Jamming signal generation method, method for jamming synthetic aperture radar, and jammer

Abstract

The present disclosure provides an interference signal generation method, an interference synthetic aperture radar method and an interference machine, which can be applied to the technical field of radar countermeasure. The interference signal generation method comprises: performing data offset processing on distance dimension data of an interference template image to generate an offset interference image; performing resampling on the offset interference image based on an azimuth dimension resampling rate and a distance dimension resampling rate to obtain a resampled interference image; performing two-dimensional Fourier transform on the resampled interference image to obtain initial interference image data; performing frequency conversion processing on radar signals intercepted from a synthetic aperture radar to obtain distance frequency domain signals corresponding to the radar signals; constructing an interference response function corresponding to the initial interference image data based on a first real-time distance, a second real-time distance, a parameter, the distance frequency domain signals and the initial interference image data; and generating target interference signals by processing the distance frequency domain signals using the interference response function.

Description

Technical Field

[0001] The present disclosure relates to the field of radar countermeasure technology, and more particularly, to a jamming signal generation method, a method for jamming synthetic aperture radar, and a jammer. Background Art

[0002] Since synthetic aperture radar (hereinafter referred to as SAR) can achieve long-distance high-resolution imaging through small antenna synthesis and has the advantages of all-day and all-weather coverage, it has important application value in intelligence reconnaissance, resource exploration, disaster assessment and key area monitoring.

[0003] With the increasing importance of SAR in reconnaissance, various electronic countermeasures against SAR have attracted considerable attention in order to protect key targets or regions of interest (ROIs) from SAR detection. For example, related technologies can intercept and process SAR signals, then send the processed signals back to the SAR to interfere with SAR detection.

[0004] In the process of realizing the inventive concept disclosed herein, the inventors discovered that the electronic countermeasure methods for SAR in related technologies have a large amount of computation and are difficult to interfere with SAR in real time. Summary of the Invention

[0005] In view of this, the present disclosure provides a jamming signal generating method, a method for jamming a synthetic aperture radar, and a jammer.

[0006] A first aspect of the present disclosure provides a method for generating an interference signal for a synthetic aperture radar, comprising: obtaining distance information corresponding to a jammer, a synthetic aperture radar, and a false target, parameters corresponding to the synthetic aperture radar, and an interference template image of the false target, wherein the distance information includes the shortest slant distance between the jammer and the synthetic aperture radar, a first real-time distance between the jammer and the synthetic aperture radar, and a second real-time distance between the false target and the synthetic aperture radar, wherein the false target is a target used to interfere with the synthetic aperture radar; performing data offset processing on distance dimension data of the interference template image based on the shortest slant distance and azimuth dimension data of the interference template image to generate an offset interference image; and performing data offset processing on the offset dimension data based on the azimuth dimension resampling rate and the distance dimension resampling rate. The interference image is resampled to obtain a resampled interference image, wherein the azimuth dimension resampling rate corresponds to the parameter and the shortest slant range, and the range dimension resampling rate corresponds to the parameter; a two-dimensional Fourier transform is performed on the resampled interference image to obtain initialized interference image data; based on the first real-time distance and the parameter, a frequency conversion process is performed on the radar signal intercepted from the synthetic aperture radar to obtain a range frequency domain signal corresponding to the radar signal; based on the first real-time distance, the second real-time distance, the parameter, the range frequency domain signal and the initialized interference image data, an interference response function corresponding to the initialized interference image data is constructed; and a target interference signal is generated by processing the range frequency domain signal using the interference response function, wherein the target interference signal is an echo signal for sending to the synthetic aperture radar.

[0007] According to an embodiment of the present disclosure, parameters include radar fast time frequency domain and radar carrier frequency; based on the first real-time distance, the second real-time distance, parameters, the distance frequency domain signal and the initialized interference image data, an interference response function corresponding to the initialized interference image data is constructed, including: determining the real-time distance difference information between the first real-time distance and the second real-time distance; based on the real-time distance difference information, the radar fast time frequency domain, the radar carrier frequency, the speed of light information and the target distribution information of the initialized interference image data, an initial interference response function is constructed, the initial interference response function including the quadratic term of the Taylor expansion corresponding to the first real-time distance and the second real-time distance, the Taylor expansion corresponding to the moment when the radar slow movement time is 0; the initial interference response function is discretized to obtain a discretized response function; based on the interpolation function used to interpolate the orientation dimension data and the discretized response function, an interference response function is constructed.

[0008] According to an embodiment of the present disclosure, the parameters also include radar slow movement time and radar movement speed; the above-mentioned interference signal generation method also includes: obtaining the real-time positions of the jammer, the synthetic aperture radar and the false target; determining the first real-time distance between the jammer and the synthetic aperture radar based on the real-time position of the jammer, the real-time position of the synthetic aperture radar, the radar slow movement time and the radar movement speed; determining the second real-time distance between the false target and the synthetic aperture radar based on the real-time position of the false target, the real-time position of the synthetic aperture radar, the radar slow movement time and the radar movement speed.

[0009] According to an embodiment of the present disclosure, the interference response function is expressed by the following formula:

[0010]

[0011]

[0012]

[0013]

[0014] Where H(X, Y; n) is the interference response function. X is the orientation dimension of the initial interference image data. Y is the distance dimension of the initial interference image data. ΔF x is the spatial frequency interval of the spatial domain for initializing the interference image data. r is the radar fast time frequency domain. c is the radar carrier frequency. s is the shortest slant distance between the synthetic aperture radar and the jammer. v is the radar moving speed. t a The radar moves slowly. a is the unit time length of the synthetic aperture radar movement. a =nT a n = 0, 1, 2, 3, ... PRT is the pulse repetition period. c is the speed of light information. L is the interpolation kernel. j is the imaginary unit. To round down.

[0015] According to an embodiment of the present disclosure, data offset processing is performed on the distance dimension data of the interference template image based on the shortest slant distance and the azimuth dimension data of the interference template image to generate an offset interference image, including: generating data offset information based on the shortest slant distance and the azimuth dimension data; processing the distance dimension data of the interference template image according to the data offset information to generate an offset interference image.

[0016] According to an embodiment of the present disclosure, the parameters include a signal sampling rate, a radar fast time frequency domain, a radar carrier frequency, a radar moving speed, a pulse repetition period, and a number of pulses required for synthetic aperture radar imaging; the above-mentioned interference signal generation method further includes: determining a range dimension resampling rate based on the radar fast time frequency domain, the radar carrier frequency, the radar moving speed, the pulse repetition period, the number of pulses, a shortest slant range, and light speed information; and determining a bearing dimension resampling rate based on the signal sampling rate.

[0017] According to an embodiment of the present disclosure, the parameters include a pulse width, a chirp rate, a radar carrier frequency, and a radar fast time frequency domain; and the frequency conversion processing of the radar signal intercepted from the synthetic aperture radar based on the first real-time distance and the parameters to obtain a distance frequency domain signal corresponding to the radar signal includes: performing down-conversion on the radar signal based on the first real-time distance, the pulse width, the chirp rate, and the radar carrier frequency to obtain a down-converted signal; and performing Fourier transform on the down-converted signal based on the radar fast time frequency domain to obtain the distance frequency domain signal.

