High-squint SAR moving target deception jamming method and device

Abstract

The invention provides a large squint SAR moving target deception jamming method and device, and belongs to the field of synthetic aperture radar countermeasure, and the method comprises the steps: completing the detection and estimation of SAR system parameters before an SAR antenna main beam irradiates a jammer, and obtaining a corrected deception jamming template; carrying out azimuth nonlinear frequency modulation scaling processing and Doppler center frequency compensation on the deception jamming template; performing range pre-compensation and Keystone transformation to generate a pre-processing frequency response function; during SAR antenna main beam irradiation, compensating a linear range walk item pulse by pulse; and completing the related compensation of the jammer position, and carrying out the convolution modulation of the generated interference signal and the intercepted SAR signal, and then carrying out the time-delay forwarding. According to the method, the modulation precision of the interference signal is remarkably improved, and meanwhile, the calculation complexity is reduced and the modulation efficiency is improved through a compensation strategy of separating a motion parameter related item from a motion parameter unrelated item.

Description

Technical Field

[0001] The invention belongs to the field of synthetic aperture radar countermeasures, and in particular relates to a method and a device for deceiving and jamming a moving target of a high-squint SAR. Background Art

[0002] Synthetic Aperture Radar (SAR) is an active microwave imaging system capable of all-day, all-weather Earth observation and is widely used in emergency monitoring, regional observation, and information acquisition. When combined with ground moving target detection, SAR can not only image static scenes but also detect moving targets, posing a potential threat to critical areas and moving targets. Consequently, jamming techniques targeting SAR systems, particularly SAR deception jamming, have garnered widespread attention. Deception jamming achieves two-dimensional coherent processing gain by adding false scene or target information to the jamming signal. This approach offers advantages such as low power consumption and high concealment, making it difficult to detect and eliminate.

[0003] Currently, SAR deception jamming methods primarily focus on generating jamming signals for stationary targets or scenes, used to protect key ground areas and critical stationary targets. However, for missile-borne SAR high-squint imaging during high-speed, level flight, existing methods exhibit low fidelity in generating the temporal motion characteristics of moving targets and suffer from a conflict between jamming modulation accuracy and efficiency. This problem is particularly prominent when generating multiple moving targets.

[0004] In the prior art, Chinese patent application CN115685098A (A method for jamming multiple false targets against SAR-GMTI) generates a moving target with a shape through point-by-point modulation, controls the position of the moving target through time delay and phase modulation, and uses segmented frequency modulation and two-dimensional intermittent sampling to generate multiple moving targets with the same shape. However, this method is computationally intensive, and the multiple moving targets generated have the same shape, making the deceptive jamming effect easily recognizable.

[0005] Reference 1: The paper “Research on Deceptive Moving Target SAR Jamming Technology” published by Xu Shaokun et al. (Xu Shaokun, Li Yanan, Fu Yaowen. Research on Deceptive Moving Target SAR Jamming Technology [J]. Modern Radar, 2008, (07): 94-98. DOI: 10.16592 / j.cnki.1004-7859.2008.07.020) reduces the computational complexity to a certain extent by approximating the jammer frequency response function. However, when the oblique angle is large or the synthetic aperture is long, the approximation error is large.

[0006] Reference 2: Wu Xiaofang et al. published a paper titled "Active Modulation Jamming Method for Uniformly Accelerated Motion False Targets in SAR-GMTI" (Wu Xiaofang, Liang Jingxiu, Wang Xuesong, et al. Active Modulation Jamming Method for Uniformly Accelerated Motion False Targets in SAR-GMTI [J]. Acta Astronautics, 2012, 33(06): 761-768). This paper can generate a moving target composed of a few scattered points by point-by-point modulation, but the approximate error in the algorithm limits its application in situations with large oblique viewing angles.

