A mono-static multi-domain interference method and device for SAR-GMTI

Abstract

The present invention discloses a single-base multi-domain interference method and device for SAR-GMTI, belonging to the technical field of radar countermeasure. The method includes measuring parameters of intercepted SAR signals, generating an initial signal with velocity modulation phase based on the measured parameters; determining the central position of the area covered by the jammer, designing a system function, and obtaining a two-dimensional time-domain signal after convolution with the initial signal; designing a multi-region position modulation template in the two-dimensional time domain to obtain a multi-region positioning signal in the two-dimensional time domain; designing a multi-scale noise interference template in the two-dimensional time domain, performing a range Fourier transform on the interference template, multiplying it with the multi-region positioning signal after the range Fourier transform, and then performing an inverse range Fourier transform to obtain a final interference signal; and forwarding the final interference signal pulse by pulse to a three-channel SAR-GMTI system. The present invention can accurately generate multiple sub-regions for suppressing interference according to the number and speed of moving targets to be protected, preventing the moving targets from being correctly detected.

Description

Technical Field

[0001] The present invention belongs to the technical field of radar countermeasure, and particularly relates to a mono-static multi-domain interference method and device for SAR-GMTI. Background Art

[0002] Synthetic Aperture Radar (SAR) is a microwave instrument for earth observation, which has all-weather and high-resolution imaging capabilities, and thus is widely used in terrain mapping, resource exploration, military reconnaissance and other aspects.

[0003] SAR with ground moving target indication (GMTI) can quickly detect and obtain information on moving targets within its effective coverage. Within a certain speed range, it can distinguish different types of moving targets, which poses a significant threat to protected targets. Therefore, the interference technology against SAR-GMTI has become a research hotspot in electronic countermeasures, with important theoretical significance and engineering value. The interference methods against SAR-GMTI can be divided into two categories: active interference and passive interference. Some researchers have proposed a multi-channel SAR-GMTI deception interference method based on the motion modulation of multiple jammers (patent application number: CN202410969993.7). By determining the area of interest and deploying the positions of multiple jammers, each jammer intercepts the transmitted signals of the enemy's multi-channel SAR-GMTI and performs down-conversion processing to obtain the baseband SAR signals, which can generate false stationary targets that can be detected and correctly repositioned in the SAR images of the multi-channel SAR-GMTI system, effectively confusing and interfering with the enemy's multi-channel SAR-GMTI system and protecting our important targets. However, this method requires multiple jammers to be arranged in the scene and has strict requirements for the interval positions of each jammer, so the engineering implementation is relatively difficult. Some other researchers have proposed a cooperative interference method for two jammers against the SAR-GMTI system. By simultaneously using two jammers to cooperate in interfering with the SAR-GMTI system, a two-dimensional interference masking area can be generated in the SAR-GMTI processing results to cover the ground moving targets and eliminate the influence of the interference weakening area. However, the interference effect it produces is a strip-shaped interference surface and cannot completely cover the entire area of interest, which means that once the protected moving target appears in the blind area of the strip-shaped masking, it may be detected. Some other researchers proposed in 2020 to modulate the characteristics of false moving targets for the interference signals, making the interference signals have characteristics similar to moving targets, so that they cannot be cancelled by the SAR-GMTI mode. On this basis, by further performing multi-phase segmented modulation on the signals, the real moving targets within a certain area can be protected. However, from its interference effect diagram, the energy of the interference area formed is relatively dispersed, and there are still interference blind areas. If the moving target appears in the area with low interference energy, it may still be detected.