[0018] According to an embodiment of the present disclosure, the target interference signal is generated by processing the distance frequency domain signal using an interference response function, wherein the target interference signal is a return signal used for sending to the synthetic aperture radar, and the processing includes: multiplying the distance frequency domain signal and the interference response function to generate a modulation signal; and performing inverse Fourier transform on the modulation signal to generate the target interference signal.

[0019] A second aspect of the present disclosure provides a method for interfering with a synthetic aperture radar, applied to a jammer, including: intercepting a radar signal transmitted by the synthetic aperture radar; generating a target interference signal corresponding to the radar signal according to any one of the above-mentioned interference signal generation methods; and sending the target interference signal to the synthetic aperture radar.

[0020] A third aspect of the present disclosure provides an interferometer, comprising: a first acquisition module configured to acquire distance information corresponding to the interferometer, a synthetic aperture radar and a false target, a parameter corresponding to the synthetic aperture radar and an interference template image of the false target, wherein a shortest slant range between the interferometer and the synthetic aperture radar, the distance information comprising a first real-time distance between the interferometer and the synthetic aperture radar and a second real-time distance between the false target and the synthetic aperture radar, and the false target is a target for interfering with the synthetic aperture radar; a data offset module configured to perform coordinate offset processing on distance dimension coordinates of the interference template image based on the shortest slant range and azimuth dimension data of the interference template image, to generate an offset interference image; a resampling module configured to resample the offset interference image based on an azimuth dimension resampling rate and a distance dimension resampling rate, to obtain a resampled interference image, wherein the azimuth dimension resampling rate corresponds to the parameter and the shortest slant range, and the distance dimension resampling rate corresponds to the parameter; a Fourier transform module configured to perform two-dimensional Fourier transform on the resampled interference image, to obtain initial interference image data; a frequency conversion module configured to perform frequency conversion processing on radar signals intercepted from the synthetic aperture radar based on the first real-time distance and the parameter, to obtain a distance frequency domain signal corresponding to the radar signals; a construction module configured to construct an interference response function corresponding to the initial interference image data based on the first real-time distance, the second real-time distance, the parameter, the distance frequency domain signal and the initial interference image data; and a generation module configured to generate a target interference signal by processing the distance frequency domain signal using the interference response function, wherein the target interference signal is a return signal for sending to the synthetic aperture radar.

[0021] According to the embodiments of the present disclosure, by performing data offset processing and image space two-dimensional frequency domain resampling processing on the interference template image, an interference response function corresponding to the entire interference template image is obtained, the processing requirement of the azimuth bandwidth parameter is solved, the determination of the azimuth time is solved, and the large amount of calculation of the point-by-point summation algorithm in some methods is overcome, the amount of calculation is reduced, and real-time interference of the SAR is realized.

[0022] Compared with the initialization of a three-dimensional matrix in the spatial domain two-dimensional interpolation algorithm, the present disclosure only performs two-dimensional Fourier transform on the interference template image, the amount of calculation and storage consumption are reduced by one dimension, the operation efficiency is improved, and the storage requirement is reduced, so that the present disclosure can be applied to scenes with high real-time signal processing requirements and limited radar volume and weight.

[0023] In addition, image distortion correction is realized by preprocessing the interference template image, and image two-dimensional spatial domain data is generated by spatial domain two-dimensional Fourier transform, thereby improving the imaging accuracy of the SAR in imaging the received target interference signal. BRIEF DESCRIPTION OF DRAWINGS

[0024] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:

[0025] Figure 1 An exemplary system architecture to which the jamming signal generation method or the method of jamming synthetic aperture radar according to embodiments of the present disclosure can be applied is schematically shown.

[0026] Figure 2 A flowchart of the jamming signal generation method according to embodiments of the present disclosure is schematically shown.

[0027] Figure 3 A schematic diagram of the jamming process according to embodiments of the present disclosure is schematically shown.

[0028] Figure 4 A flowchart of the jamming signal generation method according to another embodiment of the present disclosure is schematically shown.

[0029] Figure 5 A schematic diagram of the pre-processing of the jamming template image according to embodiments of the present disclosure is schematically shown.

[0030] Figure 6a An imaging result corresponding to the un-processed jamming template image according to embodiments of the present disclosure is schematically shown.

[0031] Figure 6b An imaging result corresponding to the pre-processed jamming template image according to embodiments of the present disclosure is schematically shown.

[0032] Figure 7a A schematic diagram of the jamming template image according to embodiments of the present disclosure is schematically shown.

[0033] Figure 7b A schematic diagram of the two-dimensional spatial frequency domain representation of the pre-processed jamming template image according to embodiments of the present disclosure is schematically shown.

[0034] Figure 8 A schematic diagram of the jamming result of SAR imaging according to embodiments of the present disclosure is schematically shown.

[0035] Figure 9 A flowchart of the method of jamming synthetic aperture radar according to embodiments of the present disclosure is schematically shown.

[0036] Figure 10 A block diagram of the structure of the jammer according to embodiments of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0038] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0039] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0040] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0041] According to the embodiments of the present disclosure, based on the effectiveness of the jamming method, the jamming methods for SAR can be mainly divided into suppression jamming methods and deception jamming methods. Suppression jamming methods mainly interfere with SAR detection by covering large areas of scenes and hiding targets. For example, in the suppression jamming method, by concentrating the jamming in the ROI area, important targets within the ROI are difficult to be detected by SAR. In the deception jamming method, the intercepted SAR signal can be processed to emit an echo signal corresponding to a false image including a false scene or false target, thereby increasing the difficulty of SAR detecting real targets.

[0042] In some embodiments, the deception jamming method for SAR is based on a modulation-retransmission mechanism. That is, in each pulse repetition interval (PRI), the jammer modulates the radar signal intercepted from the SAR to be jammed according to the image template for jamming the SAR and various other parameters (kinematic parameters and radar signal parameters, etc.) of the SAR to be jammed, generates a jamming signal and transmits the jamming signal back to the SAR as a return signal, and the SAR will obtain a false image after receiving and imaging processing the return signal. In each PRI, the deceptive jammer is modeled as a linear system, and how to obtain the frequency response of the jammer is a focus in the field of SAR deceptive jamming.

[0043] A simple method in the present disclosure is to calculate the signal propagation delay difference between each scatterer in the jammer and the template during each PRI. However, this method has a large amount of computation, especially in the case of a large jamming template image, and real-time processing is extremely difficult.

