SAR radio frequency interference suppression methods, systems, electronic devices and storage media

Abstract

This invention discloses a SAR radio frequency interference suppression method, system, electronic device, and storage medium, particularly relating to the field of communication technology. The method includes: acquiring the raw echo signal of a synthetic aperture radar (SAR) to be processed; performing multi-domain feature extraction on the raw echo signal and classifying the extracted features to obtain target signal groups with radio frequency interference; filtering the power intensity of the target signal group in the range frequency domain and determining the location of the interference frequency point based on the filtering result; smoothing the phase of the target signal group in the range frequency domain using the SG filtering algorithm, and using the smoothed phase to perform phase compensation and repair on the initial phase of the interference frequency point location to obtain the signal after interference suppression. This invention solves the problems of insufficient reliability and stability and poor suppression effect of radio frequency interference in existing SAR radio frequency interference suppression methods.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a SAR radio frequency interference suppression method, system, electronic device, and storage medium. Background Technology

[0002] Spaceborne synthetic aperture radar (SAR) is a high-resolution remote sensing imaging radar with advantages such as all-weather, all-time capability, and high resolution. SAR achieves high range resolution by transmitting a wide-bandwidth signal and compressing it with pulses, while simultaneously utilizing the synthetic aperture principle to achieve high azimuth resolution, thereby obtaining high-precision, high-resolution images.

[0003] Existing radio frequency interference (RFI) processing techniques in spaceborne SAR primarily focus on separating and eliminating interference from a signal perspective. However, existing SAR RFI suppression methods suffer from insufficient reliability and stability, resulting in poor interference suppression effectiveness.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings in reliability and stability of existing SAR radio frequency interference suppression methods, and their poor suppression effect on radio frequency interference, by providing a SAR radio frequency interference suppression method, system, electronic device, and storage medium.

[0006] The first aspect of this invention provides a SAR radio frequency interference suppression method, the method comprising: acquiring a raw synthetic aperture radar (SAR) echo signal to be processed; performing multi-domain feature extraction on the raw echo signal and classifying the extracted features to obtain a target signal group with radio frequency interference; filtering the power intensity of the target signal group in the range frequency domain and determining the location of the interference frequency point based on the filtering result; smoothing the phase of the target signal group in the range frequency domain using the SG filtering algorithm, and performing phase compensation and repair on the initial phase of the interference frequency point location using the smoothed phase to obtain a signal after interference suppression.

[0007] In one embodiment of the present invention, the step of performing multi-domain feature extraction on the original echo signal and classifying the extracted features to obtain target signal groups with radio frequency interference includes: determining the time-domain power intensity value of each azimuth pulse echo in the original echo signal, and performing Fourier transform on each azimuth pulse echo to obtain range-frequency domain data, and determining the corresponding frequency domain peak value; grouping the original echo signal according to a preset number of pulses, and determining the mean and standard deviation of the time-domain power intensity value of the pulse signal in each group, as well as the maximum value of the frequency domain peak value, to obtain a multi-domain feature matrix; after normalizing the multi-domain feature matrix, using the K-means clustering method to divide the signal into target signal groups with radio frequency interference and normal echo signal groups.

[0008] In one embodiment of the present invention, determining the time-domain power intensity value of each azimuth pulse echo in the original echo signal, and performing a Fourier transform on each azimuth pulse echo to obtain range frequency domain data, and determining the corresponding frequency domain peak value, includes: extracting the real and imaginary parts of the complex data at each sampling point in the original echo signal, determining the sum of squares of the real and imaginary parts to obtain the time-domain power intensity value of the corresponding azimuth pulse echo; performing a Fourier transform on each pulse echo of the original echo signal to convert it to the frequency domain, and extracting the maximum amplitude within the corresponding range frequency range as the frequency domain peak value.

[0009] In one embodiment of the present invention, the step of filtering the power intensity of the target signal group in the range frequency domain and determining the location of the interference frequency point based on the filtering result includes: determining the average power intensity value of the target signal group in the range frequency domain; filtering the average power intensity value using the SG filtering algorithm to obtain a filtered average power intensity value; determining the absolute value of the difference between the average power intensity value and the filtered average power intensity value, and determining an interference detection threshold in combination with a preset threshold coefficient; and extracting the frequency points where the absolute value of the difference exceeds the interference detection threshold as the location of the interference frequency point.

