SAR (Synthetic Aperture Radar) interference signal generation method based on ground target deception template

Abstract

The invention discloses a synthetic aperture radar (SAR) deception jamming signal generation method based on a ground target composite scene, which comprises the following steps of: firstly, generating a target radar image template by adopting a high-frequency electromagnetic scattering calculation method, and secondly, extracting a ground background radar image slice from an SAR image database as a false background; the method comprises the following steps of: enhancing the intensity of a false background radar image through amplitude modulation filtering to cover a weak scattering center and a shadow of a real target so as to realize fuzzification processing of target radar features; and constructing false shadows with basically consistent amplitude features and similar contour shapes and actual measurement results for a real target and a false target, finally embedding the false target into a false background radar image, and generating a deception jamming signal in combination with a radar image data inversion technology. The method solves the problem that shadow features of true and false targets in deception jamming have significant difference, can improve the fidelity of the false target, and is easy for engineering realization.

Description

Technical Field

[0001] This invention relates to a method for generating SAR jamming signals based on ground target deception templates, belonging to the field of electronic countermeasures technology. Background Technology

[0002] Synthetic Aperture Radar (SAR), as an important tool for information acquisition, has the outstanding advantage of operating around the clock and in all weather conditions, playing a crucial role in the detection, location, tracking, and identification of ground targets. To prevent important facilities or targets from being monitored by enemy SAR radar, electronic countermeasures can be used to jam enemy SAR systems.

[0003] Suppression jamming is achieved by jammers transmitting strong noise signals that cover the operating frequency band of the enemy SAR system. Its principle is simple, and it can work normally even when the operating mode and waveform parameters of the enemy SAR system are unknown. The imaging quality of SAR images subjected to suppression jamming is reduced, and in the image domain, target details or even the target itself are submerged by strong background noise. However, because the transmitted signal is incoherent, it is impossible to form a focused jamming scene in the SAR image.

[0004] Unlike suppression jamming, deception jamming intercepts the transmitted signals of enemy radar systems, modulates deception information into the echo, and then forwards it to the enemy radar system. This creates well-focused false targets or scenes in the SAR imaging results, achieving a jamming effect that makes it difficult to distinguish between real and false targets. The success of SAR deception jamming relies on a rich database of deception templates. However, due to the diversity of factors such as radar observation angle, operating frequency, and target attitude, it is difficult to construct a complete database of real target templates through actual measurement methods, thus limiting the application scope of SAR deception jamming.

[0005] On the other hand, given the characteristics of SAR (Side-Looking SAR) radar operation and imaging methods, some ground areas below the real target will be obstructed and unable to be illuminated by the radar, forming shadowed areas in the SAR image. Although the deceptive scene created by SAR spoofing jamming is coherently superimposed on the real scene, no prototype has been found in existing literature that uses echo cancellation technology to reduce the signal strength of the deployment area and create shadowed areas near the false target. The lack of shadow features indicates that current SAR spoofing jamming techniques are unable to create highly realistic false targets, and their jamming effect needs further improvement.

[0006] The prior art related to this invention is described below: 1.1 Technical Solution of Existing Technology 1 Direct radio frequency processing (RF processing) is used to intercept, modulate, and convert waveforms via RF chips, which is a traditional method for SAR deception jamming. For example, by analyzing and improving the frequency response function of the jammer, active deception jamming can be achieved by embedding deception templates of multiple aircraft targets into airport SAR images [see reference 1]. Deception jamming can also be achieved using array receivers, by deploying fake urban scene templates to obscure the outline information of the central building complex in the real scene [see reference 2].

[0007] 1.1 Disadvantages of Existing Technology 1 Using interfering templates can achieve SAR scene deception to some extent; however, the limitations of the interfering template database itself restrict its application. Furthermore, the false targets generated by this method lack shadow features, making them easy to detect and identify.