[0044] Research in another aspect mainly focuses on reducing the computational complexity. For example, the computational burden during each pulse jamming operation can be reduced by performing some preprocessing procedures. In a specific implementation, this is divided into two categories: azimuth time domain processing and azimuth frequency domain processing. The former can be implemented based on algorithms such as inverse range-Doppler algorithm and piecewise modulation algorithm. On this basis, although the azimuth time domain processing reduces the computational complexity by approximating the range equation, it causes a loss of image quality to some extent. The latter can be implemented based on algorithms such as inverse Omega-K algorithm, frequency domain three-stage algorithm, and spatial domain two-dimensional interpolation algorithm. On this basis, the azimuth frequency domain processing needs to perform two-dimensional Fourier transform and Stolt interpolation on the jamming template image, which is relatively accurate compared to the former, but still has some defects. For example, the inverse Omega-K algorithm and the frequency domain three-stage algorithm require additional azimuth bandwidth parameters and need to be determined for the azimuth time, which has a large amount of computation. The spatial domain two-dimensional interpolation algorithm has problems such as large initialization computation and large space occupation due to the image domain modulation phase, and real-time processing is difficult, which faces obstacles in practicality, and the real-time processing part needs to perform two-dimensional interpolation operation, which still has a large amount of computation. Therefore, although the above methods reduce the computational complexity of jamming signal generation to different extents, the contradiction between a large amount of computation and the demand for real-time processing has not been completely solved. With the application of high-resolution radars, the PRI interval becomes shorter, and the application of agile waveforms and other anti-jamming technologies further makes the real-time processing speed face more severe challenges.

[0045] In order to solve the above problems, the present invention proposes a method for quickly generating SAR deception interference signals based on template spatial domain processing. The method is mainly divided into two parts: initialization and real-time processing of modulated signals. The initialization part includes two parts: interference template image preprocessing and template image spatial domain conversion: first, determine the positional relationship between the synthetic aperture radar, the jammer and the false scene; then preprocess the interference template, which mainly includes two steps: distance dimension scaling of the interference template and resampling of the interference template; finally, perform a two-dimensional Fourier transform on the interference template according to the radar parameters to obtain the spatial domain data of the interference template, and complete the jammer initialization. The real-time processing process of the modulated signal is: first, the jammer intercepts the radar signal, performs frequency conversion processing on the radar signal, and obtains the frequency domain signal; then, based on the interference template image, obtains the interference response function; and then, based on the frequency domain signal and the interference response function, obtains the target interference signal after the entire interference template image is modulated.

[0046] Specifically, embodiments of the present disclosure provide a method for generating a jamming signal for a synthetic aperture radar (SAR), including obtaining distance information corresponding to a jammer, a SAR, and a false target, parameters corresponding to the SAR, and a jamming template image of the false target. The distance information includes the shortest slant range between the jammer and the SAR, a first real-time range between the jammer and the SAR, and a second real-time range between the false target and the SAR, where the false target is intended to jam the SAR. Based on the shortest slant range and azimuth dimension data of the jamming template image, data offset processing is performed on the range dimension data of the jamming template image to generate an offset jamming image. The offset jamming image is resampled based on an azimuth dimension resampling rate and a range dimension resampling rate to obtain a resampled jamming image, wherein the azimuth dimension resampling rate corresponds to the parameter and the shortest slant range, and the range dimension resampling rate corresponds to the parameter. A two-dimensional Fourier transform is performed on the resampled jamming image to obtain initialized jamming image data. Based on the first real-time range and the parameters, frequency conversion processing is performed on a radar signal intercepted from the SAR to obtain a range-frequency domain signal corresponding to the radar signal. An interference response function corresponding to the initialized interference image data is constructed based on the first real-time range, the second real-time range, the parameters, the range-frequency domain signal, and the initialized interference image data. A target interference signal is generated by processing the range-frequency domain signal using the interference response function. The target interference signal is an echo signal for transmission to a synthetic aperture radar.

[0047] Figure 1 The following schematically illustrates an exemplary system architecture 100 to which the jamming signal generation method or the method for jamming synthetic aperture radar according to an embodiment of the present disclosure can be applied. Figure 1The examples shown are merely examples of system architectures to which the embodiments of the present disclosure may be applied, to help those skilled in the art understand the technical content of the present disclosure, but do not mean that the embodiments of the present disclosure may not be used in other devices, systems, environments or scenarios.

[0048] like Figure 1 As shown, the exemplary system architecture 100 of this embodiment includes a SAR to be jammed 110 and a jammer 120 .

[0049] SAR 110 can be used to detect a target. The target can include a target object or a target scene. For example, SAR 110 can transmit a radar signal toward the target and receive an echo signal. By processing the echo signal, an image of the target can be obtained.

[0050] The jammer 120 can be used to interfere with the detection process of the SAR 110. For example, if the SAR 110 transmits a radar signal to a target within the radar detection area, the jammer 120, also located within the radar detection area, can intercept the radar signal. The jammer 120 can process the intercepted radar signal according to a false interference template image and generate an interference signal. The jammer 120 interferes with the SAR 110 by transmitting the interference signal to the SAR 110. Based on this, after the SAR 110 receives the interference signal and performs imaging processing, the resulting image is not an image of the target, but rather an image of the false interference template.

[0051] SAR 110 can be mounted on a mobile machine or fixed at a predetermined location. For example, the machine used to mount SAR 110 may include a satellite, an aircraft, or an unmanned aerial vehicle, etc., and this disclosure does not limit this. Similarly, jammer 120 can be mounted on a mobile machine or fixed at a predetermined location. For example, the machine used to mount jammer 120 may include an aircraft, a vehicle, or a ship, etc., and this disclosure does not limit this. The machine used to mount SAR 110 and jammer 120 can be the same machine or different machines, and this disclosure does not limit this.

[0052] It should be understood that the implementation of the present disclosure is not limited to whether the SAR 110 and the jammer 120 are in a mobile state. For example, if at least one of the SAR 110 and the jammer 120 is mounted on a movable machine and is in a mobile state, the SAR 110 can still detect the target by sending a radar signal to the target. The jammer 120 can still intercept the radar signal of the SAR 110 and generate a jamming signal to interfere with the SAR 110.

[0053] The following is based on Figure 1 The exemplary architecture shown, combined with Figures 2-8The contents of the present disclosure are described in detail.

[0054] Figure 2 The flowchart of the interference signal generation method according to the embodiment of the present disclosure is schematically shown.

[0055] like Figure 2 As shown, the method includes operations S201 to S207.

[0056] In operation S201, distance information corresponding to a jammer, a synthetic aperture radar, and a false target, parameters corresponding to the synthetic aperture radar, and an interference template image of the false target are obtained, wherein the distance information includes a shortest slant range between the jammer and the synthetic aperture radar, a first real-time distance between the jammer and the synthetic aperture radar, and a second real-time distance between the false target and the synthetic aperture radar, where the false target is a target used to interfere with the synthetic aperture radar.

[0057] In operation S202 , data offset processing is performed on the distance dimension data of the interference template image based on the shortest slant range and the azimuth dimension data of the interference template image to generate an offset interference image.

[0058] In operation S203, the offset interference image is resampled based on the azimuth dimension resampling rate and the range dimension resampling rate to obtain a resampled interference image, wherein the azimuth dimension resampling rate corresponds to the parameter and the shortest slant distance, and the range dimension resampling rate corresponds to the parameter.

[0059] In operation S204 , a two-dimensional Fourier transform is performed on the resampled interference image to obtain initialized interference image data.

