A method for suppressing intermittent sampling and forwarding interference based on multi-channel singular spectrum analysis

Abstract

A method for suppressing intermittent sampling and forwarding interference based on multi-channel singular spectrum analysis uses the principle of multi-channel singular spectrum analysis to decompose time series into trend terms, periodic terms and noise terms. Based on the characteristics of intermittent sampling and forwarding interference signals being non-continuous in time domain and high interference-to-signal ratio required for effective interference, the real and imaginary parts of radar target echo signals containing intermittent sampling and forwarding interference are jointly processed, the trend term after signal decomposition is used as the interference signal, the interference parameters are extracted and the interference is reconstructed, so as to obtain a better suppression effect on intermittent sampling and forwarding interference.

Description

Technical Field

[0001] The invention relates to the field of radar countermeasures, and in particular to an intermittent sampling forwarding interference suppression method based on multi-channel singular spectrum analysis. Background Art

[0002] The interference and anti-interference of radar are developed synchronously and promote each other. Linear frequency modulation (LFM) pulse compression radar can simultaneously obtain high range resolution and large detection range by transmitting large time-bandwidth product signals and matching filtering or de-frequency modulation processing during reception. Since the pulse compression gain cannot be obtained for signals irrelevant to the radar, pulse compression radar has strong anti-interference ability and has been widely used in current radars. The interference of linear frequency modulation pulse compression radar is generally achieved by forwarding interference through digital radio frequency memory (DRFM) technology. Effective interference styles include complete forwarding interference, intermittent sampling forwarding interference and smart noise interference. Among them, intermittent sampling forwarding interference is a new type of interference style. It can generate a large number of coherent false target interference by using DRFM to sample the radar signal and forward it multiple times. It has the advantages of fast response speed, low requirements for interference hardware resources, and flexible interference mode. Therefore, it is a commonly used linear frequency modulation pulse compression radar interference method.

[0003] Corresponding to the research on intermittent sampling forwarding interference, anti-intermittent sampling forwarding interference has also received extensive attention. Intermittent sampling forwarding interference is discontinuous in the time domain, frequency domain and time-frequency domain, and the interference signal is coherent with the radar transmission signal. After pulse compression processing, multiple peaks similar to the target appear, making it difficult to suppress by traditional methods. At present, the suppression of intermittent sampling forwarding interference is generally achieved by the method of interference reconstruction. First, the type of interference is identified, and then the interference parameters are obtained according to the time domain, frequency domain and time-frequency domain characteristics of the interference. The interference is reconstructed according to the estimated parameters and the intermittent sampling forwarding interference model, and finally the echo signal and the reconstructed interference are cancelled. Both theoretical and measured data processing show that interference reconstruction is an effective method to resist intermittent sampling forwarding interference, and the key to this method is how to reconstruct the interference parameters, among which the key interference parameters include the interference start time, interference sampling period, interference sampling duration, interference power, etc.

[0004] In the prior art, the parameter estimation method based on Hilbert-Huang transform (HHT) is used for intermittent sampling forwarding interference parameter estimation. HHT transform can process nonlinear and non-stationary signals. This method first obtains an intrinsic mode function (IMF) of the echo signal received by the radar through the empirical mode decomposition (EEMD) method, performs Hilbert transform on each intrinsic mode function, generates a complex analytical signal, and obtains the instantaneous frequency; then, the instantaneous frequency and instantaneous amplitude of all intrinsic mode functions are combined over time to obtain the time-frequency spectrum of all time series segments of the signal, that is, the Hilbert-Huang spectrum; finally, by searching the time point of the frequency jump in the Hilbert-Huang spectrum, the time point of each interference slice can be obtained, and the key parameters such as the starting sampling time, sampling period, and sampling duration of the intermittent sampling forwarding interference can be estimated.

