Radar high-speed and high-maneuverability target detection method and system based on sparse reconstruction

Abstract

The present invention discloses a radar high-speed and high-maneuverability target detection method and system based on sparse reconstruction, belonging to the field of radar signal processing, the method comprising: establishing a radar echo model of a high-speed and high-maneuverability target; obtaining a pulse compression echo signal by pulse compression processing; eliminating the odd-order distance and Doppler migration of the echo by using motion parameter separation technology; correcting the residual distance migration by second-order Keystone transformation; and compensating the residual Doppler migration by using slow-time dimension orthogonal matching pursuit (OMP) processing, thereby obtaining the sparse reconstruction result of the high-speed and high-maneuverability target echo and realizing target detection. The present invention avoids the multi-dimensional search process of the motion parameters of the high-speed and high-maneuverability target, and can realize the joint correction of different-order distances and Doppler migrations.

Description

Technical Field

[0001] The present invention relates to radar signal processing technology, and in particular to a radar high-speed and high-maneuverability target detection method and system based on sparse reconstruction. Background Art

[0002] In recent years, with the rapid development of aerospace technology, more and more high-speed and high-maneuvering targets have become the objects that radar needs to detect. Compared with conventional slow targets, the echoes of high-speed and high-maneuvering targets are very likely to have range migration and Doppler migration during the radar observation time, which causes the signal energy to diffuse along the range dimension and speed dimension respectively, seriously reducing the moving target detection (MTD) performance and increasing the difficulty of radar detection of such targets.

[0003] At present, the commonly used moving target detection methods under the influence of migration are mainly based on non-coherent accumulation and coherent accumulation. The non-coherent accumulation algorithm uses technologies such as Radon transform and Hough transform, which has high computational efficiency but low accumulation gain. The coherent accumulation algorithm usually considers the case of uniform or uniformly accelerated target motion, and has insufficient correction ability for complex migration. Although the generalized Radon-Fourier transform (GRFT) has been proposed to realize the joint correction of high-order distance and Doppler migration, this method requires traversal search of the target multi-dimensional parameter space, and the computational complexity is high.

[0004] Therefore, how to coherently accumulate echo signal energy without searching for multi-dimensional parameters has become an urgent problem to be solved in high-speed and high-maneuverability target detection. Summary of the invention

[0005] The object of the present invention is to provide a radar high-speed and high-maneuverability target detection method and system based on sparse reconstruction.

[0006] The technical solution to achieve the purpose of the present invention is as follows: In a first aspect, the present invention provides a radar high-speed and high-maneuverability target detection method based on sparse reconstruction, comprising the following steps:

[0007] Establish radar high-speed and high-maneuvering target echo model;

[0008] Acquire pulse compression echo signal through pulse compression processing;

[0009] Use motion parameter separation technology to eliminate echo odd-order distance and Doppler migration;

[0010] Residual range migration correction is performed through the second-order Keystone transform;

[0011] Orthogonal matching pursuit processing in slow time dimension is used to compensate for residual Doppler migration, so as to obtain sparse reconstruction results of high-speed and high-maneuvering target echoes and realize target detection.

[0012] Furthermore, the established radar high-speed and high-maneuvering target echo model expression is as follows:

[0013]

[0014] in, represents the slow time variable, , and represent the number of pulses and the pulse repetition interval respectively, is the fast time variable, is the echo signal amplitude, is the pulse width, is the speed of light, is the signal frequency modulation slope, is the signal wavelength, Indicates the instantaneous slant range of the target relative to the radar, , , and They are the initial slant range, radial velocity, acceleration and jerk of the target relative to the radar.

[0015] Furthermore, after the echo signal is pulse compressed in step 2, the slow time-distance frequency dimension pulse pressure echo signal obtained is expressed as

[0016]

[0017] in, is the distance frequency variable, is the amplitude of the signal after pulse compression, is the signal bandwidth, is the signal carrier frequency.

[0018] Furthermore, the expression for motion parameter separation and elimination of odd-order motion is:

[0019]

[0020] in, express The reverse sequence of .