[0060] In operation S205 , frequency conversion processing is performed on the radar signal intercepted from the synthetic aperture radar based on the first real-time distance and parameters to obtain a range-frequency domain signal corresponding to the radar signal.

[0061] In operation S206 , an interference response function corresponding to the initialized interference image data is constructed based on the first real-time distance, the second real-time distance, the parameter, the range frequency domain signal, and the initialized interference image data.

[0062] In operation S207 , a target interference signal is generated by processing the range-frequency domain signal using an interference response function, wherein the target interference signal is an echo signal for transmitting to a synthetic aperture radar.

[0063] According to an embodiment of the present disclosure, the false target can include a false scene, a false object, or the like. The interference template image can be an image of a pre-set false scene or an image of a pre-set false object. In the embodiment of the present disclosure, the SAR can emit radar signals to a direction where the real target is located for detection. The jammer located in the same area as the real target can intercept the radar signals emitted to the real target, and process the radar signals according to the interference template image set based on the false target to obtain interference signals, so as to interfere with the SAR using the interference signals to avoid obtaining the image of the real target by the SAR.

[0064] According to an embodiment of the present disclosure, the distance dimension data of the interference template image is processed by data offsetting according to the shortest slant range and the interference template image, and the offset interference image is resampled based on the azimuth dimension resampling rate and the distance dimension resampling rate, so as to complete the preprocessing of the interference template image, realize the distortion correction of the interference template image, and reduce the amount of calculation in the generation process of the interference response function.

[0065] On this basis, the present disclosure only performs two-dimensional Fourier transform on the preprocessed interference template image, and the amount of calculation and storage consumption of the three-dimensional matrix of the spatial domain two-dimensional interpolation algorithm in the above-mentioned embodiment is reduced by one dimension.

[0066] According to an embodiment of the present disclosure, the parameters corresponding to the synthetic aperture radar can include kinematic parameters of the SAR and radar signal parameters. The kinematic parameters of the SAR can include but are not limited to the radar moving speed, the real-time position of the SAR, and the radar moving slow time, and the like. The radar signal parameters can include but are not limited to the radar fast time frequency domain, the radar carrier frequency, the pulse width, the chirp rate, the pulse repetition period, and the pulse number, and the like.

[0067] In the embodiment of the present disclosure, the azimuth dimension resampling rate and the distance dimension resampling rate can be pre-determined. The azimuth dimension resampling rate can be determined based on the kinematic parameters and the radar signal parameters. And the distance dimension resampling rate can be determined based on the radar signal parameters.

[0068] In the embodiment of the present disclosure, the radar signal intercepted from the synthetic aperture radar can be frequency-converted based on the first real-time distance and the radar signal parameters to obtain a distance frequency domain signal corresponding to the radar signal.

[0069] In the embodiments of the present disclosure, the interference response function corresponding to the initial interference image data can be constructed based on the first real-time distance, the second real-time distance, the radar signal parameter, the distance frequency domain signal, and the initial interference image data. The interference response function can be a function for processing the radar signal to generate a target interference signal for interfering with the SAR. For example, by performing operation on the interference response function and the distance frequency domain signal corresponding to the radar signal, the target interference signal can be obtained.

[0070] According to the embodiments of the present disclosure, by performing data offset processing and image space two-dimensional frequency domain resampling processing on the interference template image, the interference response function corresponding to the whole interference template image is obtained, the processing requirement of the azimuth bandwidth parameter is solved, the determination of the azimuth time is solved, and the disadvantages of the point-by-point summation algorithm in some deception jamming methods are overcome, the operation amount is reduced, and the real-time jamming of the SAR is realized.

[0071] Compared with the initialization of the three-dimensional matrix in the spatial domain two-dimensional interpolation algorithm, the present disclosure only performs two-dimensional Fourier transform on the interference template image, the operation amount and storage consumption are reduced by one dimension, the operation efficiency is improved, and the storage requirement is reduced, so that the present disclosure can be applied to the scene where the real-time signal processing requirement is high and the volume and weight of the radar are limited.

[0072] In addition, the image distortion correction is realized by preprocessing the interference template image, the image two-dimensional spatial domain data is generated by the spatial domain two-dimensional Fourier transform, and the imaging accuracy of the SAR for imaging the received target interference signal is improved.

[0073] According to the embodiments of the present disclosure, the parameters further include the radar moving slow time and the radar moving speed. The above interference signal generation method further includes: acquiring the real-time positions of the jammer, the synthetic aperture radar, and the false target respectively. Based on the real-time position of the jammer, the real-time position of the synthetic aperture radar, the radar moving slow time, and the radar moving speed, the first real-time distance between the jammer and the synthetic aperture radar is determined. Based on the real-time position of the false target, the real-time position of the synthetic aperture radar, the radar moving slow time, and the radar moving speed, the second real-time distance between the false target and the synthetic aperture radar is determined.

[0074] According to the embodiments of the present disclosure, the real-time position of the jammer is defined as (0, 0), and the real-time position of the false target is defined as (x, y).

[0075] Based on this, the first real-time distance R(t a ) can be represented as:

[0076] (1)

[0077] The second real-time distance RF (t a ) can be expressed as:

[0078] (2)

[0079] Among them, R s is the shortest slant distance between SAR and jammer, v is the radar moving speed, t a It should be noted that, for the sake of convenience, the same symbols are used in this disclosure to represent the same physical meanings.

[0080] According to an embodiment of the present disclosure, data offset processing is performed on distance dimension data of an interference template image based on the shortest slant range and azimuth dimension data of the interference template image to generate an offset interference image, including: generating data offset information based on the shortest slant range and azimuth dimension data; and processing the distance dimension data of the interference template image according to the data offset information to generate the offset interference image.

[0081] According to the embodiment of the present disclosure, the image azimuth coordinates are kept unchanged, and an offset related to the azimuth is added in the distance direction, that is, X=x, Y=y+X 2 / 2R s , from which we can get the offset interference image σ(X,Y), where X 2 / 2R s That is the above data offset information, R s is the shortest slant distance between the SAR and the jammer, X represents the distance dimension data of the jamming template image and the offset jamming image, and Y represents the azimuth dimension data in the offset jamming image.

[0082] According to an embodiment of the present disclosure, parameters include signal sampling rate, radar fast time and frequency domain, radar carrier frequency, radar motion speed, pulse repetition period, and the number of pulses required for synthetic aperture radar imaging. The above-mentioned interference signal generation method further includes: determining the azimuth dimension resampling rate based on radar fast time and frequency domain, radar carrier frequency, radar motion speed, pulse repetition period, number of pulses, shortest slant range, and speed of light information; and determining the range dimension resampling rate based on the signal sampling rate.

[0083] According to an embodiment of the present disclosure, after the offset interference image is generated, the offset interference image may be resampled based on a range dimension resampling rate and an azimuth dimension resampling rate.

[0084] The distance dimension resampling rate is F y =2F s / c, where F s is the signal sampling rate of the radar signal, and c is the speed of light information.