[0005] Singular spectrum analysis (SSA) is a nonlinear signal processing method that can decompose a one-dimensional signal into the sum of several independent subsequences. When SSA is used for echo signal extraction, it can automatically remove the noise of the echo signal and separate and extract the signal components of different frequency bands. The radar echo signal can be regarded as a one-dimensional signal contaminated by noise, and the SSA method can also be used for noise suppression. Since the interference signal in intermittent sampling and forwarding interference is non-continuous in the time domain, and to achieve effective interference, a higher interference-to-signal ratio is required, that is, the amplitude of the interference echo must be significantly greater than the amplitude of the target echo. Therefore, when there is intermittent sampling and forwarding interference, the radar echo signal containing interference is significantly different from the radar echo signal containing noise, and the singular spectrum analysis method cannot be directly used to suppress or extract the interference signal.

[0006] Regardless of whether it is based on HHT or SSA, the input of the radar echo analysis method is a one-dimensional real sequence, and the received interference signal is a complex signal synthesized by I and Q. Therefore, only the real part or the imaginary part of the complex signal can be selected for processing. Since both the real and imaginary parts of the signal contain target information and interference information, processing only part of the data will lose a lot of effective information, resulting in limited accuracy of parameter estimation. Summary of the invention

[0007] The object of the present invention is to provide an intermittent sampling forwarding interference suppression method based on multi-channel singular spectrum analysis, so as to solve the above-mentioned problems existing in the prior art.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A method for suppressing intermittent sampling and forwarding interference based on multi-channel singular spectrum analysis comprises the following steps:

[0010] S1, extract the real part and imaginary part of the target echo signal containing intermittent sampling forwarding interference received by the radar, and generate a two-dimensional matrix X;

[0011] S2. Generate a data matrix X based on the two-dimensional matrix X obtained in step S1:

[0012]

[0013] Where: x i,j ,i=1,2,j=1,2…,N-M+1 represents the element in the i-th row and j-th column of the matrix X, N is the number of columns of the matrix X, and M is the window length; X is a (2M)×(N-M+1) matrix, and each of its rows is a subsequence of the original echo signal;

[0014] S3, performing singular value decomposition on the data matrix X in step S2;

[0015] S4, grouping and reconstructing the components formed in step S3, the reconstruction formula is expressed as:

[0016]

[0017] S5, the interference signal z reconstructed according to step S4 1,1 ,z 1,2 ,…,z 1,N , set the energy threshold E of the interference signal t and time threshold T t ; When the energy of the reconstructed interference signal is greater than the energy threshold E t When , it is judged that there is intermittent sampling forwarding interference, otherwise there is no interference; according to the time interval of the reconstructed interference signal and the time threshold T t , determine whether two adjacent interference slices belong to the same interference;

[0018] S6, reconstructing the interference signal in complex form according to the parameters of the interference signal obtained in step S5, and calculating and obtaining the signal after frequency modulation;

[0019] S7, canceling the radar received callback signal with the reconstructed interference signal after frequency modulation in step S6, so as to obtain an echo signal after intermittent sampling and forwarding interference suppression.

[0020] Preferably, the generation of the two-dimensional matrix in step S1 includes the following steps:

[0021] S11. Set the linear frequency modulation signal emitted by the radar to:

[0022] Where rect[·] is the rectangular window function, t is the time, T p is the pulse width, is the imaginary unit, f c is the center frequency, K is the frequency modulation frequency;

[0023] S12. According to the transmitted signal, the radar echo signal s(t) of the ideal target point is obtained:

[0024]

[0025] Wherein, τ is the delay of the radar echo signal of the ideal target point, R is the distance between the radar and the ideal target point;

[0026] and the radar signal captured by the jammer J (t):

[0027]

[0028] Among them, τ J is the echo delay of the radar transmission signal captured by the jammer, then R J is the distance between the jammer and the radar;

[0029] S13, setting the intermittent sampling pulse train q(t) of the jammer;

[0030] S14, according to the radar signal captured by the jammer in step S12 and the intermittent sampling pulse string in step S13, the jammer generated interference signal J is obtained ISDJ (t): J ISDJ (t)=q(t)*s J (t);

[0031] S15, total signal s received by radar receiver Total (t) is the sum of radar target echo and interference signal, expressed as: s Total (t) = s(t) + J ISDJ (t-τ r ) is, where τ r is the signal transmission delay of the jammer;

