Method for resisting multi-main-lobe intermittent sampling interference through two-stage mismatch filtering

Abstract

The invention discloses a method for resisting multi-main-lobe intermittent sampling interference through two-stage mismatch filtering. The method comprises the following steps: firstly, establishing a radar receiving waveform model in a multi-target multi-intermittent sampling interference scene; secondly, designing a target mismatched filter based on a radar emission signal, performing target mismatched filtering on a radar echo signal by using the filter, and extracting an interference coverage section signal on a radar echo time domain in combination with the target mismatched filtering; and then designing an interference mismatch filter based on the interference signal and the radar emission signal, and performing interference mismatch filtering on the radar echo signal by using the filter to suppress the multi-interval sampling interference signal in the echo. According to the method, interference signals are extracted pulse by pulse and filtered out, dependence on accurate interference parameter prior information is not needed, the method is still effective under the conditions of target and interference overlapping and multi-interference, the method can adapt to multi-intermittent sampling interference parameter pulse level dynamic change scenes, practicability is high, robustness is high, complexity is low, and the method is suitable for large-scale popularization and application. And the method has high engineering application value.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of signal processing, and particularly relates to a two-stage mismatch filtering anti-multi-main-lobe intermittent sampling jamming method. BACKGROUND

[0002] With the rapid development of digital radio frequency memory (DRFM) technology, intermittent sampling repetitive jamming (ISRJ) as a new type of deception jamming technology has rapidly emerged and become an effective countermeasure against new radar systems. ISRJ can generate a large number of high-fidelity false targets at extremely low power consumption, posing a serious threat to radar systems. In order to effectively improve the survivability of radar systems in complex electromagnetic environments, effective anti-jamming means need to be implemented to suppress ISRJ signals in radar returns.

[0003] There are many studies on ISRJ suppression, mainly divided into three methods: the first method assumes that the exact interference parameters are known, and uses parameter joint design to design the transmit waveform and filter to filter out the interference. Literature "Y. Gao, H. Fan, L. Ren, Z. Liu, Q. Liu and E. Mao, 'Joint design of waveform and mismatched filter for Interrupted Sampling Repeater Jamming suppression,' in IEEE Transactions on Aerospace and Electronic Systems, vol. 59, no. 6, pp. 8037-8050, Dec. 2023" is based on accurate estimation of interference parameters, and uses the maximum-minimum optimization iterative algorithm to solve the joint design problem of transmit waveform and receive filter, and combines the constraint conditions to effectively control the signal-to-noise ratio loss and other indicators. But this method depends on the accurate estimation of interference parameters, and it is difficult to achieve the requirement of rapid response in electronic countermeasure. The second method is to extract the interference-free signal in the radar echo, and construct filters in time domain, frequency domain, time-frequency domain and other dimensions to filter out the interference. Literature "X. Wang, B. Li, H. Chen, W. Liu, Y. Zhu, J. Luo, L. Ni, 'Interrupted-Sampling Repeater Jamming countermeasure based on intrapulse frequency-coded joint frequency modulation slope agile waveform,' Remote Sensing. 2024; 16(15): 2810" uses compressed sensing technology to reconstruct the target and interference in the interference echo, and uses the interference-free echo to construct a time-domain filter to further filter the echo signal in the time domain to reduce the range sidelobes. This method does not need to estimate the prior information of the interference, but it is only suitable for the case where the target signal and the interference signal do not overlap or overlap less, and the suppression effect is poor for self-defense jamming and accompanying jamming. The third method is to use the feature difference of the interference and target echo after signal processing such as short-time Fourier transform and fractional Fourier transform, to identify true and false targets in the dimension where the interference and target signals do not overlap.The document "Li Jinjie, Cao Yunhe, Zhang Yulin, etc. Interleaved sampling and forwarding interference suppression based on STFrFT [J]. System Engineering and Electronics, 2024, 46(10):3312-3324" designs an intra-pulse chirp signal and uses STFrFT for time-frequency analysis, and finally uses the feature difference of interference and target in the time-frequency domain, combined with imageology method to remove the interference, and forms effective suppression to the high jamming-to-signal ratio interference from the main lobe. The method can better solve the problem of interference suppression in a single interference scene, but in actual battlefield, false target type interference often appears, and its suppression effect is greatly reduced. SUMMARY

[0004] To solve the above problems existing in the prior art, the present application provides a two-stage mismatch filtering method for resisting multi-main-lobe intermittent sampling interference.