[0010] In one embodiment of the present invention, the step of smoothing the phase of the target signal group in the range frequency domain using the SG filtering algorithm, and then using the smoothed phase to compensate and repair the initial phase at the interference frequency point to obtain the interference-suppressed signal, includes: extracting the initial phase information of each pulse frequency domain data in the target signal group; performing SG filtering on the initial phase information to obtain a filtered smoothed phase; replacing the original initial phase information with the smoothed phase at the interference frequency point to restore phase continuity, while keeping the original data unchanged at non-interference frequency point locations, to obtain compensated frequency domain data; and performing an inverse Fourier transform on the compensated frequency domain data to obtain the interference-suppressed signal.

[0011] A second aspect of the present invention provides a SAR radio frequency interference suppression system, comprising: a signal acquisition module for acquiring raw synthetic aperture radar (SAR) echo signals to be processed; a feature classification module for performing multi-domain feature extraction on the raw echo signals and classifying the extracted features to obtain a target signal group with radio frequency interference; a frequency point determination module for filtering the power intensity of the target signal group in the range frequency domain and determining the location of the interference frequency point based on the filtering result; and a phase compensation module for smoothing the phase of the target signal group in the range frequency domain using an SG filtering algorithm and performing phase compensation and repair on the initial phase of the interference frequency point location using the smoothed phase to obtain a signal after interference suppression.

[0012] In one embodiment of the present invention, the feature classification module includes: a first determining submodule, configured to determine the time-domain power intensity value of each azimuth pulse echo in the original echo signal, and perform Fourier transform on each azimuth pulse echo to obtain range-frequency domain data, and determine the corresponding frequency domain peak value; a classification submodule, configured to group the original echo signal according to a preset number of pulses, and determine the mean and standard deviation of the time-domain power intensity value of the pulse signal in each group, as well as the maximum value of the frequency domain peak value, to obtain a multi-domain feature matrix; and a first processing submodule, configured to normalize the multi-domain feature matrix and then use the K-means clustering method to divide the signal into a target signal group with radio frequency interference and a normal echo signal group.

[0013] In one embodiment of the present invention, the phase compensation module includes: a second processing submodule for extracting initial phase information of each pulse frequency domain data in the target signal group; a first filtering submodule for performing SG filtering on the initial phase information to obtain a filtered smooth phase; a third processing submodule for replacing the original initial phase information with the smooth phase to restore phase continuity at the interference frequency point location, while keeping the original data unchanged at non-interference frequency point locations to obtain compensated frequency domain data; and a fourth processing submodule for performing inverse Fourier transform on the compensated frequency domain data to obtain the interference-suppressed signal.

[0014] A third aspect of the present invention provides an electronic device, comprising: a memory for storing a computer program; and a processor for executing the computer program to implement the steps of the SAR radio frequency interference suppression method as described in the first aspect.

[0015] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the SAR radio frequency interference suppression method as described in the first aspect.

[0016] Compared with the prior art, the technical effects achieved by the present invention are as follows:

[0017] This invention acquires the raw echo signal of a synthetic aperture radar (SAR) to be processed; performs multi-domain feature extraction on the raw echo signal and classifies the extracted features to obtain target signal groups with radio frequency interference; filters the power intensity of the target signal group in the range frequency domain and determines the location of the interference frequency point based on the filtering result; smooths the phase of the target signal group in the range frequency domain using the SG filtering algorithm, and uses the smoothed phase to perform phase compensation and repair on the initial phase of the interference frequency point location to obtain the signal after interference suppression. This embodiment improves the rapid detection and suppression effect of spaceborne SAR radio frequency interference signals, significantly enhances the imaging quality of spaceborne SAR in strong electromagnetic countermeasures environments, and solves the problems of insufficient reliability and stability and poor suppression effect of radio frequency interference in existing SAR radio frequency interference suppression methods. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating a SAR radio frequency interference suppression method according to an embodiment of the present invention. Figure 2 This is a time-domain signal power diagram of the original echo azimuth pulse according to an embodiment of the present invention; Figure 3 This is a frequency domain diagram of the interfered portion of the signal according to an embodiment of the present invention; Figure 4It is the original interfered SAR image according to an embodiment of the present invention; Figure 5 This is a SAR image after interference suppression processing according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the framework of a SAR radio frequency interference suppression system according to an embodiment of the present invention. Figure 7 This is a schematic diagram of the frame of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0019] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0020] The technical solution of the present invention is illustrated below through specific embodiments. It should be understood that the one or more steps mentioned in the present invention do not preclude the existence of other methods and steps before or after the combined steps, or that other methods and steps may be inserted between these explicitly mentioned steps. It should also be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Unless otherwise stated, the numbering of each method step is only for the purpose of identifying each method step, and not for limiting the order of each method or limiting the scope of the present invention. Changes or adjustments to their relative relationships, without substantial changes to the technical content, can also be considered as within the scope of the present invention.