[0032] S16, assuming that pulse compression adopts the frequency modulation method, the transmitted signal p(t) is used as the reference signal S ref (t), that is, S ref (t) = p(t), according to the total signal received by the radar receiver in step S15, the signal after FM reception is obtained as follows: in S ref The complex conjugate of (t);

[0033] S17, the signal S after the FM reception in step S16 is removed r(t) is sampled, quantized, and converted into a digital signal, denoted as S r (nT s ), where T s is the jammer sampling period, n=1,2,…,N is the sampling sequence;

[0034] S18, the digital signal S in step S17 r (nT s ), extract its real part and imaginary part respectively, and form a two-dimensional matrix X, that is, Where Re{S r (nT s )} and Im{S r (nT s )} respectively represent S r (nT s )'s real and imaginary parts.

[0035] Preferably, the intermittent sampling pulse train of the jammer is:

[0036] Among them, T s is the jammer sampling period, τ s is the sampling duration, N is the number of sampling points, represents the convolution operation, and δ(t) is the unit impulse.

[0037] Preferably, the components in step S4 are grouped in the following manner: define a matrix S=XX T , X T is the transposed matrix of X; let the eigenvalues ​​of matrix S be λ1,…,λ M And in descending order, (λ1≥…≥λ M ≥0), the largest eigenvalue after singular value decomposition is λ1, so the matrix corresponding to the eigenvalue λ1 as an interference signal.

[0038] Preferably, the parameter estimation method for the reconstructed interference signal in step S5 is: when the time interval between two interference slices is less than the time threshold T t When the time interval is greater than the time threshold T t When , it is determined to be the next interference slice; by estimating the start time and end time of each interference slice, the interference start time can be estimated Interference sampling period Sampling time

[0039] Where N represents the total number of interfering slices, Tstart n Indicates the starting time of the nth slice, T end n Indicates the end time of the nth slice.

[0040] The beneficial effects of the present invention are as follows: the present invention discloses an intermittent sampling forwarding interference suppression method based on multi-channel singular spectrum analysis, which utilizes the principle of multi-channel singular spectrum analysis to decompose a time series into a trend term, a periodic term and a noise term, and based on the characteristics of the intermittent sampling forwarding interference signal being non-continuous in the time domain and the high interference-to-signal ratio required for effective interference, the real and imaginary parts of the radar target echo signal containing intermittent sampling forwarding interference are jointly processed, the trend term after signal decomposition is used as the interference signal, the interference parameters are extracted and the interference is reconstructed, so as to obtain a better suppression effect on the intermittent sampling forwarding interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a flow chart of the intermittent sampling and forwarding interference suppression method based on multi-channel singular spectrum analysis;

[0042] Figure 2 It is the time domain waveform and spectrum diagram of the radar transmission signal;

[0043] Figure 3 It is the time domain waveform and spectrum diagram of the echo signal received by the ideal point target;

[0044] Figure 4 It is the result of receiving signal pulse compression;

[0045] Figure 5 It is the time domain waveform and spectrum received by the jammer;

[0046] Figure 6 It is the time domain waveform after the intermittent sampling and forwarding interference signal is de-frequency modulated;

[0047] Figure 7 It is the pulse compression result of the intermittent sampling and forwarding interference signal;

[0048] Figure 8 These are the component signals decomposed by the MSSA and HHT methods;

[0049] Fig. 9 It is the interference signal extracted by MSSA and HHT methods;

[0050] Fig.10 The interference signal envelope is obtained by using two methods, MSSA and HHT.

[0051] Fig.11 It is the result of MSSA and HHT methods after amplitude thresholding;

[0052] Fig.12It is the reconstruction result of the interference signal MSSA and HHT methods;

[0053] Fig.13 It is the echo signal after interference suppression obtained by the MSSA and HHT methods;

[0054] Fig.14 It is the pulse compression result of the echo signal after interference suppression by the MSSA and HHT methods. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation methods described herein are only used to explain the present invention and are not used to limit the present invention.