[0004] Therefore, it has important research value and application prospects to design a multi-region interference method that uses one jammer to achieve uniform interference energy coverage and no interference blind areas against SAR-GMTI. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a single - base multi - domain interference method and device for SAR - GMTI. By combining the basic interference signal with motion - modulation phase, interference - machine coverage - area system - function modulation, multi - area modulation template, and multi - scale noise - interference template, and according to the number and speed of moving targets to be protected, multiple sub - regions for suppressing interference are accurately generated, which can prevent moving targets from being correctly detected.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A single - base multi - domain interference method for SAR - GMTI, the method comprising:

[0008] Step 1: The jammer intercepts the SAR signal, performs down - conversion processing and digital - to - analog conversion on the intercepted SAR signal, then measures the parameters, and generates an initial signal with velocity - modulation phase based on the measured parameters;

[0009] Step 2: Determine the central position of the area covered by the jammer, design a system function in range - frequency domain - azimuth - time domain based on the central position, multiply the system function by the initial signal after range - direction Fourier transform, and then obtain a two - dimensional time - domain signal after inverse range - direction Fourier transform;

[0010] Step 3: According to the offsets of multiple targets to be protected from the central position, design a multi - area position - modulation template in two - dimensional time domain, multiply the multi - area position - modulation template by the two - dimensional time - domain signal, and obtain a multi - area positioning signal in two - dimensional time domain;

[0011] Step 4: According to the structural characteristics of multiple targets to be protected, design a multi - scale noise - interference template in two - dimensional time domain. After performing range - direction Fourier transform on the interference template, multiply it by the multi - area positioning signal after range - direction Fourier transform, and obtain the final interference signal after inverse range - direction Fourier transform;

[0012] Step 5: After performing digital - to - analog conversion and up - conversion processing on the final interference signal, forward it pulse - by - pulse to a three - channel SAR - GMTI system.

[0013] On the other hand, the present invention provides a single - base multi - domain interference device for SAR - GMTI, comprising:

[0014] An initial - signal acquisition module, configured to use a jammer to intercept the SAR signal, perform down - conversion processing and digital - to - analog conversion on the intercepted SAR signal, then measure the parameters, and generate an initial signal with velocity - modulation phase based on the measured parameters;

[0015] The two-dimensional time-domain signal acquisition module is used to determine the central position of the area covered by the jammer, design a system function of range-frequency domain - azimuth time-domain based on the central position, multiply the system function by the initial signal after range-direction Fourier transform, and then obtain the two-dimensional time-domain signal through inverse range-direction Fourier transform;

[0016] The multi-region positioning signal acquisition module is used to design a multi-region position modulation template in two-dimensional time-domain according to the offsets of multiple targets to be protected from the central position, multiply the multi-region position modulation template by the two-dimensional time-domain signal, and obtain the multi-region positioning signal in two-dimensional time-domain;

[0017] The interference signal acquisition module is used to design a multi-scale noise interference template in two-dimensional time-domain according to the structural characteristics of multiple targets to be protected, after performing range-direction Fourier transform on the interference template, multiply it by the multi-region positioning signal after range-direction Fourier transform, and then obtain the final interference signal through inverse range-direction Fourier transform;

[0018] The implementation module is used to perform digital-to-analog conversion and up-conversion processing on the final interference signal, and then forward it pulse by pulse to the three-channel SAR-GMTI system.

[0019] In a third aspect, the present invention provides an electronic device, including: one or more processors; a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors are caused to implement the foregoing single-base multi-domain interference method for SAR-GMTI.

[0020] In a fourth aspect, the present invention provides a computer-readable storage medium, on which executable instructions are stored, and when the instructions are executed by a processor, the processor is enabled to implement the foregoing single-base multi-domain interference method for SAR-GMTI.

[0021] The beneficial effects of the present invention are as follows:

[0022] By adding a motion phase to the transmitted interference signal, and then successively through interference coverage area modulation, suppression interference sub-area modulation, and multi-scale noise template modulation, the present invention can use one jammer to achieve the protection of suppressing interference on multiple moving targets. The engineering implementation is easier compared to the combined suppression interference of multiple jammers. It can simultaneously generate multiple suppression interference sub-areas. After multi-channel cancellation, the energy coverage of the formed suppression interference area is relatively complete, without interference blind spots, and is easier to implement. Description of the Drawings

[0023] Figure 1 is a flowchart of a single-base multi-domain interference method for SAR-GMTI according to the present invention;

[0024] Figure 2 It is a typical SAR - GMTI interference scenario diagram;

[0025] Figure 3 It is the un - accelerated ship SAR image generated for testing the suppression effect;

[0026] Figure 4 It is the two - dimensional suppression interference effect diagram generated by this method before SAR - GMTI multi - channel cancellation;

