SAR-GMTI segmented frequency shift modulation interference method based on phase-adjustable metasurface

Abstract

The invention discloses an SAR-GMTI segmented frequency shift modulation interference method based on a phase-adjustable metasurface, and relates to the technical field of microwave remote sensing, a frequency shift modulation signal and a multi-phase segmented modulation signal can be respectively obtained through slow time frequency shift modulation and slow time multi-phase segmented modulation, the two kinds of modulation signals are synthesized into a segmented frequency shift modulation signal, and the segmented frequency shift modulation signal and the multi-phase segmented modulation signal are output. A multi-region segmented frequency shift interference signal is formed; according to the slow time frequency shift modulation, the frequency of a signal is slowly changed in a time domain, so that a wider frequency spectrum characteristic is presented; the slow-time multi-phase segmentation modulation performs segmentation processing of multiple phases, so that the number and the positions of phase segments can be flexibly adjusted, and fine control is performed on the signals; therefore, the segmented frequency shift interference signal controls the number and position of the phase segments, can present a wider frequency spectrum characteristic, does not influence each other, is not liable to generate more disordered signals, and can carry out targeted regulation and interference on different frequency bands and working modes of the SAR-GMTI system.

Description

Technical Field

[0001] The present invention relates to the field of microwave remote sensing technology, and in particular to a SAR-GMTI segmented frequency shift modulation interference method, device, equipment and medium based on a phase-adjustable metasurface. Background Art

[0002] Synthetic aperture radar (SAR) has the advantages of all-day, all-weather, strong penetration, long-distance, and high-resolution ground observation. When combined with ground moving target indication (GMTI) technology, it can achieve effective detection and imaging of moving targets, posing a serious threat to the military deployment, combat status, and wartime survival of important high-value ground moving targets. Aiming at the moving target detection characteristics of SAR-GMTI systems, exploring effective interference countermeasures has become a key research direction for anti-space / air-based reconnaissance.

[0003] At present, the research on SAR-GMTI interference mainly focuses on two methods: active deception interference and passive interference. In active deception interference, with the update of radar technology, the interference effect of traditional towed interference has dropped sharply, and new interference styles such as dense false targets such as delayed superposition interference and intermittent sampling and forwarding interference continue to emerge, which requires the radar party to urgently study interference identification algorithms for these new interference styles. In passive interference, generally in extreme cases, if the passive interference is strong enough, it will make the communication signal unable to be reliably detected, resulting in communication interruption, which usually has a serious impact on military and civilian communications.

[0004] The emergence and development of electromagnetic metasurface technology has provided a new solution for improving SAR-GMTI interference technology. Thanks to the flexible control capability of electromagnetic metasurfaces on important parameters such as electromagnetic wave delay, amplitude, phase, and frequency, it only needs to modulate the incident electromagnetic wave without actively emitting high-power signals, thus realizing an effective combination of the advantages of traditional active interference and passive interference. At present, the modulation of electromagnetic metasurfaces is mainly multi-degree-of-freedom joint control, because metasurfaces can realize simultaneous control of electromagnetic wave phase, amplitude, polarization and other degrees of freedom. For example, by jointly controlling the phase and amplitude of electromagnetic waves, three-dimensional super holography can be realized; by jointly controlling the phase and polarization of electromagnetic waves, vector vortex light can be realized; by jointly controlling the phase and frequency of electromagnetic waves, functions such as nonlinear super lens can be realized. However, when multi-degree-of-freedom joint control is used to simultaneously control the phase, amplitude, polarization and other degrees of freedom of electromagnetic waves, there is usually a high degree of mutual influence between the phase, amplitude, polarization and other degrees of freedom, resulting in more clutter signals when modulating the incident electromagnetic wave, making it difficult to carry out targeted interference on different frequency bands and working modes of the SAR-GMTI system. Summary of the invention

[0005] The embodiment of the present invention provides a SAR-GMTI segmented frequency shift modulation interference method based on a phase-adjustable metasurface, which can solve the problem in the prior art that the current method has a large number of clutter signals when modulating the incident electromagnetic waves, making it difficult to carry out targeted interference on different frequency bands and working modes of the SAR-GMTI system.

