SAR interference suppression method based on echo asynchronous pulse detection

Abstract

The invention discloses an SAR interference suppression method based on echo asynchronous pulse detection, and the method comprises the steps: constructing a local odd-even channel comparison mode or a global reference pulse comparison mode, directly carrying out the processing in a time domain of an SAR echo data matrix, determining a corresponding mode through the energy characteristics of an interference signal, and carrying out the detection of the interference signal. Constructing a channel difference mask and an outlier mask in the corresponding mode, and finally obtaining an interference mask in each mode; establishing a mask matrix based on the interference mask, and processing the amplitude matrix to obtain an amplitude matrix after interference suppression processing; and combining the phase matrix to obtain a final non-interference SAR echo data matrix. According to the method, interference artifacts brought to SAR image data by the forwarding type coherent interference can be suppressed, and the phenomenon of sidelobe deterioration of strong scattering points in the image after frequency domain notch is eliminated, so that the forwarding type coherent interference existing in the SAR echo data is effectively suppressed.

Description

Technical Field

[0001] This invention relates to the field of radar signal processing technology, specifically to a SAR interference suppression method based on echo asynchronous pulse detection, which is applied to the detection and suppression of repeater-type coherent radio frequency interference in synthetic aperture radar echo data processing. Background Technology

[0002] Spaceborne Synthetic Aperture Radar (SAR), as an important remote sensing imaging technology, features all-weather, all-time, and high-resolution Earth observation. However, with the increasing complexity of the space electromagnetic environment, spaceborne SAR systems are frequently subjected to radio frequency interference (RFI) from other radiation sources during operation. Among these, repeater-based coherent interference is one of the more common and damaging types of interference.

[0003] Coherent interference typically exhibits time-frequency characteristics similar to SAR signals, enabling it to coherently superimpose with radar echo signals, severely degrading SAR imaging quality and the accuracy of subsequent interpretation. Existing interference suppression methods mostly remove interference through filtering in the frequency or time-frequency transform domains. These methods usually require Fourier transforms or short-time Fourier transforms, resulting in high computational complexity and poor real-time performance. Furthermore, when the interference signal and the useful signal highly overlap in the frequency domain, such as in the case of coherent interference, frequency-domain methods can easily lose the useful signal while suppressing the interference, leading to a deterioration in imaging results. Summary of the Invention

[0004] The purpose of this invention is to provide a SAR interference suppression method based on echo asynchronous pulse detection, which can effectively detect and suppress repeater coherent interference in the time domain, while preserving the original signal details to the maximum extent, thereby achieving efficient interference suppression.

[0005] To achieve the above objectives, the present invention employs the following technical solution: A SAR interference suppression method based on echo asynchronous pulse detection includes: Obtain the SAR echo data matrix and determine its amplitude matrix and phase matrix; Based on the amplitude matrix, the corresponding interference concentration index is constructed by determining its azimuth power distribution variance and range power distribution variance, and a comprehensive decision function is constructed using the interference concentration index; based on the comprehensive decision function and the decision threshold, the local odd-even channel comparison mode or the global reference pulse comparison mode is selected. In the local odd-even channel comparison mode, the amplitude matrix is ​​separated along the azimuth direction according to odd and even to obtain odd and even channel data matrices; based on the average power of each row of data in the odd and even channel data matrices, the average power ratio is determined; based on the average power ratio and the threshold ratio, it is determined whether each row of data in the odd and even channel data matrices contains interference; for odd and even channel data with interference, its energy pulse difference is determined and smoothed before constructing a channel difference mask; For the global reference pulse comparison mode, the power of each pulse in the amplitude matrix is ​​determined, and then the reference pulse is determined based on the power threshold. By calculating the difference between each pulse in the amplitude matrix and the reference pulse, an interference mask is constructed and outlier detection is performed using the median absolute deviation method, thereby determining the outlier mask. Interference masks are determined in local odd-even channel contrast mode and global reference pulse contrast mode, respectively. Interference intervals in amplitude matrix are determined based on interference masks. The interference mask is extended in the distance direction and combined with the interference intervals to obtain the extended mask matrix. The amplitude matrix is ​​processed using the mask matrix to obtain the amplitude matrix after interference suppression. Based on the amplitude and phase matrices after interference suppression processing, an interference-free SAR echo data matrix is ​​obtained.