[0056] A method for suppressing intermittent sampling and forwarding interference based on multi-channel singular spectrum analysis, such as Figure 1 As shown, the following steps are included:

[0057] S1. For the target echo signal received by the radar containing intermittent sampling and forwarding interference, extract the real part and imaginary part of the signal respectively to generate a two-dimensional matrix:

[0058] The generation of a two-dimensional matrix includes the following steps:

[0059] S11. Assume that the linear frequency modulation signal emitted by the radar is:

[0060]

[0061] Where rect[·] is the rectangular window function, t is time, T p is the pulse width, is the imaginary unit, f c is the center frequency, K is the frequency modulation frequency;

[0062] S12. Based on the radar's transmitted signal, without considering the signal amplitude, the radar echo signal s(t) corresponding to the ideal target point is:

[0063]

[0064] Among them, τ is the delay of the echo signal of the ideal target point, R is the distance between the radar and the ideal target point;

[0065] and the radar signal captured by the jammer J (t):

[0066]

[0067] Among them, τJ is the echo delay of the radar transmission signal captured by the jammer, then R J is the distance between the jammer and the radar;

[0068] S13. Assume that the intermittent sampling pulse train of the jammer is:

[0069] Among them, T s is the jammer sampling period, τ s is the sampling duration, N is the number of sampling points, represents the convolution operation, δ(t) is the unit impulse;

[0070] S14, according to the radar signal captured by the jammer in step S12 and the intermittent sampling pulse string in step S13, the jammer generated interference signal J is obtained ISDJ (t): J ISDJ (t) = q(t)*s J (t);

[0071] S15, total signal s received by radar receiver Total (t) is the sum of radar target echo and interference signal, expressed as: s Total (t) = s(t) + J ISDJ (t-τ r ) is, where τ r is the signal transmission delay of the jammer;

[0072] S16, assuming that pulse compression adopts the frequency modulation method, the transmitted signal p(t) is used as the reference signal S ref (t), that is, S ref (t) = p(t), according to the total signal received by the radar receiver in step S15, the signal after FM reception is obtained as follows: in S ref The complex conjugate of (t);

[0073] S17, the signal S after the FM reception in step S16 is removed r (t) is sampled, quantized, and converted into a digital signal, denoted as S r (nT s ), where T s is the jammer sampling period, n=1,2,…,N is the sampling sequence;

[0074] S18, the digital signal S in step S17 r (nT s ), extract its real part and imaginary part respectively, and form a two-dimensional matrix X, that is, Where Re{S r(nT s )} and Im{S r (nT s )} respectively represent S r (nT s )'s real and imaginary parts.

[0075] S2. Based on the two-dimensional matrix X obtained in step S1, the data matrix X is generated as follows:

[0076]

[0077] Where: x i,j ,i=1,2,j=1,2…,N-M+1 represents the element in the i-th row and j-th column of the two-dimensional matrix X, N is the number of columns of the two-dimensional matrix X, and M is the window length; the data matrix X is a (2M)×(N-M+1) matrix, and each of its rows is a subsequence of the original echo signal;

[0078] S3, perform singular value decomposition on the data matrix X in step S2:

[0079] Define the matrix S = XX T , X T is the transposed matrix of X; let the eigenvalues ​​of matrix S be λ1,…,λ M And in descending order, (λ1≥…≥λ M ≥0), the corresponding eigenvectors are E1,…,E M , where E i Satisfies: ||E i ||=1, when i≠j, (E i ,E j ) = 0. Let d = rank(X), Then the matrix X can be expressed as: X = X1 + X2 + ... + X d ; where the matrix It has the same matrix structure as the data matrix X. is the eigenvalue of X. After the eigenvalue and the size of the eigenvector are determined, the trend term, period term and noise term can be obtained by performing singular value decomposition on X.

[0080] S4, grouping and reconstructing the components formed in step S3:

[0081] Grouping is to group the matrix X iThe interference signal is divided into independent subsets, which represent different components of the time series, such as trend terms, periodic terms and noise terms. Since the time of intermittent sampling and forwarding interference signals is discontinuous, and the amplitude of the interference signal is much larger than the amplitude of the target echo, a multi-channel singular spectrum analysis is performed on the radar echo with interference. The interference signal corresponds to the trend term after decomposition, that is, the interference signal corresponds to the largest eigenvalue component. After singular value decomposition, the largest eigenvalue is λ1, so the matrix corresponding to the eigenvalue λ1 is as an interference signal.