[0021] The first aspect of this invention discloses a SAR radio frequency interference suppression method, such as... Figure 1 As shown, the method includes: S101, acquire the raw echo signal of the synthetic aperture radar (SAR) to be processed; S102, perform multi-domain feature extraction on the original echo signal and classify the extracted features to obtain the target signal group with radio frequency interference; S103, filter the power intensity of the target signal group in the range frequency domain, and determine the location of the interference frequency point based on the filtering result; S104 uses the SG filtering algorithm to smooth the phase of the target signal group in the range frequency domain, and uses the smoothed phase to compensate and repair the initial phase at the interference frequency point, thus obtaining the signal after interference suppression.

[0022] In this embodiment, the original, unprocessed echo signal that needs suppression is retrieved through the spaceborne SAR ground sharing service system. The metadata file corresponding to the original echo signal is obtained, and the spaceborne SAR data imaging parameters, including the sampling rate, are read. Number of distance-oriented signal sampling points Signal bandwidth Total number of azimuth pulses Information such as range and pulse count is used to analyze the raw echo signal data. Based on the number of range sampling points and the total number of pulses, the raw echo signals are read sequentially according to the pulse echo time sequence. Each sampling point is stored in the form of a complex number (real part + imaginary part), and all pulse echoes are arranged in azimuth time sequence. The spaceborne SAR echo signal is represented as: ,in This represents the azimuth pulse echo time series, with the sequence number ranging from 1 to... , Represents the distance-oriented sampling sequence. The serial numbers are from 1 to ; Then, multi-domain feature extraction was performed on the original echo signal. Based on the characteristics of the original echo signal of spaceborne SAR, such as slow variation in azimuth, increased signal energy and significant fluctuations when RFI interference occurs, and the appearance of spikes in the frequency domain, the original echo signal data was processed according to... Each azimuth pulse is segmented, and signal features are extracted in both the time and frequency domains. These features include time-domain power intensity (characterizing energy characteristics), time-domain power standard deviation (characterizing energy fluctuation characteristics), and frequency-domain peak value (frequency domain characteristics). The extracted features are then classified to identify target signal groups exhibiting radio frequency interference.

[0023] Next, the power intensity of the target signal group in the range frequency domain is filtered for the original echo signal of the target signal group with interference, and the location of the interference frequency point is determined based on the filtering result. Finally, the phase of the target signal group in the range frequency domain is smoothed using the SG filtering algorithm, and the initial phase at the interference frequency point is compensated and repaired using the smoothed phase to obtain the signal after interference suppression.

[0024] This invention provides an embodiment for acquiring the raw echo signal of a synthetic aperture radar (SAR) to be processed; performing multi-domain feature extraction on the raw echo signal and classifying the extracted features to obtain target signal groups with radio frequency interference; filtering the power intensity of the target signal groups in the range-frequency domain and determining the location of the interference frequency point based on the filtering result; smoothing the phase of the target signal groups in the range-frequency domain using the SG filtering algorithm, and using the smoothed phase to perform phase compensation and repair on the initial phase of the interference frequency point location to obtain the signal after interference suppression. This embodiment improves the rapid detection and suppression effect of spaceborne SAR radio frequency interference signals, significantly enhances the imaging quality of spaceborne SAR in strong electromagnetic countermeasures environments, and solves the problems of insufficient reliability and stability and poor suppression effect of existing SAR radio frequency interference suppression methods. Optionally, in this embodiment, step S102 includes, but is not limited to: S1021, determine the time domain power intensity value of each azimuth pulse echo in the original echo signal, and perform Fourier transform on each azimuth pulse echo to obtain range frequency domain data, and determine the corresponding frequency domain peak value. First, the real and imaginary parts of the complex data at each sampling point in the original echo signal are extracted, and the sum of the squares of the real and imaginary parts is determined to obtain the time-domain power intensity value of the corresponding azimuth pulse echo, including: Specifically, the signal power intensity value of each pulse echo is calculated for the parsed original echo signal, using the following formula: (1) Then, a Fourier transform is performed on each pulse echo of the original echo signal to convert it to the frequency domain, and the maximum amplitude is extracted within the corresponding distance-to-frequency range as the frequency domain peak value, including: Specifically, a Fourier transform is performed on each pulse echo of the analyzed original echo signal to obtain the corresponding distance-frequency domain data, and the peak value of each pulse in the frequency domain is determined, as shown in the following formula: (2) in, This indicates Fourier transform processing. This indicates taking the maximum value. This indicates that the pulse signal has been transformed into its frequency domain form through Fourier transform. Indicates the range frequency. This represents the azimuth pulse echo time series, from 1 to... .

