A method for suppressing main lobe suppressed polarization agile jamming

Abstract

The application discloses a main lobe suppression type polarization agile jamming suppression method, and aims at the main lobe suppression type jamming with dynamic polarization parameters, constructs the instantaneous polarization projection vector (IPPV) of the quadrature polarization receiving signal based on the quadrature polarization receiving signal of the dual-polarization radar. The heuristic segmentation algorithm is used to detect the polarization parameter mutation point of the quadrature polarization receiving signal, and the polarization parameter mutation point is used to segment the quadrature polarization receiving signal to obtain the polarization segmented receiving signal. For the polarization segmented receiving signal with different polarization parameters, the adaptive polarization cancellation algorithm based on the minimum variance criterion is used to obtain the jamming cancellation parameter and perform jamming suppression to obtain the jamming suppression signal. According to the jamming cancellation parameter of the different polarization segmented receiving signal, the amplitude and phase compensation of the jamming suppression signal is performed, and the reference signal for pulse compression is reconstructed, and after the pulse compression processing, the main lobe suppression type polarization agile jamming cancellation and target detection are realized.

Description

Technical Field

[0001] This invention relates to the field of radar signal processing technology, and is particularly applicable to a method for suppressing main lobe-suppressed polarization agility interference. Background Technology

[0002] Modern electronic warfare technology can suppress or deceive radar echo signals across all dimensions, including the time, frequency, and spatial domains. Therefore, it is crucial to research new dimensions and characteristic differences to distinguish and suppress interference, especially in main lobe jamming scenarios. In such scenarios, when the polarization parameters of the jamming signal remain constant within the signal reception time range, interference can be suppressed through methods such as polarization filtering. However, with the continuous development of jamming technology in modern electronic warfare, the jamming polarization parameters have evolved from simple fixed-polarization jamming to controllable variations and even random polarization jamming, severely weakening the effectiveness of existing polarization-domain anti-jamming technologies.

[0003] The paper "Research on Variable Polarization Interference Cancellation Algorithm Based on Auxiliary Antenna" proposes a method to extract the interference polarization state by constructing a fully polarized auxiliary antenna, thereby achieving polarization cancellation. Simulation results show that the algorithm has a good interference suppression effect under the condition that the intra-pulse interference polarization parameters remain unchanged, but it does not consider the scenario where the intra-pulse interference polarization parameters change. The paper "Characteristic Analysis and Suppression of Interference Suppression by Dual-Polarized Radar in Experimental Measured Results" analyzes the polarization characteristics of signals under several interference suppression conditions, including noise frequency modulation, comb spectrum, discontinuous noise, and function frequency sweep, and designs dual-polarized interference filtering, but it does not consider the case where the interference polarization parameters change. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for suppressing main lobe-suppressed polarization agility interference in a dual-polarization radar system. The dual-polarization radar transmits and receives electromagnetic waves with arbitrary polarization parameters, and the radar receiving antenna array in the dual-polarization radar system outputs both horizontally and vertically polarized signals.

[0005] This includes: Step S1, for the dynamic changes of the suppressive polarization interference parameters in the suppressive polarization interference scenario, establishing a radar receiving antenna array output signal model and constructing the transient polarization projection vector IPPV.

[0006] Step S2: Based on the features of the transient polarization projection vector IPPV constructed in Step S1, the interference polarization abrupt change point of the interference polarization parameter is detected using a heuristic segmentation algorithm. Step S3: According to the interference polarization abrupt change point obtained in Step S2, the echo signal is segmented, and the interference cancellation parameter is solved using an adaptive polarization cancellation algorithm based on the minimum variance criterion. Interference suppression is then performed on the segmented echo signal to obtain the interference suppression signal. Step S4: According to the interference cancellation parameter in Step S3, amplitude and phase compensation are performed on the interference suppression signal to reconstruct the reference signal for pulse compression. Step S5: Matched filtering is performed using the reconstructed reference signal in Step S4 and the phase-compensated interference suppression signal to achieve main lobe suppression interference suppression and target detection.

[0007] Preferably, step S1 includes: step S11, establishing a radar receiving antenna array output signal model; assuming the polarization parameters of the interference signal during the duration The inner remains unchanged, determining the first The signal yi(t) is output for a duration of segment.

[0008] ,in, For the first Horizontal polarization received signal during a certain duration For the first Vertically polarized received signal during a given duration For the first The target echo signal received during the period of time, For the first Interference signals received during the duration of the segment; It is the target's polarization scattering matrix. With the polarization vector of the transmitted signal The product of, where The horizontal polarization vector of the target at the radar receiver. The vertical polarization vector of the target at the radar receiver. Indicates the first The polarization vector of the interference signal during the duration of the segment; For the first Noise signal received during the duration of the segment, and These are the horizontally polarized receiver noise and the vertically polarized receiver noise, respectively, with a mean of 0 and a variance of . complex Gaussian distribution .