[0006] The embodiment of the present invention provides a SAR-GMTI segmented frequency shift modulation interference method based on a phase-adjustable metasurface, comprising the following steps:

[0007] Design a phase-controlled metasurface and install it on the target surface;

[0008] When the protected target is moving, the phase-controlled metasurface designed on the surface receives the radar transmission signals of the SAR-GMTI system in the form of multiple regions, and the phase-controlled metasurface performs slow-time frequency-shift modulation and slow-time multi-phase segmented modulation on the transmission signals of the multiple regions, respectively, obtains frequency-shift modulation signals and multi-phase segmented modulation signals, generates segmented frequency-shift modulation signals according to the frequency-shift modulation signals and the multi-phase segmented modulation signals, and forms segmented frequency-shift modulation signals of multiple regions;

[0009] A multi-region segmented frequency shift interference signal is generated according to the spectrum of the segmented frequency shift modulation signal, and the SAR-GMTI system is interfered with by the multi-region segmented frequency shift interference signal.

[0010] Preferably, the formation of the segmented frequency shift modulation signal includes:

[0011] When the radar transmission signal of the SAR-GMTI system is incident on the phase control metasurface, the phase of the electromagnetic wave signal incident on the phase control metasurface is subjected to slow-time frequency shift modulation and slow-time multi-phase segmented modulation, respectively, to obtain a frequency shift modulation signal and a multi-phase segmented modulation signal, respectively, to form a segmented frequency shift modulation signal;

[0012] The segmented frequency shift modulation signal is:

[0013]

[0014] Where: N, τ n , Δt n and f n They represent the number of segments, segment duration, delay and frequency shift of the segmented frequency shift modulation signal respectively; t m represents slow time; p(t m ) represents a segmented frequency shift modulation signal.

[0015] Preferably, the formation of the multi-region segmented frequency shift interference signal includes:

[0016] The spectrum of the segmented frequency shift modulation signal in the frequency domain is extracted, and the spectrum of the segmented frequency shift modulation signal is replicated multiple times in the azimuth direction of the protection target. The spectrum of the segmented frequency shift modulation signal is replaced with the replicated multiple different spectra in sequence to form multiple harmonic components of the segmented frequency shift modulation signal, and the multiple harmonic components are synthesized into a segmented frequency shift interference signal, thereby forming a multi-region segmented frequency shift interference signal.

[0017] Preferably, the total echo signal received by the SAR-GMTI system also includes the echo signal generated by background clutter and system noise, which is expressed as follows:

[0018]

[0019] in: Represents the total echo signal received by the SAR-GMTI system; Indicates the echo signal generated by background clutter; represents the system noise; Indicates a segmented frequency-shift interference signal;

[0020] The segmented frequency shift interference signal is:

[0021]

[0022] in: Represents the unmodulated moving target echo signal.

[0023] Preferably, interfering with the SAR-GMTI system includes:

[0024] The SAR-GMTI system receives multi-region segmented frequency-shifted jamming signals, and performs range-direction matched filtering, range migration correction, and clutter suppression on the jamming signals, thereby forming a multi-region array of false targets at different intervals along the azimuth of the protected target in the jamming image, thereby jamming the SAR-GMTI system.

[0025] The number of false targets is determined by the number of segments N of the segmented frequency shift modulation signal, and the offset of the false target relative to the protected target in azimuth is:

[0026]

[0027] Where: f n It represents the frequency shift of the segmented frequency shift modulation signal; γ represents the Doppler modulation frequency.

[0028] Preferably, the echo signal generated by the segmented frequency-shifted interference signal and the background clutter is expressed as follows after being processed by range-matched filtering and range migration correction:

[0029]

[0030] Where: A represents the complex reflection coefficient of the target; T a represents synthetic aperture time; λ represents wavelength; c represents the speed of light; B r represents the bandwidth of the transmitted signal; j represents the imaginary part;

[0031] The dual-channel offset phase center antenna (DPCA) method is used to suppress clutter and obtain the final segmented frequency shift interference signal.