[0008] 2.1 Technical solution of prior art 2 To address the issue of insufficient scene deception templates, this was achieved by adding pixel-by-pixel units to SAR images. By using random phases between the images, the image is transformed into complex image data with phase information. Combined with the CS inversion algorithm, a deception scene template is generated, realizing the SAR deception interference signal generation technology based on image inversion technology [see reference 3], which alleviates the problem of insufficient template database to a certain extent.

[0009] 2.2 Disadvantages of Existing Technology Two Ground surfaces are rough, with height variations much greater than the radar wavelength, resulting in a uniform phase distribution for ground clutter, making the addition of random phases feasible. However, man-made targets have smooth surfaces with height variations much smaller than the radar wavelength, leading to a more constant phase, primarily related to the target's geometry within the radar-illuminated area. The added random phases result in differences in radar image phase distribution between false targets and real targets, potentially being used for target identification and causing interference failure.

[0010] 3.1 The technical solution of existing technology three and its disadvantages To ensure similarity between the imaging results of real and decoy targets, this scheme requires that the generated ground clutter signal matches the texture characteristics of real scene clutter and accurately fills in the shadow areas of the real target during enemy SAR system imaging. To achieve this, on the one hand, the jammer needs to pre-store a library of environmental clutter features of the target's location to generate ground clutter template signals. On the other hand, the shape and contour of the real target's shadow area and the undulation characteristics of the ground within that area must also be considered when generating the jamming signal. However, existing ground clutter template generation algorithms lack sufficient accuracy, resulting in imaging results that deviate somewhat from the real scene. Furthermore, the computing power of SAR jammers is limited, making it difficult to support real-time calculation of clutter in the shadow areas of real targets. Therefore, this method presents significant challenges in engineering implementation.

[0011] To accurately fill in the shadow areas of real targets, the texture features of the generated ground clutter signal must be consistent with the real scene, and the jamming signal must be generated according to the shape and outline of the real shadow area of ​​the target in order to effectively eliminate shadow features and avoid detection by enemy personnel. This places very high technical requirements on both the hardware and software of the SAR jammer, making its engineering implementation extremely difficult. Summary of the Invention

[0012] The technical problem solved by this invention is: in the existing technology, the ground area of ​​the real target shadow zone is blocked and cannot be illuminated by radar, shadow areas are easily formed in SAR images, and the false targets generated by the deception jamming method do not have shadow features and are easily detected and identified. Therefore, a method for generating SAR jamming signals based on ground target deception template is proposed.

[0013] The present invention solves the above-mentioned technical problem through the following technical solution: A method for generating SAR jamming signals based on ground target deception templates includes: By specifying false targets embedded in rough ground, a target template database of false targets is obtained through electromagnetic scattering simulation calculations and filtered inverse projection algorithms; Obtain the measured SAR image database, and extract SAR false backgrounds from the measured SAR image database according to the ground cover type of the interference scene where the false target is located; Based on the SAR false background size parameters, amplitude modulation filtering is performed on the SAR false background; Determine the pose information and observation angle of false and real targets in a SAR false scene, and construct target shadow features; Based on the target shadow features, false targets are projected to a given location in the false scene, and a deception template of a composite scene of ground targets is generated by vector overlay; The ground target composite scene deception template is inverted and resampled to generate interference signals.

[0014] The method for obtaining the target template database of fake targets is as follows: Based on the geometric shape characteristics of our equipment, a three-dimensional geometric model of the false target on the rough ground is established; Obtain the enemy radar operating parameters, perform electromagnetic scattering calculations on the three-dimensional geometric model of the false target, and generate the false target SAR echo signal; The generated false target SAR echo signal is processed using a filtered inverse projection algorithm to generate a two-dimensional radar image of the false target; By iterating through the observation parameters, two-dimensional radar images of false targets covering various observation angles are generated, and a database of false target templates is constructed.