[0009] The horizontally polarized and vertically polarized received signals output from the radar receiving antenna array are sampled to obtain the sampled signals. .

[0010] .

[0011] in, The sampling period of the radar receiver is and the sampling frequency is . , , where n is the nth sampling point of the sampled signal; For the first Horizontal polarization received sampling signal during the duration of the segment. For the first Vertical polarization received sampling signal during the duration of the segment. For the first The target echo sampling signal received during the duration of the segment, For the first Interference sampling signals received during the duration of the segment; It is the target's polarization scattering matrix. With the polarization vector of the transmitted signal The product of, where The horizontal polarization vector of the target at the radar receiver. The vertical polarization vector of the target at the radar receiver. Indicates the first The polarization vector of the interference signal during the duration of the segment; For the first The noise sampling signal received during the duration of the segment. and These are sampled signals of horizontally polarized received noise and vertically polarized received noise, respectively, with a mean of 0 and a variance of . complex Gaussian distribution .

[0012] Considering the polarization-agile interference scenario, the signal model y output by the radar receiving antenna array is: ,in, For the first During a given period of time, both horizontally and vertically polarized signals are received. For the first During a given period of time, both horizontally and vertically polarized signals are received. For the first The horizontally polarized and vertically polarized signals received during the duration of the segment are of dimension 1. ; For the first The target echo signal in the horizontally polarized and vertically polarized received signals during a certain period of time. It is a one-dimensional horizontal quantity. length It is the first During the duration of the segment, the dimension is Interference signals, It is the first During the duration of the segment, the dimension is The noise signals received by horizontal polarization and vertical polarization. This represents the number of times the polarization parameters of the interference signal change during the radar reception time.

[0013] Step S12: Construct the transient polarization projection vector IPPV; determine the Stokes parameters and transient polarization projection vector IPPV of the nth sampling point of the horizontally polarized and vertically polarized received signals.

[0014] , .

[0015] in, Represents the complex conjugate operation. Representative of the real part, The imaginary part is taken as the representative. Indicates the intensity of electromagnetic waves. This indicates the strength difference between the horizontally polarized and vertically polarized received signals; Indicates the degree of linear polarization; Indicates the degree of circular polarization. , , These are the first, second, and third components of the transient polarization projection vector IPPV. IPPV is the transient polarization projection vector; (n) represents the horizontally polarized received signal. It is for vertically polarized signal reception.

[0016] Prioritized, step S2, based on the features of the transient polarization projection vector IPPV constructed in step S1, uses a heuristic segmentation algorithm to detect and obtain the interference polarization abrupt change points of the interference polarization parameters, including: S21, setting the first component... The component includes M data points, determining the first... Combined bias of data points .

[0017] In the formula, For the first The length of the sequence to the left of each data point. For the first The length of the sequence to the right of each data point. For the first The standard deviation of the sequence to the left of each data point For the first The standard deviation of the sequence to the right of each data point.

[0018] use Statistical sequence for the test Measuring the difference between the means of the sequences on the left and right sides of a data point: In the formula, It is the first The mean of the sequence to the left of each data point. It is the first The mean of the sequence to the right of each data point; for the first component Calculate for each data point to obtain Statistical sequence for the test .

[0019] set up Statistical sequence for the test The maximum value is Calculate statistical sequences Maximum value Corresponding statistical significance : In the formula, , , The total number of data points. , If statistical significance is Then the j-th data point is the interference polarization abrupt change point, and the first component is based on the j-th data point. Divide into two segments to obtain a segmented sequence; otherwise, do not segment the first component. .

[0020] S22. If the length of all segmented sequences is greater than or equal to the minimum segment length. If so, then step S21 is executed for all segmented sequences; otherwise, based on the first component... All the interfering polarization abrupt change points constitute the first abrupt change point set; for the second component Perform steps S21 and S22 to obtain the second set of mutation points; for the third component Perform steps S21 and S22 to obtain the third set of mutation points; then perform data fusion on the first set of mutation points, the second set of mutation points, and the third set of mutation points.

[0021] Firstly, data fusion is performed on the first set of mutation points, the second set of mutation points, and the third set of mutation points, including: sorting the first set of mutation points, the second set of mutation points, and the third set of mutation points in ascending order to obtain a one-dimensional sequence. Where P1 represents the first interference polarization abrupt change point, and P2 represents the second interference polarization abrupt change point. Representing the One interfering polarization abrupt point, Representing the +1 interfering polarization abrupt change point, Representing the -1 interference polarization abrupt change point, Representing the A disturbance polarization abrupt point; when When calculating the interval The average value is used to obtain the estimated value of the m-th actual interference polarization abrupt change point. : In the formula, () represents the integer operation.