[0082] Reconstruction is to convert X1 back into a sub-time series of length N, and define Z = X1, z 1,1 ,z 1,2 ,…,z 1,N is the sequence obtained by diagonal averaging of Z, let M * =min(M,K),K * =max(M,K), where N = M-K+1. If M>K, then otherwise The reconstruction formula is expressed as:

[0083]

[0084] S5, the interference signal z reconstructed according to step S4 1,1 ,z 1,2 ,…,z 1,N , set the energy threshold E of the interference signal t and time threshold T t ; When the energy of the reconstructed interference signal is greater than the energy threshold E t When , it is judged that there is intermittent sampling forwarding interference, otherwise there is no interference; according to the time interval of the reconstructed interference signal and the time threshold T t , determine whether two adjacent interference slices belong to the same interference, when the time interval between them is less than the time threshold T t When the time interval is greater than the time threshold T t When , it is determined to be the next interference slice; by estimating the start time and end time of each interference slice, the interference start time can be estimated Interference sampling period Sampling time

[0085] Where N represents the total number of interfering slices, T start n Indicates the starting time of the nth slice, T end n Indicates the end time of the nth slice.

[0086] S6. Reconstruct the interference signal in complex form according to the parameters of the interference signal obtained in step S5:

[0087]

[0088] in, is the interference start time estimated in step S5, is the interference sampling period estimated in step S5, is the interference duration estimated in step S5; the reconstructed interference signal is de-modulated to obtain a signal after de-modulation: in S ref (nT s ), the complex conjugate of ref (nT s ) is S ref (t) the sampled signal;

[0089] S7, canceling the radar received callback signal with the reconstructed interference signal after frequency modulation in step S6, so as to obtain an echo signal after intermittent sampling and forwarding interference suppression: in, For S r (nT s )The normalized signal.

[0090] S8, the echo signal S obtained after suppression in step S7 t '(n) Perform inverse Fourier transform to obtain the pulse compression result after interference suppression.

[0091] Example

[0092] Assume that the parameters of the radar transmitting linear frequency modulation signal are: time width 10us, bandwidth 30MHz, and the target distance from the radar is 3.5km, then its echo delay is 23.33us; the intermittent sampling direct forwarding interference parameters are: sampling period 2us, sampling time 0.5us, a total of 5 slices, interference delay 0.4us, signal-to-noise ratio 10dB, interference-to-signal ratio 10dB, and sampling frequency 150MHz.

[0093] The time domain waveform and spectrum of the transmitted signal are as follows: Figure 2 As shown, the time domain waveform and spectrum of the received signal are as follows Figure 3 As shown; the received signal is de-frequency modulated and the pulse compression result after inverse Fourier transform is as follows Figure 4 shown.

[0094] When intermittent sampling and forwarding interference exists, the time domain waveform and spectrum of the signal received by the jammer are as follows: Figure 5As shown, the received wave is de-FM received and the result is as follows Figure 6 The pulse compression results are shown in Figure 7 shown.

[0095] right Figure 6 The results shown are decomposed by MSSA to obtain the results of each component as follows Figure 8 (a) For comparison, the IMF components of the HHT method are shown in Figure 8 (b) as shown; Figure 8 As can be seen from (a), the first two components of MSSA decomposition mainly contain interference echoes. Figure 8 As can be seen in (b), the first two IMFs decomposed by EEMD also mainly contain interference echoes.