[0015] The target template database is , r Represents distance sampling in space. y The azimuth-oriented spatial sampling is used to characterize the full-angle imaging results of false targets; the ground type of the interference scene where the false target is located includes grassland, sand, farmland, artificial surface or other types of ground; the SAR false background is a ground background radar image slice corresponding to the scene to be interfered with in the measured SAR image database.

[0016] The method for amplitude modulation filtering of SAR false background is as follows: Based on the SAR false background size parameters, a two-dimensional low-pass filter is designed in the complex image domain. Amplitude modulation filtering is performed on the SAR false background to ensure the intensity of the false background after amplitude modulation. σ D Greater than the actual background intensity σ R The amplitude modulation filtering processing method is as follows:

[0017] In the formula, It is a two-dimensional low-pass filter. This is a false background for SAR after amplitude modulation filtering. This is a false background for SAR.

[0018] The method for constructing target shadow features is as follows: The pose information of false and real targets in the SAR false scene is determined, and the observation angle of the local radar for the false and real targets is determined. The hidden shadow removal algorithm is adopted. Based on the three-dimensional geometric model of the false target, the shadow regions formed by the false and real targets in the interference scene are marked. The shadow region reconstruction filter is constructed in the complex image domain, and the target shadow features are constructed by the image domain band-stop filtering method.

[0019] The reconstruction filter for constructing the shadow region in the complex image domain is: ; The method for constructing target shadow features using image domain band-stop filtering is as follows:

[0020] In the formula, This is a false SAR background that includes target shadow features.

[0021] The method for generating a composite scene deception template for ground targets is as follows: Amplitude modulation is used to randomly adjust the scattering intensity of the false target template within a preset range. The false target is then projected to a given position in the false scene through image domain convolution operation. Vector superposition is used to generate a deception template for a composite scene of ground targets.

[0022] The ground target composite scene deception template The expression is:

[0023] In the formula, N It is the total number of false targets. A n It is the amplitude perturbation coefficient of the false target. It is a unit impulse function. It is the first n The location of a fake target. It is the convolution operator.

[0024] The method for inverting and resampling ground target composite scene deception templates is as follows: The FFT transform is used to invert the deception template of the complex scene of the ground target from the complex image domain to the wavenumber domain. Based on the enemy radar operating parameters, frequency dimension and azimuth dimension downsampling point positions, the interference signal is generated by resampling.

[0025] The methods for calculating the sampling point positions in the frequency and azimuth dimensions are as follows:

[0026]

[0027] In the formula, i It is a frequency-dimensional index. j It is a directional index. n y and n x These are the number of pixels in the range and azimuth directions of the radar image, respectively. L y and L x It is a two-dimensional imaging distance. θ It was an enemy radar observation of the ground edge. It's the azimuth. k It is the wave number.

[0028] The advantages of this invention compared to the prior art are: (1) The present invention provides a method for generating SAR jamming signals based on a ground target deception template. The proposed deception template undergoes two filtering and modulation processes. On the one hand, it enhances the intensity of the false background radar image to cover up the weak scattering center and shadow of the real target, thereby blurring the radar features of the target. On the other hand, it attenuates the pixel intensity of the target's adjacent area in the false background to construct a false shadow with basically consistent amplitude features and similar contour shape to the measured results for the real and false targets. This solves the problem of the lack of shadow features of false targets in SAR deception jamming and significantly improves the realism of false targets. (2) Compared with the prior art, this invention adopts a high-frequency electromagnetic scattering simulation method that combines the bouncing ray method with the equivalent electromagnetic current method to generate false ground target SAR echo signals. It can quickly generate false target templates with phase information in the full-angle domain and full-frequency band. Because the electromagnetic scattering simulation process is based on the three-dimensional geometric model of the ground target, when the geometric model is sufficiently refined and the shape and structure are the same as the actual target, the target template generated by the simulation is highly consistent with the measured results in terms of outline and strong scattering point position. Only some weak scattering points cannot be completely matched. Since the weak scattering center will be submerged by the modulated strong background clutter, this difference has no substantial impact on the deception and interference effect. (3) The present invention does not require obtaining the shape and contour of the actual shadow area of ​​the target, nor does it require inverting to generate the clutter signal of the interference area. The principle is simple, the dependence on the measured data is low, and it is easier to implement in engineering. Attached Figure Description