[0032] The embodiment of the present invention also provides a SAR-GMTI segmented frequency shift modulation jammer based on a phase-adjustable metasurface, comprising:

[0033] A design module, used to design a phase-controlled metasurface and install it on the target surface;

[0034] Modulation module: When the protected target is moving, the phase-controlled metasurface designed on the surface receives the radar transmission signal of the SAR-GMTI system in the form of multiple regions. The phase-controlled metasurface performs slow-time frequency shift modulation and slow-time multi-phase segmented modulation on the transmission signals of the multiple regions, respectively, obtains frequency shift modulation signals and multi-phase segmented modulation signals, generates segmented frequency shift modulation signals according to the frequency shift modulation signals and the multi-phase segmented modulation signals, and forms segmented frequency shift modulation signals in multiple regions;

[0035] The SAR-GMTI system interference module generates multi-region segmented frequency shift interference signals according to the spectrum of the segmented frequency shift modulation signal, and interferes with the SAR-GMTI system through the multi-region segmented frequency shift interference signals.

[0036] An embodiment of the present invention further provides an electronic device, including a memory and a processor;

[0037] The memory is used to store computer programs;

[0038] The processor is used to implement the steps of the SAR-GMTI segmented frequency shift modulation interference method based on the phase-adjustable metasurface as described above when executing the computer program stored in the memory.

[0039] An embodiment of the present invention also provides a computer-readable storage medium, characterized in that it is used to store a computer program, and when the computer program is executed by a processor, the steps of the SAR-GMTI segmented frequency shift modulation interference method based on the phase-adjustable metasurface as described above are implemented.

[0040] The embodiment of the present invention provides a SAR-GMTI segmented frequency shift modulation jamming method based on a phase-adjustable metasurface. Compared with the prior art, the method has the following beneficial effects:

[0041] The present invention can obtain frequency shift modulation signals and multi-phase segmented modulation signals respectively through slow time frequency shift modulation and slow time multi-phase segmented modulation, and the two modulation signals synthesize the segmented frequency shift modulation signal and form a segmented frequency shift interference signal in multiple regions; the slow time frequency shift modulation makes the signal present a wider spectrum characteristic in the frequency domain by slowly changing the frequency of the signal in the time domain, and the modulation method effectively utilizes the spectrum resources; while the slow time multi-phase segmented modulation allows segmented processing of multiple phases in the time domain of the signal, and the modulation method can flexibly adjust the number and position of the phase segments to perform fine control on the signal; therefore, the segmented frequency shift interference signal synthesized by the two modulation signals controls the number and position of the phase segments, and can present a wider spectrum characteristic, and has no influence on each other, and is not prone to more clutter signals, and can perform targeted regulation on different frequency bands and working modes of the SAR-GMTI system, and realize interference to the SAR-GMTI system.

[0042] Moreover, the formation of segmented frequency shift modulation signal further enhances the complexity and diversity of interference, making it difficult for the SAR-GMTI system to extract useful target information from the interference, effectively interfering with the normal operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic diagram of the overall process of a SAR-GMTI segmented frequency shift modulation interference method based on a phase-adjustable metasurface provided in an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of an interference model of a SAR-GMTI segmented frequency shift modulation interference method based on a phase-adjustable metasurface provided in an embodiment of the present invention;

[0045] Figure 3 A schematic diagram of the design of a phase-adjustable metasurface for a SAR-GMTI segmented frequency shift modulation interference method based on a phase-adjustable metasurface provided in an embodiment of the present invention; (a) is a schematic diagram of the structure of the metasurface; (b) is a schematic diagram of a metasurface array;

[0046] Figure 4 A schematic diagram of single-channel SAR imaging results without interference using the SAR-GMTI segmented frequency shift modulation interference method based on a phase-adjustable metasurface provided in an embodiment of the present invention;

[0047] Figure 5 A schematic diagram of single-channel SAR interference imaging results of the SAR-GMTI segmented frequency shift modulation interference method based on the phase-adjustable metasurface provided in an embodiment of the present invention;