[0005] The technical scheme adopted by the present application is as follows: a two-stage mismatch filtering method for resisting multi-main-lobe intermittent sampling interference, specifically comprising the following steps:

[0006] S1, constructing a radar receiving waveform model under a multi-target multi-intermittent sampling interference scene;

[0007] S2, designing a target mismatch filter based on the radar transmitting signal;

[0008] S3, performing target mismatch filtering on the radar echo based on the target mismatch filter designed in step S2, combining target matched filtering, and extracting the interference coverage section signal in the radar echo;

[0009] S4, designing an interference mismatch filter based on the interference coverage section signal extracted in step S3;

[0010] S5, performing interference mismatch filtering on the radar echo based on the interference mismatch filter designed in step S4, to suppress the multi-intermittent sampling interference signal in the echo.

[0011] Further, the step S1 is specifically as follows:

[0012] U targets and Z intermittent sampling interferences are set, the distance and speed of the u-th (u∈[1, 2, …, U]) target relative to the radar are R u and v u , and the distance and speed of the z-th (z∈[1, 2, …, Z]) interference relative to the radar are R z and v z ;

[0013] The radar receiving waveform s R (t) is as follows:

[0014]

[0015] where s T (t) is the radar transmitted signal, t∈[0, ∞) represents the time variable, λ and c represent the radar transmitted waveform wavelength and electromagnetic wave propagation speed respectively; and represent the complex amplitudes of the u-th target echo and the z-th jamming waveform respectively, denotes the complex domain, J z (t) represents the z-th down-converted jamming waveform, and n(t) represents the Gaussian white noise signal.

[0016] Further, the step S2 is specifically as follows:

[0017] Define the radar transmitted signal s T The discrete sequence expression obtained after sampling s

[0018]

[0019] where N represents the length of the discrete signal;

[0020] Design a target mismatch filter with a length of N By minimizing the cross-correlation sidelobe integral level between the target mismatch filter and the target signal and the frequency domain template matching error, combined with the filter energy constraint, the optimal target mismatch filter is solved, and the specific optimization problem is as follows:

[0021]

[0022] where ξ1 represents a multi-target linear weighting coefficient, (·) H denotes the conjugate transpose operation, denotes the shift matrix, denotes the Fourier transform matrix, denotes the frequency spectrum template, and ||·||2 denotes the 2-norm.

[0023] Further, the step S3 is specifically as follows:

[0024] S31, target mismatch filtering and CME detection;

[0025] First, use the optimal target mismatch filter solved in step S2 to perform target mismatch filtering on the radar echo, and the filtered signal is denoted as

[0026] Then, use the CME algorithm to perform interference detection on in the time domain, and the obtained interference position index set is is a discrete point position index. In order to obtain a continuous interference position, a connected domain algorithm is used to The point position indexes in are connected. After the connection, a plurality of connected regions are obtained, and the longest connected region is taken as the final interference coverage range, denoted as .

[0027] S32, target matched filtering and CME detection;

[0028] First, a target matched filter is used to perform target matched filtering on the radar echo, and the filtered signal is denoted as

[0029] Then, a CME algorithm is used to perform interference detection on in the time domain, and the obtained interference position index set is The point position indexes in are discrete, and in order to obtain a continuous interference position, a connected domain algorithm is used to connect the point position indexes in. After the connection, a plurality of connected regions are obtained, and the longest connected region is taken as the final interference coverage range, denoted as

[0030] S33, interference signal extraction;

[0031] First, the intersection of the two interference position index sets and obtained in steps S31 and S32 is calculated, and the new interference position index set is as follows:

[0032]

[0033] Among them, ∩ represents the set intersection operator.

[0034] Then, a CFAR algorithm is used to perform detection on the radar echo, and the peak point position index set is obtained. The smallest peak point position index l min in the set that is contained in is found.

[0035] Finally, the [l min , a end ] segment signal extracted from the radar echo time domain signal is the interference coverage segment signal, where a end represents the last element in , and the extracted interference signal is denoted as b, with a length of M.

[0036] Further, the step S4 is specifically as follows:

[0037] According to the interference signal extracted in step S3 and the radar transmission signal, a length-M interference mismatch filter ​​By minimizing the cross-correlation sidelobe integral level between the interference mismatch filter and the interference signal, combining the cross-correlation sidelobe integral level constraint between the interference mismatch filter and the target signal, the target main lobe peak energy constraint after interference mismatch filtering and the interference mismatch filter energy constraint, the optimal interference mismatch filter is solved, and the specific optimization problem is as follows:

[0038]

[0039] Wherein, ξ2 represents the cross-correlation sidelobe integral level constraint coefficient between the interference mismatch filter and the target signal, δ represents the interference mismatch filter energy constraint coefficient, Indicates a shift matrix, Indicates a 0 padding matrix, wherein, I N Indicates an N-dimensional unit matrix.