[0029] Figure 1 The flowchart of the SAR deception jamming signal generation method based on the deception template of the ground target composite scene provided by the present invention is shown below. Figure 2 This is a schematic diagram of a measured SAR scene provided by the present invention; Figure 3 This is a schematic diagram of a simulated radar image of a tank at a radar observation azimuth angle of 162.5° provided by the present invention. Figure 4 This is a schematic diagram of a false SAR background provided by the present invention; Figure 5 This is a schematic diagram of a SAR deception template for a composite scene of ground targets provided by the present invention; Figure 6 The image shows the effect of SAR deception and interference in a real-world scenario, as provided by this invention. Detailed Implementation

[0030] A method for generating SAR jamming signals based on ground target deception templates is proposed. This method enhances the intensity of the false background radar image to mask the weak scattering center and shadow of the real target, thereby blurring the radar features of the target. At the same time, by attenuating the pixel intensity of the target's neighboring region in the false background, a false shadow with basically consistent amplitude characteristics and contour shape and similar to the measured results is constructed for the real and false targets. This method can improve the realism of the false target and is easy to implement in engineering.

[0031] A method for generating deception jamming signals based on complex ground target scenarios, comprising the following steps: By specifying false targets embedded in rough ground, and using electromagnetic scattering simulation calculations and filtered inverse projection algorithms, a target radar image template database of the false targets is obtained. Obtain the measured SAR image database, and extract SAR false backgrounds from the measured SAR image database according to the ground cover type of the interference scene where the false target is located; Based on the SAR false background size parameters, amplitude modulation filtering is performed on the SAR false background; Determine the pose information and observation angle of false and real targets in a SAR false scene, and construct target shadow features; Based on the target shadow features, false targets are deployed to a given location in the false scene, and a deception template of a composite scene of ground targets is generated by vector overlay. The ground target composite scene deception template is inverted and resampled to generate interference signals.

[0032] The method for obtaining the target template database of fake targets is as follows: Obtain enemy radar operating parameters and establish a three-dimensional geometric model of false targets on rough ground; Electromagnetic scattering simulation calculations are performed on the three-dimensional geometric model of the false target to generate the SAR echo signal of the false target; The SAR echo signal of the generated false target is processed using a filtered inverse projection algorithm to generate a two-dimensional radar image of the false target; By iterating through the observation parameters, two-dimensional radar images of false targets covering various observation angles are generated, and a database of false target templates is constructed.

[0033] The target template database is , r Represents distance sampling in space. y The azimuth-oriented spatial sampling is used to characterize the full-angle imaging results of false targets; the ground type of the interference scene where the false target is located includes grassland, sand, farmland, artificial surface or other types of ground; the SAR false background is a ground background radar image slice corresponding to the scene to be interfered with in the measured SAR image database.

[0034] The method for amplitude modulation filtering of SAR false background is as follows: Based on the SAR false background size parameters, a two-dimensional low-pass filter is designed in the complex image domain. Amplitude modulation filtering is performed on the SAR false background to ensure the intensity of the false background after amplitude modulation. σ D Greater than the actual background intensity σ R .

[0035] The method for constructing target shadow features is as follows: The pose information of false and real targets in the SAR false scene is determined, and the observation angle of the enemy radar on the false and real targets is determined. The hidden target elimination algorithm is adopted. Based on the three-dimensional geometric model of the false target, the shadow regions formed by the false and real targets in the interference scene are marked. The shadow region reconstruction filter is constructed in the complex image domain, and the target shadow features are constructed by the image domain band-stop filtering method.

[0036] The method for generating a composite scene deception template for ground targets is as follows: Amplitude modulation is used to randomly adjust the scattering intensity of the false target template within a preset range. The false target is then projected to a given position in the false scene through image domain convolution operation. Vector superposition is used to generate a deception template for a composite scene of ground targets.