[0006] Furthermore, the interference concentration index includes an azimuth interference concentration index. and distance-oriented interference concentration index :

[0007] in, The variance of the azimuth power distribution. Let Variance be the power distribution variance in the distance direction. The azimuth average power, The average power in the range direction; Establish a comprehensive decision function:

[0008] in For the weighting coefficients, satisfying ; when When selecting the local odd / even channel contrast mode; when Select the global reference pulse comparison mode; This indicates the threshold for the decision.

[0009] Furthermore, the decision threshold ;in and These are the decision functions. The mean and standard deviation, It is the standard deviation factor.

[0010] Furthermore, based on the average power of each row of data in the odd and even channel data matrices, the average power ratio is determined; based on the average power ratio and the threshold ratio, it is determined whether each row of data in the odd and even channel data matrices contains interference, including: Calculate the average power ratio of each row of data in the odd and even channels:

[0011] Among them, the average power of odd and even channel data and By analyzing the odd channel data matrix Coupled Channel Data Matrix The Middle The result is obtained by averaging the row data. when At that time, further comparison of the first The average power of odd-channel and even-channel data is used; the channel with the higher average power contains interference. This represents the threshold ratio.

[0012] Furthermore, for odd and even channel data with interference, after determining their energy pulse difference and smoothing them, a channel difference mask is constructed, including: Calculate the first Energy difference pulses between odd-channel and even-channel data:

[0013] in , These represent the odd channel data matrices respectively. Coupled Channel Data Matrix The Middle The pulse, the first j Data at the distance to the gate; For the The energy difference pulses of the odd-channel and even-channel data are smoothed:

[0014] in, For the length of the smooth window, This is a smoothing function; Finally, use all the smoothed energy difference pulses. Constructing a channel difference mask ,in For the first The channel data with higher average power in the row is in the amplitude matrix The corresponding pulse number.

[0015] Further, the power of each row of pulses in the amplitude matrix is ​​determined, and then a reference pulse is determined based on a power threshold, including: First, calculate the magnitude matrix. The Middle The power of the pulse is measured, and the power threshold of the pulse is determined. In the amplitude matrix Select power less than threshold The region defined by the maximum number of consecutive pulses is used as the reference region, and the pulse with the median power within this region is selected as the reference pulse. .

[0016] Furthermore, by calculating the difference between each row of pulses in the amplitude matrix and the reference pulse, an interference mask is constructed, and outlier detection is performed using the median absolute deviation method, thereby determining the outlier mask, including: Through the first traveling pulse With reference pulse The waveform yields the difference signal, which is then used to generate a binarized interference mask:

[0017] Based on the interference mask, outliers are detected using the median absolute deviation method, resulting in an outlier mask. .

[0018] Furthermore, interference masks are determined in the local odd-even channel contrast mode and the global reference pulse contrast mode, respectively, including: For the local odd-even channel contrast mode, the interference mask is:

[0019] For the global reference pulse contrast mode, the interference mask is:

[0020] in, For channel difference mask, As an outlier mask, To interfere with the mask, Represents the logical AND operation.

[0021] Furthermore, by performing a difference operation with the interference mask, the interference interval in the amplitude matrix is ​​determined. If the interference range Width greater than the preset minimum width threshold Then, and the interference range Update:

[0022]

[0023] in, For expansion factor, The length of the smooth window.

[0024] Furthermore, the interference mask The expanded mask matrix is ​​obtained by extending it in the distance direction. This makes the expanded mask matrix Dimension and magnitude matrix same; for any position in :

[0025] The amplitude matrix after interference suppression processing :

[0026] in, This indicates element-wise multiplication.

[0027] Furthermore, the amplitude matrix after interference suppression processing... With phase matrix The newly synthesized data is the final processed interference-free SAR echo matrix. :

[0028] in It is a natural constant. It is the imaginary unit.

[0029] A terminal device includes a processor, a memory, and a computer program stored in the memory; when the processor executes the computer program, it implements the SAR interference suppression method based on echo asynchronous pulse detection.

[0030] A computer-readable storage medium storing a computer program; when executed by a processor, the computer program implements the SAR interference suppression method based on echo asynchronous pulse detection.