[0025] S1022, the original echo signal is grouped according to a preset number of pulses, and the mean and standard deviation of the time domain power intensity value of the pulse signal in each group, as well as the maximum value of the frequency domain peak value, are determined to obtain a multi-domain feature matrix. Specifically, multi-domain eigenvalues ​​are calculated piecewise, according to... Grouping the pulses together, we get a total of Group datasets. Calculate the values ​​in each group separately. The average signal power intensity of each pulse and standard deviation ,as well as The maximum value of a pulse signal in the frequency domain Therefore, we obtain the first... The feature matrix of the dataset, where The value range is from 1 to The expression is as follows: (3) S1023, after normalizing the multi-domain feature matrix, the K-means clustering method is used to divide the signal into a target signal group with radio frequency interference and a normal echo signal group.

[0026] Specifically, the feature matrix is ​​normalized using the Z-score normalization method, which is applied to the above-mentioned features. Transform the three eigenvalues ​​into sequence data with a mean of 0 and a standard deviation of 1. .

[0027] Then, the K-means clustering method is used to cluster the sequence data. The data are divided into two categories: interference and non-interference. Signals with lower time-domain power intensity, smaller time-domain power standard deviation, and smaller frequency-domain peak power intensity are considered normal echo signals. Signals with larger time-domain power intensity, larger standard deviation, and larger frequency-domain peak power intensity are considered to have RFI interference. The expression is shown below.

[0028] (4) Here, constant 0 indicates that the data group is a normal echo signal, and constant 1 indicates that the data group has RFI interference.

[0029] Optionally, in this embodiment, step S103 includes, but is not limited to: S1031, determine the average power intensity value of the target signal group in the range frequency domain; Specifically, for those with RFI interference For each signal group in the range frequency domain, calculate the values ​​for each group separately. Average power intensity value within the pulse frequency domain The formula is expressed as follows: (5) in, Indicates the range frequency. From 1 to , This indicates a data set with interference, ranging in size from 1 to... .

[0030] S1032, The average power intensity value is filtered by the SG filtering algorithm to obtain the filtered average power intensity value; Specifically, considering the frequency domain spikes in narrowband or comb-spectrum interference, the SG filtering algorithm is used for filtering. A local sampling window is set. and polynomial order ,right The filtering process is performed, and the average power intensity value after filtering is obtained. The formula is as follows: (6) in, This represents the SG filtering algorithm function, sampling window. The size is usually taken as 31. The value is usually 3.

[0031] S1033, determine the absolute value of the difference between the average power intensity value and the filtered average power intensity value, and determine the interference detection threshold in combination with the preset threshold coefficient; according to and Calculate the interference detection threshold adaptively in the frequency domain. The formula is as follows: (7) in, This represents the threshold coefficient, which is usually set to 4.

[0032] S1034, extract the frequency points where the absolute value of the difference exceeds the interference detection threshold as the interference frequency point positions.

[0033] The location of RFI interference in the frequency domain is extracted based on the interference detection threshold, and the value in the frequency domain is calculated. and The absolute value of the difference exceeds The frequency point is denoted as the interference frequency point location. The formula is as follows: (8) in, Indicates the range frequency. From 1 to .