[0048] Figure 6A schematic diagram of clutter suppression results in the absence of interference using the SAR-GMTI segmented frequency shift modulation jamming method based on a phase-adjustable metasurface provided in an embodiment of the present invention;

[0049] Figure 7 A schematic diagram of clutter suppression results of the SAR-GMTI segmented frequency shift modulation jamming method based on a phase-adjustable metasurface provided in an embodiment of the present invention;

[0050] Figure 8 A schematic diagram of the detection results of moving targets in the absence of interference using the SAR-GMTI segmented frequency shift modulation interference method based on a phase-adjustable metasurface provided in an embodiment of the present invention;

[0051] Fig. 9 A schematic diagram of the moving target detection results of the SAR-GMTI segmented frequency shift modulation interference method based on the phase-adjustable metasurface provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0053] See also Figure 1 The embodiment of the present invention provides a SAR-GMTI segmented frequency shift modulation interference method based on a phase-adjustable metasurface, comprising the following steps:

[0054] Step 1: Design of phase-tunable metasurface.

[0055] Step 2: Establishment of segmented frequency shift modulation signal model based on phase-adjustable metasurface.

[0056] Step 3: Construction of a multi-channel SAR-GMTI interference signal model based on phase-adjustable metasurface.

[0057] Step 4: Multi-channel SAR-GMTI processing and interference effect analysis.

[0058] The design of the phase-tunable metasurface in step 1 is as follows:

[0059] First, a double-layer butterfly metal structure is designed, and a lumped element, a varactor diode, is added between the butterfly metal gap structures. The voltage on both sides of the varactor diode is adjusted to change the equivalent capacitance, thereby achieving continuous change in the phase of the incident electromagnetic wave. The designed electromagnetic metasurface unit structure and array structure are shown in Figure 2. Figure 3 As shown, the array structure layout is achieved by performing a two-dimensional periodic translation of the unit structure, thereby realizing a complete two-dimensional electromagnetic metasurface array structure.

[0060] The establishment of the segmented frequency shift modulation signal model in step 2 is specifically as follows:

[0061] Inspired by the superior interference effects of frequency shift modulation and segmented modulation in traditional active interference methods, the present invention combines frequency shift modulation with segmented modulation by using a phase-adjustable metasurface to generate a segmented frequency shift modulation signal, which can be expressed as:

[0062]

[0063] Where: N, τ n , Δt n and f n They respectively represent the number of segments, segment duration, delay and frequency shift of the modulated signal.

[0064] The construction of the multi-channel SAR-GMTI interference signal model in step 3 is as follows:

[0065] The dual-channel SAR-GMTI interference model based on time-modulated metasurface is as follows: Figure 2 As shown in the figure; it is assumed that the SAR-GMTI system works in the positive side-view mode, the radar platform is at a height of H from the ground, and flies along the X-axis at a constant speed V; a phased array antenna is placed horizontally along the tangent direction of the radar track, and the antenna is divided into two sub-antennas, d is the distance between the two sub-antennas; a single-transmit dual-receive working mode is adopted, antenna 1 transmits the LFM signal, and the two sub-antennas receive the echo signal simultaneously; according to the antenna phase center equivalent principle, the antenna one-transmit multiple-receive data acquisition mode can be equivalent to the multi-antenna self-transmitting and self-receiving mode; at the azimuth slow time t m At time , the position vector of the i-th equivalent antenna is expressed as and are the unit vectors of the X-axis and Z-axis respectively; the liquid crystal tunable metasurface is placed on the surface of the protected moving target in the observation scene, and the target moves at a speed v(t m ) moves in the scene, and the position vector is expressed as in, represents the unit vector of the Y axis, x0 and y0 are the initial positions of the moving target, and v x and v r =v y sinφ represents the tangential velocity and radial velocity of the moving target, v y is the ground range velocity of the moving target, and φ represents the radar downward viewing angle.