[0031] Compared with the prior art, the present invention has the following technical features: Compared with the prior art, the present invention has the following advantages: This method is performed in the time domain, avoiding complex operations such as Fourier transform, significantly reducing the amount of computation, and is easy to implement in engineering and for real-time system processing; by comparing the energy and waveform between asynchronous pulses (adjacent pulses or reference pulses), it can accurately identify abnormal energy mutations caused by coherent interference, accurately locate them, and reduce the loss of the original echo signal; it supports two different detection modes and adjustable detection parameters, and can also adaptively select based on the statistical characteristics of the pulses, which has good flexibility. Attached Figure Description

[0032] Figure 1 This is a schematic flowchart of the method of the present invention; Figure 2 The two-dimensional time domain of the interfering echo signal; Figure 3 For local time-domain details of the interfering echo signal; Figure 4 The imaging results are for interference-laden echo signals; Figure 5 For time-domain pulse accumulation of interfering echo signals; Figure 6 For the range-frequency domain of interfering echo signals; Figure 7 For the time-frequency domain of the pulse containing interference; Figure 8 The echo signal after interference suppression is in the two-dimensional time domain; Figure 9 This shows the local time-domain details of the echo signal after interference suppression. Figure 10 The echo signal in the range-frequency domain after interference suppression; Figure 11 The image shows the echo signal imaging results after interference suppression. Detailed Implementation

[0033] This invention provides a SAR interference suppression method based on echo asynchronous pulse detection. Taking advantage of the multi-dimensional characteristics of coherent radio frequency interference—significant time-domain periodicity, high frequency-domain overlap, and strong energy—it directly processes the SAR echo data matrix in the time domain. Utilizing the energy characteristics of the interference signal and combining multiple methods to select the interference detection benchmark, it eliminates the need for complex time-frequency transformations. This method can efficiently and accurately identify and suppress repeating coherent interference while protecting useful signals from damage, thus improving the final SAR image quality. This invention can suppress interference artifacts caused by repeating coherent interference to SAR image data and eliminate the sidelobe deterioration of strong scattering points in the image after frequency-domain notch filtering, thereby effectively suppressing repeating coherent interference in SAR echo data.

[0034] The present invention provides a SAR interference suppression method based on echo asynchronous pulse detection, comprising the following steps: Step 1: Obtain the SAR echo data matrix and determine its amplitude matrix and phase matrix.

[0035] SAR echo data matrix ,in The number of azimuth sampling points corresponds to the slow time. , The number of sampling points in the distance direction corresponds to the fast time. Extract the amplitude matrix of the echo data matrix. and determine the phase matrix. .

[0036] (1) in, express A complex matrix of dimension 1 Phase Matrix : (2) in, This represents the phase function with respect to a complex number.

[0037] Subsequent interference detection and suppression operations are all performed on the amplitude matrix. Perform the above steps and save the phase matrix. This facilitates the reconstruction of the echo upon completion of processing; echo data matrix Amplitude matrix Each row corresponds to a pulse, and each column corresponds to a distance gate.

[0038] Step 2: Based on the amplitude matrix, construct the corresponding interference concentration index by determining its azimuth power distribution variance and range power distribution variance, and construct a comprehensive decision function using the interference concentration index; based on the comprehensive decision function and the decision threshold, determine whether to select the local odd-even channel comparison mode or the global reference pulse comparison mode.

[0039] To achieve adaptive processing, this invention analyzes the SAR echo data matrix. Based on the statistical characteristics of the interference features, the optimal processing mode is adaptively selected.

[0040] First, extract the interference characteristic parameters and calculate the variance of the azimuth power distribution: (3) in For the direction of the first Average power of each pulse echo data matrix The i The power of each pulse reflects the energy characteristics of the signal within the pulse from different directions; Amplitude matrix No. i The pulse number j Data at the distance to the gate.

[0041] Calculate the variance of the range-directed power distribution: (4) in For distance to the first j Average power of each distance gate; echo data matrix The j The total power within a distance gate reflects the overall energy characteristics of the signal within the same slant range.

[0042] Then, the spatial distribution characteristics of the interference are quantified, and two interference concentration indices are defined: azimuth interference concentration index. and distance-oriented interference concentration index : (5) Establish a comprehensive decision function: (6) in For the weighting coefficients, satisfying .

[0043] Set decision thresholds based on statistical characteristics of the data : (7) in and These are the decision functions. The mean and standard deviation, This is the standard deviation factor, and in practice, 1 standard deviation is usually chosen.