[0037] The method for inverting and resampling ground target composite scene deception templates is as follows: The deception template of the complex scene of the ground target is inverted from the complex image domain to the wavenumber domain by using FFT transformation. Based on the enemy radar operating parameters, frequency dimension and azimuth dimension downsampling point positions, the deception jamming signal is generated by resampling.

[0038] The following description, in conjunction with the accompanying drawings and preferred embodiments, provides further details: In the current embodiment, a method for generating synthetic aperture radar (SAR) deception jamming signals based on a deception template for a complex ground target scene is given, along with its specific operation process. Figure 1 As shown, the specific steps include: For example Figure 2 The MSTAR measured SAR scene shown is used for deception jamming. The resampled image resolution is 0.035m, and the radar image size is 10601 (slant range) × 8759 (azimuth). A tank target is located approximately 100m laterally and approximately 200m slant range away. Considering that this invention employs active background clutter enhancement technology, the jamming area is explicitly declared. To prevent the enemy from using saturation attack methods, in practice, in addition to jamming areas containing real targets, deception jamming is also performed on another open area using seven false target templates to achieve large-scale scene deception jamming.

[0039] Step 1: A high-frequency electromagnetic scattering simulation method combining the bouncing ray method and the equivalent electromagnetic current method is used to perform electromagnetic scattering simulation calculations on the three-dimensional geometric model of a false target placed on rough ground. The center frequency is set to 9.39 GHz, the bandwidth to 600 MHz, the radar observation ground grazing angle to 17°, the azimuth sweep angle to 3.53°, and the polarization mode to HH polarization. By changing the center observation azimuth angle, an all-around SAR echo signal of the target is generated. Combined with a filtered inverse projection algorithm, a two-dimensional radar image of the false target is generated. For example... Figure 3 As shown, a simulated radar image of a tank at a radar observation azimuth angle of 162.5° is given, generated by a high-frequency electromagnetic scattering simulation method combined with a filtered inverse projection algorithm.

[0040] Step 2: Using other MSTAR measured SAR scene radar images as the SAR image database, and based on the ground type of the interference scene, use grassland ground background radar image slices as SAR false backgrounds. .

[0041] Step 3: Design a two-dimensional low-pass filter in the complex image domain based on the size of the SAR false scene. Among them, the passband gain A pass = 3.16, which sets the false background intensity after amplitude modulation. σ D Intensity compared to real background σ R Approximately 10dB higher: (1) in Indicates a SAR false background library, This represents a two-dimensional low-pass filter.

[0042] This step addresses two major issues: firstly, it eliminates the shadow features of the real target; secondly, it increases the intensity of false background clutter, laying the foundation for the next step of modulating the false shadow features using amplitude attenuation techniques. Furthermore, by constructing a two-dimensional low-pass filter, the pixel intensity of the false background edge region is attenuated, achieving blurring of the boundary between the real and false scenes.

[0043] Step 4: Based on the position and attitude of false and real targets in the SAR false scene, as well as the observation angle of the enemy radar, the Z-buffer hidden target removal algorithm is used, combined with the target's 3D geometric model, to mark the shadow areas formed by the false and real targets in the interference scene, and a shadow area reconstruction filter is constructed in the complex image domain. ,in , σ D and σR Representing the false background intensity and the true background intensity respectively, the target shadow region is generated using image domain band-stop filtering: (2) Shadow features, a typical characteristic of SAR scenes, are used for real and false target detection. Therefore, this paper considers assigning the same shadow to real and false targets to confuse enemy interpretation of SAR images. However, due to limitations in software algorithms and hardware, it is currently impossible to suppress clutter echoes from the real background. Traditional interception and retransmission deception jamming often manifests as additive interference in SAR images; that is, the SAR scene image generated by the enemy based on the radar received signal will always contain scattering intensities of [missing information]. σ R The real background clutter. Therefore, the jammer can only cover the real scene clutter signal by sending a stronger false background signal, and then generate a false shadow region through regional amplitude attenuation. In this embodiment, by reasonably designing the shadow region reconstruction filter, the final SAR false background is as follows: Figure 4 As shown, this is the SAR false background after processing by an amplitude modulation filter and a shadow region reconstruction filter, provided in the embodiment. Figure 4 (a) is the deceptive scene of interference area 1, which includes a total of 6 shadows, including the false shadow area of ​​the real target. Figure 4 (b) is the deception scene in area 2, containing 5 shadow blocks.