[0096] The first two components obtained by the two processing methods are synthesized respectively to obtain the interference signals extracted by the MSSA method and the HHT method as shown in Fig. 9 As shown in Figure 2, compared with the HHT method, the echo signal obtained by the MSSA method in the interference gap is more stable. Fig. 9 The envelope of the interference signal is extracted respectively, and the results are as follows Fig.10 As shown. Set a suitable threshold value. Fig.10 The envelope of the detector is detected to obtain the slice where interference exists. Fig.11 As shown. Fig.11 The starting and ending time of each interference slice can be extracted, and the interference parameters can be estimated, including the interference start time, interference sampling period and interference duration; the three parameters extracted by the MSSA method are 0.407us, 0.515us and 2.000us, the three parameters extracted by the HHT method are 0.360us, 0.476us and 1.913us, and the real interference parameters are 0.400us, 0.500us and 2.000us. It can be seen that the interference parameters extracted by the MSSA method are closer to the real values.

[0097] According to the two sets of parameters extracted above, the intermittent sampling forwarding interference signal is reconstructed respectively, such as Fig.12 As shown; the reconstructed interference signal is cancelled with the normalized echo signal, and the result after cancellation is as follows Fig.13 As shown in Figure 2, it can be seen that after MSSA cancellation, less interference signal remains, while in the HHT method, due to the large error in estimating the interference sampling period, the subsequent cancellation effect accumulation error is large. The final pulse compression result is shown in Figure 2. Fig.14 As shown, it can be seen that the intermittent sampling forwarding interference suppression method proposed in the present invention has a performance that is significantly better than the existing HHT method.

[0098] By adopting the above-mentioned technical scheme disclosed in the present invention, the following beneficial effects are obtained: the present invention discloses a method for suppressing intermittent sampling forwarding interference based on multi-channel singular spectrum analysis, which utilizes the principle of multi-channel singular spectrum analysis to decompose a time series into trend terms, periodic terms and noise terms, and based on the characteristics of intermittent sampling forwarding interference signals that are non-continuous in the time domain and that the interference-to-signal ratio required for effective interference is high, the real and imaginary parts of the radar target echo signal containing intermittent sampling forwarding interference are jointly processed, the trend term after signal decomposition is used as the interference signal, the interference parameters are extracted and the interference is reconstructed, so as to obtain a better suppression effect on intermittent sampling forwarding interference.

[0099] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. A method for suppressing intermittent sampling and forwarding interference based on multi-channel singular spectrum analysis, characterized in that: The following steps are involved: S1, extract the real part and imaginary part of the target echo signal containing intermittent sampling forwarding interference received by the radar, and generate a two-dimensional matrix X; S2. Generate a data matrix X based on the two-dimensional matrix X obtained in step S1: Where: x i,j ,i=1,2,j=1,2…,N represents the element in the i-th row and j-th column of the two-dimensional matrix X, N is the number of columns of the two-dimensional matrix X, and M is the window length; the data matrix X is a (2M)×(N-M+1) matrix, and each of its rows is a subsequence of the original echo signal; S3, perform singular value decomposition on the data matrix X in step S2: Define the matrix S = XX T , X T is the transposed matrix of X; let the eigenvalues ​​of matrix S be λ1,…,λ M And in descending order, λ1≥…≥λ M ≥0, the corresponding eigenvectors are E1,…,E M , where E i Satisfies: ||E i ||=1, when i≠j, (E i ,E j )=0; let d=rank(X), i=1,…,d, then the matrix X can be expressed as: X=X1+X2+…+X d ; where the matrix It has the same matrix structure as the data matrix X; i=1,…,d is the eigenvalue of X. After the eigenvalue and the size of the eigenvector are determined, the trend term, period term and noise term can be obtained by performing singular value decomposition on X. S4, grouping and reconstructing the components formed after the singular value decomposition in step S3, Grouping is to group the matrix X i The interference signal is divided into independent subsets, which represent different components of the trend term, periodic term and noise term of the time series. Since the time of intermittent sampling and forwarding interference signal is discontinuous, and the amplitude of the interference signal is much larger than the amplitude of the target echo, a multi-channel singular spectrum analysis is performed on the radar echo with interference. The interference signal corresponds to the trend term after decomposition, that is, the interference signal corresponds to the largest eigenvalue component. The largest eigenvalue after singular value decomposition is λ1, so the matrix corresponding to the eigenvalue λ1 is As a jamming signal; Reconstruction is to convert X1 back into a sub-time series of length N, and define Z = X1, z 1,1 ,z 1,2 ,…,z 1,N is the sequence obtained by diagonal averaging of Z, let M * =min(M,K),K * =max(M,K), where N = M-K+1. If M>K, then otherwise The reconstruction formula is expressed as: S5, the interference signal z reconstructed according to step S4 1,1 ,z 1,2 ,…,z 1,N , set the energy threshold E of the interference signal t and time threshold T t ; When the energy of the reconstructed interference signal is greater than the energy threshold E t When , it is judged that there is intermittent sampling forwarding interference, otherwise there is no interference; according to the time interval of the reconstructed interference signal and the time threshold T t , determine whether two adjacent interference slices belong to the same interference; when the time interval between them is less than the time threshold T t When the time interval is greater than the time threshold T t When the interference slice is determined to be the next interference slice, the interference start time is estimated by estimating the start time and end time of each interference slice. Interference sampling period Interference sampling duration Where n = 1, 2, ..., N' is the number of sampling points, N' represents the total number of interference slices, that is, the total number of sampling points, T startn Indicates the starting time of the nth slice, T endn Indicates the end time of the nth slice; S6, reconstructing the interference signal in complex form according to the interference start time, interference sampling period and interference sampling duration of the interference signal obtained in step S5, and calculating and obtaining the signal after frequency modulation; The interference signal reconstructed in step S6 is: in, is the interference start time estimated in step S5, is the interference sampling period estimated in step S5, is the interference duration estimated in step S5, rect[·] is the rectangular window function, t is the time, is the imaginary unit, f c is the center frequency, K is the frequency modulation frequency; S7, canceling the radar received callback signal with the reconstructed interference signal after frequency modulation in step S6, so as to obtain an echo signal after intermittent sampling and forwarding interference suppression.