[0007] Reference 3: Sun, Q. Sun, T. Shu, K. -B. Yu and W. Yu, "Efficient Deceptive Jamming Method of Static and Moving Targets Against SAR," in IEEE Sensors Journal, vol. 18, no. 9, pp. 3610-3618, 1 May 2018, doi:10.1109 / JSEN.2018.2813521. This paper, based on the equivalent slant range model of a moving target, derives a two-dimensional frequency-domain form of the target-related terms in the jammer frequency response function. The jammer frequency response function is rapidly generated through operations such as fast Fourier transform, Stolt interpolation, and complex multiplication. However, the interference modulation accuracy and modulation efficiency of this method are heavily dependent on the accuracy and efficiency of Stolt interpolation, and there are redundant processing steps when generating multiple moving targets under different motion parameters, which affects the interference modulation efficiency to a certain extent.

[0008] Therefore, for missile-borne SAR high-squint imaging during high-speed level flight, there is an extremely urgent practical need to study a high-squint SAR moving target deception jamming method that takes into account both jamming modulation accuracy and modulation efficiency. Summary of the Invention

[0009] Traditional moving target deception jamming methods usually use low-order approximation of the slant range model and two-dimensional separation processing to reduce the calculation complexity of the jammer frequency response function, or use fast Fourier transform and interpolation calculation to avoid double integration operations to achieve rapid generation of the jammer frequency response function. The above strategies are difficult to take into account the contradiction between jamming modulation accuracy and jamming modulation efficiency. This contradiction is particularly prominent when generating multiple moving targets under different motion parameters. In order to solve the above technical problems, the present invention provides a large squint SAR moving target deception jamming method and device.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] A high squint SAR moving target deception jamming method comprises the following steps:

[0012] Step 1: Before the SAR antenna main beam illuminates the jammer, the jammer completes the reconnaissance and estimation of the SAR platform parameters, SAR antenna parameters, and SAR signal parameters; based on the jamming parameter information and SAR system parameter information, it obtains a deception jamming template at a specific location and obtains a corrected deception jamming template through geometric correction;

[0013] Step 2: In the range time domain and the azimuth time-frequency transform domain, the corrected deception jamming template is subjected to azimuth nonlinear frequency modulation scaling and Doppler center frequency compensation, thereby obtaining a frequency response function after Doppler correlation compensation.

[0014] Step 3: In the range frequency domain and azimuth time domain, phase multiplication is performed on the frequency response functions to achieve compensation for the residual range-related terms of the azimuth space variation; the frequency response functions related to the motion parameters are superimposed and summed, and then a Keystone transform is performed to obtain the pre-generated frequency response function;

[0015] Step 4: While the SAR antenna main beam is illuminating the jammer, the jammer enters the real-time modulation phase; the pre-generated frequency response function is phase multiplied pulse by pulse in the frequency domain to achieve linear range movement compensation and obtain a frequency response function related to the characteristics of the moving target;

[0016] Step 5: The jammer performs phase multiplication on the frequency response function related to the characteristics of the moving target pulse by pulse in the frequency domain to complete the compensation of the part related to the jammer position and obtain the jammer frequency response function; the frequency response function is convoluted and modulated with the intercepted SAR signal and then delayed and forwarded, thereby quickly generating a moving target deception jamming signal.

[0017] The present invention also proposes a high-squint SAR moving target deception jamming device, comprising the following modules:

[0018] The template geometric correction module is used to enable the jammer to complete the reconnaissance and estimation of SAR platform parameters, SAR antenna parameters, and SAR signal parameters before the SAR antenna main beam illuminates the jammer; based on the jamming parameter information and SAR system parameter information, it obtains the deception jamming template at a specific location and obtains the corrected deception jamming template through geometric correction;

[0019] The Doppler phase compensation module performs azimuth nonlinear frequency modulation and scaling on the corrected deception jamming template in the range time domain and azimuth time-frequency transform domain, and compensates for the Doppler center frequency term, thereby obtaining a frequency response function after compensating for the Doppler correlation term.

[0020] The range pre-compensation module performs phase multiplication on the frequency response functions in the range frequency domain and the azimuth time domain to compensate for the residual range-related terms of the azimuth space-variation. The frequency response functions related to the motion parameters are superimposed and summed, and then a Keystone transform is performed to obtain the pre-generated frequency response function.