[0040] Further, the step S5 is specifically as follows:

[0041] The optimal interference mismatch filter w solved in step S4 is used for interference mismatch filtering processing on the radar echo, and the filtered signal is represented as

[0042] The method of the present application firstly establishes a radar receiving waveform model under a multi-target multi-interval sampling interference scene, secondly designs a target mismatch filter based on the radar transmitting signal, uses the filter to perform target mismatch filtering on the radar echo signal, and extracts the interference coverage section signal on the radar echo time domain in combination with the target matched filtering; then designs an interference mismatch filter based on the interference signal and the radar transmitting signal, and uses the filter to perform interference mismatch filtering on the radar echo signal to suppress the multi-interval sampling interference signal in the echo. The method of the present application extracts the interference signal pulse by pulse and filters out, does not need to rely on accurate interference parameter prior information, is still effective in the case of target and interference overlap and multiple interference, can adapt to the multi-interval sampling interference parameter pulse level dynamic change scene, has high practicability, strong robustness and low complexity, and has high engineering application value. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 It is a flow chart of a two-stage mismatch filtering method against multi-main lobe interval sampling interference of the present application.

[0044] Figure 2 It is a schematic diagram of an interference signal extraction framework based on target mismatch filtering and target matched filtering in the embodiment of the present application.

[0045] Figure 3 It is a schematic diagram of an interference mismatch filter design framework based on the interference signal and the radar transmitting signal in the embodiment of the present application.

[0046] Figure 4 Figure 1 is a schematic diagram of an anti-jamming performance analysis in an embodiment of the present application. DETAILED DESCRIPTION

[0047] The method of the present application is further illustrated below in conjunction with the accompanying drawings and examples.

[0048] As shown in Figure 2, a flow chart of a two-stage mismatched filtering anti-multi-main-lobe intermittent sampling jamming method of the present application, the specific steps are as follows: Figure 1

[0049] S1, construct a radar receiving waveform model under a multi-target multi-intermittent sampling jamming scenario;

[0050] S2, design a target mismatched filter based on the radar transmitted signal;

[0051] S3, based on the target mismatched filter designed in step S2, perform target mismatched filtering on the radar echo, and in combination with target matched filtering, extract the jamming coverage segment signal in the radar echo;

[0052] S4, based on the jamming signal extracted in step S3, design a jamming mismatched filter;

[0053] S5, based on the jamming mismatched filter designed in step S4, perform jamming mismatched filtering on the radar echo to suppress the multi-intermittent sampling jamming signal in the echo.

[0054] In this embodiment, step S1 is specifically as follows:

[0055] Suppose the radar transmits a linear frequency modulation signal, and the waveform s T (t) is expressed as follows:

[0056] s T (t) = rect(t / T p )exp(2f0πt + jπB / T p t 2 ),

[0057] where t ∈ [0, ∞) represents a time variable, rect(·) represents a rectangular window function, B and f0 represent the bandwidth and carrier frequency of the radar transmitted signal respectively, and T p represents the pulse width of s T (t);

[0058] Suppose there is a single point target and Z jamming sources, the distance and speed of the target relative to the radar are R T and v T respectively, and the distance and speed of the z = 1, 2, …, Z jamming sources relative to the radar are R z and v z respectively;

[0059] ​Radar received waveform s R (t) is composed of target echo, jamming and noise, and the expression is as follows:

[0060]

[0061] Wherein, λ and c respectively represent the wavelength of radar transmitted waveform and the propagation speed of electromagnetic wave; And the complex amplitude of the zth jamming waveform, Indicates the complex domain, J z (t) represents the zth down-converted jamming waveform, n(t)

[0062] Indicates a Gaussian white noise signal;

[0063] Intermittent sampling and repeated forwarding of jamming in radar received waveform J z (t), the expression is as follows:

[0064]

[0065] Wherein, the expression of g(t) is as follows:

[0066]

[0067] Wherein, T L And T S Respectively represent the sampling duration and sampling interval, Indicates the number of forwarding times, Indicates the number of sampling times; T p Indicates the pulse width of the jamming machine intercepted waveform s J (t); s J (t) = s T (t-T0) represents the radar waveform intercepted by the jamming machine, T0 represents the starting sampling time of the jamming machine, which takes the time when the radar waveform is intercepted.