[0044] Step 5: Even targets of the same model will exhibit varying scattering intensities in real-world scenarios. Random values ​​are selected between [0.5, 2], and amplitude modulation techniques are used to adjust the scattering intensity of each false target template. Through image domain convolution operations, the false targets are projected onto a given location within the false scene. Vector overlay techniques are then used to generate a composite scene deception template for ground targets. (3) in N It is the total number of false targets. An It is the amplitude perturbation coefficient of the false target. It is a unit impulse function. It is the first n The location of a fake target. It is the convolution operator. It is the first n A template radar image of a false target.

[0045] The two deception templates that were finally obtained are as follows: Figure 5 The image shows the final SAR deception template for a composite scene of ground targets, where... Figure 5 (a) is the deception template for interference region 1. Figure 5(b) is the deception template for jamming area 2. Through the steps described above, a shadow area is assigned to each false target, and a shadow area is also retained at the location of the real target. When the enemy SAR system simultaneously receives the jamming signal and the real scene radar signal, the shadow area and the target image are superimposed to form a false shadow effect of the real target.

[0046] Step 6: The ground target composite scene deception template needs to be converted from a complex image to a complex signal before it can be modulated and forwarded to the enemy SAR system using a jammer. An FFT transform is used to invert the scene deception template from the complex image domain to the wavenumber domain. Based on the radar operating frequency band of 9.3GHz ~ 9.9GHz, the azimuth sweep angle is [-1.8°, 1.8°], and resampling is performed to generate the jamming signal. The sampling point positions in the frequency and azimuth dimensions are as follows: (4) (5) in i It is a frequency-dimensional index. j It is a directional dimension index, with distance as the length dimension. L y =362m, number of pixels n y =10601, azimuth direction L x =299m, number of pixels n x =8759, θ= 17° is the enemy radar's ground-grazing angle. It is the azimuth angle of the sampling point. k It is the wavenumber of the sampling point.

[0047] Simultaneously forwarding two deception templates, the effect image after SAR scene deception interference is as follows: Figure 6 The image shown is an illustration of the SAR deception jamming effect in a real-world scenario. The deceiving scene is successfully integrated into the background to be deceived. Zooming in on jamming area 1, as shown... Figure 6 As shown in (a), this is a magnified view of the interference area. Figure 6 As shown in (b), it was found that although the strong clutter background caused the ground clutter intensity in the target area to exceed the true value, it was difficult to distinguish between real and fake targets in the interference area because the false targets all had rich radar features and were extremely realistic.

[0048] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0049] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for generating SAR jamming signals based on ground target deception templates, characterized in that... include: By specifying false targets embedded in rough ground, a target template database of false targets is obtained through electromagnetic scattering simulation calculations and filtered inverse projection algorithms; Obtain the measured SAR image database, and extract SAR false backgrounds from the measured SAR image database according to the ground cover type of the interference scene where the false target is located; Based on the SAR false background size parameters, amplitude modulation filtering is performed on the SAR false background; Determine the pose information and observation angle of false and real targets in a SAR false scene, and construct target shadow features; Based on the target shadow features, false targets are projected to a given location in the false scene, and a deception template of a composite scene of ground targets is generated by vector overlay; The ground target composite scene deception template is inverted and resampled to generate interference signals.