[0021] The movement compensation module, during the period when the SAR antenna main beam illuminates the jammer, the jammer enters the real-time modulation stage; the pre-generated frequency response function is phase multiplied pulse by pulse in the frequency domain to achieve linear range movement compensation and obtain a frequency response function related to the characteristics of the moving target;

[0022] The real-time generation module is used to perform phase multiplication of the frequency response function related to the characteristics of the moving target pulse by pulse in the frequency domain of the jammer, complete the compensation of the part related to the position of the jammer, and obtain the frequency response function of the jammer; the frequency response function is convoluted and modulated with the intercepted SAR signal and then delayed and forwarded, thereby quickly generating a moving target deception jamming signal.

[0023] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the above-mentioned method for deceiving and jamming moving targets of a high-squint SAR are implemented.

[0024] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the above-mentioned high-squint SAR moving target deception and jamming method are implemented.

[0025] Beneficial effects:

[0026] 1. The present invention significantly improves the modulation accuracy of jamming signals by employing the Keystone transform and azimuth nonlinear frequency modulation scaling. When generating jamming signals for moving targets in high-squint SAR imaging mode, the maximum offset error of the imaging position of the moving scattering points generated by the present invention is only 0.07%, and the maximum azimuth ambiguity width error is only 1.38%. Compared with the patent applications, Documents 1, and 2 mentioned in the background art, the present invention has a significant advantage in jamming signal modulation accuracy.

[0027] 2. This invention employs a strategy of "separate compensation for items related to motion parameters and unified compensation for items unrelated to them" to rapidly generate deceptive interference signals for multiple moving targets under different motion parameters. By avoiding redundant operations, the computational complexity is significantly reduced. Compared with Reference 3, the total computational complexity of this invention is reduced by 28.51% when generating a single moving target; when generating five moving targets with different motion parameters, the total computational complexity is reduced by 70.59%, demonstrating higher interference signal modulation efficiency.

[0028] 3. The present invention relies solely on basic operations such as complex addition, complex multiplication, and fast Fourier transform (FFT) to achieve high-precision and high-efficiency jamming signal generation. Compared to the complex Stolt interpolation operation in Reference 3, the present invention's technical solution is simpler and better meets the practical needs of SAR repeater jammers based on digital radio frequency storage technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the geometric model of high squint SAR deception jamming;

[0030] Figure 2 Schematic diagram of a high squint SAR moving target deception jamming device of the present invention;

[0031] Figure 3 This is an enlarged image of the false motion scattering point P1 deceptive interference imaging result;

[0032] Figure 4 Generate an enlarged image of the imaging result of the moving scattering point P1 point by point;

[0033] Figure 5 This is an enlarged image of the false motion scattering point P2 deceptive interference imaging result;

[0034] Figure 6 Generate an enlarged image of the imaging result of the moving scattering point P2 point by point;

[0035] Figure 7 This is the result of real scene echo imaging;

[0036] Figure 8 This is the image of the moving target deception interference imaging result;

[0037] Figure 9 The present invention is a flow chart of a method for deceiving and jamming moving targets of a high-squint SAR. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Figure 2 , Figure 9 As shown, the present invention provides a method for deceiving and jamming a moving target of a high-squint SAR, comprising the following steps:

[0039] Step 1, parameter reconnaissance and template correction: before the main beam of the SAR system antenna illuminates the jammer, the jammer completes the reconnaissance and estimation of the SAR platform parameters, SAR antenna parameters and SAR signal parameters; according to the interference parameter information and SAR system parameter information, the jammer obtains the parameters located at The deception interference template at the position is corrected by geometric correction and located at Deception jammer template at the location; is the zero Doppler distance, is the azimuth position, For P The slope distance at the moment, is the azimuth slow time, v is the flight speed, is the position time of P, is the scaling factor, usually set to 0.55;

[0040] Step 2: Doppler compensation and scaling: Perform azimuth nonlinear frequency modulation scaling and Doppler center frequency compensation on the corrected deception jamming template in the range time domain and azimuth time-frequency transform domain to obtain the frequency response function after compensating the Doppler related terms. ; is the distance time domain, t is the azimuth time domain;

[0041] Step 3: Distance compensation and Keystone transform: frequency response function in distance frequency domain, azimuth time domain Phase multiplication is performed to achieve the compensation of the residual distance-related term of the azimuth space variation, and the frequency response function is obtained ; The frequency response function related to the motion parameters After superposition and summation, Keystone transform is performed to obtain the pre-generated frequency response function ; is the distance frequency, Slow time for orientation;