[0034] Optionally, in this embodiment, step S104 includes, but is not limited to: S1041, Extract the initial phase information of each pulse frequency domain data in the target signal group; Specifically, for the frequency domain signal of each pulse in the signal group containing interference. Calculate its phase information using the following formula: (9) in, This indicates the phase of each pulse's frequency domain data being extracted. Indicates the first A pulse signal that is subject to interference. Indicates the range frequency. From 1 to .

[0035] S1042, Perform SG filtering on the initial phase information to obtain a filtered smooth phase; Specifically, the SG filtering algorithm is used to filter each pulse phase. A local sampling window is set. and polynomial order ,right Filtering is performed, and the average phase value after filtering is obtained. The formula is as follows: (10) in, This represents the SG filtering algorithm function, sampling window. The size is usually taken as 31. The value is usually 2.

[0036] S1043, For the location of the interference frequency point, the original initial phase information is replaced by the smooth phase to restore phase continuity. For the location of the non-interference frequency point, the original data is kept unchanged to obtain the compensated frequency domain data. Based on the location of the interference frequency point Information, using Phase compensation is performed at the interference frequency points to restore phase continuity at the interference frequencies. The calculation formula is as follows: (11) in, This represents the imaginary part of a complex number. This indicates the calculation of the natural exponential function.

[0037] S1044, Perform an inverse Fourier transform on the compensated frequency domain data to obtain the signal after interference suppression.

[0038] Specifically, for the frequency domain after interference detection and suppression processing The data undergoes inverse Fourier transform to obtain the original echo time-domain signal, which is then used for subsequent SAR imaging processing and other business processes.

[0039] In practical application scenarios, such as Figure 2 The diagram shown is a time-domain signal power map of the SAR raw echo azimuth pulse. Figure 3 The frequency domain diagram of the interfered part of the signal shown and Figure 4 The original interfered SAR image is shown. After processing by the SAR radio frequency interference suppression method in this embodiment, the image obtained is as follows. Figure 5 The image shown is a SAR image after interference suppression processing. (Comparison) Figure 4 and Figure 5It can be seen that the original interfered SAR image ( Figure 4 The image contains obvious bright lines and bright spot artifacts caused by radio frequency interference, which obscure the texture of some weakly scattering features and reduce the overall image contrast. After interference suppression processing based on adaptive SG filtering provided in this embodiment, ( Figure 5 The comb-like interference stripes and bright spots in the image were effectively eliminated. At the same time, thanks to the complex domain phase compensation mechanism, the filtering process did not disrupt the phase continuity of the normal ground object signal, so that the edge contours of strong scattering targets such as ground buildings and coastlines were well preserved and restored. There was no defocusing or sidelobe lifting phenomenon caused by traditional notch filtering, which significantly improved the visual quality of SAR images and the ability to interpret ground objects.

[0040] This embodiment constructs a three-dimensional feature space using time-domain energy, time-domain stability, and frequency-domain peak values. It then uses k-means clustering to classify interference and normal signals, overcoming the problem of missed interference detection in complex interference scenarios due to single features. Furthermore, it avoids misjudging normal echo signals in situations involving land-sea boundaries or strong scattering objects (such as buildings or ships). Simultaneously, this embodiment employs a complex-domain adaptive SG filtering framework. Addressing the limitation of traditional SG filtering which only processes real-valued signals, it proposes a complex-domain separable SG filtering algorithm. This algorithm constructs adaptive SG filtering methods for both the amplitude and phase of the original echo signal in the frequency domain. It uses amplitude to detect interference frequencies and uses the filtered phase to compensate for signal loss. This overcomes the problem of traditional frequency-domain notch filtering, which only suppresses signal amplitude, leading to phase breakage and the formation of false targets in the image.

[0041] According to a second aspect of the present invention, a SAR radio frequency interference suppression system is provided, such as Figure 6 As shown, the system includes: Signal acquisition module 60 is used to acquire the raw echo signal of synthetic aperture radar SAR to be processed; The feature classification module 62 is used to perform multi-domain feature extraction on the original echo signal and classify the extracted features to obtain the target signal group with radio frequency interference. The frequency point determination module 64 is used to filter the power intensity of the target signal group in the distance frequency domain and determine the location of the interference frequency point based on the filtering result. The phase compensation module 66 is used to smooth the phase of the target signal group in the range frequency domain using the SG filtering algorithm, and to perform phase compensation and repair on the initial phase of the interference frequency point using the smoothed phase, so as to obtain the signal after interference suppression.