[0068] In this embodiment, the step S2 is specifically as follows:

[0069] The discrete sequence expression obtained after sampling the radar transmitted signal s T (t) is as follows:

[0070]

[0071] Wherein, N represents the length of the discrete signal.

[0072] Design target mismatch filter Suppress the target signal in the echo and highlight the jamming signal, and the expression is as follows:

[0073]

[0074] where N denotes the length of the target mismatched filter.

[0075] The optimal target mismatched filter is solved by minimizing the cross-correlation sidelobe integral level between the target mismatched filter and the target signal and the frequency-domain template matching error, combined with the filter energy constraint. The specific optimization problem is as follows:

[0076]

[0077] where ξ1 denotes a multi-target linear weighting coefficient, (·) H denotes a conjugate transpose operator, denotes a shift matrix, and ||·||2 denotes a 2-norm, whose (k m ,k n ) element value is defined as follows:

[0078]

[0079] F denotes a Fourier transform matrix, and its expression is as follows:

[0080]

[0081] where denotes a spectrum template, which can be expressed as:

[0082]

[0083] The above optimization problem is a quadratic constraint quadratic programming (QCQP) problem with a single constraint, and the optimal target mismatched filter has a closed-form solution.

[0084] In the embodiment, the step S3 is based on the interference signal extraction framework of target mismatched filtering and target matched filtering as Figure 2 shown, and the specific process is as follows:

[0085] S31, target mismatched filtering and CME detection;

[0086] First, the radar echo is subjected to target mismatched filtering processing by using the optimal target mismatched filter solved in the step S2, and the filtered signal is denoted as

[0087] Then, the CME algorithm is used to perform interference detection on in the time domain. It is assumed that D iterations are experienced in the CME detection process, and an interference position index set is obtained in each iteration:

[0088] ​

[0089] wherein, denotes the interference position index set obtained in the dth iteration, and the set contains elements in total.

[0090] The interference position index set finally obtained through the CME algorithm detection is as follows:

[0091]

[0092] wherein, denotes the set union operator.

[0093] is a discrete point position index, in order to obtain a continuous interference position, the point position index in is connected by using the connected domain algorithm. The specific operation is as follows: if the distance between an element and the next element in is greater than T p / 2*f s , wherein f s is a sampling frequency, it is considered that the element and the next element are not connected; if the distance between an element and the next element in is less than or equal to T p / 2*f s , it is considered that the element and the next element are connected. After the connection, a plurality of connected regions are obtained, and the longest connected region is taken as the final interference coverage range, denoted by , wherein, denotes the first element in , denotes the last element in .

[0094] S32, target matching filtering and CME detection;

[0095] First, the target matching filter is used to perform target matching filtering processing on the radar echo, and the filtered signal is denoted by

[0096] Then, the CME algorithm is used to perform interference detection on in the time domain, and it is assumed that D iterations are experienced in the CME detection process, and an interference position index set is obtained in each iteration:

[0097]

[0098] wherein, denotes the interference position index set obtained in the dth iteration, and the set contains elements in total. ​

[0099] The set of interference location indices obtained by the CME algorithm after D iterations is as follows:

[0100]

[0101] The values ​​in the table are discrete point location indices. To obtain a continuous set of interference locations, a connected component algorithm is used. Connect the points within the range using their position indices. Specifically, if... The distance between a certain element and the next element is greater than T. p / 2*f s If the element is not connected to the next element, then it is considered that the element is not connected to the next element; if The distance between a certain element and the next element is less than or equal to T. p / 2*f s If an element is connected to the next element, then it is considered connected. After connecting the elements, several connected regions are obtained. The longest connected region is taken as the final interference coverage area. It means that, among them, express The first element in express The last element in the middle.

[0102] S33. Interference signal extraction;

[0103] First, the two sets of interference location indices obtained in steps S31 and S32 are processed. and Finding the intersection yields the following new set of interference location indices:

[0104]

[0105] Where ∩ represents the set intersection operator, express The number of elements in, a begin express The first element, a end express The last element in the middle.

[0106] The CFAR algorithm is then used to detect the radar echo, resulting in a set of peak point location indices. This set contains Find the elements in the set. China belongs to Minimum peak point location index

[0107]

[0108] wherein min(·) denotes a minimum value operator of a sequence.