[0022] Prioritized, in step S3, based on the interference polarization abrupt change point obtained in step S2, the echo signal is segmented, and the interference cancellation parameters are solved using an adaptive polarization cancellation algorithm based on the minimum variance criterion. Interference suppression is then applied to the segmented echo signals to obtain interference-suppressed signals, including: based on the first... The horizontally polarized and vertically polarized signals received during the duration of the segment Determine the interference suppression signal : In the formula, Interference cancellation parameters for the polarization channel. Represents complex conjugation operations; determines interference cancellation parameters for polarization channels: Determine the first Interference suppression signal after cancellation during the duration of the segment : ,in, It is a complex number. , They are the first The target amplitude and phase change factor after interference cancellation within a certain duration. To cancel the noise signal, For the first The target echo signal received within a certain duration.

[0023] Preferably, step S4, which involves performing matched filtering on the reconstructed reference signal from step S3 and the phase-compensated interference suppression signal, includes: performing matched filtering on the first... Interference suppression signal during the duration of the segment Noise normalization is performed to obtain a normalized interference suppression signal. : The phase change of the target echo signal caused by the cancellation is compensated to obtain the compensated interference suppression signal. .

[0024] ,make ,but The value is a non-negative real number; compensation is performed on the reference signal for pulse compression, assuming the radar pulse signal exists in the first... To the Section Within a given duration, the length of each pulse signal segment is as follows: And the total length of the pulse information is Determine the reference signal for reconstruction. : ,in, The dimension is A vector whose elements are all 1s. The operation represents the dimension as The elements of a vector are converted to The diagonal elements of the matrix, The remaining elements of the matrix are 0. The target echo signal.

[0025] Preferably, step S5 includes: using the reconstructed reference signal With the compensated interference suppression signal Perform matched filtering to obtain the output signal. : ,in, This represents the convolution operation.

[0026] Preferably, the present invention provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of any of the methods described herein.

[0027] Preferably, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described herein.

[0028] Compared with existing technologies, this invention has the following advantages: It solves the problem that adaptive polarization cancellation cannot resist main lobe suppression polarization agility interference: it utilizes a heuristic segmentation algorithm to detect interference polarization abrupt changes and accurately segments the echo signal. It uses a polarization cancellation method to suppress interference in each echo signal segment. Finally, it uses interference cancellation parameters to compensate for the target echo signal after interference suppression, achieving both main lobe suppression interference countermeasures and target detection. Attached Figure Description

[0029] Figure 1 This is a flowchart related to the method for suppressing main lobe-suppressed polarization agile interference in this invention.

[0030] Figure 2 This is a diagram showing the relationship between the suppression-polarized agile interference and the echo pulse position in the first case of this invention.

[0031] Figure 3 This is a diagram showing the relationship between the suppression-polarized agile interference and the echo pulse position in the second case of this invention.

[0032] Figure 4 This is a diagram showing the relationship between the suppression-polarized agile interference and the echo pulse position in the third case of this invention.

[0033] Figure 5 This is a diagram showing the relationship between the suppression-polarized agile interference and the echo pulse position in the fourth case of this invention.

[0034] Figure 6 This is the IPPV distribution diagram of suppressed polarization agile interference under the simulated polarization auxiliary angle change in this invention.

[0035] Figure 7 This is the IPPV distribution diagram of suppressed polarization agile interference under the simulated polarization phase difference change in this invention.

[0036] Figure 8 This is a graph showing the relationship between the noise-to-interference ratio and the segmentation accuracy in the simulation of this invention.

[0037] Figure 9 This is a graph showing the relationship between the interference polarization state interval and the segmentation result in the simulation of this invention.

[0038] Figure 10 This is a graph showing the relationship between the rate of change of interference polarization parameters and the segmentation results in the simulation of this invention.

[0039] Figure 11 This is a graph showing the relationship between the segmentation threshold and the segmentation result in the simulation of this invention.

[0040] Figure 12 This is a graph showing the relationship between the segmentation threshold and the segmentation result when considering segmentation error in the simulation of this invention.