[0044] Based on the echo data matrix Based on the overall characteristics in the azimuth direction, select a suitable asynchronous pulse detection mode: when When the signal is relatively dispersed, it indicates that the interference signal is relatively scattered. Therefore, the local odd-even channel contrast mode is selected, which is very effective for sparse and scattered interference. When the signal is concentrated, it indicates that the interference signal is relatively concentrated. Therefore, the global reference pulse comparison mode is selected, which is very effective against dense and continuous interference.

[0045] Step 3: In the local odd-even channel comparison mode, the amplitude matrix is ​​separated into odd and even channels along the azimuth direction to obtain odd and even channel data matrices; based on the average power of each row of data in the odd and even channel data matrices, the average power ratio is determined; based on the average power ratio and the threshold ratio, it is determined whether each row of data in the odd and even channel data matrices contains interference; for odd and even channel data with interference, the energy pulse difference is determined and smoothed before constructing a channel difference mask.

[0046] In this step, for the local odd-even channel contrast mode, the amplitude matrix is ​​first... Separate the data along the azimuth direction according to parity to obtain the odd channel data matrix. Coupled Channel Data Matrix : (8) (9) in, Represents the real number field. This indicates rounding down to the nearest integer.

[0047] For the odd channel data matrix respectively Coupled Channel Data Matrix The Middle The average power of the odd and even channel data is obtained by averaging the row data. and : (10) (11) in Amplitude matrix In the odd channel data matrix Coupled Channel Data Matrix The corresponding pulse sequence number (i.e., row number).

[0048] Calculate the average power ratio of each row of data in the odd and even channels: (12) when At that time, determine the odd channel data matrix Coupled Channel Data Matrix The Middle Interference exists in both odd and even channel data; further comparison of the average power of odd and even channel data reveals that the channel with the higher average power contains interference. This is the preset threshold ratio. Calculate the first Energy difference pulses between odd-channel and even-channel data: (13) in , These represent the odd channel data matrices respectively. Coupled Channel Data Matrix The Middle The pulse, the first j Data at the distance to the gate.

[0049] For the The energy difference pulses of the odd-channel and even-channel data are smoothed: (14) in, For the length of the smooth window, As a smoothing factor, This is a smoothing function.

[0050] Finally, use all the smoothed energy difference pulses. Constructing a channel difference mask ,in For the first The channel data with higher average power in the row is in the amplitude matrix The corresponding pulse sequence number (i.e., row number) in the middle. For the corresponding amplitude matrix The Middle row (i.e., the first row) The channel difference mask (of the pulses) has a value of the first pulse. Energy difference pulse of line .

[0051] Step 4: For the global reference pulse comparison mode, determine the power of each row of pulses in the amplitude matrix, and then determine the reference pulse based on the power threshold; construct an interference mask by calculating the difference between each row of pulses in the amplitude matrix and the reference pulse, and use the median absolute deviation method to detect outliers, thereby determining the outlier mask.

[0052] In global reference pulse comparison mode, the amplitude matrix is ​​calculated first. The Middle Power of the traveling pulse: (15) The power threshold of the pulse is determined by methods such as quantile detection and outlier detection. In the amplitude matrix Select power less than threshold The region defined by the maximum number of consecutive pulses is used as the reference region, and the pulse with the median power within this region is selected as the reference pulse. .

[0053] Through the first traveling pulse With reference pulse The waveform yields the difference signal, which is then used to generate a binarized interference mask: (16) Detect outliers using the Median Absolute Deviation (MAD) method: (17) (18) in k As a threshold factor, three times the median deviation is typically used. This indicates finding the median of a sequence. It serves as an outlier mask.

[0054] Step 5: Determine the interference mask in the local odd-even channel contrast mode and the global reference pulse contrast mode respectively, and determine the interference interval in the amplitude matrix based on the interference mask; extend the interference mask in the distance direction and combine it with the interference interval to obtain the extended mask matrix; use the mask matrix to process the amplitude matrix to obtain the amplitude matrix after interference suppression.

[0055] The final interference mask is generated by combining power difference and outlier information, and the interference range is found through differential operation.

[0056] For the local odd-even channel contrast mode, the interference mask is: (19) For the global reference pulse contrast mode, the interference mask is: (20) in, Represents the logical AND operation.

[0057] interference mask The expanded mask matrix is ​​obtained by extending it in the distance direction. This makes the expanded mask matrix Dimension and magnitude matrix The same applies; the amplitude matrix is ​​determined by performing a difference operation with the interference mask. Interference range in If the interference range Width greater than the preset minimum width threshold Then, and the interference range Update: (twenty one) (twenty two) in, These are the lower bound and the upper bound of the interval, respectively. For expansion factor, The length of the smooth window.