[0042] Optionally, in this embodiment, the feature classification module 62 includes: The first determining submodule is used to determine the time domain power intensity value of each azimuth pulse echo in the original echo signal, and to perform Fourier transform on each azimuth pulse echo to obtain range frequency domain data, and determine the corresponding frequency domain peak value. The classification submodule is used to group the original echo signal according to a preset number of pulses, and determine the mean and standard deviation of the time domain power intensity value of the pulse signal in each group, as well as the maximum value of the frequency domain peak value, so as to obtain a multi-domain feature matrix. The first processing submodule is used to normalize the multi-domain feature matrix and then use the K-means clustering method to divide the signal into a target signal group with radio frequency interference and a normal echo signal group.

[0043] Optionally, in this embodiment, the phase compensation module 66 includes: The second processing submodule is used to extract the initial phase information of each pulse frequency domain data in the target signal group; The first filtering submodule is used to perform SG filtering on the initial phase information to obtain a filtered smooth phase. The third processing submodule is used to replace the original initial phase information with the smoothed phase to restore phase continuity for the interference frequency point location, and to keep the original data unchanged for non-interference frequency point locations, so as to obtain the compensated frequency domain data. The fourth processing submodule is used to perform an inverse Fourier transform on the compensated frequency domain data to obtain the signal after interference suppression.

[0044] Optionally, in this embodiment, the first determining submodule includes: The first processing unit is used to extract the real and imaginary parts of the complex data of each sampling point in the original echo signal, and calculate the sum of squares of the real and imaginary parts to obtain the time-domain power intensity value of the corresponding azimuth pulse echo. The second processing unit is used to perform a Fourier transform on each pulse echo of the original echo signal to convert it to the frequency domain, and extract the maximum value of the amplitude within the corresponding distance-to-frequency range as the frequency domain peak value.

[0045] Optionally, in this embodiment, the frequency point determination module 64 includes: The second determining submodule is used to calculate the average power intensity value of the target signal group in the range frequency domain; The second filtering submodule is used to filter the average power intensity value using the SG filtering algorithm to obtain the filtered average power intensity value. The third determining submodule is used to determine the absolute value of the difference between the average power intensity value and the filtered average power intensity value, and to determine the interference detection threshold in combination with a preset threshold coefficient; The fifth processing submodule is used to extract the frequency points where the absolute value of the difference exceeds the interference detection threshold as the interference frequency point location.

[0046] Another embodiment of the present invention relates to an electronic device, such as Figure 7 As shown, it includes: at least one processor 701; and a memory 702 communicatively connected to the at least one processor 701; wherein the memory 702 stores instructions executable by the at least one processor 701, the instructions being executed by the at least one processor 701 to enable the at least one processor 701 to perform the SAR radio frequency interference suppression method in the above embodiments.

[0047] The memory and processor are connected via a bus, which can include any number of interconnecting buses and bridges, connecting various circuits of one or more processors and memories. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and will not be described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over the wireless medium via an antenna, which further receives data and transmits it to the processor.

[0048] The processor manages the bus and general processing, and also provides various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory is used to store data used by the processor during operation.

[0049] Another embodiment of the present invention relates to a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements a method embodiment of the above-described SAR radio frequency interference suppression method.

[0050] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0051] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0052] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for suppressing SAR radio frequency interference, characterized in that, The method includes: Acquire the raw echo signal of synthetic aperture radar (SAR) to be processed; Multi-domain feature extraction is performed on the original echo signal, and the extracted features are classified to obtain the target signal group with radio frequency interference. The power intensity of the target signal group in the range frequency domain is filtered, and the location of the interference frequency point is determined based on the filtering result; The target signal group is smoothed in the range frequency domain using the SG filtering algorithm, and the initial phase at the interference frequency point is compensated and repaired using the smoothed phase to obtain the signal after interference suppression.

2. The method according to claim 1, characterized in that, The step of performing multi-domain feature extraction on the original echo signal and classifying the extracted features to obtain the target signal group with radio frequency interference includes: The time-domain power intensity value of each azimuth pulse echo in the original echo signal is determined, and a Fourier transform is performed on each azimuth pulse echo to obtain range frequency domain data, and the corresponding frequency domain peak value is determined. The original echo signal is grouped according to a preset number of pulses, and the mean and standard deviation of the time domain power intensity value and the maximum value of the frequency domain peak value of the pulse signal in each group are determined to obtain a multi-domain feature matrix. After normalizing the multi-domain feature matrix, the K-means clustering method is used to divide the signal into a target signal group with radio frequency interference and a normal echo signal group.