[0041] Figure 13 This is a signal-to-noise ratio gain diagram before and after reference signal reconstruction in the simulation of this invention. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0043] like Figure 1As shown, this invention provides a method for suppressing main lobe-suppressed polarization agile interference, comprising: S1, establishing a radar receiving antenna array output signal model and constructing a transient polarization projection vector (IPPV) for a suppression polarization interference scenario with dynamically changing polarization parameters; S2, based on the features of the IPPV constructed in step S1, using a heuristic segmentation algorithm to detect interference polarization abrupt changes in the interference polarization parameters; S3, segmenting the echo signal according to the interference polarization abrupt changes detected in step S2, solving for the cancellation parameters using an adaptive polarization cancellation algorithm based on the minimum variance criterion, and suppressing interference in the segmented echo signals respectively; S4, performing amplitude and phase compensation on the interference suppression signal according to the interference cancellation parameters in step S3, and reconstructing the pulse compression reference signal; S5, performing matched filtering on the reconstructed reference signal and the compensated interference suppression signal in step S4 to achieve main lobe suppression interference suppression and target detection.

[0044] In this embodiment, step S1 is specifically as follows: S11, establish a radar receiving antenna array output signal model; assume that the polarization parameters of the interference signal are respectively in duration The interior remains unchanged. It is an integer. Indicates the first Duration of segment, determine the first The horizontally polarized and vertically polarized signals received during the duration of the segment : ,in, For the first Horizontal polarization received signal during a certain duration For the first Vertically polarized received signal during a given duration For the first The target echo signal received during the period of time, For the first Interference signals received during the duration of the segment; It is the target's polarization scattering matrix. With the polarization vector of the transmitted signal The product of, where The horizontal polarization vector of the target at the radar receiver. The vertical polarization vector of the target at the radar receiver. Indicates the first The polarization vector of the interference signal during the duration of the segment; For the first Noise signal received during the duration of the segment, and These are the horizontally polarized receiver noise and the vertically polarized receiver noise, respectively, with a mean of 0 and a variance of . complex Gaussian distribution The horizontally polarized and vertically polarized received signals output from the radar receiving antenna array are sampled to obtain the sampled signals. : .

[0045] in, The sampling period of the radar receiver is and the sampling frequency is . , , where n is the nth sampling point of the sampled signal; For the first Horizontal polarization received sampling signal during the duration of the segment. For the first Vertical polarization received sampling signal during the duration of the segment. For the first The target echo sampling signal received during the duration of the segment, For the first Interference sampling signals received during the duration of the segment; It is the target's polarization scattering matrix. With the polarization vector of the transmitted signal The product of, where The horizontal polarization vector of the target at the radar receiver. The vertical polarization vector of the target at the radar receiver. Indicates the first The polarization vector of the interference signal during the duration of the segment; For the first The noise sampling signal received during the duration of the segment. and These are sampled signals of horizontally polarized received noise and vertically polarized received noise, respectively, with a mean of 0 and a variance of . complex Gaussian distribution .

[0046] Assume the pulse width of the radar transmitted signal is The sampling window length of the received signal is ( Then the sampling length of the pulse signal is The total length of signal sampling within the receiving window is ,in This represents the floor operation. For the sake of simplicity, let's assume... That is, the time interval between changes in the interference parameters is fixed, and the duration is... The signal sampling length within is The number of times the interference polarization parameter changes during the radar reception time is defined as... The number of times the interference polarization parameter changes within the pulse width is .according to , and The size relationship and the influence of main lobe interference can be analyzed in four cases.

[0047] In the first scenario, The polarization parameters of the interference signal remain unchanged during the radar reception time, i.e. The radar employs a conventional adaptive polarization interference cancellation method to suppress interference; in the second case, The polarization parameters of the interference signal change during the radar reception time. Each interference segment requires separate interference suppression. The starting distance of the target echo signal is uncertain, and the interference polarization parameters may not change within its pulse width, or may change at most once. or The third scenario, ,but and Having the same order of magnitude: the polarization parameters of the interference signal change during the radar reception time. The interference polarization parameters also change within the pulse width of the target echo signal, but the parameter changes slowly and the number of changes is limited. The fourth scenario, The polarization of the interference signal changes during the radar reception time. The interference polarization parameters also change within the pulse width of the target echo signal, and these parameters change rapidly and frequently. In the most extreme case, the interference is a non-polarized wave, and the received signal components of the two orthogonally polarized channels are uncorrelated.

[0048] In the first scenario, interference suppression can be achieved directly using a conventional adaptive polarization interference cancellation method. In practical applications, the polarization parameter switching time interval of the jammer is several... Up to dozens This corresponds to cases 2 and 3 above. Therefore, this article focuses on analyzing these cases. The four cases can be uniformly represented by the following formula: ,in, For the first During a given period of time, both horizontally and vertically polarized signals are received. For the first During a given period of time, both horizontally and vertically polarized signals are received. For the first The horizontally polarized and vertically polarized signals received during the duration of the segment are of dimension 1. ; For the first The target echo signal in the horizontally polarized and vertically polarized received signals during a certain period of time. It is a one-dimensional horizontal quantity. length It is the first During the duration of the segment, the dimension is Interference signals, It is the first During the duration of the segment, the dimension is The noise signals received by horizontal polarization and vertical polarization. This represents the number of times the polarization parameters of the interference signal change during the radar reception time.