[0042] Step 4: Real-time modulation and distance movement compensation: When the SAR system antenna main beam illuminates the jammer, the jammer enters the real-time modulation stage; the jammer generates a pre-generated frequency response function pulse by pulse in the frequency domain. Phase multiplication is performed to achieve linear distance movement compensation and obtain the frequency response function related to the characteristics of the moving target ;

[0043] Step 5: Jamming signal generation and forwarding: The jammer generates a frequency response function related to the characteristics of the moving target on a pulse-by-pulse basis. Perform phase multiplication to complete the compensation of the jammer position-related part and obtain the jammer frequency response function ; The jammer frequency response function is convoluted with the intercepted SAR signal and then delayed forwarded to achieve the jamming signal deception of moving targets Rapid generation of .

[0044] The present invention will be further explained below with reference to the accompanying drawings.

[0045] The geometric model of high squint SAR deception jamming is established with point O as the coordinate origin. Figure 1 As shown, the X-axis direction is the flight direction of the SAR platform, the XOY plane is the ground plane, and the Z-axis direction is the height direction. The SAR platform flies at a speed of v, a flight altitude of h, and a slant angle of . For the azimuth slow time, At time t, the SAR platform is at point Q, and the center of the antenna beam illuminates the jammer , and is the azimuth and ground distance position of the jammer J, and the slant distance of the wave velocity center is , the instantaneous slope distance is expressed as , the gray area is the interference area. At this moment, the SAR platform is located at point , the center of the antenna main beam illuminates the moving target , and is the azimuth and ground distance position of the moving target P. At this time, the slant distance between the moving target and the SAR platform is , the zero Doppler distance is Let the velocity and acceleration of P be and , the included angle between the moving direction and the moving direction of the SAR platform is , the ground-rubbing angle is β, and the motion parameters are recorded as , then the instantaneous slope distance is expressed as .also, and are the velocity and acceleration components of the moving target P projected in the zero Doppler range direction; and are the velocity and acceleration components of the moving target P projected on the X-axis.

[0046] Furthermore, the step 1 comprises the following steps:

[0047] Step 1.1: Before the SAR system antenna main beam illuminates the jammer, the jammer detects and estimates the SAR system parameters, which mainly include:

[0048] SAR platform parameters, such as flight speed v and flight altitude h;

[0049] SAR antenna parameters, such as beam pattern characteristics, slant angle and the rubbing angle β;

[0050] SAR signal parameters, such as operating wavelength , signal bandwidth and pulse repetition frequency ;

[0051] Step 1.2, obtain the location based on the interference parameter information and SAR system parameter information The deception interference template at the position is corrected by geometric correction and located at The deception jamming template at the position is as follows:

[0052] 1) Get the Deception interference template of the position and perform mapping operation: , convert the deceptive interference template to the oblique direction ; For the moving target P The slope distance at the moment, For azimuth slow time, is the scaling factor, which is generally set to 0.55;

[0053] 2) Perform distance translation operations separately and azimuth translation operations , convert the deception interference template into . is an exponential function, j is an imaginary unit, c is the speed of light, For oblique viewing angle, is the distance frequency, is the azimuth frequency;

[0054] 3) Adjust the sampling interval of the deception jamming template azimuth according to The mapping relationship is used to perform azimuth interpolation operation to obtain the The deception interference template at the position, the signal form is expressed as:

[0055] (1)

[0056] in, is the distance time domain, t is the azimuth time domain, is the position time of the moving target P, is the Doppler bandwidth. is the scattering coefficient of the moving target, It is the signal form of the modified deceptive interference template.

[0057] Furthermore, step 2 includes the following steps:

[0058] Step 2.1, perform azimuth Fourier transform on the corrected deception jamming template and compensate for the azimuth non-space-variant Doppler phase term. , and obtain the frequency response function :

[0059] (2)

[0060] (3)

[0061] in, represents the azimuthal Fourier transform, Nonlinear frequency modulation coefficients in various coefficients 、 、 、 and It is expressed as follows:

[0062] (4)

[0063] Undetermined coefficient , Therefore, the prior knowledge that needs to be known is as follows: 、 and Doppler frequency modulation The expansion coefficients of various orders; and is the Doppler cubic phase coefficient The expansion coefficients of various orders. Among them, is the instantaneous slant distance exist at derivatives, .