2. The SAR jamming signal generation method based on ground target deception template according to claim 1, characterized in that: The method for obtaining the target template database of fake targets is as follows: Based on the geometric shape characteristics of our equipment, a three-dimensional geometric model of the false target on the rough ground is established; Obtain the enemy radar operating parameters, perform electromagnetic scattering calculations on the three-dimensional geometric model of the false target, and generate the false target SAR echo signal; The generated false target SAR echo signal is processed using a filtered inverse projection algorithm to generate a two-dimensional radar image of the false target; By iterating through the observation parameters, two-dimensional radar images of false targets covering various observation angles are generated, and a database of false target templates is constructed.

3. The SAR jamming signal generation method based on ground target deception template according to claim 2, characterized in that: The target template database is , r Represents distance sampling in space. y The azimuth spatial sampling is used to characterize the full-angle imaging results of false targets; The ground types in the interference scene where the false target is located include grassland, sand, farmland, artificial surface or other types of ground. The SAR false background is a ground background radar image slice corresponding to the scene to be interfered with in the measured SAR image database.

4. The SAR jamming signal generation method based on ground target deception template according to claim 2, characterized in that: The method for amplitude modulation filtering of SAR false background is as follows: Based on the SAR false background size parameters, a two-dimensional low-pass filter is designed in the complex image domain. Amplitude modulation filtering is performed on the SAR false background to ensure the intensity of the false background after amplitude modulation. σ D Greater than the actual background intensity σ R The amplitude modulation filtering processing method is as follows: In the formula, It is a two-dimensional low-pass filter. This is a false background for SAR after amplitude modulation filtering. This is a false background for SAR.

5. The SAR jamming signal generation method based on ground target deception template according to claim 4, characterized in that: The method for constructing target shadow features is as follows: The pose information of false and real targets in the SAR false scene is determined, and the observation angle of the local radar for the false and real targets is determined. The hidden shadow removal algorithm is adopted. Based on the three-dimensional geometric model of the false target, the shadow regions formed by the false and real targets in the interference scene are marked. The shadow region reconstruction filter is constructed in the complex image domain, and the target shadow features are constructed by the image domain band-stop filtering method.

6. The SAR jamming signal generation method based on ground target deception template according to claim 5, characterized in that: The reconstruction filter for constructing the shadow region in the complex image domain is: ; The method for constructing target shadow features using image domain band-stop filtering is as follows: In the formula, This is a false SAR background that includes target shadow features.

7. The SAR jamming signal generation method based on ground target deception template according to claim 5, characterized in that: The method for generating a composite scene deception template for ground targets is as follows: Amplitude modulation is used to randomly adjust the scattering intensity of the false target template within a preset range. The false target is then projected to a given position in the false scene through image domain convolution operation. Vector superposition is used to generate a deception template for a composite scene of ground targets.

8. The SAR jamming signal generation method based on ground target deception template according to claim 5, characterized in that: The ground target composite scene deception template The expression is: In the formula, N It is the total number of false targets. A n It is the amplitude perturbation coefficient of the false target. It is a unit impulse function. It is the first n The location of a fake target. It is the convolution operator.

9. A method for generating SAR jamming signals based on ground target deception templates according to claim 7, characterized in that: The method for inverting and resampling ground target composite scene deception templates is as follows: The FFT transform is used to invert the deception template of the complex scene of ground target from the complex image domain to the wavenumber domain. Based on the enemy radar operating parameters, frequency dimension and azimuth dimension downsampling point positions, the interference signal is generated by resampling.

10. A method for generating SAR jamming signals based on a ground target deception template according to claim 9, characterized in that: The methods for calculating the sampling point positions in the frequency and azimuth dimensions are as follows: In the formula, i It is a frequency-dimensional index. j It is a directional index. n y and n x These are the number of pixels in the range and azimuth directions of the radar image, respectively. L y and L x It is a two-dimensional imaging distance. θ It was an enemy radar observation of the ground edge. It's the azimuth. k It is the wave number.

Images