[0049] S12. Construct the transient polarization projection vector IPPV; the Stokes parameters and IPPV of the nth sampling point of the echo signal are expressed under the horizontal and vertical polarization basis as follows: and ,in, Represents the complex conjugate operation. Representative of the real part, The imaginary part is taken as the representative. Indicates the intensity of electromagnetic waves. This represents the intensity difference between the horizontal and vertical components; Indicates the degree of linear polarization; Indicates the degree of circular polarization. , , These are the three components of IPPV.

[0050] In this embodiment, step S2 is specifically as follows: S21, using a heuristic segmentation algorithm to detect the interference polarization abrupt change points of the interference polarization parameters; let the first component... It consists of M data points, the first... The combined deviation of the data points is expressed as:

[0051] In the formula, , The first The sequence lengths on the left and right sides of each data point , The first The standard deviation of the sequences to the left and right of each data point; using Statistical sequence for the test Measuring the difference between the means of the sequences on the left and right sides of a data point:

[0052] In the formula, , It is the first The mean of the sequences on both sides of each data point; for the first component Calculate for each data point to obtain Statistical sequence for the test ; The larger the value, the higher the number of digits. The greater the difference between the means of the sequences on the left and right sides of a data point, the more likely it is to be true; let Statistical sequence for the test The maximum value is ,calculate Corresponding statistical significance : In the formula, , , The total number of data points. , Set a critical value If statistical significance Then the j-th data point is the interference polarization abrupt change point, and the first component is based on the j-th data point. Divide into two segments to obtain a segmented sequence; otherwise, do not segment the first component. ;right , , The above operations are performed on the three components respectively to obtain three sets of mutation points.

[0053] S22. Perform data fusion on the set of mutation points; first component mutation point, second component mutation point and third component The mutation points differ from the actual interference polarization mutation points, necessitating data fusion. The first, second, and third mutation point sets are sorted in ascending order to obtain a one-dimensional sequence. Where P1 represents the first interference polarization abrupt change point, and P2 represents the second interference polarization abrupt change point. Representing the One interfering polarization abrupt point, Representing the +1 interfering polarization abrupt change point, Representing the -1 interference polarization abrupt change point, Representing the A disturbance polarization abrupt point; when When calculating the interval The average value is used to obtain the estimated value of the m-th actual interference polarization abrupt change point. : In the formula, () represents the integer operation.

[0054] In this embodiment, step S3 is specifically as follows: based on the first The horizontally polarized and vertically polarized signals received during the duration of the segment Determine the polarization canceller output interference suppression signal : In the formula, Interference cancellation parameters for the polarization channel. Represents complex conjugate operation; the interference component in the received signal is much larger than the target and noise components, determining the interference cancellation parameters for the polarization channel: ; Determine the first Interference suppression signal during the duration of the segment : ,in, It is a complex number. , They are the first The target amplitude and phase change factor after the duration of the interference are cancelled. To cancel the noise signal, For the first The target echo signal received during a certain period of time.

[0055] In this embodiment, step S4 is specifically as follows: for the first Interference suppression signal during the duration of the segment Noise normalization is performed to obtain a normalized interference suppression signal. : To compensate for the phase change in the target echo signal caused by interference cancellation, a compensated interference suppression signal is obtained. : ,make ,but The value is a non-negative real number; compensation is performed on the reference signal for pulse compression, assuming the radar pulse signal exists in the first... To the Section Within a given duration, the length of each pulse signal segment is as follows: And the total length of the pulse information is Determine the reference signal for reconstruction. : ,in, The dimension is A vector whose elements are all 1s. The operation represents the dimension as The elements of a vector are converted to The diagonal elements of the matrix, The remaining elements of the matrix are 0. The target echo signal.

[0056] In this embodiment, step S5 is specifically as follows: Matched filtering is performed using the reconstructed reference signal and the compensated interference suppression signal to obtain the output signal. : ,in, This represents the convolution operation.

[0057] The feasibility of the method of the present invention will be further verified through experimental simulation below. Figures 2-5 This diagram illustrates the positional relationship between the interference polarization agility and the echo pulse in a suppression-type polarization agility interference scenario. This invention mainly targets interference suppression in the second and third scenarios.