[0027] Figure 5 It is the three - dimensional suppression interference effect diagram generated by this method before SAR - GMTI multi - channel cancellation;

[0028] Figure 6 It is the two - dimensional suppression interference effect diagram generated by this method after SAR - GMTI multi - channel cancellation;

[0029] Figure 7 It is the three - dimensional suppression interference effect diagram generated by this method after SAR - GMTI multi - channel cancellation;

[0030] Figure 8 It is the damage effect on the structure of the protected target after the suppression interference generated by this method passes through multi - channel cancellation under different signal - to - interference ratios;

[0031] Figure 9(a) is the original interference effect diagram of the present invention;

[0032] Figure 9(b) is based on the present invention at the false alarm rate The effect diagram after CFAR detection;

[0033] Figure 9(c) is based on the present invention at the false alarm rate The effect diagram after CFAR detection;

[0034] Figure 9(d) is based on the present invention at the false alarm rate The effect diagram after CFAR detection;

[0035] Figure 9(e) is based on the present invention at the false alarm rate The effect diagram after CFAR detection;

[0036] Figure 9(f) is based on the present invention at the false alarm rate The effect diagram after CFAR detection;

[0037] Figure 10(a) is the original scenario with multiple moving targets without interference;

[0038] Figure 10(b) is the scenario image with interference added;

[0039] Figure 10(c) is the image after DPCA cancellation;

[0040] Figure 11 This is an example diagram of the framework of a single - base multi - domain interference device for SAR - GMTI in the present invention. Detailed implementation manners

[0041] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0042] The object of the present invention is to provide a method, device, equipment and storage medium for generating interference signals that combine motion - modulation phase, interference - machine coverage - area system - function modulation, multi - area modulation templates and multi - scale noise - interference templates, so as to flexibly achieve precise suppression interference on multiple moving targets, such as Figure 1 shown, including the following steps:

[0043] Step 1: The jammer intercepts the signal transmitted from the SAR platform, performs down - conversion processing and A / D conversion on the intercepted SAR signal, measures parameters such as the carrier fixed frequency, frequency modulation, azimuth sampling rate of the signal, as well as the distance and altitude parameters from the SAR platform to the jammer, and generates an initial signal with velocity - modulation phase through the above - mentioned parameters.

[0044] Step 2: Determine the central position of the entire area covered by the jammer. Those moving targets to be protected are distributed near this central position. According to the central position, design the system function in the range - frequency domain and azimuth - time domain of the central position, multiply the system function with the initial signal after range - direction Fourier transform, and then perform inverse range - direction Fourier transform to obtain a two - dimensional time - domain signal.

[0045] Step 3: According to the offsets of multiple targets to be protected from the central position, design a multi - area position - modulation template in the two - dimensional time domain. The purpose of the multi - area position - modulation template is to separate multiple interference sub - areas relative to the center point of the overall interference area. Multiply the multi - area position - modulation template with the two - dimensional time - domain signal in Step 2 to obtain a two - dimensional time - domain multi - area positioning signal.

[0046] Step 4: According to the structural characteristics of multiple moving targets to be protected, pre - design a multi - scale noise - interference template in the two - dimensional time domain. After performing range - direction Fourier transform on the interference template, multiply it with the multi - area positioning signal in the previous step, and then perform inverse range - direction Fourier transform to obtain the final interference signal.

[0047] Step 5: Perform digital - to - analog conversion and up - conversion processing on the signal in Step 4 and forward it pulse - by - pulse to a three - channel SAR - GMTI system.

[0048] A typical three - channel SAR - GMTI interference scenario is as Figure 2 shown. Assume that the flight direction of the SAR platform is along the x - axis, the direction perpendicular to the flight path is along the y - axis, and the upward direction perpendicular to the ground is along the z - axis. The velocity of the SAR platform is expressed as , the beam direction of the SAR is side-looking, and the flight altitude is , the position of the jammer is , taking the SAR flight direction as the axis, and the vertically upward direction as the axis to establish a coordinate system. It is set that the shortest slant range from the jammer to the SAR platform is . The SAR platform transmits a chirp signal from channel 1, and the echo signal is received by the first, second, and third channels. The three channels are respectively denoted as channel 0, 1, and 2, that is, channel 1 transmits, and channels 0, 1, and 2 receive. The pulse repetition frequency is expressed as , and the signal carrier frequency is expressed as . The interval between adjacent channels is expressed as , satisfying , represents any positive integer.