[0021] Furthermore, the expression for compensating the residual range migration caused by target acceleration using the second-order Keystone transform is:

[0022]

[0023] in, is a virtual slow time variable, is the signal amplitude after the second-order Keystone transform.

[0024] Furthermore, the process of using slow-time dimension OMP processing to compensate for residual Doppler motion is specifically as follows:

[0025] enter: Neidi The slow-time signal corresponding to the distance unit , sensor matrix ,in , , signal sparsity ;

[0026] Output: echo sparse reconstruction result ;

[0027] (1) Initialization: initial residual , the initial index set , the initial set of atoms , number of iterations ;

[0028] (2) Find the index , so that ,in Indicates The residual error of the iteration, express No. List;

[0029] (3) Order Indicates The index set of iterations, Indicates The set of atoms for the iteration;

[0030] (4) Obtain the reconstruction coefficients using the least squares method ;

[0031] (5) Update residual ;

[0032] (6) Order ,like Then return to step (2), otherwise stop the iteration.

[0033] After the slow-time OMP processing, the radar high-speed and high-maneuvering target echo will be sparsely reconstructed in the range-acceleration dimension, thereby obtaining the target detection result.

[0034] In a second aspect, the present invention provides a radar high-speed and high-maneuverability target detection system based on sparse reconstruction, which is used to implement the method described in the first aspect, and the system includes:

[0035] The first module is used to establish the radar high-speed and high-maneuvering target echo model;

[0036] The second module obtains the pulse compression echo signal through pulse compression processing;

[0037] The third module uses motion parameter separation technology to eliminate echo odd-order distances and Doppler migration;

[0038] The fourth module performs residual range migration correction through the second-order Keystone transform;

[0039] The fifth module uses slow-time orthogonal matching pursuit processing to compensate for residual Doppler migration, thereby obtaining sparse reconstruction results of high-speed and high-maneuvering target echoes and realizing target detection.

[0040] In a third aspect, the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in the first aspect when executing the program.

[0041] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the steps of the method described in the first aspect.

[0042] In a fifth aspect, the present invention provides a computer program product, comprising a computer program, characterized in that when the computer program is executed by a processor, the steps of the method described in the first aspect are implemented.

[0043] Compared with the prior art, the present invention has the following significant advantages:

[0044] (1) For radar moving targets with high speed and high maneuverability, the combination of motion parameter separation, second-order Keystone transform and slow-time dimension OMP processing can achieve joint correction of different-order ranges and Doppler migrations, and coherently accumulate echo energy while avoiding multi-dimensional parameter search;

[0045] (2) By making full use of the transform domain sparsity of the high-speed and high-maneuvering target echo, a sensor matrix including the second-order Doppler migration correction factor is constructed. On this basis, the echo signal is sparsely reconstructed in the range-acceleration dimension, which can achieve effective target detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a complete technical solution flow chart of the present invention.

[0047] Figure 2 Schematic diagram of the target motion trajectory after pulse compression.

[0048] Figure 3 Schematic diagram of the target motion trajectory after motion parameter separation.

[0049] Figure 4 Schematic diagram of target motion trajectory after second-order Keystone transform.

[0050] Figure 5 Schematic diagram of the echo sparse reconstruction results after slow-time OMP processing.

[0051] Figure 6 Schematic diagram of the sparse reconstruction results of the proposed method under multi-target conditions. DETAILED DESCRIPTION

[0052] The present invention proposes a radar high-speed and high-maneuverability target detection method based on sparse reconstruction. Figure 1 The steps of the method of the present invention are described in detail.

[0053] like Figure 1 As shown, a radar high-speed and high-maneuverability target detection method based on sparse reconstruction includes the following steps:

[0054] Step 1: radar high-speed and high-maneuver target echo modeling:

[0055] make represents the instantaneous slant range of the target relative to the radar, where , , and They are the initial slant range, radial velocity, acceleration and jerk of the target relative to the radar. The radar echo model expression of high-speed and high-maneuvering targets is as follows:

[0056]

[0057] in, represents the slow time variable, and represent the number of pulses and the pulse repetition interval respectively, is the fast time variable, is the echo signal amplitude, is the pulse width, is the speed of light, is the signal frequency modulation slope, is the signal wavelength.