[0058] Figure 6 and Figure 7 The IPPV distribution map of the received signal is shown. The received signal sampling length is 6000 points, the polarization parameters of the interference signal change every 2000 points, and the interference-to-noise ratio (JNR) is 30dB. Figure 6 The polarization phase difference of the corresponding interference signal remains unchanged: The polarization auxiliary angle changes: ,in ; Figure 7 The polarization auxiliary angle of the corresponding interference signal remains unchanged: The polarization phase difference changes: ,in .Depend on Figure 6 and Figure 7 As can be seen, when the polarization parameters of the interference signal change, the IPPV of the signal also changes accordingly.

[0059] Figure 8 This graph shows the relationship between interference-to-noise ratio (IRR) and segmentation accuracy. The received signal sampling length is 8000 points, the interference polarization parameter changes every 400 points, and the segmentation threshold is... Take 0.8 as the minimum segment length. Using a value of 25 and a signal-to-noise ratio of 0dB, 1000 Monte Carlo experiments were conducted to calculate the segmentation accuracy as a function of JNR. In the simulation, segmentation was considered accurate when the identified set of segmentation points contained all interfering polarization abrupt changes. The simulation results are as follows: Figure 8 As shown, the results indicate that the accuracy reaches 80% when JNR=15dB; the curve converges when JNR is greater than 21dB.

[0060] The distance of the interference signal polarization state can be measured by the central angle of the corresponding IPPV on the Poincare unit sphere. In a description, specifically in the normalized Jones vector, the polarization state interval between the two polarization states can be expressed as: In the formula: and These are the IPPVs corresponding to two adjacent interference signals.

[0061] Figure 9This graph shows the relationship between the interference polarization state interval and the curve convergence speed. Assuming the received signal sampling length is 8000 points, the interference polarization parameter changes every 400 points, and the segmentation threshold is... Take 0.8 as the minimum segment length. The value is set to 25, and the signal-to-noise ratio is 0dB. Assuming the interference polarization state changes at fixed angle intervals, three different sets of changes are set: , , 1000 Monte Carlo experiments were conducted to calculate the segmentation accuracy as a function of the disturbance polarization state interval. The simulation results are as follows: Figure 9 As shown, the results indicate that the accuracy curve converges faster as the interference polarization state interval increases. This is because the polarization parameters between adjacent interference segments change more significantly with the increase of the interference polarization state interval, allowing for effective segmentation of the interference signal even with a low JNR.

[0062] Figure 10 The curve showing the impact of interference polarization agility speed on the performance of the heuristic segmentation algorithm is presented. It is assumed that the interference polarization agility speed changes randomly every 50, 100, and 150 points, and the interference signal is divided into 20 segments during the radar reception time, meaning the interference polarization parameters change 19 times. Segmentation threshold Take 0.8 as the minimum segment length. With a value of 25 and a signal-to-noise ratio of 0dB, the simulation results are as follows: Figure 10 As shown in the figure. Experiments show that as the speed of interference polarization agility increases, the JNR required for the accuracy curve to converge becomes higher.

[0063] Figure 11 and Figure 12 This is a graph showing the impact of the segmentation threshold on the segmentation results. Assuming the received signal sampling length is 8000 points, and the interference signal polarization parameters change randomly every 400 points, the minimum segmentation length is... A value of 25 was chosen, with a signal-to-noise ratio of 0 dB. Monte Carlo experiments were conducted at different segmentation thresholds, and the results are as follows: Figure 11 and Figure 12 As shown. It can be observed that: with As the value decreases, the curve converges faster. In fact, Decreasing the value lowers the threshold for segmentation. When the identified segmentation point set includes all interfering polarization abrupt change points, increasing the number of segmentation points, while not affecting the calculation of the segmentation signal cancellation coefficient, increases the algorithm complexity. For the fused data, we define the judgment points outside the range of fuzzy segmentation points as segmentation error points. Then, the segmentation accuracy at this point can be expressed as: Taking the segmentation error into account, the above experiment was repeated, and the results are as follows: Figure 12 As shown, it can be seen that If the value is too small, the accuracy curve converges more slowly. If the value is too large, the segmentation error will be high at low noise-to-interference ratios. Taking all factors into consideration, 0.8 is acceptable.

[0064] Figure 13 Assuming the signal-to-noise ratio gain diagram before and after signal reconstruction, let's assume... The interference polarization parameter changes once at the center of the echo pulse. The transmitted signal is a linearly polarized wave. , The two interference polarization parameters at the echo pulse position are as follows: , ; , The interference ratio (IR) is 30dB, and the signal-to-noise ratio (SNR) is 0dB. Take 0.8, Take 25, = The signal-to-noise ratio of the target pulse after compression is calculated, and the results are as follows: Figure 13 As shown in the figure. Experiments show that, under these conditions, the signal-to-noise ratio gain is improved by 23.88 dB using the modified pulse compression method.

