to the speed measurement range required by the target scene. The following steps are used: Based on the classic pulse radar waveform, the starting time of each pulse is randomly jittered before and after the fixed pulse repetition interval, and the interval between two adjacent pulses after the inter-pulse repetition frequency is set to T l , Define the undersampling factor as The number of time domain undersampling points is N = Lγ, and the maximum unambiguous speed of the waveform after repetition frequency jitter is the maximum unambiguous speed determined by ξ; it is required that two adjacent pulses do not overlap in time, and the design is based on the above criteria and ξ;

[0059] Where T is the fixed pulse repetition interval; is the time control code word of the lth pulse, and Within the value range, it obeys independent and identical distribution; ξ is the minimum time jitter interval; L is the number of pulses; γ is the wavelength; T l is the interval between two adjacent pulses.

[0060] Specifically, the construction of pulse working carrier frequency coding and the design of carrier frequency agility parameters according to the distance resolution required by the target scene include: setting the working carrier frequency of the lth pulse to f l , The maximum value of is M, and the resolution of fine range image is The pulse bandwidth is required to be greater than the minimum frequency modulation interval and is designed according to the above standards. with Δf;

[0061] Among them, f0 is the initial carrier frequency; is the frequency control codeword of the lth pulse, which obeys independent and identical distribution within the value range; Δf is the minimum frequency hopping interval; M is the number of carrier frequency agility points, M is given by Determine; c is the speed of light.

[0062] Specifically, the pulse transmitting antenna sequence coding is constructed and the spatial agility parameters are designed according to the side angle accuracy of the target scene. The following are based on the time division multiplexing MIMO equally spaced linear array system. The transmitting antenna transmits according to the sequence number. The path difference between two adjacent pulses caused by the transmitting antenna is d l , The angular resolution is The angular resolution is determined by H; the number of transmitting and receiving antennas is determined based on the above criteria;

[0063] where d t is the distance between adjacent transmitting antennas; is the spatial control codeword, The value range is independent and identically distributed; θ is the azimuth; H is the number of virtual channels defined, that is, the product of the number of transmitting antennas and receiving antennas; where d r represents the distance between adjacent receiving antennas; λ represents the wavelength.

[0064] Specifically, the multi-domain agile waveform coding mode is jointly implemented. According to the designed coding mode, there are I receiving array elements. After down-mixing and ignoring the high-order phase terms, the echo signal of the i-th receiving array element obtained by the l-th pulse of the point target in the multi-domain agile waveform coding mode can be expressed as:

[0065]

[0066] Where α(t) represents the baseband signal; t represents the fast time; R0, v, and θ represent the distance, speed, and azimuth angle of the target, respectively; t l represents the starting time of the first pulse; c is the speed of light; f l is the operating carrier frequency of the first pulse; d l is the path difference between two adjacent pulses caused by the transmitting antenna; d r represents the distance between adjacent receiving antennas.

[0067] A radar multi-domain agile waveform sparse recovery processing method based on a radar multi-domain agile waveform design method includes the following steps:

[0068] S1. Design a selection matrix according to the multi-domain agile waveform coding mode, and obtain an observation matrix by multiplying the selection matrix and the Fourier basis matrix;

[0069] S2. According to the number of targets in the target scene, select the corresponding sparsity, input the echo signal and observation matrix into the subspace tracking algorithm for sparse recovery, and obtain the target's distance, speed, and angle information.

[0070] Specifically, step S1 adopts a sparse recovery method to accurately reconstruct the target parameters using the sparse prior information of the target in the scene to be observed. The abstract formula is:

[0071] y=Bx

[0072] Among them, y is the echo signal; x is the spectrum to be estimated, which is a column vector; B is the observation matrix;

[0073] The measurement matrix B=ΦΨ, where Φ is a selection matrix, and the elements in the selection matrix take values ​​from 0 or 1; Ψ is a Fourier basis matrix;

[0074] The Fourier basis matrix is:

[0075]

[0076] Where E = e -j2π / NMH , the three-dimensional Fourier basis matrices of the multi-domain agile waveform coding are Kronecker products to form Ψ, and the number of rows and columns of the Fourier basis matrix of the multi-domain agile waveform coding are N, M, and H respectively;

[0077] Substituting B = ΦΨ, we can obtain the relationship between the echo signal and the spectrum to be estimated:

[0078] y=ΦΨx=Bx

[0079] Specifically, in step S2, the subspace tracking algorithm is used to perform sparse recovery processing, and the steps are as follows:

[0080] S201. Input K, B, and y, where K is the target sparsity, i.e., the maximum index number;

[0081] S202. Find Γ (0) ={In B H The indices of the K elements with the largest absolute values ​​in y};

[0082] S203, let Bt0 = {Γ (0) The corresponding K column of B};

[0083] S204, let the residual r (0) =y-Bt0x0;

[0084] Among them, x0 is the least squares solution:

[0085] S205, set the initial value q=0;

[0086] S206, start loop, q=q+1;

[0087] S207, Γ (q) ={In B H r (q-1) The indices of the K elements with the largest absolute values ​​in};

[0088] S208, Bt q ={Γ (q) The corresponding K column of B};

[0089] S209, solve using the least squares method:

[0090] S210, residual r (q) =y-Bt q x q ;

[0091] S211, when ‖r (q) ‖2>‖r (q-1) ‖2, end the loop;

[0092] S212, output x q , the x q is the vector to be estimated, x q It is expanded into three two-dimensional matrices, namely speed-high-resolution distance dimension, speed-angle dimension, and angle-high-resolution distance dimension. The distance, speed, and angle of the target can be determined by the peak value.

[0093] Example:

[0094] The radar echo used in this example contains one target, with a target velocity V = 20 m / s, a distance R0 = 35.27 m, and an angle θ = 10°. The waveform parameters are configured as follows based on the target parameters and the design criteria in step S1 above (where the selection of each pulse time control codeword, frequency control codeword, and spatial control codeword follows a uniform distribution).

[0095] Parameter selection:

[0096] Number of pulses L = 64

[0097] Carrier frequency agility points M = 9

[0098] ·Number of time domain undersampling points N=3

[0099] Carrier frequency f0 = 10 GHz

[0100] Bandwidth B = 150 MHz

[0101] Fixed pulse repetition interval PRT = 240us

[0102] Sampling rate f s =10GHz

[0103] Number of transmitting elements nt = 3

[0104] Number of receiving elements I = 4

[0105] Receiving antenna spacing

[0106] Distance d between adjacent transmitting antennas t =4×d r =0.0076m

[0107] Minimum frequency hopping interval Δf = 150 MHz

[0108] Minimum time jitter interval ξ=80us

[0109] Sparsity K = 1

[0110] The processing is performed according to steps S1-S2 of a sparse recovery processing method for radar multi-domain agile waveform.

[0111] Experimental results:

[0112] like Figure 5-10 The figures show the results of traditional multi-domain agile waveform filtering and the sparse recovery of the multi-domain agile waveform of the present invention. Comparing the results shows a significant improvement in the range resolution and velocity measurement range of the waveform, indicating that the multi-domain agile waveform designed by the present invention has better detection performance than traditional waveforms. Furthermore, the subspace tracking algorithm can address the underdetermined estimation problem caused by this waveform, suppressing sidelobes and achieving multi-dimensional, high-precision estimation of target parameters.

[0113] The above content is a further detailed description of the present invention in conjunction with specific embodiments, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A radar multi-domain agile waveform design method, characterized by: Construct a multi-domain agile waveform coding mode with inter-pulse repetition frequency coding, working carrier frequency coding, and transmitting antenna sequence coding. Design the required waveform parameters according to the target scene detection requirements, and obtain the echo signal through the multi-domain agile waveform coding mode. Among them, the inter-pulse repetition frequency coding is constructed and the repetition frequency jitter parameters are designed according to the speed measurement range required by the target scene. The following steps are used: Based on the classic pulse radar waveform, the starting time of each pulse is randomly jittered before and after the fixed pulse repetition interval, and the interval between two adjacent pulses after the inter-pulse repetition frequency is set to T l , Define the undersampling factor as The number of time domain undersampling points is N = Lγ, and the maximum unambiguous speed of the waveform after repetition frequency jitter is the maximum unambiguous speed determined by ξ; it is required that two adjacent pulses do not overlap in time, and the design is based on the above criteria and ξ; Where T is the fixed pulse repetition interval; is the time control code word of the lth pulse, and It obeys independent and identical distribution within the value range; ξ is the minimum time jitter interval; L is the number of pulses; λ is the wavelength; T l is the interval between two adjacent pulses; Constructing the working carrier frequency coding and designing the carrier frequency agility parameters according to the distance resolution required by the target scene include: setting the working carrier frequency of the lth pulse to f l , The maximum value of is M, and the resolution of fine range image is The pulse bandwidth is required to be greater than the minimum frequency modulation interval and is designed according to the above standards. with Δf; Among them, f0 is the initial carrier frequency; is the frequency control codeword of the lth pulse, which obeys independent and identical distribution within the value range; Δf is the minimum frequency hopping interval; M is the number of carrier frequency agility points, M is given by Determine; c is the speed of light; Construct the transmitting antenna sequence coding and design the spatial agility parameters according to the side angle accuracy of the target scene. The parameters include: based on the time division multiplexing MIMO equally spaced linear array system, the transmitting antenna transmits according to the sequence number, and the path difference between two adjacent pulses caused by the transmitting antenna is d l , The angular resolution is The angular resolution is determined by H; the number of transmitting and receiving antennas is determined based on the above criteria; where d t is the distance between adjacent transmitting antennas; is the spatial control codeword, The value range is independent and identically distributed; θ is the azimuth; H is the number of virtual channels defined, that is, the product of the number of transmitting antennas and receiving antennas; where d r represents the distance between adjacent receiving antennas; λ represents the wavelength.