[0058] Step 2, pulse compression:

[0059] For high-speed and high-maneuvering target echo signals After pulse compression processing, the slow time-distance frequency dimension pulse pressure echo signal expression can be obtained as follows:

[0060]

[0061] in, is the distance frequency variable, is the amplitude of the signal after pulse compression, is the signal bandwidth, is the signal carrier frequency.

[0062] Depend on It can be seen that due to and Due to the coupling between the two, the echo of high-speed and high-maneuvering targets will experience range migration. In addition, the Doppler spectrum of the target echo signal will be broadened in the slow time dimension, resulting in Doppler migration. Range migration and Doppler migration will cause the echo energy to diffuse along the range dimension and speed dimension respectively, reducing the target detection performance.

[0063] Step 3: Separation of motion parameters to eliminate odd-order motions:

[0064] For slow time variables , construct the corresponding inverse slow time series :

[0065]

[0066] At this time, the corresponding pulse pressure echo signal is expressed as

[0067]

[0068] The following motion parameter separation operation is performed on the pulse pressure echo:

[0069]

[0070] Depend on It can be seen that since the phases corresponding to the two motion parameters of velocity and jerk are eliminated, the odd-order range and Doppler migrations have been compensated, leaving only the residual migration caused by the target acceleration.

[0071] Step 4: Second-order Keystone transform to compensate for residual distance migration:

[0072] Constructing virtual slow time variables , which is related to slow time The following scale transformation relationship is satisfied:

[0073]

[0074] Will and Substitute the relationship between , and then perform distance dimension inverse FFT, we can get

[0075]

[0076] in, is the signal amplitude after the second-order Keystone transform.

[0077] according to It can be seen that after the second-order Keystone transform, the residual range migration caused by the target acceleration has been corrected.

[0078] Step 5, slow-time OMP processing to compensate for residual Doppler motion and detect the target:

[0079] The non-uniform inverse Fourier transform basis matrix is ​​selected as the sensing matrix, that is, ,in . Then for No. The slow-time signal corresponding to the distance unit , which can be sparsely represented as On this basis, slow time dimension OMP processing is performed, and the specific process is as follows:

[0080] Input: Observation signal , sensor matrix , signal sparsity .

[0081] Output: echo sparse reconstruction result .

[0082] (1) Initialization: residual , index collection , , ;

[0083] (2) Find the index , so that ,in express No. List;

[0084] (3) Order , ;

[0085] (4) According to the least squares method, we can get ;

[0086] (5) Update residual ;

[0087] (6) Order ,like Then return to step (2), otherwise stop the iteration.

[0088] After the slow-time OMP processing, the radar high-speed and high-maneuvering target echo will be sparsely reconstructed in the range-acceleration dimension, thereby obtaining the target detection result.

[0089] Based on the same inventive concept, the present invention also provides a radar high-speed and high-maneuverability target detection system based on sparse reconstruction, the system comprising:

[0090] The first module is used to establish the radar high-speed and high-maneuvering target echo model;

[0091] The second module obtains the pulse compression echo signal through pulse compression processing;

[0092] The third module uses motion parameter separation technology to eliminate echo odd-order distances and Doppler migration;

[0093] The fourth module performs residual range migration correction through the second-order Keystone transform;

[0094] The fifth module uses slow-time orthogonal matching pursuit processing to compensate for residual Doppler migration, thereby obtaining sparse reconstruction results of high-speed and high-maneuvering target echoes and realizing target detection.

[0095] The specific implementation methods of the above modules are the same as the steps of the aforementioned radar high-speed and high-maneuverability target detection method based on sparse reconstruction, and will not be repeated here.

[0096] The present invention will be further described below in conjunction with specific embodiments.

[0097] The radar transmit signal carrier frequency is set to 0.15GHz, signal bandwidth is 20MHz, pulse width is 10us, pulse repetition frequency is 1000Hz, and accumulation time is 1.024s. The initial slant range, radial velocity, acceleration, and jerk of the target relative to the radar are 30km, 800m / s, and 200m / s respectively. 2 and 100m / s 3 .