[0065] In this embodiment of the application, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of any of the methods described above.

[0066] In this application embodiment, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described above.

[0067] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0068] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention described herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not invented herein. The specification and embodiments are to be considered exemplary only.

[0069] The above specific embodiments further illustrate the purpose, technical solution and beneficial effects of this application. It should be understood that the above are only specific embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of this application should be included within the scope of protection of this application.

Claims

1. A method for suppressing main lobe-suppressed polarization agile interference, characterized in that, Used in dual-polarization radar systems, dual-polarization radars transmit and receive electromagnetic waves with arbitrary polarization parameters, and the radar receiving antenna array in the dual-polarization radar system outputs two signals, one horizontally polarized and one vertically polarized, including: Step S1: For the dynamic changes in the suppression polarization interference parameters under a suppression polarization interference scenario, establish a radar receiving antenna array output signal model and construct the transient polarization projection vector IPPV; Step S1 includes: Step S11: Establish a model of the radar receiving antenna array output signal; Assume the polarization parameters of the interference signal during the duration The inner remains unchanged, determining the first The signal y output during the duration of the segment i (t) is: ， in, For the first Horizontal polarization received signal during a certain period of time For the first Vertically polarized received signal during a given duration For the first The target echo signal received during the period of time, For the first Interference signals received during the duration of the segment; It is the target's polarization scattering matrix. With the polarization vector of the transmitted signal The product of, where The horizontal polarization vector of the target at the radar receiver. The vertical polarization vector of the target at the radar receiver. Indicates the first The polarization vector of the interference signal during the duration of the segment; For the first Noise signal received during the duration of the segment, and These are the horizontally polarized receiver noise and the vertically polarized receiver noise, respectively, with a mean of 0 and a variance of . complex Gaussian distribution ; The horizontally polarized and vertically polarized received signals output from the radar receiving antenna array are sampled to obtain the sampled signals. : ， in, The sampling period of the radar receiver is and the sampling frequency is . , , where n is the nth sampling point of the sampled signal; For the first Horizontal polarization received sampling signal during the duration of the segment. For the first Vertical polarization received sampling signal during the duration of the segment. For the first The target echo sampling signal received during the duration of the segment, For the first Interference sampling signals received during the duration of the segment; It is the target's polarization scattering matrix. With the polarization vector of the transmitted signal The product of, where The horizontal polarization vector of the target at the radar receiver. The vertical polarization vector of the target at the radar receiver. Indicates the first The polarization vector of the interference signal during the duration of the segment; For the first The noise sampling signal received during the duration of the segment. and These are sampled signals of horizontally polarized received noise and vertically polarized received noise, respectively, with a mean of 0 and a variance of . complex Gaussian distribution ; Considering the polarization-agile interference scenario, the signal model y output by the radar receiving antenna array is: ， in, For the first During a given period of time, both horizontally and vertically polarized signals are received. For the first During a given period of time, both horizontally and vertically polarized signals are received. For the first The horizontally polarized and vertically polarized signals received during the duration of the segment are of dimension 1. , The signal sampling length; For the first The target echo signal in the horizontally polarized and vertically polarized received signals during a certain period of time. It is a one-dimensional horizontal quantity. Length ≤ Signal sampling length It is the first During the duration of the segment, the dimension is Interference signals, It is the first During the duration of the segment, the dimension is The noise signals received by horizontal polarization and vertical polarization. This represents the number of times the polarization parameters of the interference signal change during the radar reception time. Step S12: Construct the transient polarization projection vector IPPV; Determine the Stokes parameters and transient polarization projection vector (IPPV) at the nth sampling point of the horizontally and vertically polarized received signals: ， ， in, Represents the complex conjugate operation. Representative of the real part, The imaginary part is taken as the representative. Indicates the intensity of electromagnetic waves. This indicates the strength difference between the horizontally polarized and vertically polarized received signals; Indicates the degree of linear polarization; Indicates the degree of circular polarization. , , These are the first, second, and third components of the transient polarization projection vector IPPV. IPPV is the transient polarization projection vector; (n) represents the horizontally polarized received signal. For vertical polarization signal reception; Step S2: Based on the features of the transient polarization projection vector IPPV constructed in step S1, a heuristic segmentation algorithm is used to detect and obtain the interference polarization abrupt change points of the interference polarization parameters; Step S2, based on the features of the transient polarization projection vector IPPV constructed in step S1, uses a heuristic segmentation algorithm to detect and obtain the interference polarization abrupt change points of the interference polarization parameters, including: S21, Let the first component be... The component includes M data points, determining the first... Combined bias of data points : ， In the formula, For the first The length of the sequence to the left of each data point. For the first The length of the sequence to the right of each data point. For the first The standard deviation of the sequence to the left of each data point For the first The standard deviation of the sequence to the right of each data point; use Statistical sequence for the test Measuring the difference between the means of the sequences on the left and right sides of a data point: ， In the formula, It is the first The mean of the sequence to the left of each data point. It is the first The mean of the sequence to the right of each data point; for the first component Calculate for each data point to obtain Statistical sequence for the test ; set up Statistical sequence for the test The maximum value is Calculate statistical sequences Maximum value Corresponding statistical significance : ， In the formula, , , The total number of data points. , ; If statistical significance is Then the j-th data point is the interference polarization abrupt change point, and the first component is based on the j-th data point. Divide into two segments to obtain a segmented sequence; otherwise, do not segment the first component. ; S22. If the length of all segmented sequences is greater than or equal to the minimum segment length. If so, then step S21 is executed for all segmented sequences; otherwise, based on the first component... All the interfering polarization abrupt points constitute the first set of abrupt points; For the second component Perform steps S21 and S22 to obtain the second set of mutation points; For the third component Perform steps S21 and S22 to obtain the third set of mutation points; Data fusion is performed on the first set of mutation points, the second set of mutation points, and the third set of mutation points; Step S3: Based on the interference polarization abrupt change point obtained in step S2, the echo signal is segmented, and the interference cancellation parameters are solved using the adaptive polarization cancellation algorithm based on the minimum variance criterion. Interference suppression is then performed on the segmented echo signals to obtain the interference suppression signal. Step S4: Based on the interference cancellation parameters in step S3, perform amplitude and phase compensation on the interference suppression signal to reconstruct the reference signal for pulse compression. Step S5: Use the reconstructed reference signal from step S4 and the phase-compensated interference suppression signal for matched filtering to achieve main lobe suppression interference suppression and target detection.