[0049] Among them, the specific implementation process of the first step is as follows:

[0050] The target SAR system transmits a signal with the following expression:

[0051] (1)

[0052] Among them, is the amplitude of the signal, is the range-time, is the pulse width, is the chirp rate of the chirp signal, and j represents the imaginary unit.

[0053] After adding the motion modulation phase, the initial signal in the two-dimensional time domain is expressed as:

[0054] (2)

[0055] Among them:

[0056] (3)

[0057] (4)

[0058] Among them, is the azimuth-time, , are respectively the coordinates of the center of the area covered by the jammer along the axis and along the axis, , are respectively the along the axis and along the The speed of the axis, is the shortest slant range from the target to the SAR platform. is the coefficient of the first-order azimuth time of the velocity modulation phase, is the coefficient of the second-order azimuth time of the velocity modulation phase.

[0059] Among them, the specific implementation process of the second step is as follows:

[0060] Step 2.1, as mentioned above, assume that the SAR platform emits a chirp signal from the second channel, and the echo signal is received by the first, second, and third channels. Calculate the interference signal with a uniform motion phase received by the second channel from the jammer:

[0061] (5)

[0062] Among them, represents the convolution operation, represents the speed of light, represents the carrier frequency, represents the length of a synthetic aperture time, represents the real-time slant range of the signal from the jammer to receiving channel 1:

[0063] (6)

[0064] Step 2.2, set a reference moving point target at the center position of the area covered by the jammer, and calculate the echo signal received by the second channel from the reference moving point target; set a reference moving point target at the center point of the interference scene as , the echo signal received by channel 1 from the reference moving point target is expressed as:

[0065] (7)

[0066] represents the length of a synthetic aperture time.

[0067] Among them:

[0068] (8)

[0069] represents the real-time slant range of the signal from the reference reference moving point target to channel 1.

[0070] In order to generate the reference moving point target , the system function of the jammer should satisfy the equation:

[0071] (9)

[0072] Wherein:

[0073] (10)

[0074] Wherein represents the backscattering coefficient at the reference moving point target at, the backscattering coefficient represents the impulse function

[0075] and

[0076] (11)

[0077] represents the difference between the real-time slant range of the signal from the reference moving point target to channel 1 and the real-time slant range of the signal from the jammer to receiving channel 1.

[0078] Step 2.3: Obtain the system function in the range frequency domain - azimuth time domain based on the calculation results of Step 2.1 and the calculation results of Step 2.2, multiply the system function by the initial signal after range Fourier transform, and then perform inverse range Fourier transform to obtain the two-dimensional time domain signal.

[0079] In practice, the calculation is performed as a multiplication in the range frequency domain to quickly generate the interference signal. Therefore, the system function in the range frequency domain can be expressed as:

[0080] (12)

[0081] Where represents the range frequency.

[0082] Therefore, the two-dimensional time domain signal obtained in Step 2 is:

[0083] (13)

[0084] Where represents the range fast Fourier transform represents the inverse range fast Fourier transform represents the product operation.

[0085] Wherein, the specific implementation process of Step 3 is as follows:

[0086] Control the position of the interference sub-region by the two-dimensional frequency shift method. If the range frequency shift amount of the signal is , and the azimuth frequency shift amount is . Then the expression of the signal without additional motion modulation phase is:

[0087] (14)

[0088] The imaging expression after the range-Doppler imaging algorithm is as follows:

[0089] (15)

[0090] It can be seen from the expression that the result will produce a position offset in the imaging result, and the corresponding range-direction position offset is:

[0091] (16)

[0092] The azimuth-direction position offset is:

[0093] (17)

[0094] where the azimuth Doppler frequency modulation rate is expressed as:

[0095] (18)

[0096] When different suppression regions need to be generated in the scene, the frequency shift corresponding to the center point of each region is saved as:

[0097] (19)

[0098] Let represent the multi-region position modulation template, and let represent the discrete Fourier transform of, then there is:

[0099] (20)

[0100] Then the signal expression of two-dimensional frequency shift can be expressed by as:

[0101] (21)

[0102] Since the system response of SAR imaging is only related to the time terms and therefore, the terms related to the fixed frequency shift can be separated, and the imaging result is:

[0103] (22)

[0104] Therefore, can be designed according to the position of the protected target and multiplied with the signal. Then, by modulating to generate multiple points for target positioning. Combining the echo signal of the reference moving point target generated by the jammer received by Channel 1 in Step 2 of , the multi-region positioning signal generated in Step 3 can be expressed as the following equation:

[0105] (23)

[0106] Through , the jammer can generate signals of multiple false moving point targets. Then, by convolving with the noise template generated in Step 4 later, multiple suppression interference regions can be generated.

[0107] Among them, the specific implementation process of Step 4 is as follows:

[0108] Step 4.1: Calculate the multi-scale structural similarity according to the brightness comparison function, contrast comparison function, and structure comparison function; by designing weight coefficients for the multi-scale noise template, compared with the single-scale noise interference, better structural damage can be caused to the target. The multi-scale structural similarity is expressed as:

[0109] (24)

[0110] Among them, represents the number of different scales, , and represent the weight coefficients of the th and th scales. This formula consists of three parts: the brightness comparison function, the contrast comparison function, and the structure comparison function, which are expressed as , and . Among them:

[0111] (25)

[0112] (26)

[0113] (27)

[0114] Among them and represent the positions of the image pixel points, , and represent very small constants, , , , respectively represent and The mean and standard deviation. Represents the position of the image pixel points and The covariance.

[0115] Step 4.2: Calculate noise templates with multiple different scales based on multi-scale structural similarity to obtain the interference signal received by the second channel; when there are noise templates of different scales, the final noise template is expressed as:

[0116] (28)

[0117] Where Represents the weight coefficient of the th scale, Represents the root mean square height. and Indicates the th scale along and along The correlation length. Is the random number between 0 and 1 on the th scale, following the normal distribution and constrained by the correlation length and root mean square height of the th scale.

[0118] The final interference signal received by channel 1 can be expressed as:

[0119] (29)

[0120] Step 4.3: After performing range Fourier transform on the interference signal, multiply it with the multi-region positioning signal after range Fourier transform, and then perform inverse range Fourier transform to obtain the final interference signal. Therefore, the signal finally relayed by the jammer, that is, the signal without slant range delay, can be expressed as:

[0121] (30)

[0122] Where Represents the initial signal with velocity modulation phase, Represents the system function for determining the overall coverage area of the interference, Represents the position modulation function for controlling the suppression positions of multiple sub-regions, Represents the multi-scale noise template.

[0123] Among them, the specific implementation process of step five is as follows:

[0124] The digital interference signal modulated in the range and azimuth directions is converted into an analog interference signal by a digital-to-analog converter, and the jammer forwards it to the SAR-GMTI system pulse by pulse after up-conversion processing. The analog interference signal passes through down-conversion, analog-to-digital conversion, and imaging processing of the target SAR-GMTI system, and suppression interference sub-regions will be generated at the positions of multiple targets. And after multi-channel cancellation processing, a certain proportion of the interference energy can still be retained. The retained proportion is calculated as follows:

[0125] (31)

[0126] represents the image after cancellation of channels 0 and 1, represents the image after cancellation of channels 1 and 2.

[0127] Next, combined with the simulation results, the theoretical model of the present invention is verified and analyzed. Set the target The system operates in the strip imaging mode, and the operating frequency band is band, the center frequency is , the carrier speed is , the signal bandwidth is , the signal chirp rate is , the pulse repetition frequency is . The squint angle is , the antenna length , the adjacent channel interval .

[0128] First, in order to accurately analyze the interference effect of this method, the influence of the stationary background clutter is temporarily ignored when calculating the multi-scale structural similarity (MS-SSIM). In this part, the real ship images in the SAR ship dataset constructed by Sentinel-1 SAR and GF-3 SAR are used as the protected targets. According to the above simulation parameters, the imaging results of five stationary ships generated by product modulation are as Figure 3 shown.