3. The method according to claim 2, characterized in that, The process of determining the time-domain power intensity value of each azimuth pulse echo in the original echo signal, and performing a Fourier transform on each azimuth pulse echo to obtain range-frequency domain data, and determining the corresponding frequency domain peak value, includes: Extract the real and imaginary parts of the complex data at each sampling point in the original echo signal, and determine the sum of squares of the real and imaginary parts to obtain the time-domain power intensity value of the corresponding azimuth pulse echo; Each pulse echo of the original echo signal is subjected to a Fourier transform to convert it to the frequency domain, and the maximum amplitude is extracted within the corresponding distance-to-frequency range as the frequency domain peak value.

4. The method according to claim 1, characterized in that, The step of filtering the power intensity of the target signal group in the range frequency domain and determining the location of the interference frequency point based on the filtering result includes: Determine the average power intensity value of the target signal group in the range frequency domain; The average power intensity value is filtered using the SG filtering algorithm to obtain the filtered average power intensity value. Determine the absolute value of the difference between the average power intensity value and the filtered average power intensity value, and combine it with a preset threshold coefficient to determine the interference detection threshold; The frequency points whose absolute value of the difference exceeds the interference detection threshold are extracted as the interference frequency point locations.

5. The method according to claim 1, characterized in that, The step of smoothing the phase of the target signal group in the range frequency domain using the SG filtering algorithm, and then using the smoothed phase to compensate and repair the initial phase at the interference frequency point to obtain the interference-suppressed signal, includes: Extract the initial phase information of each pulse frequency domain data in the target signal group; The initial phase information is subjected to SG filtering to obtain a filtered smooth phase; For the interference frequency points, the original initial phase information is replaced with the smoothed phase to restore phase continuity. For non-interference frequency points, the original data is kept unchanged to obtain compensated frequency domain data. The inverse Fourier transform is performed on the compensated frequency domain data to obtain the signal after interference suppression.

6. A SAR radio frequency interference suppression system, characterized in that, The system includes: The signal acquisition module is used to acquire the raw echo signal of the synthetic aperture radar (SAR) to be processed. The feature classification module is used to extract multi-domain features from the original echo signal and classify the extracted features to obtain the target signal group with radio frequency interference. The frequency point determination module is used to filter the power intensity of the target signal group in the distance frequency domain and determine the location of the interference frequency point based on the filtering result. The phase compensation module is used to smooth the phase of the target signal group in the range frequency domain using the SG filtering algorithm, and to compensate and repair the initial phase of the interference frequency point using the smoothed phase, so as to obtain the signal after interference suppression.

7. The system according to claim 6, characterized in that, The feature classification module includes: The first determining submodule is used to determine the time domain power intensity value of each azimuth pulse echo in the original echo signal, and to perform Fourier transform on each azimuth pulse echo to obtain range frequency domain data, and determine the corresponding frequency domain peak value. The classification submodule is used to group the original echo signal according to a preset number of pulses, and determine the mean and standard deviation of the time domain power intensity value of the pulse signal in each group, as well as the maximum value of the frequency domain peak value, so as to obtain a multi-domain feature matrix. The first processing submodule is used to normalize the multi-domain feature matrix and then use the K-means clustering method to divide the signal into a target signal group with radio frequency interference and a normal echo signal group.

8. The system according to claim 6, characterized in that, The phase compensation module includes: The second processing submodule is used to extract the initial phase information of each pulse frequency domain data in the target signal group; The first filtering submodule is used to perform SG filtering on the initial phase information to obtain a filtered smooth phase. The third processing submodule is used to replace the original initial phase information with the smoothed phase to restore phase continuity for the interference frequency point location, and to keep the original data unchanged for non-interference frequency point locations, so as to obtain the compensated frequency domain data. The fourth processing submodule is used to perform an inverse Fourier transform on the compensated frequency domain data to obtain the signal after interference suppression.

9. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the steps of the SAR radio frequency interference suppression method as described in any one of claims 1 to 5 when executing the computer program.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the SAR radio frequency interference suppression method as described in any one of claims 1 to 5.

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