[0098] Figure 2 The target motion trajectory after pulse compression is given, and it can be seen that the high-speed and high-maneuverability motion of the target leads to serious migration phenomenon. Figure 3 and Figure 4 These are the target motion trajectories after motion parameter separation and second-order Keystone transformation. It can be seen that the range migration has been corrected. Figure 5 This is the result of echo sparse reconstruction after slow-time OMP processing. It can be seen that the target signal energy is coherently accumulated in the range-acceleration plane.

[0099] When there are multiple targets in the radar detection area, the sparse reconstruction results of the proposed method are as follows: Figure 6 As shown, the parameters of target 1 are consistent with the above simulation settings, and the distance, speed, acceleration and jerk parameters of target 2 are 31km, 300m / s, and 150m / s respectively. 2and 50m / s 3 It can be seen that the proposed method can effectively realize the sparse reconstruction and detection of each target echo.

[0100] The above embodiments are described in a relatively specific and detailed manner, but they should not be construed as limiting the scope of the invention patent.

Claims

1. A radar high-speed and high-maneuverability target detection method based on sparse reconstruction, characterized in that: The following steps are involved: The radar high-speed and high-maneuvering target echo model is established, and the expression is as follows: ； in, represents the slow time variable, , and represent the number of pulses and the pulse repetition interval respectively, is the fast time variable, is the echo signal amplitude, is the pulse width, is the speed of light, is the signal frequency modulation slope, is the signal wavelength, Indicates the instantaneous slant range of the target relative to the radar, , , and are the initial slant range, radial velocity, acceleration and jerk of the target relative to the radar; The pulse compression echo signal is obtained by pulse compression processing; after the echo signal is subjected to pulse compression processing, the slow time-distance frequency dimension pulse compression echo signal obtained is expressed as ； in, is the distance frequency variable, is the amplitude of the signal after pulse compression, is the signal bandwidth, is the signal carrier frequency; The motion parameter separation technique is used to eliminate the odd-order range and Doppler motion of the echo. The expression for eliminating the odd-order motion by motion parameter separation is: ； in, express The reverse sequence of The residual range motion correction is performed by the second-order Keystone transform. The expression for compensating the residual range motion caused by target acceleration using the second-order Keystone transform is: ； in, is a virtual slow time variable, is the signal amplitude after the second-order Keystone transform; The slow-time dimension orthogonal matching pursuit processing is used to compensate for the residual Doppler migration, so as to obtain the sparse reconstruction result of the high-speed and high-maneuvering target echo and realize target detection. The process of using the slow-time dimension OMP processing to compensate for the residual Doppler migration is as follows: enter: Neidi The slow-time signal corresponding to the distance unit , sensor matrix ,in , , signal sparsity ; Output: echo sparse reconstruction result ; (1) Initialization: initial residual , the initial index set , the initial set of atoms , number of iterations ; (2) Find the index , so that ,in Indicates The residual error of the iteration, express No. List; (3) Order Indicates The index set of iterations, Indicates The set of atoms for the iteration; (4) Obtain the reconstruction coefficients using the least squares method ; (5) Update residual ; (6) Order ,like Then return to step (2), otherwise stop the iteration; After the slow-time OMP processing, the radar high-speed and high-maneuvering target echo will be sparsely reconstructed in the range-acceleration dimension, thereby obtaining the target detection result.

2. A radar high-speed and high-maneuverability target detection system based on sparse reconstruction, characterized in that: For implementing the method described in claim 1, the system comprises: The first module is used to establish the radar high-speed and high-maneuvering target echo model; The second module obtains the pulse compression echo signal through pulse compression processing; The third module uses motion parameter separation technology to eliminate echo odd-order distances and Doppler migration; The fourth module performs residual range migration correction through the second-order Keystone transform; The fifth module uses slow-time orthogonal matching pursuit processing to compensate for residual Doppler migration, thereby obtaining sparse reconstruction results of high-speed and high-maneuvering target echoes and realizing target detection.

3. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the method according to claim 1 are implemented.

4. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to claim 1 are implemented.

5. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to claim 1 are implemented.

Images