[0066] The instantaneous slant range R between the i-th (i=1,2) equivalent antenna and the moving targeti (t m ) is expressed as:

[0067]

[0068] Assume that the LFM signal transmitted by the SAR-GMTI system is expressed as:

[0069]

[0070] in: Indicates distance to fast time; T r represents the pulse width; rect(·) represents the rectangular function; f0 represents the center frequency of the transmitted signal; μ represents the modulation frequency of the transmitted LFM signal.

[0071] The time-modulated metasurface on the target surface intercepts the radar transmission signal and performs interference modulation on it. Under the control of the external bias voltage, the time metasurface modulates the phase information of the transmission signal in real time and forwards the modulated signal to the SAR-GMTI system. The SAR-GMTI system performs detection and demodulation on the received interference echo signal. The complex baseband interference signal corresponding to the equivalent antenna i can be expressed as:

[0072]

[0073] in: represents the unmodulated moving target echo signal received by antenna i, and its expression is:

[0074]

[0075] Where: A represents the complex reflection coefficient of the target; T a represents the synthetic aperture time; λ and c represent the wavelength and the speed of light, respectively.

[0076] In addition to the above interference signals, the total echo signal received by the radar is Also includes the echo signal generated by background clutter and system noise Echo signal The expression is:

[0077]

[0078] Since the phase information in the moving target echo signal is destroyed by the modulated signal, false targets or defocused images appear in the SAR image after clutter suppression and imaging processing, which effectively interferes with the detection and imaging of moving targets.

[0079] The multi-channel SAR-GMTI processing and interference effect analysis in step 4 are as follows:

[0080] First, the radar echo signal is processed by range-Doppler SAR imaging. After range-matched filtering and range migration correction, the interference signal and background clutter echo signal can be expressed as:

[0081]

[0082]

[0083] Among them: B r Indicates the transmit signal bandwidth.

[0084] Converting the radar echo signal to the Doppler frequency domain, the relationship between the stationary clutter echo signals received by the two antennas can be expressed as:

[0085]

[0086] Where: γ c =-2V 2 / (λR B );Δt=d / V;B a Represents the signal Doppler bandwidth.

[0087] The relationship between the interference signals received by the two antennas can be expressed as:

[0088]

[0089] According to the relationship between the echo signals received by the two antennas, the present invention uses a dual-channel offset phase center antenna (DPCA) method to achieve clutter suppression, and its expression is:

[0090]

[0091] in: Represents residual clutter and noise caused by non-ideal factors.

[0092] The echo signal after clutter suppression is processed by azimuth matched filtering to obtain the final interference SAR-GMTI image, which is expressed as:

[0093]

[0094] in:

[0095]

[0096] Among them: B a represents the signal Doppler bandwidth; γ represents the Doppler modulation frequency; B n =γτ n .

[0097] It can be seen that the number of false moving targets in the jamming SAR-GMTI image is determined by the number of segments N, and the offset of the false moving target relative to the real moving target in the azimuth direction can be expressed as:

[0098]

[0099] Finally, the constant false alarm rate (CFAR) detector is used to detect moving targets.

[0100] The specific tests are:

[0101] A reference moving target RT and three protected moving targets MT1-2 are set at the center of the imaging scene, and uniform background clutter and noise with a signal-to-noise ratio of SCNR=0dB are added; the echo signal of the protected target is segmented frequency-shifted modulated using a phase-adjustable metasurface, and the modulation parameters are set to N=3, f n =-20Hz,20Hz,50Hz,τ n =5 / 14T a ,4 / 14T a ,6 / 14T a , Δt n =0,5 / 14T a ,9 / 14T a ; Perform range-Doppler SAR imaging processing on the unmodulated echo signal and the interference signal respectively to obtain the unmodulated single-channel SAR imaging result and the single-channel interference imaging result, respectively as follows Figure 4 and Figure 5 As shown, it can be seen that the moving target is submerged in the clutter, making it difficult to directly detect the moving target.