[0064] At the same time, the beam center slant distance is obtained according to the circle model theory and slope distance The analytical relationship between them is as follows:

[0065] (5)

[0066] Substitute Equation (5) into the Doppler modulation frequency and Doppler cubic phase , using slope distance variables replace , and perform Taylor expansion to derive and Azimuth space-variant mathematical model:

[0067] (6)

[0068] It should be noted that Equations (4), (5) and (6) are used to explain Equation (2) and the parameters involved in the following text, and do not involve the operation process.

[0069] Step 2.2: The frequency response function obtained in step 2.1 Perform inverse Fourier transform in azimuth and compensate a fourth-order frequency modulation scaling function , and obtain the frequency response function :

[0070] (7)

[0071] (8)

[0072] in, represents the inverse Fourier transform of the azimuth.

[0073] Step 2.3, the frequency response function obtained in step 2.2 Perform azimuth FFT and compensate with a fourth-order filter function , and obtain the frequency response function :

[0074] (9)

[0075] (10)

[0076] Step 2.4: The frequency response function obtained in step 2.3 Perform inverse Fourier transform in azimuth and compensate for the Doppler center frequency term , and obtain the frequency response function :

[0077] (11)

[0078] (12)

[0079] Furthermore, step 3 includes the following steps:

[0080] Step 3.1: The frequency response function obtained in step 2 Perform Fourier transform of the distance and compensate for the residual distance-related term of the azimuth space variation , and obtain the frequency response function :

[0081] (13)

[0082] (14)

[0083] in, is the instantaneous slant distance exist Moment The derivative is , and the parameter is recorded as . 、 and Substitute the coefficient into formula (5) about The expansion coefficient of . and Represents the distance Fourier transform and its inverse transform.

[0084] Step 3.2, when generating different moving targets under multiple motion parameters, the operations before this step are the same as the deception interference template The processing flow needs to be completed separately depending on the motion parameters involved. In this step, the frequency response function related to the motion parameters is After superposition and summation, the frequency response function is obtained :

[0085] (15)

[0086] Where i is the index value and M is the type of motion parameter used to generate the motion target.

[0087] Step 3.3, the frequency response function obtained in step 3.2 Perform Keystone transform to obtain the pre-generated frequency response function :

[0088] (16)

[0089] Where KT represents Keystone transform.

[0090] Furthermore, in step 4, during the period when the main beam of the SAR system antenna illuminates the jammer, the jammer enters the real-time modulation stage. The jammer pregenerates a frequency response function pulse by pulse in the frequency domain. Perform phase multiplication to achieve linear distance travel term Compensation to obtain the frequency response function related to the characteristics of the moving target :

[0091] (17)

[0092] (18)

[0093] Furthermore, the step 5 comprises the following steps:

[0094] Step 5.1: The jammer's pulse-by-pulse frequency response function related to the moving target's characteristics in the frequency domain Conduct jammer location related parts The compensation of the jammer frequency response function is expressed as :

[0095] (19)

[0096] (20)

[0097] in, is the instantaneous slant range at the jammer J, and is the azimuth and zero Doppler range position of the jammer J. Instantaneous slant range Expressed as:

[0098] (twenty one)

[0099] in, is the instantaneous slant distance exist at derivatives, It should be noted that Equation (20) is obtained by ignoring the spatial variability of the range compression term and the residual high-order range migration term.

[0100] Step 5.2: Compare the jammer frequency response function with the intercepted SAR signal Perform convolution modulation and then delay forwarding to achieve moving target deception interference signal Rapid generation of .

[0101] (twenty two)

[0102] (twenty three)

[0103] in, is the frequency modulation slope, and Both represent the demodulated two-way echo.