2. The radar multi-domain agile waveform design method according to claim 1, characterized in that: The multi-domain agile waveform coding mode is jointly implemented. According to the designed coding mode, there are I receiving array elements. After down-mixing and ignoring the high-order phase terms, the echo signal of the i-th receiving array element obtained by the l-th pulse of the point target in the multi-domain agile waveform coding mode can be expressed as: Where α(t) represents the baseband signal; t represents the fast time; R0, v, and θ represent the distance, speed, and azimuth angle of the target, respectively; t l represents the starting time of the first pulse; c is the speed of light; f l is the operating carrier frequency of the first pulse; d l is the path difference between two adjacent pulses caused by the transmitting antenna; d r represents the distance between adjacent receiving antennas.

3. A radar multi-domain agile waveform sparse recovery processing method based on the radar multi-domain agile waveform design method according to any one of claims 1-2, characterized in that: The following steps are involved: S1. Designing a selection matrix according to the multi-domain agile waveform coding mode, and multiplying the selection matrix with the Fourier basis matrix to obtain an observation matrix; S2. According to the number of targets in the target scene, select the corresponding sparsity, input the echo signal and the measurement matrix into the subspace tracking algorithm for sparse recovery, and obtain the distance, speed, and angle information of the target.

4. The radar multi-domain agile waveform sparse recovery processing method according to claim 3, characterized in that: In step S1, a sparse recovery method is used to accurately reconstruct the target parameters using the sparse prior information of the target in the scene to be observed. The abstract formula is: y=Bx Among them, y is the echo signal; x is the spectrum to be estimated, which is a column vector; B is the observation matrix; The measurement matrix B=ΦΨ, where Φ is a selection matrix, and the elements in the selection matrix take values ​​from 0 or 1; Ψ is a Fourier basis matrix; The Fourier basis matrix is: Where E = e -j2π / NMH The three-dimensional Fourier basis matrices of the multi-domain agile waveform coding are Kronecker products to form Ψ, and the number of rows and columns of the Fourier basis matrix of the multi-domain agile waveform coding are N, M, and H respectively.

5. The radar multi-domain agile waveform sparse recovery processing method according to claim 3, characterized in that: In step S2, a subspace tracking algorithm is used to perform sparse recovery processing. The steps are: S201. Input K, B, and y, where K is the target sparsity, i.e., the maximum index number; S202. Find Γ (0) ={In B H The indices of the K elements with the largest absolute values ​​in y}; S203, let Bt0 = {Γ (0) The corresponding K column of B}; S204, let the residual r (0) =y-Bt0x0; Among them, x0 is the least squares solution: S205, set the initial value q=0; S206, start loop, q=q+1; S207, Γ (q) ={In B H r (q-1) The indices of the K elements with the largest absolute values ​​in}; S208, Bt q ={Γ (q) The corresponding K column of B}; S209, solve using the least squares method: S210, residual r (q) =y-Bt q x q ; S211, when ‖r (q) ‖2>‖r (q-1) ‖2, end the loop; S212, output x q , the x q is the vector to be estimated, x q It is expanded into three two-dimensional matrices, namely speed-high-resolution distance dimension, speed-angle dimension, and angle-high-resolution distance dimension. The distance, speed, and angle of the target can be determined by the peak value.

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