[0129] By introducing the influence of the target's speed into the slant range calculation between the target and the SAR platform, five real moving ships can be simulated. Then, using this method, five moving suppression interference regions with an area of are assigned the same speed as the ships. Before multi-channel cancellation and along-track interferometry of the SAR system, the two-dimensional interference effect is as Figure 4 shown, and the three-dimensional energy retention situation is as Figure 5As shown. The results show that multi-region motion suppression interference can correctly cover moving targets in SAR images without correcting the interference position because the suppression regions generated by this method can produce the same position offset as real targets with the same speed.

[0130] After multi-channel cancellation and along-track interference in the SAR system, the two-dimensional interference effect is as Figure 6 shown, and the three-dimensional energy retention situation is as Figure 7 shown. After multi-channel cancellation and along-track interference, the suppression regions and moving targets are corrected to the actual positions. The remaining interference energy is about 0.73 times that of the original interference energy, which is consistent with the theoretical calculation value. Experiments prove that after the three-channel SAR-GMTI system, the interference energy can be retained to a large extent, effectively protecting moving targets.

[0131] By calculating the MS-SSIM values of this method at different signal-to-interference ratios, it can be proved that this method can achieve good interference effects at low interference powers. The experimental results are as Figure 8 shown.

[0132] Through the constant false alarm rate (CFAR) detection method, it can be verified that the suppression interference generated by this method can effectively reduce the probability of being correctly detected by CFAR at a low false alarm rate (PFA). The experimental results at different orders of magnitude of the common false alarm rates are shown in Figure 9. From Figure 9(a) to Figure 9(f) in sequence, the false alarm rates are set to . It can be found that when the false alarm rate is high, the false detection rate of CFAR detection after suppression interference is very high. As the false alarm rate decreases, it is always difficult to correctly detect the five moving targets with a low false detection rate. This proves the effectiveness of this method in protecting moving targets.

[0133] Figures 10(a)-10(c) show the interference effects of this method on moving target groups with different speeds. The speeds of Target 1 and Target 2 are -15 m / s in the azimuth direction and -1 m / s in the range direction. The azimuth direction speed of Target 3 is -25 m / s, and the range direction speed is -1.2 m / s. The speeds of Targets 4, 5, and 6 are 20 m / s in the azimuth direction and 2 m / s in the range direction. This suppression interference can produce an energy broadening effect similar to that of moving targets in the azimuth direction, so that the broadened part of the moving target's energy can still be covered by the broadened interference region.

[0134] Therefore, the novel SAR-GMTI interference method proposed by the present invention can suppress multiple moving targets simultaneously and can accurately adjust the number and position of sub-interference regions. After three-channel SAR-GMTI cancellation, the energy of the suppression interference can be uniformly and effectively retained, making it difficult to detect the protected moving targets, thus proving the effectiveness of this method.

[0135] As Figure 11 shown, a mono-static multi-domain interference method and device for SAR-GMTI of the present invention include: an initial signal acquisition module, configured to intercept SAR signals by using a jammer, perform down-conversion processing and digital-to-analog conversion on the intercepted SAR signals, and then perform parameter measurement, and generate an initial signal with a velocity modulation phase based on the measured parameters;

[0136] a two-dimensional time-domain signal acquisition module, configured to determine the central position of the area covered by the jammer, design a system function in range frequency domain-azimuth time domain based on the central position, and multiply the system function by the initial signal to obtain a two-dimensional time-domain signal;

[0137] a multi-region positioning signal acquisition module, configured to design a multi-region position modulation template in two-dimensional time domain according to the offsets of multiple targets to be protected from the central position, and multiply the multi-region position modulation template by the two-dimensional time-domain signal to obtain a multi-region positioning signal in two-dimensional time domain;

[0138] a jamming signal acquisition module, configured to design a multi-scale noise jamming template in two-dimensional time domain according to the structural characteristics of multiple targets to be protected, perform range-direction Fourier transform on the jamming template, and then multiply it by the multi-region positioning signal to obtain a final jamming signal;

[0139] an implementation module, configured to perform digital-to-analog conversion and up-conversion processing on the final jamming signal, and then forward it pulse by pulse to a three-channel SAR-GMTI system.