[0104] like Figure 2As shown, the present invention also proposes a high squint SAR moving target deception jamming device, comprising the following modules:

[0105] The template geometric correction module is used to enable the jammer to complete the reconnaissance and estimation of SAR platform parameters, SAR antenna parameters, and SAR signal parameters before the SAR antenna main beam illuminates the jammer; based on the jamming parameter information and SAR system parameter information, it obtains the deception jamming template at a specific location and obtains the corrected deception jamming template through geometric correction;

[0106] The Doppler phase compensation module performs azimuth nonlinear frequency modulation and scaling on the corrected deception jamming template in the range time domain and azimuth time-frequency transform domain, and compensates for the Doppler center frequency term, thereby obtaining a frequency response function after compensating for the Doppler correlation term.

[0107] The range pre-compensation module performs phase multiplication on the frequency response functions in the range frequency domain and the azimuth time domain to compensate for the residual range-related terms of the azimuth space-variation. The frequency response functions related to the motion parameters are superimposed and summed, and then a Keystone transform is performed to obtain the pre-generated frequency response function.

[0108] The movement compensation module, during the period when the SAR antenna main beam illuminates the jammer, the jammer enters the real-time modulation stage; the pre-generated frequency response function is phase multiplied pulse by pulse in the frequency domain to achieve linear range movement compensation and obtain a frequency response function related to the characteristics of the moving target;

[0109] The real-time generation module is used to perform phase multiplication of the frequency response function related to the characteristics of the moving target pulse by pulse in the frequency domain of the jammer, complete the compensation of the part related to the position of the jammer, and obtain the frequency response function of the jammer; the frequency response function is convoluted and modulated with the intercepted SAR signal and then delayed and forwarded, thereby quickly generating a moving target deception jamming signal.

[0110] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the above-mentioned method for deceiving and jamming moving targets of a high-squint SAR are implemented.

[0111] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the above-mentioned high-squint SAR moving target deception and jamming method are implemented.

[0112] In order to verify the effectiveness of the present invention, the present invention is simulated. Assuming that the SAR system parameters are as shown in Table 1:

[0113] Table 1

[0114]

[0115] The first set of simulation experiments is to analyze the temporal motion characteristics of the moving target generated by the present invention, which is mainly manifested in two aspects: position offset and azimuth ambiguity. Four scattering points are set in the interference scene, and the positions are P1 (1, 1), P2 (-1, -1), P3 (0, 1) and P4 (0, -1), respectively, with the unit being km. The motion parameters are set to v r =2m / s, v x =-2m / s, a r =0.1m / s 2 and a x =0.1m / s 2 . Figure 3 and Figure 5 The enlarged images of the imaging results after SAR imaging processing of the deceptive jamming signals of the moving scattering points P1 and P2 generated by the method of the present invention are respectively shown. Figure 4 and Figure 6 The magnified images of the point-by-point generated images of moving scattering points P1 and P2 are shown, compared with the deceptive jamming imaging results of the proposed method. The position offset and azimuth blur width of each scattering point are shown in Table 2.

[0116] Table 2

[0117]

[0118] The results of the first set of simulation experiments show that the motion scattering point deception jamming signal generated by the method of the present invention has extremely high jamming accuracy, and is basically consistent with the time domain motion characteristics of the SAR system simulating the real motion scattering points.

[0119] The second set of simulation experiments used ship targets as deception jamming templates to construct a deception jamming simulation experiment of moving ship targets near the coastline. Figure 7 The real scene imaging results are shown. Figure 8 The imaging results of the SAR imaging processing of the moving ship target deception jamming signal and the scene echo signal generated by the method of the present invention are shown. Among them, the jammer is located at point J, and the positions of the ship targets are T1(1,1), T2 (1,0) and T3(-0.3,0.7), respectively, in km. The motion parameters of T1 and T2 are set to v r =2m / s and v x =-2m / s, T3 motion parameter setting v r =1m / s,v x= 1m / s. It can be seen that the moving ship targets generated by the method of the present invention exhibit highly realistic time-domain motion characteristics, and the position offset and azimuth ambiguity of the moving ship targets are as expected. Furthermore, the moving ship targets generated by the method of the present invention retain deceptive electromagnetic characteristics such as points, lines, surfaces, and brightness, achieving a highly realistic deceptive jamming effect while maintaining reasonable power control.