[0058] for any position in : (twenty three) In the amplitude matrix The extended mask matrix The amplitude within is set to zero, thereby achieving accurate coherent interference time-domain suppression and obtaining the amplitude matrix after interference suppression processing. : (twenty four) in, This indicates element-wise multiplication.

[0059] Step 6: Based on the amplitude matrix and phase matrix after interference suppression processing, obtain the interference-free SAR echo data matrix.

[0060] The amplitude matrix after interference suppression processing With the phase matrix in step 1 The newly synthesized data is the final processed interference-free SAR echo matrix. : (twenty one) in It is a natural constant. It is the imaginary unit.

[0061] Example: In one embodiment of the present invention, such as Figure 2 , Figure 3 As shown, interference can be observed in the echo time domain; the imaging results of this echo data are as follows. Figure 4 As shown, coherent interference manifests as bright spots with a certain degree of focus in the imaging results, affecting subsequent image interpretation and target detection. The data matrix dimension in this embodiment is 6000×24358, i.e. The pulse range containing coherent interference is 1000-2500. Typical processing parameters are set: threshold ratio. Minimum interference width Smoothing factor expansion factor Weighting coefficient Decision threshold .

[0062] like Figure 5As shown, the interference signal exhibits significant energy characteristics in time-domain pulse accumulation. Figure 6 As shown, the interference is not significant in the range-frequency domain, and further as... Figure 7 As shown, due to the coherence of the interference signal, traditional interference suppression methods are difficult to use effectively. Therefore, the amplitude and phase of the echo data are separated, an appropriate detection method is selected on the amplitude matrix, and the amplitude statistical features of the pulse are extracted. In this embodiment, the decision function... greater than the judgment threshold Therefore, the reference pulse is extracted based on energy selection, a global reference pulse comparison mode is executed, the power ratio of the pulse to the reference pulse is calculated line by line, and the presence of interference is detected.

[0063] Based on the suppression of detected coherent interference by the interference mask in the time domain, and the reconstruction of the suppressed echo data by combining phase information, such as... Figure 8 , 9 As shown; from Figure 10 As can be seen, this method results in minimal loss of the echo signal in the frequency domain, preserving the characteristics of the original signal to the greatest extent possible; for example... Figure 11 The image shows the echo signal imaging result after interference suppression, where the interference signal has been effectively suppressed, completing the interference suppression process.

[0064] This invention adaptively employs two processing strategies—a local odd-even channel comparison mode and a global reference pulse comparison mode—based on the temporal energy characteristics of interference. It accurately locates the interference position through power ratio judgment and outlier detection, generates an interference mask, and performs interference suppression. Experimental results show that this method has high detection accuracy, good suppression effect, and high computational efficiency, effectively improving SAR imaging quality and possessing significant application value in the field of radar signal processing.

[0065] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A SAR interference suppression method based on echo asynchronous pulse detection, characterized in that, include: Obtain the SAR echo data matrix and determine its amplitude matrix and phase matrix; Based on the amplitude matrix, the corresponding interference concentration index is constructed by determining its azimuth power distribution variance and range power distribution variance, and a comprehensive decision function is constructed using the interference concentration index; based on the comprehensive decision function and the decision threshold, the local odd-even channel comparison mode or the global reference pulse comparison mode is selected. In the local odd-even channel comparison mode, the amplitude matrix is ​​separated along the azimuth direction according to odd and even to obtain the odd and even channel data matrices; The average power ratio is determined based on the average power of each row of data in the odd and even channel data matrix. Based on the average power ratio and threshold ratio, it is determined whether each row of data in the odd and even channel data matrix contains interference; for odd and even channel data with interference, the energy pulse difference is determined and smoothed before constructing a channel difference mask. For the global reference pulse comparison mode, the power of each pulse in the amplitude matrix is ​​determined, and then the reference pulse is determined based on the power threshold. By calculating the difference between each pulse in the amplitude matrix and the reference pulse, an interference mask is constructed and outlier detection is performed using the median absolute deviation method, thereby determining the outlier mask. The interference masks in the local odd-even channel contrast mode and the global reference pulse contrast mode are determined respectively, and the interference interval in the amplitude matrix is ​​determined based on the interference masks. The interference mask is extended in the distance direction and combined with the interference interval to obtain the extended mask matrix; The amplitude matrix is ​​processed using a mask matrix to obtain the amplitude matrix after interference suppression. Based on the amplitude and phase matrices after interference suppression processing, an interference-free SAR echo data matrix is ​​obtained.