[0140] Specifically, the system includes a signal detection and reception module for detecting and receiving the signals transmitted by the target SAR system; a down-conversion module for performing down-conversion processing on the received SAR signals; an analog-to-digital conversion module for sampling and converting the intercepted target SAR transmitted signals into digital signals; a signal parameter measurement module for measuring signal parameters such as the pulse width, bandwidth, and pulse repetition frequency of the received signals; a motion phase modulation module for adding a motion modulation phase to the intercepted signals to produce the same position offset effect and similar energy broadening effect as a real moving target; an interference machine coverage area modulation module for controlling the position of the entire area covered by the interference machine; a suppression interference sub-area modulation module for controlling the central position of the sub-area of the suppression interference; a multi-scale noise template modulation module for adding a multi-scale noise suppression interference effect of a rectangle with a controllable area to each sub-area of the suppression interference. A digital-to-analog conversion module for converting the obtained digital interference signals into analog signals; an up-conversion module for performing up-conversion processing on the analog interference signals; and a transmission module for transmitting interference signals pulse by pulse.

[0141] A storage medium of the present invention, the storage medium is a computer-readable storage medium capable of storing a computer program, and when the program is called and executed by a processor, the device where the storage medium is located executes the method for generating multi-region suppression interference signals for three-channel SAR-GMTI based on a single interference machine disclosed by the present invention.

[0142] An electronic device of the present invention includes an antenna unit, a processor unit, and a storage unit; wherein, the antenna unit includes a pulse antenna, an array antenna, etc., and is mainly used for receiving and transmitting interference signals to the signals transmitted by the target SAR system. The processor unit includes a central processor, a digital signal processor, a field programmable gate array, etc., and is mainly used for calling and executing various programs to implement functions such as down-conversion, analog-to-digital conversion, signal parameter measurement, motion phase modulation, interference machine coverage area system function modulation, suppression interference sub-area position modulation, multi-scale noise template modulation with a controllable area, digital-to-analog conversion, up-conversion, etc.; the storage unit includes a digital radio frequency memory, a mobile hard disk, a read-only memory, etc., and is mainly used for storing signal data and programs. When the programs in the memory are executed by the processor, the electronic device executes the method of the present invention.

[0143] In the above specific embodiments, the purpose, technical solution, and beneficial effects of the present invention are further described in detail. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A single-base multi-domain interference method for SAR-GMTI, characterized in that: The method comprises: Step 1: The jammer intercepts the SAR signal, performs down-conversion processing and digital-to-analog conversion on the intercepted SAR signal, and then measures parameters, and generates an initial signal with a velocity modulation phase based on the measured parameters; Step 2: Determine the center position of the area covered by the jammer, design a system function of the distance frequency domain-azimuth time domain based on the center position, multiply the system function with the initial signal, and then obtain a two-dimensional time domain signal through inverse Fourier transform in the distance direction; Step 3: designing a two-dimensional time domain multi-region position modulation template according to the offsets of the multiple targets to be protected from the central position, and multiplying the multi-region position modulation template and the two-dimensional time domain signal to obtain a two-dimensional time domain multi-region positioning signal; Step 4: design a two-dimensional time domain multi-scale noise interference template according to the structural characteristics of multiple targets to be protected, perform a distance Fourier transform on the interference template, and then multiply it with the multi-region positioning signal to obtain a final interference signal; Step 5: After performing digital-to-analog conversion and up-conversion processing on the final interference signal, it is forwarded pulse by pulse to the three-channel SAR-GMTI system.

2. A single-base multi-domain interference method for SAR-GMTI according to claim 1, characterized in that: In the step 1, the measured parameters include the signal's carrier frequency, frequency modulation, azimuth, sampling rate, and the distance and height from the SAR platform to the jammer.