[0085] The resampling rate of the azimuth dimension is F x, to avoid phase loss in the subsequent processing, it needs to satisfy:

[0086] (3)

[0087] where PRT is the pulse repetition period of the SAR signal, N s is the number of pulses. f r is the radar fast time frequency domain. f c is the radar carrier frequency. v is the radar moving speed. c is the light speed information. R s is the shortest slant range between the SAR and the jammer.

[0088] After resampling, a resampled jamming image σ new (X,Y) is obtained, and the number of image points is UxV.

[0089] According to an embodiment of the present disclosure, the parameters include the radar fast time frequency domain and the radar carrier frequency. Based on the first real-time distance, the second real-time distance, the parameters, the distance frequency domain signal, and the initial jamming image data, a jamming response function corresponding to the initial jamming image data is constructed, including: determining real-time distance difference information between the first real-time distance and the second real-time distance. Based on the real-time distance difference information, the radar fast time frequency domain, the radar carrier frequency, the light speed information, and the target distribution information of the initial jamming image data, an initial jamming response function is constructed, and the initial jamming response function includes a quadratic term of a Taylor expansion corresponding to the first real-time distance and the second real-time distance, and the Taylor expansion corresponds to a moment when the radar moving slow time is 0. The initial jamming response function is discretized to obtain a discretized response function. Based on an interpolation function used for interpolating the azimuth dimension data and the discretized response function, the jamming response function is constructed.

[0090] According to an embodiment of the present disclosure, the real-time distance difference information ΔR can be calculated by the following formula:

[0091] (4)

[0092] On this basis, for the whole jamming template image, the system response function H(x,y; t a ) can be represented as:

[0093] (5)

[0094] Where σ(x,y) is the target distribution information of the jamming template image, and j is the imaginary unit.

[0095] The first real-time distance R(t a ) and the second real-time distance R F (t a ) at ta =0, the system response function can be further expressed as:

[0096] (6)

[0097] Since the intercepted radar signal is sampled into N f points, and after Fourier transform, the radar fast time domain is: .

[0098] Therefore, the two-dimensional Fourier transform of σ new (X,Y) is: .

[0099] For example, the number of points in the range dimension of the resampled jamming image is N f , and after range dimension Fourier transform, the spatial domain representation of the resampled jamming image is: ; the number of points in the azimuth dimension of the resampled jamming image is N s , and after azimuth dimension Fourier transform, the spatial domain representation of the resampled jamming image is: . Thus, the initialization of the entire jamming process is completed. K(u,v) is the sampling value of the spatial spectrum of K(W X ,W Y ;t a ) in the spatial frequency .

[0100] After the jamming template image is initialized to obtain the initialized jamming image data, the system response function can be re-expressed as:

[0101] (7)

[0102] Since the system response function can be regarded as the value of the two-dimensional Fourier transform of the resampled jamming image at a specific position, the system response function can be further expressed as:

[0103] (8)

[0104] Where δ is a predetermined impulse function.

[0105] Since t a =nT a , n=0,1,2,3,…, the discretized response function can be obtained after discretization of the system response function, which is expressed as:

[0106] (9)

[0107] It can be seen that the system response function can be expressed as the phase value at the two-dimensional frequency domain response position of the initial interference image data. Y and direction W X The corresponding positions are:

[0108] (10)

[0109] It can be seen that the position corresponding to the distance dimension does not increase with the number of pulses, while the azimuth dimension has different values ​​at different slow-time phases, that is, when n changes, the position corresponding to the azimuth dimension will also change accordingly.

[0110] The range-frequency domain of radar signals , and the spatial frequency domain data of the resampled interference image after two-dimensional Fourier transform , we can get:

[0111] (11)

[0112] Based on this, the previous parameter selection can ensure that the frequency corresponding to the distance dimension in the two-dimensional frequency domain of the image is equal to the modulation phase, so only the azimuth dimension of the image needs to be interpolated.

[0113] (12)

[0114] in, Indicates rounding down, ΔF x =F x / U is the spatial frequency interval of the image space domain. The interpolation process can be expressed as:

[0115] (13)

[0116] in, corresponds to the above interpolation function.

[0117] At this point, the rapid construction of the interference response function is completed.

[0118] Based on this, the interference response function is expressed by the following formula:

[0119] (13)

[0120] (14)

[0121] (11)

[0122] (12)

[0123] Where H(X, Y; n) is the interference response function. X is the orientation dimension of the initial interference image data. Y is the distance dimension of the initial interference image data. ΔF x is the spatial frequency interval of the spatial domain for initializing the interference image data. r is the radar fast time frequency domain. c is the radar carrier frequency. s is the shortest slant distance between the synthetic aperture radar and the jammer. v is the radar moving speed. t a The radar moves slowly. a is the unit time length of the synthetic aperture radar movement. a =nT a n = 0, 1, 2, 3, ... PRT is the pulse repetition period. c is the speed of light information. L is the interpolation kernel. j is the imaginary unit. To round down.

[0124] According to embodiments of the present disclosure, compared to the aforementioned spatial domain 2D interpolation algorithm, this method corrects the interference template image by performing data offset and 2D resampling on the interference template image. This further reduces the computational complexity involved in generating the real-time interference response function, reducing the range-azimuth 2D resampling in the aforementioned spatial domain 2D interpolation algorithm to a single dimension (i.e., the azimuth dimension). Furthermore, the present disclosure uses the aforementioned interpolation function to implement interpolation at specific locations, thereby achieving point-by-point modulation for generating the interference response function. Because the entire process utilizes a 2D Taylor expansion of the distance function, this distance function corresponds to the aforementioned initial interference response function, resulting in higher SAR imaging accuracy.

[0125] Compared to other solutions in some embodiments, the present invention only requires a single 2D Fourier transform during the initialization phase, storing a pair of 2D frequency domain data. During the real-time phase, only azimuth interpolation is required, reducing the computational effort and enabling real-time interference with SAR. Furthermore, the present disclosure, based on a quadratic Taylor expansion of range error, can achieve higher SAR imaging accuracy. The 2D frequency domain data corresponds to the aforementioned initial interference image data.

[0126] According to an embodiment of the present disclosure, the parameters include pulse width, chirp rate, radar carrier frequency, and radar fast time-frequency domain. Based on a first real-time range and the parameters, a radar signal intercepted from a synthetic aperture radar is frequency-converted to obtain a range-frequency domain signal corresponding to the radar signal. This includes down-converting the radar signal based on the first real-time range, pulse width, chirp rate, and radar carrier frequency to obtain a down-converted signal. Based on the radar fast time-frequency domain, Fourier transforming the down-converted signal to obtain a range-frequency domain signal is performed.

[0127] According to an embodiment of the present disclosure, the radar signal intercepted at the jammer is directly returned to the radar receiving end, and the down-converted signal S r (t f ,t a ;τ1) can be represented as:

[0128] (15)

[0129] wherein t represents time, τ1=R(t a ) / c, T represents pulse width, K r represents the chirp rate.