[0109] Finally, the [l min end ] segment signal extracted from the radar echo time-domain signal is the interference coverage segment signal, denoted as:

[0110]

[0111] wherein M denotes the length of the extracted interference segment signal.

[0112] In the embodiment, the step S4 is based on an interference mismatch filter design framework of the interference signal and the radar transmission signal, as shown in Figure 3 , and specifically as follows:

[0113] According to the interference signal and the radar transmission signal extracted in the step S3, an interference mismatch filter , and the expression is as follows:

[0114]

[0115] wherein M denotes the length of the interference mismatch filter.

[0116] By minimizing the cross-correlation sidelobe integral level between the interference mismatch filter and the interference signal, combining the cross-correlation sidelobe integral level constraint between the interference mismatch filter and the target signal, the target main lobe peak energy constraint after the interference mismatch filtering, and the energy constraint of the interference mismatch filter, the optimal interference mismatch filter is solved, and the specific optimization problem is as follows:

[0117]

[0118] wherein ξ2 denotes the cross-correlation sidelobe integral level constraint coefficient between the interference mismatch filter and the target signal, δ denotes the energy constraint coefficient of the interference mismatch filter, denotes a shift matrix, denotes a 0 padding matrix, wherein I N denotes an N-dimensional unit matrix.

[0119] The above optimization problem is a convex problem with multiple constraints, which can be efficiently solved by using a convex optimization solver (such as CVX).

[0120] In the embodiment, the step S5 is specifically as follows:

[0121] The optimal interference mismatch filter solved in the step S4 is used to perform interference mismatch filtering processing on the radar echo, and the filtered signal is denoted as At this time, ​The main lobe peak value of the target signal is retained after the target signal is greatly suppressed.

[0122] Figure 4 The figure is used for analyzing the anti-interference performance of the embodiment of the present application. Figure 4 (a) is the result of the radar echo after target matched filtering and CFAR processing; Figure 4 (b) and (c) are respectively the results of the radar echo after target matched filtering and target mismatched filtering processing, and the point results and connected results obtained by the CME algorithm after the results of filtering; Figure 4 (d) is the comparison of the interference signal extracted by the algorithm and the real interference signal; Figure 4 (e) is the result of the radar echo after interference suppression by the optimal interference mismatched filter solved; Figure 4 (f) is the figure for comparing and analyzing the anti-interference performance of the method of the present application with the shape domain filtering method and the time-frequency filtering method.

[0123] It can be seen that compared with the waveform domain filtering method and the time-frequency filtering method, the method of the present application has higher signal-to-interference ratio improvement and smaller signal-to-noise ratio loss, and can resist the interference scene in which multiple intermittent sampling interference with strong energy overlaps with the target signal.

[0124] In summary, the method of the present application designs a target mismatched filter by using the radar transmitting signal, extracts the interference signal based on target mismatched filtering, target matched filtering and CFAR processing in the time domain of the radar echo, designs an interference mismatched filter based on the extracted interference signal, and filters the radar echo by using the optimal interference mismatched filter solved to resist the intermittent sampling interference. The method of the present application has the advantage of not needing accurate interference parameter estimation, can adapt to the scene in which multiple intermittent sampling interference with different parameters is superimposed and the target and the interference are highly overlapped, has adaptability to scene changes, has significant feasibility and practicability in engineering implementation, and has high engineering application value.

[0125] Those skilled in the art will realize that the embodiments described herein are for the purpose of helping the reader understand the principles of the present application, and should be understood as not limiting the protection scope of the present application to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations according to the technical inspiration disclosed by the present application without departing from the essence of the present application, and these modifications and combinations are still within the protection scope of the present application.

Claims

1. A two-stage mismatched filtering anti-multi-main-lobe intermittent sampling interference method, specifically comprising the following steps: S1. Constructing a radar receiving waveform model under a multi-target multi-intermittent sampling interference scenario; S2. Designing a target mismatched filter based on a radar transmitting signal; S3. Target mismatched filtering the radar echo based on the target mismatched filter designed in step S2, combining target matched filtering, and extracting an interference coverage section signal in the radar echo; S4. Designing an interference mismatched filter based on the interference coverage section signal extracted in step S3; S5. Interference mismatched filtering the radar echo based on the interference mismatched filter designed in step S4, and suppressing the multi-intermittent sampling interference signal in the echo.