2. The method for suppressing main lobe-suppressed polarization agile interference according to claim 1, characterized in that, Data fusion is performed on the first set of mutation points, the second set of mutation points, and the third set of mutation points, including: Sort the first set of mutation points, the second set of mutation points, and the third set of mutation points in ascending order to obtain a one-dimensional sequence: ， Where P1 represents the first interfering polarization abrupt change point, and P2 represents the second interfering polarization abrupt change point. Representing the One interfering polarization abrupt point, Representing the +1 interfering polarization abrupt change point, Representing the -1 interference polarization abrupt change point, Representing the One interfering polarization abrupt change point; when When calculating the interval The average value is used to obtain the estimated value of the m-th actual interference polarization abrupt change point. : ， In the formula, () represents the integer operation.

3. The method for suppressing main lobe-suppressed polarization agile interference according to claim 1, characterized in that, In step S3, based on the interference polarization abrupt change point obtained in step S2, the echo signal is segmented, and the interference cancellation parameters are solved using an adaptive polarization cancellation algorithm based on the minimum variance criterion. Interference suppression is then applied to the segmented echo signals to obtain interference-suppressed signals, including: Based on the The horizontally polarized and vertically polarized signals received during the duration of the segment Determine the interference suppression signal : ， In the formula, Interference cancellation parameters for the polarization channel. Represents the complex conjugate operation; Determine the interference cancellation parameters for the polarization channel: ， Determine the first Interference suppression signal after cancellation during the duration of the segment : ， in, It is a complex number. , They are the first The target amplitude and phase change factor after interference cancellation within a certain duration. To cancel the noise signal, For the first The target echo signal received within a certain duration.

4. The method for suppressing main lobe-suppressed polarization agility interference according to claim 3, characterized in that, Step S4, which involves performing matched filtering using the reconstructed reference signal from step S3 and the phase-compensated interference suppression signal, includes: For the Interference suppression signal during the duration of the segment Noise normalization is performed to obtain a normalized interference suppression signal. : ， The phase change of the target echo signal caused by the cancellation is compensated to obtain the compensated interference suppression signal. : ， make ,but It is a non-negative real number; Compensation is performed on the reference signal for pulse compression, assuming the radar pulse signal exists at the _th_ ... To the Section Within a given duration, the length of each pulse signal segment is as follows: And the total length of the pulse information is Determine the reference signal for reconstruction. : ， in, The dimension is A vector whose elements are all 1s. The operation represents the dimension as The elements of a vector are converted to The diagonal elements of the matrix, The remaining elements of the matrix are 0. The target echo signal.

5. The method for suppressing main lobe-suppressed polarization agile interference according to claim 4, characterized in that, Step S5 includes: Using the reconstructed reference signal With the compensated interference suppression signal Perform matched filtering to obtain the output signal. : ， in, This represents the convolution operation.

Images