[0130] The Fourier transform is performed on the down-converted signal S r (t f ,t a ;τ1) to the range frequency to obtain a range frequency domain signal S r (t f ,t a ), which can be represented as:

[0131] (16)

[0132] According to an embodiment of the present disclosure, the range frequency domain signal is processed by using a jamming response function to generate a target jamming signal, wherein the target jamming signal is a return signal used for sending to the synthetic aperture radar, comprising: multiplying the range frequency domain signal and the jamming response function to generate a modulation signal. The inverse Fourier transform is performed on the modulation signal to generate the target jamming signal.

[0133] According to an embodiment of the present disclosure, the range frequency domain signal at the jammer is multiplied by the jamming response function, and the inverse Fourier transform is performed to obtain a modulation signal S r-m (f r ,t a ), which can be represented as:

[0134] (17)

[0135] At this time, the modulation on the whole image is completed, and the return signal at the false target position, i.e., the above-mentioned modulation signal, is perfectly recovered. The inverse Fourier transform is performed on the modulation signal, and the time domain signal, i.e., the above-mentioned target jamming signal S r-m (t r ,t a ), which can be represented as:

[0136] (18)

[0137] Figure 3 A schematic diagram of the jamming process according to an embodiment of the present disclosure is schematically shown.

[0138] like Figure 3 As shown, the jammer amplifies the intercepted radio frequency (RF) radar signal, downconverts it to baseband, and then performs analog-to-digital (A / D) conversion. It then performs a series of operations, including a fast Fourier transform (FFT), on the signal to the baseband frequency domain, generating a range-frequency domain signal. The jammer preprocesses the jamming template image using SAR system parameters (SAR platform speed, carrier frequency, pulse duration, chirp rate, repetition rate, etc.) and jammer modulation parameters (location, coverage area, etc.). A two-dimensional Fourier transform is then performed to generate the two-dimensional spatial frequency domain data of the initialized jamming image, resulting in the jammer response function. The jammer then multiplies the range-frequency domain signal with the jammer response function and performs an inverse FFT (IFFT) to obtain the baseband jammer signal, i.e., the target jammer signal. The jammer then retransmits the RF target jammer signal to the SAR through digital-to-analog (D / A) conversion, upconversion, and gain control. By repeating these steps for each intercepted pulse, the SAR generates a false image, thereby jamming the SAR.

[0139] Figure 4 The flowchart of the interference signal generation method according to another embodiment of the present disclosure is schematically shown.

[0140] like Figure 4 As shown, the radar jamming method of this embodiment includes operations S401 to S404.

[0141] In operation S401 , the interference template image is preprocessed to obtain a resampled interference image.

[0142] In operation S402 , spatial domain transformation is performed on the resampled interference image to obtain initialized interference image data.

[0143] In operation S403 , an interference response function corresponding to the initialized interference image data is constructed in real time based on an interpolation function for interpolating the orientation-dimensional data.

[0144] In operation S404, the intercepted radar signal is processed according to the interference response function to obtain a target interference signal.

[0145] The performance of the proposed method will be verified through simulation experiments to prove the correctness of the theoretical analysis. The specific simulation experiment parameters are shown in Table 1. Figure 5 The schematic diagram of the pre-processing interference template image according to the embodiment of the present disclosure is schematically shown. Figure 5 In the figure, the image on the left represents the interference template image, and the image on the right represents the resampled interference image after preprocessing. Based on this, this paper simulates interference imaging results based on both unprocessed and preprocessed interference template images to demonstrate the impact of preprocessing on the interference imaging results.

[0146] On this basis, Figure 6a and Figure 6b The following diagram schematically shows the effect of pre-processing on interference imaging results. Figure 6a The imaging result corresponding to the interference template image without preprocessing is schematically shown; Figure 6b The imaging result corresponding to the pre-processed interference template image is schematically shown. Figure 6a and Figure 6b In , Azimuth corresponds to the orientation dimension and Range corresponds to the distance dimension. Figure 7a The interference template image is schematically shown. Figure 7b The two-dimensional spatial frequency domain representation of the pre-processed interference template image is schematically shown. Figure 8 Based on this, it can be seen that when the interference template image is pre-processed to improve the interference efficiency and achieve real-time interference, a good interference effect on SAR can still be guaranteed.

[0147] Table 1 Radar simulation parameters

[0148]

[0149] To this end, the present invention preprocesses the interference image (scaling the interference template's distance dimension and resampling it), then performs a two-dimensional Fourier transform to obtain its spatial domain data. Then, based on the spatial frequency domain positions at different slow times, azimuth-dimensional interpolation is performed within the two-dimensional spatial domain data of the interference image. This allows for the rapid acquisition of the interference response function modulated across the entire image. By multiplying this with the frequency domain of the radar intercepted signal, the frequency domain representation of the jammer's forwarded signal is obtained. An inverse Fourier transform is then used to recover the time domain signal of the jammer's forwarded signal, i.e., the target interference signal. This entire process is fast and memory-efficient, overcoming the constraints of conventional point-by-point modulation, where the computational complexity varies with the size of the interference image. It is suitable for applications requiring high real-time radar processing and where the jammer's size and weight are limited.

[0150] Figure 9 The flowchart of the method for interfering with synthetic aperture radar according to an embodiment of the present disclosure is schematically shown.

[0151] like Figure 9 As shown, the method is applied to a jammer, including operations S901 to S903.

[0152] In operation S901 , a radar signal transmitted by a synthetic aperture radar is intercepted.

[0153] In operation S902 , a target interference signal corresponding to a radar signal is generated according to the interference signal generating method of the present disclosure.

[0154] In operation S903 , a target interference signal is sent to the synthetic aperture radar.

[0155] Based on the above interference signal generation method, the present disclosure also provides a jammer. Figure 10 The jammer is described in detail.

[0156] Figure 10 The following schematically shows a structural block diagram of a jammer according to an embodiment of the present disclosure.

[0157] like Figure 10 As shown, the jammer 1000 of this embodiment includes a first acquisition module 1010 , a data offset module 1020 , a resampling module 1030 , a Fourier transform module 1040 , a frequency conversion module 1050 , a construction module 1060 and a generation module 1070 .

[0158] The first acquisition module 1010 is configured to acquire distance information corresponding to the jammer, the synthetic aperture radar, and the false target, parameters corresponding to the synthetic aperture radar, and a jamming template image of the false target. The distance information includes the shortest slant range between the jammer and the synthetic aperture radar, a first real-time range between the jammer and the synthetic aperture radar, and a second real-time range between the false target and the synthetic aperture radar. The false target is a target used to jam the synthetic aperture radar. In one embodiment, the first acquisition module 1010 can be configured to perform operation S210 described above, which will not be further described herein.

[0159] The data offset module 1020 is used to perform data offset processing on the distance dimension data of the interference template image based on the shortest slant range and the azimuth dimension data of the interference template image to generate an offset interference image. In one embodiment, the data offset module 1020 can be used to perform the operation S220 described above, which will not be repeated here.

[0160] Resampling module 1030 is configured to resample the offset interference image based on an azimuth resampling rate and a range resampling rate to obtain a resampled interference image, wherein the azimuth resampling rate corresponds to the parameter and the shortest slant range, and the range resampling rate corresponds to the parameter. In one embodiment, resampling module 1030 can be configured to perform operation S230 described above, which will not be further described here.