[0120] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk drives, CD-ROMs, optical storage devices, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention may be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0121] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0122] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0123] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1A step that specifies a function in one or more boxes.

[0124] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0125] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for deceiving and jamming moving targets of a high squint SAR, characterized in that: The steps include: Step 1: Before the SAR antenna main beam illuminates the jammer, the jammer completes the reconnaissance and estimation of the SAR platform parameters, SAR antenna parameters, and SAR signal parameters; based on the jamming parameter information and SAR system parameter information, it obtains a deception jamming template at a specific location and obtains a corrected deception jamming template through geometric correction; Step 2: In the range time domain and the azimuth time-frequency transform domain, the corrected deception jamming template is subjected to azimuth nonlinear frequency modulation scaling and Doppler center frequency compensation, thereby obtaining a frequency response function after Doppler correlation compensation. Step 3: In the range frequency domain and azimuth time domain, phase multiplication is performed on the frequency response functions to achieve compensation for the residual range-related terms of the azimuth space variation; the frequency response functions related to the motion parameters are superimposed and summed, and then a Keystone transform is performed to obtain the pre-generated frequency response function; Step 4: While the SAR antenna main beam is illuminating the jammer, the jammer enters the real-time modulation phase; the pre-generated frequency response function is phase multiplied pulse by pulse in the frequency domain to achieve linear range movement compensation and obtain a frequency response function related to the characteristics of the moving target; Step 5: The jammer performs phase multiplication on the frequency response function related to the characteristics of the moving target pulse by pulse in the frequency domain to complete the compensation of the part related to the jammer position and obtain the jammer frequency response function; the frequency response function is convoluted and modulated with the intercepted SAR signal and then delayed and forwarded, thereby quickly generating a moving target deception jamming signal.

2. The method for deceiving and jamming a moving target of a high squint SAR according to claim 1, wherein: In step 1, the SAR platform parameters include flight speed v, flight altitude h; SAR antenna parameters include beam pattern characteristics, slant angle and grazing angle β; SAR signal parameters include operating wavelength , signal bandwidth and pulse repetition frequency ; According to the interference parameter information and SAR system parameter information, the The deception interference template at the position is corrected by geometric correction and located at Deception jamming templates at the location, including: Get the Deception interference template of the position and perform mapping operation: , convert the deceptive interference template to the oblique direction ; is the slant distance between the moving target P and the SAR platform, is the zero Doppler distance, is the azimuth position, For P The slope distance at the moment, is the azimuth slow time, v is the flight speed, is the position time of P, is the scaling factor, usually set to 0.55; Perform distance translation operations separately and azimuth translation operations , convert the deception interference template into ; is an exponential function, j is an imaginary unit, c is the speed of light, For oblique viewing angle, is the distance frequency, is the azimuth frequency; Adjust the sampling interval of the deception jamming template azimuth according to The mapping relationship is used to perform azimuth interpolation operation to obtain the The deception interference template at position, its signal form is expressed as: （1） in, is the distance time domain, t is the azimuth time domain, is the position time of the moving target P, is the Doppler bandwidth, is the scattering coefficient of the moving target, It is the signal form of the modified deceptive interference template.

3. The method for deceiving and jamming moving targets of a high-squint SAR according to claim 2, characterized in that: The step 2 includes: Step 2.1, perform azimuth Fourier transform on the corrected deception jamming template and compensate for the azimuth non-space-variant Doppler phase term. , and obtain the frequency response function : (2) in, 、 、 、 and is the nonlinear frequency modulation scaling coefficient; Doppler frequency modulation About location and time and beam center slant range The constant coefficient of the expansion, is the working wavelength; is the instantaneous slant distance exist at derivatives, , is the parameter of the moving target P, and the slant distance between P and the SAR platform satisfy: （5） in, is the beam center slant distance, and are the velocity and acceleration in the zero Doppler range direction, and are the velocity and acceleration in the azimuthal direction, To wipe the corners.