3. The single-base multi-domain interference method for SAR-GMTI according to claim 1, characterized in that: The second step comprises: Step 2.1, assuming that the SAR platform transmits a linear frequency modulation signal from the second channel, and the echo signal is received by the first, second, and third channels, and the interference signal with a uniform motion phase received by the second channel from the jammer is calculated; Step 2.2, set a reference moving point target at the center of the area covered by the jammer, and calculate the echo signal from the reference moving point target received by the second channel; Step 2.3: Based on the calculation results of step 2.1 and step 2.2, obtain the system function of distance frequency domain-azimuth time domain, multiply the system function with the initial signal after distance Fourier transform, and then perform distance inverse Fourier transform to obtain a two-dimensional time domain signal.

4. The single-base multi-domain interference method for SAR-GMTI according to claim 1, characterized in that: In step 3, it is assumed that different positions need to be generated in the scene target suppression areas, save the frequency shift from the center point of each suppression area to the center position, and design a multi-area position modulation template to separate multiple interference sub-areas relative to the center point of the overall interference area; Represents a multi-region position modulation template, set Represents a multi-region position modulation template The discrete Fourier transform of is: ， In the formula, ( , ) represents the frequency shift from the center point of each suppression area to the center position, is the azimuth time, For distance to time.

5. The single-base multi-domain interference method for SAR-GMTI according to claim 1, characterized in that: The fourth step comprises: Step 4.1, calculating the multi-scale structural similarity according to the brightness comparison function, the contrast comparison function and the structure comparison function; Step 4.2, calculating noise templates with multiple different scales based on multi-scale structural similarity to obtain an interference signal received by the second channel; Step 4.3: After performing range Fourier transform on the interference signal, multiply it with the multi-region positioning signal after range Fourier transform, and then perform inverse range Fourier transform to obtain the final interference signal.

6. The single-base multi-domain interference method for SAR-GMTI according to claim 1, characterized in that: The step five includes: using a digital-to-analog converter to convert the final interference signal modulated in the range and azimuth directions into an analog interference signal, and forwarding it to the SAR-GMTI system pulse by pulse after up-conversion processing; the analog interference signal is down-converted, analog-to-digital converted and imaged by the target SAR-GMTI system to generate suppression interference sub-areas at the locations of multiple targets.

7. A single-base multi-domain interference method for SAR-GMTI according to claim 6, characterized in that: The final interference signal is a jammer transmission signal without slant range delay.

8. A single-base multi-domain jammer for SAR-GMTI, characterized in that: include: An initial signal acquisition module is used to intercept the SAR signal using a jammer, perform down-conversion processing and digital-to-analog conversion on the intercepted SAR signal, and then perform parameter measurement, and generate an initial signal with a velocity modulation phase based on the measured parameters; A two-dimensional time domain signal acquisition module is used to determine the center position of the area covered by the jammer, design a system function of the distance frequency domain-azimuth time domain based on the center position, and multiply the system function with the initial signal to obtain a two-dimensional time domain signal through a distance-direction inverse Fourier transform; A multi-region positioning signal acquisition module is used to design a two-dimensional time domain multi-region position modulation template according to the offsets of multiple targets to be protected from the central position, and multiply the multi-region position modulation template and the two-dimensional time domain signal to obtain a two-dimensional time domain multi-region positioning signal; An interference signal acquisition module is used to design a two-dimensional time domain multi-scale noise interference template according to the structural characteristics of multiple targets to be protected, and after performing a distance Fourier transform on the interference template, multiply it with the multi-region positioning signal to obtain a final interference signal; The implementation module is used to perform digital-to-analog conversion and up-conversion processing on the final interference signal, and then forward it pulse by pulse to the three-channel SAR-GMTI system.

9. An electronic device, characterized in that: include: Antenna unit, processor unit and storage unit; The antenna unit is used to receive the target SAR system transmission signal and transmit interference signals; The processor unit is used to call and execute various programs; The storage unit is used to store signal data and programs. When the program in the storage unit is executed by the processor unit, the electronic device executes the single-base multi-domain interference method for SAR-GMTI described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: Executable instructions are stored thereon, and when the instructions are executed by a processor, the processor can implement a single-base multi-domain interference method for SAR-GMTI as described in any one of claims 1-7.

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