[0161] The Fourier transform module 1040 is used to perform a two-dimensional Fourier transform on the resampled interference image to obtain the initialized interference image data. In one embodiment, the Fourier transform module 1040 can be used to perform the operation S240 described above, which will not be repeated here.

[0162] Frequency conversion module 1050 is configured to perform frequency conversion processing on the radar signal intercepted from the synthetic aperture radar based on the first real-time range and parameters to obtain a range-frequency domain signal corresponding to the radar signal. In one embodiment, frequency conversion module 1050 can be configured to perform operation S250 described above, which will not be further described here.

[0163] The construction module 1060 is configured to construct an interference response function corresponding to the initialized interference image data based on the first real-time distance, the second real-time distance, the parameter, the range-frequency signal, and the initialized interference image data. In one embodiment, the construction module 1060 may be configured to perform operation S260 described above, which will not be further described herein.

[0164] The generation module 1070 is configured to generate a target interference signal by processing the range-frequency domain signal using an interference response function, where the target interference signal is an echo signal for transmitting to the synthetic aperture radar. In one embodiment, the generation module 1070 can be configured to perform operation S270 described above, which will not be further described here.

[0165] According to an embodiment of the present disclosure, the construction module 1060 includes a determination submodule, a first construction submodule, a discretization submodule, and a second construction submodule. The determination submodule is used to determine the real-time distance difference information between the first real-time distance and the second real-time distance; the first construction submodule is used to construct an initial interference response function based on the real-time distance difference information, the radar fast time frequency domain, the radar carrier frequency, the speed of light information, and the target distribution information of the initialized interference image data. The initial interference response function includes a quadratic term of a Taylor expansion corresponding to the first real-time distance and the second real-time distance, and the Taylor expansion corresponds to the moment when the radar slow movement time is 0; the discretization submodule is used to discretize the initial interference response function to obtain a discretized response function; and the second construction submodule is used to construct the interference response function based on the interpolation function used to interpolate the orientation dimension data and the discretized response function.

[0166] According to an embodiment of the present disclosure, the jammer 1000 further includes a second acquisition module, a first determination module, and a second determination module. The second acquisition module is configured to acquire the real-time positions of the jammer, the synthetic aperture radar, and the false target; the first determination module is configured to determine a first real-time distance between the jammer and the synthetic aperture radar based on the real-time position of the jammer, the real-time position of the synthetic aperture radar, the radar slow movement time, and the radar movement speed; and the second determination module is configured to determine a second real-time distance between the false target and the synthetic aperture radar based on the real-time position of the false target, the real-time position of the synthetic aperture radar, the radar slow movement time, and the radar movement speed.

[0167] According to an embodiment of the present disclosure, the data offset module 1020 includes a first generation submodule and a second generation submodule. The first generation submodule is configured to generate data offset information based on the shortest slant range and azimuth dimension data, and the second generation submodule is configured to process the distance dimension data of the interference template image according to the data offset information to generate an offset interference image.

[0168] According to an embodiment of the present disclosure, the jammer 1000 further includes a third determination module and a fourth determination module. The third determination module is configured to determine the azimuth dimension resampling rate based on radar fast time-frequency domain, radar carrier frequency, radar moving speed, pulse repetition period, number of pulses, shortest slant range, and speed of light information; and the fourth determination module is configured to determine the range dimension resampling rate based on the signal sampling rate.

[0169] According to an embodiment of the present disclosure, the frequency conversion module 1050 includes a down-conversion submodule and a Fourier transform submodule. The down-conversion submodule is configured to down-convert the radar signal based on the first real-time range, pulse width, chirp rate, and radar carrier frequency to obtain a down-converted signal; the Fourier transform submodule is configured to perform a Fourier transform on the down-converted signal based on the radar fast time frequency domain to obtain a range-frequency domain signal.

[0170] According to an embodiment of the present disclosure, the generation module 1070 includes a third generation submodule and a fourth generation submodule. The third generation submodule is configured to multiply the range-frequency domain signal and the interference response function to generate a modulated signal, and the fourth generation submodule is configured to perform an inverse Fourier transform on the modulated signal to generate a target interference signal.

[0171] According to an embodiment of the present disclosure, the jammer 1000 further includes an interception module and a transmission module, wherein the interception module is used to intercept radar signals transmitted by a synthetic aperture radar, and the transmission module is used to transmit target jamming signals to the synthetic aperture radar.

[0172] According to an embodiment of the present disclosure, any multiple modules among the first acquisition module 1010, the data offset module 1020, the resampling module 1030, the Fourier transform module 1040, the frequency conversion module 1050, the construction module 1060, and the generation module 1070 can be combined into a single module for implementation, or any one of these modules can be split into multiple modules. Alternatively, at least part of the functionality of one or more of these modules can be combined with at least part of the functionality of other modules and implemented in a single module. According to an embodiment of the present disclosure, at least one of the first acquisition module 1010, the data offset module 1020, the resampling module 1030, the Fourier transform module 1040, the frequency conversion module 1050, the construction module 1060, and the generation module 1070 may be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application specific integrated circuit (ASIC), or may be implemented in hardware or firmware by any other reasonable means of circuit integration or packaging, or implemented in any one of the three implementation modes of software, hardware, and firmware, or in any appropriate combination of any of them. Alternatively, at least one of the first acquisition module 1010, the data offset module 1020, the resampling module 1030, the Fourier transform module 1040, the frequency conversion module 1050, the construction module 1060, and the generation module 1070 may be at least partially implemented as a computer program module, which, when executed, may perform the corresponding function.

[0173] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or a part of code, and the above-mentioned module, program segment, or a part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0174] Those skilled in the art can understand that the features described in various embodiments of the present disclosure can be combined and / or integrated in various combinations, even if such combinations or integrations are not explicitly described in the present disclosure. In particular, the features described in various embodiments of the present disclosure can be combined and / or integrated in various combinations without departing from the spirit and teachings of the present disclosure. All such combinations and / or integrations are within the scope of the present disclosure.

[0175] The above describes embodiments of the present disclosure. However, these embodiments are merely for illustrative purposes, and are not intended to limit the scope of the present disclosure. Although each embodiment is described above separately, this does not mean that the measures in various embodiments cannot be used advantageously in combination. Various alternatives and modifications can be made to the embodiments without departing from the scope of the present disclosure, and such alternatives and modifications shall fall within the scope of the present disclosure.