2. The SAR interference suppression method based on echo asynchronous pulse detection according to claim 1, characterized in that, The interference concentration index includes the azimuth interference concentration index. and distance-oriented interference concentration index : in, The variance of the azimuth power distribution. Let Variance be the power distribution variance in the distance direction. The azimuth average power, The average power in the range direction; Establish a comprehensive decision function: in For the weighting coefficients, satisfying ; when When selecting the local odd / even channel contrast mode; when Select the global reference pulse comparison mode; This indicates the threshold for the decision.

3. The SAR interference suppression method based on echo asynchronous pulse detection according to claim 1, characterized in that, The average power ratio is determined based on the average power of each row of data in the odd and even channel data matrix. Based on the average power ratio and threshold ratio, determine whether each row of data in the odd and even channel data matrices contains interference, including: Calculate the average power ratio of each row of data in the odd and even channels: Among them, the average power of odd and even channel data and By analyzing the odd channel data matrix Coupled Channel Data Matrix The Middle The result is obtained by averaging the row data. when At that time, further comparison of the first The average power of odd-channel and even-channel data is used; the channel with the higher average power contains interference. This represents the threshold ratio.

4. The SAR interference suppression method based on echo asynchronous pulse detection according to claim 1, characterized in that, For odd and even channel data with interference, after determining the energy pulse difference and smoothing it, a channel difference mask is constructed, including: Calculate the first Energy difference pulses between odd-channel and even-channel data: in , These represent the odd channel data matrices respectively. Coupled Channel Data Matrix The Middle The pulse, the first j Data at the distance to the gate; For the first The energy difference pulses of the odd-channel and even-channel data are smoothed: (14) in, For the length of the smooth window, This is a smoothing function; Finally, use all the smoothed energy difference pulses. Constructing a channel difference mask ,in For the first The channel data with higher average power in the row is in the amplitude matrix The corresponding pulse number.

5. The SAR interference suppression method based on echo asynchronous pulse detection according to claim 1, characterized in that, Determine the power of each pulse in the amplitude matrix, and then determine the reference pulse based on the power threshold, including: First, calculate the magnitude matrix. The Middle The power of the pulse is measured, and the power threshold of the pulse is determined. In the amplitude matrix Select power less than threshold The region defined by the maximum number of consecutive pulses is used as the reference region, and the pulse with the median power within this region is selected as the reference pulse. .

6. The SAR interference suppression method based on echo asynchronous pulse detection according to claim 1, characterized in that, An interference mask is constructed by calculating the difference between each row of pulses in the amplitude matrix and the reference pulse, and outlier detection is performed using the median absolute deviation method, thereby determining the outlier mask, including: Through the first traveling pulse With reference pulse The waveform yields the difference signal, which is then used to generate a binarized interference mask: Based on the interference mask, outliers are detected using the median absolute deviation method, resulting in an outlier mask. .

7. The SAR interference suppression method based on echo asynchronous pulse detection according to claim 1, characterized in that, The interference masks in the local odd-even channel contrast mode and the global reference pulse contrast mode are determined respectively, including: For the local odd-even channel contrast mode, the interference mask is: For the global reference pulse contrast mode, the interference mask is: in, For channel difference mask, As an outlier mask, To interfere with the mask, Represents the logical AND operation.

8. The SAR interference suppression method based on echo asynchronous pulse detection according to claim 1, characterized in that, By performing a difference operation with the interference mask, the interference interval in the amplitude matrix is ​​determined. If the interference range Width greater than the preset minimum width threshold Then, and the interference range Update: in, For expansion factor, The length of the smooth window.

9. The SAR interference suppression method based on echo asynchronous pulse detection according to claim 1, characterized in that, interference mask The expanded mask matrix is ​​obtained by extending it in the distance direction. This makes the expanded mask matrix Dimension and magnitude matrix same; for any position in the middle : The amplitude matrix after interference suppression processing : in, This indicates element-wise multiplication.

10. A terminal device, comprising a processor, a memory, and a computer program stored in the memory; characterized in that, When the processor executes the computer program, it implements the SAR interference suppression method based on echo asynchronous pulse detection as described in any one of claims 1-9.

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