2. The two-stage mismatched filtering method against multi-main-lobe intermittent sampling interference according to claim 1, characterized in that, The step S1 is specifically as follows: Let the existence of U targets and Z intermittent sampling interference, the distance and speed of the u (u ∈ [1, 2, …, U]) target relative to the radar are R u And v u , the distance and speed of the z (z ∈ [1, 2, …, Z]) interference relative to the radar are R z And v z ; Radar receive waveform s R (t) as follows: where s T (t) is the radar transmitted signal, t∈[0,∞) represents the time variable, λ and c represent the radar transmitted waveform wavelength and electromagnetic wave propagation speed respectively; respectively represent the complex amplitude of the u-th target echo and the z-th jamming waveform, represents the complex domain, J z (t) represents the z-th down-converted jamming waveform, and n(t) represents a Gaussian white noise signal.

3. The two-stage mismatched filtering method against multi-main-lobe intermittent sampling interference according to claim 2, characterized in that, The step S2 is specifically as follows: The radar transmit signal s is defined as T (t) The discrete sequence representation after sampling is given by Wherein, N represents the length of a discrete signal. Designing a target mismatch filter of length N The optimal target mismatch filter is solved by minimizing the cross-correlation sidelobe integral level and the frequency-domain template matching error between the target mismatch filter and the target signal, combined with the filter energy constraint. The specific optimization problem is as follows: wherein, ξ1 represents a multi-objective linear weighting coefficient, (·) H denotes a conjugate transpose operation, denotes a shift matrix, denotes a Fourier transform matrix, denotes a spectrum template, and ||·||2 denotes a 2-norm.

4. The two-stage mismatched filtering method against multi-main-lobe intermittent sampling interference according to claim 3, characterized in that, The step S3 is specifically as follows: S31. Target mismatched filtering and CME detection; First, the optimal target mismatch filter solved in step S2 is used The radar echo is target mismatch filtered, and the filtered signal is denoted as The CME algorithm is used to detect interference in the time domain to obtain a set of interference position indexes The set of interference position indexes is discrete. To obtain a continuous interference position, the connected domain algorithm is used to connect the indexes in The indexes in are discrete. To obtain a continuous interference position, the connected domain algorithm is used to connect the indexes in After connection, a number of connected regions are obtained. The longest connected region is taken as the final interference coverage range, denoted as ​ S32. Target matched filtering and CME detection; Firstly, the target matched filter is used The radar echo is target matched filtered, and the filtered signal is denoted as Then, the CME algorithm is used to detect the jamming in time domain The obtained jamming position index set is is the discrete point position index, in order to obtain a continuous jamming position, the connected domain algorithm is used to connect the point position index in After connection, a plurality of connected regions are obtained, and the longest connected region is taken as the final jamming coverage range, denoted as ​ S33. Interference signal extraction; First, the two sets of interference position indexes obtained in step S31 and step S32 are intersected to obtain a new set of interference position indexes as follows: and ​ Wherein, ∩ represents a set intersection operator. The CFAR algorithm is used for detecting the radar echo to obtain a peak point position index set Finding the minimum peak point position index l in the set min .​ Finally, the [l min ,a end ] segment signal extracted from the radar echo time-domain signal is the interference coverage segment signal, where a end represents the last element, and the extracted interference signal is denoted by b, with a length of M.

5. The two-stage mismatched filtering method against multi-main-lobe intermittent sampling interference according to claim 4, characterized in that, The step S4 is specifically as follows: According to the interference signal and the radar transmitting signal extracted in step S3, an interference mismatch filter with a length of M is designed By minimizing the cross-correlation sidelobe integral level between the interference mismatch filter and the interference signal, combining the cross-correlation sidelobe integral level constraint between the interference mismatch filter and the target signal, the target main lobe peak energy constraint after the interference mismatch filtering, and the energy constraint of the interference mismatch filter, the optimal interference mismatch filter is solved, and the specific optimization problem is as follows: wherein ξ2 represents a cross-correlation sidelobe integral level constraint coefficient between the interference mismatched filter and the target signal, and δ represents an interference mismatched filter energy constraint coefficient, denotes a shift matrix, denotes a zero padding matrix, wherein I N denotes an N-dimensional identity matrix.

6. The two-stage mismatched filtering method against multi-main-lobe intermittent sampling interference according to claim 5, characterized in that, The step S5 is specifically as follows: The optimal interference mismatch filter solved in step S4 is used The radar echo is subjected to interference mismatch filtering, and the filtered signal is represented as

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