Claims

1. A method for generating an interference signal for a synthetic aperture radar, comprising: Acquiring distance information corresponding to a jammer, a synthetic aperture radar, and a false target, parameters corresponding to the synthetic aperture radar, and a jamming template image of the false target, wherein the distance information includes a shortest slant range between the jammer and the synthetic aperture radar, a first real-time distance between the jammer and the synthetic aperture radar, and a second real-time distance between the false target and the synthetic aperture radar, wherein the false target is a target used to jam the synthetic aperture radar; Based on the shortest slant distance and the azimuth dimension data of the interference template image, data offset processing is performed on the distance dimension data of the interference template image to generate an offset interference image; based on the shortest slant distance and the azimuth dimension data of the interference template image, data offset processing is performed on the distance dimension data of the interference template image to generate an offset interference image, including: generating data offset information based on the shortest slant distance and the azimuth dimension data; processing the distance dimension data of the interference template image according to the data offset information to generate the offset interference image; resampling the offset interference image based on an azimuth dimension resampling rate and a range dimension resampling rate to obtain a resampled interference image, wherein the azimuth dimension resampling rate corresponds to the parameter and the shortest slant range, and the range dimension resampling rate corresponds to the parameter; Performing a two-dimensional Fourier transform on the resampled interference image to obtain initialized interference image data; performing frequency conversion processing on a radar signal intercepted from the synthetic aperture radar based on the first real-time distance and the parameter to obtain a range-frequency domain signal corresponding to the radar signal; constructing an interference response function corresponding to the initialized interference image data based on the first real-time distance, the second real-time distance, the parameter, the distance frequency domain signal, and the initialized interference image data; The range-frequency domain signal is processed by using the interference response function to generate a target interference signal, wherein the target interference signal is an echo signal for transmitting to the synthetic aperture radar.

2. The method according to claim 1, wherein The parameters include radar fast time frequency domain and radar carrier frequency; The constructing an interference response function corresponding to the initialized interference image data based on the first real-time distance, the second real-time distance, the parameter, the distance frequency domain signal, and the initialized interference image data includes: determining real-time distance difference information between the first real-time distance and the second real-time distance; constructing an initial interference response function based on the real-time distance difference information, the radar fast time frequency domain, the radar carrier frequency, the speed of light information, and the target distribution information of the initialized interference image data, the initial interference response function including a quadratic term of a Taylor expansion corresponding to the first real-time distance and the second real-time distance, the Taylor expansion corresponding to a moment when the radar slow movement time is 0; Discretizing the initial interference response function to obtain a discretized response function; The interference response function is constructed based on an interpolation function for interpolating the orientation dimension data and the discretization response function.

3. The method according to claim 2, wherein: The parameters also include radar movement slow time and radar movement speed; The method further comprises: Obtaining the real-time positions of the jammer, the synthetic aperture radar, and the false target; determining a first real-time distance between the jammer and the synthetic aperture radar based on the real-time position of the jammer, the real-time position of the synthetic aperture radar, the radar moving slow time, and the radar moving speed; A second real-time distance between the false target and the synthetic aperture radar is determined based on the real-time position of the false target, the real-time position of the synthetic aperture radar, the radar moving slow time, and the radar moving speed.

4. The method according to claim 3, wherein: The interference response function is expressed by the following formula: Wherein, H(X, Y; n) is the interference response function; X is the azimuth dimension data of the initialization interference image data; Y is the distance dimension data of the initialization interference image data; ΔF x is the spatial frequency interval of the spatial domain of the initialization interference image data; r is the radar fast time frequency domain; f c is the radar carrier frequency; R s is the shortest slant distance between the synthetic aperture radar and the jammer; v is the moving speed of the radar; t a T is the radar moving slow time; a is the unit time length of the synthetic aperture radar movement; t a =nT a ; n = 0, 1, 2, 3 ... ; PRT is the pulse repetition period; c is the light speed information; L is the interpolation kernel; j is the imaginary unit; is rounded down; δ is the predetermined impulse function; σ new (X, Y) is the resampled interference image; FFT X,Y is the two-dimensional Fourier transform.

5. The method according to claim 1, wherein The parameters include signal sampling rate, radar fast time frequency domain, radar carrier frequency, radar moving speed, pulse repetition period and the number of pulses required for synthetic aperture radar imaging; The method further comprises: Determining an azimuth dimension resampling rate based on the radar fast time frequency domain, the radar carrier frequency, the radar moving speed, the pulse repetition period, the number of pulses, the shortest slant range, and the speed of light information; The distance dimension resampling rate is determined based on the signal sampling rate.

6. The method according to claim 1, wherein The parameters include pulse width, chirp rate, radar carrier frequency and radar fast time frequency domain; The performing frequency conversion processing on the radar signal intercepted from the synthetic aperture radar based on the first real-time distance and the parameter to obtain a range-frequency domain signal corresponding to the radar signal includes: Down-converting the radar signal based on the first real-time distance, the pulse width, the chirp rate, and the radar carrier frequency to obtain a down-converted signal; Based on the radar fast time frequency domain, the down-converted signal is Fourier transformed to obtain the range frequency domain signal.

7. The method according to claim 1, wherein The generating a target interference signal by processing the range-frequency domain signal using the interference response function, wherein the target interference signal is an echo signal for sending to the synthetic aperture radar, includes: Multiplying the range frequency domain signal and the interference response function to generate a modulated signal; Performing an inverse Fourier transform on the modulated signal to generate the target interference signal.

8. A method for jamming a synthetic aperture radar, applied to a jammer, comprising: intercepting a radar signal transmitted by the synthetic aperture radar; generating a target interference signal corresponding to the radar signal according to the interference signal generation method according to any one of claims 1 to 7; The target interference signal is sent to the synthetic aperture radar.

9. A jammer comprising: a first acquisition module, configured to acquire distance information corresponding to a jammer, a synthetic aperture radar, and a false target, parameters corresponding to the synthetic aperture radar, and a jamming template image of the false target, wherein the shortest slant range between the jammer and the synthetic aperture radar, the distance information including a first real-time distance between the jammer and the synthetic aperture radar, and a second real-time distance between the false target and the synthetic aperture radar, and the false target being a target used to jam the synthetic aperture radar; A data offset module is configured to perform coordinate offset processing on the distance dimension coordinates of the interference template image based on the shortest slant distance and the azimuth dimension data of the interference template image to generate an offset interference image; the data offset processing on the distance dimension data of the interference template image based on the shortest slant distance and the azimuth dimension data of the interference template image to generate an offset interference image comprises: generating data offset information based on the shortest slant distance and the azimuth dimension data; processing the distance dimension data of the interference template image according to the data offset information to generate the offset interference image; a resampling module, configured to resample the offset interference image based on an azimuth dimension resampling rate and a range dimension resampling rate to obtain a resampled interference image, wherein the azimuth dimension resampling rate corresponds to the parameter and the shortest slant range, and the range dimension resampling rate corresponds to the parameter; A Fourier transform module, configured to perform a two-dimensional Fourier transform on the resampled interference image to obtain initialized interference image data; a frequency conversion module, configured to perform frequency conversion processing on the radar signal intercepted from the synthetic aperture radar based on the first real-time distance and the parameter, to obtain a range-frequency domain signal corresponding to the radar signal; a construction module, configured to construct an interference response function corresponding to the initialized interference image data based on the first real-time distance, the second real-time distance, the parameter, the distance frequency domain signal, and the initialized interference image data; A generating module is configured to generate a target interference signal by processing the range-frequency domain signal using the interference response function, wherein the target interference signal is an echo signal for sending to the synthetic aperture radar.

Images