4. The method for deceiving and jamming moving targets of a high-squint SAR according to claim 3, wherein: The step 2 further comprises: Step 2.2: The frequency response function obtained in step 2.1 Perform inverse Fourier transform in azimuth and compensate with a fourth-order frequency modulation scaling function , and obtain the frequency response function : （8） in, represents the inverse Fourier transform of the azimuth direction; Step 2.3, the frequency response function obtained in step 2.2 Perform azimuth Fourier transform and compensate with a fourth-order filter function , and obtain the frequency response function : （10） in, represents the azimuthal Fourier transform. Step 2.4: The frequency response function obtained in step 2.3 Perform inverse Fourier transform in azimuth and compensate for the Doppler center frequency term , and obtain the frequency response function : （12）。 5. The method for deceiving and jamming moving targets of a high squint SAR according to claim 4, characterized in that: The step 3 comprises: Step 3.1: The frequency response function obtained in step 2 Perform Fourier transform of distance and compensate for the residual distance-related term of azimuth space variation , and obtain the frequency response function : （13） in, is the instantaneous slant distance exist Moment derivatives, is the parameter of the moving target P at the jammer position, 、 and is the coefficient About location and time and beam center slant range The expansion coefficient of Step 3.2, when generating different motion targets under multiple motion parameters, the frequency response function related to the motion parameters After superposition and summation, the frequency response function is obtained ; Step 3.3, the frequency response function obtained in step 3.2 Perform Keystone transform to obtain the pre-generated frequency response function .

6. The method for deceiving and jamming moving targets of a high-squint SAR according to claim 5, characterized in that: In step 4, the jammer pregenerates a frequency response function pulse by pulse in the frequency domain. Perform phase multiplication to achieve linear distance travel term Compensation to obtain the frequency response function related to the characteristics of the moving target : （18）。 7. The method for deceiving and jamming a moving target of a high squint SAR according to claim 6, characterized in that: The step 5 comprises: Step 5.1: The jammer's pulse-by-pulse frequency response function related to the moving target's characteristics in the frequency domain Conduct jammer location related parts The compensation of the jammer frequency response function is expressed as : （20） in, is the instantaneous slant range at the jammer's position J, and are the azimuth and zero Doppler range positions of J. Step 5.2: Convolutionally modulate the jammer frequency response function with the intercepted SAR signal and then delay forwarding it to achieve the jamming signal deception of the moving target. Quick generation of: （23） in, It represents the demodulated two-way echo, i.e. the intercepted SAR signal; represents the inverse Fourier transform of the distance, represents the Fourier transform of distance.

8. A high squint SAR moving target deception jamming device, characterized in that: Includes the following modules: The template geometric correction module is used to enable the jammer to complete the reconnaissance and estimation of SAR platform parameters, SAR antenna parameters, and SAR signal parameters before the SAR antenna main beam illuminates the jammer; based on the jamming parameter information and SAR system parameter information, it obtains the deception jamming template at a specific location and obtains the corrected deception jamming template through geometric correction; The Doppler phase compensation module performs azimuth nonlinear frequency modulation and scaling on the corrected deception jamming template in the range time domain and azimuth time-frequency transform domain, and compensates for the Doppler center frequency term, thereby obtaining a frequency response function after compensating for the Doppler correlation term. The range pre-compensation module performs phase multiplication on the frequency response functions in the range frequency domain and the azimuth time domain to compensate for the residual range-related terms of the azimuth space-variation. The frequency response functions related to the motion parameters are superimposed and summed, and then a Keystone transform is performed to obtain the pre-generated frequency response function. The movement compensation module, during the period when the SAR antenna main beam illuminates the jammer, the jammer enters the real-time modulation stage; the pre-generated frequency response function is phase multiplied pulse by pulse in the frequency domain to achieve linear range movement compensation and obtain a frequency response function related to the characteristics of the moving target; The real-time generation module is used to perform phase multiplication of the frequency response function related to the characteristics of the moving target pulse by pulse in the frequency domain of the jammer, complete the compensation of the part related to the position of the jammer, and obtain the frequency response function of the jammer; the frequency response function is convoluted and modulated with the intercepted SAR signal and then delayed and forwarded, thereby quickly generating a moving target deception jamming signal.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the high-squint SAR moving target deception and jamming method described in any one of claims 1 to 7 are implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the high-squint SAR moving target deception jamming method according to any one of claims 1 to 7 are implemented.

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