2. The method for suppressing intermittent sampling and forwarding interference based on multi-channel singular spectrum analysis according to claim 1, characterized in that: The generation of the two-dimensional matrix in step S1 includes the following steps: S11. Set the linear frequency modulation signal emitted by the radar to: Among them, T p is the pulse width; S12. According to the transmitted signal, the radar echo signal s(t) of the ideal target point is obtained: Wherein, τ is the delay of the radar echo signal of the ideal target point, R is the distance between the radar and the ideal target point; and the radar signal captured by the jammer J (t): Among them, τ J is the echo delay of the radar transmission signal captured by the jammer, then R J is the distance between the jammer and the radar; S13, setting the intermittent sampling pulse train q(t) of the jammer; S14, according to the radar signal captured by the jammer in step S12 and the intermittent sampling pulse string in step S13, the jammer generated interference signal J is obtained ISDJ (t): J ISDJ (t)=q(t)*s J (t); S15, total signal s received by radar receiver Total (t) is the sum of radar target echo and interference signal, expressed as: s Total (t) = s(t) + J ISDJ (t-τ r ) is, where τr is the signal transmission delay of the jammer; S16, assuming that pulse compression adopts the frequency modulation method, the transmitted signal p(t) is used as the reference signal S ref (t), that is, S ref (t) = p(t), according to the total signal received by the radar receiver in step S15, the signal after FM reception is obtained as follows: in S ref The complex conjugate of (t); S17, the signal S after the FM reception in step S16 is removed r (t) is sampled, quantized, and converted into a digital signal, denoted as S r (nT s ), where T s is the jammer sampling period; S18, the digital signal S in step S17 r (nT s ), extract its real part and imaginary part respectively, and form a two-dimensional matrix X, that is, Where Re{S r (nT s )} and Im{S r (nT s )} respectively represent S r (nT s )'s real and imaginary parts.

3. The method for suppressing intermittent sampling and forwarding interference based on multi-channel singular spectrum analysis according to claim 2, characterized in that: The intermittent sampling pulse train of the jammer is: Among them, τ s is the sampling duration, represents the convolution operation, and δ(t) is the unit impulse.

4. The method for suppressing intermittent sampling and forwarding interference based on multi-channel singular spectrum analysis according to claim 2, characterized in that: The interference suppressed echo signal obtained in step S7 is: in, For S r (nT s )The normalized signal.

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