[0102] After dual-channel DPCA processing, the non-interference clutter suppression results and the modulation interference clutter suppression results are obtained as follows: Figure 6 and Figure 7 As shown in Figure 2, it can be seen that after the segmented frequency shift modulation processing based on the phase-adjustable metasurface, the protected moving target MTi can generate three false moving targets in the azimuth direction, thereby effectively hiding the real target position; on this basis, CFAR detection is performed on the clutter-suppressed SAR-GMTI image to obtain the final moving target detection results. The non-interference detection results and the modulation interference detection results are shown in Figure 2, respectively. Figure 8 and Fig. 9 As shown in the figure, the interference image obtained by segmented frequency shift modulation processing contains three false moving targets, thereby interfering with the detection and recognition of moving targets and achieving the purpose of deception interference.

[0103] The present invention uses a phase-adjustable metasurface to perform slow-time segmented frequency shift modulation on radar signals to generate multi-channel SAR segmented frequency shift jamming signals; by performing range-Doppler imaging and clutter suppression processing on the multi-channel SAR segmented frequency shift jamming signals, theoretical analysis and experimental results show that the present invention generates multiple false moving targets at specified azimuth positions, thereby effectively hiding the position and velocity information of real moving targets, and has a highly flexible, high-fidelity, and low-cost SAR-GMTI jamming effect.

[0104] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. The SAR-GMTI segmented frequency shift modulation jamming method based on phase-adjustable metasurface is characterized by: include: Design a phase-controlled metasurface and install it on the target surface; When the protected target is moving, the phase-controlled metasurface designed on the surface receives the radar transmission signals of the SAR-GMTI system in the form of multiple regions, and the phase-controlled metasurface performs slow-time frequency-shift modulation and slow-time multi-phase segmented modulation on the transmission signals of the multiple regions, respectively, obtains frequency-shift modulation signals and multi-phase segmented modulation signals, generates segmented frequency-shift modulation signals according to the frequency-shift modulation signals and the multi-phase segmented modulation signals, and forms segmented frequency-shift modulation signals of multiple regions; A multi-region segmented frequency shift interference signal is generated according to the frequency spectrum of the segmented frequency shift modulation signal, and the SAR-GMTI system is interfered with by the multi-region segmented frequency shift interference signal.

2. The SAR-GMTI segmented frequency shift modulation jamming method based on phase-adjustable metasurface according to claim 1 is characterized in that: The formation of the segmented frequency shift modulation signal includes: When the radar transmission signal of the SAR-GMTI system is incident on the phase control metasurface, the phase of the electromagnetic wave signal incident on the phase control metasurface is subjected to slow-time frequency shift modulation and slow-time multi-phase segmented modulation, respectively, to obtain a frequency shift modulation signal and a multi-phase segmented modulation signal, respectively, to form a segmented frequency shift modulation signal; The segmented frequency shift modulation signal is: Where: N, τ n , Δt n and f n They represent the number of segments, segment duration, delay and frequency shift of the segmented frequency shift modulation signal respectively; t m represents slow time; p(t m ) represents a segmented frequency shift modulation signal.

3. The SAR-GMTI segmented frequency shift modulation jamming method based on phase-adjustable metasurface according to claim 2 is characterized in that: The formation of the multi-region segmented frequency shift interference signal includes: The spectrum of the segmented frequency shift modulation signal in the frequency domain is extracted, and the spectrum of the segmented frequency shift modulation signal is replicated multiple times in the azimuth direction of the protection target. The spectrum of the segmented frequency shift modulation signal is replaced with the replicated multiple different spectra in sequence to form multiple harmonic components of the segmented frequency shift modulation signal, and the multiple harmonic components are synthesized into a segmented frequency shift interference signal, thereby forming a multi-region segmented frequency shift interference signal.

4. The SAR-GMTI segmented frequency shift modulation jamming method based on phase-adjustable metasurface according to claim 2 is characterized in that: The total echo signal received by the SAR-GMTI system also includes the echo signal generated by background clutter and system noise, which is expressed as: in: Represents the total echo signal received by the SAR-GMTI system; Indicates the echo signal generated by background clutter; represents the system noise; Indicates a segmented frequency-shift interference signal; The segmented frequency shift interference signal is: in: Represents the unmodulated moving target echo signal.

5. The SAR-GMTI segmented frequency shift modulation jamming method based on phase-adjustable metasurface according to claim 4 is characterized in that: The interference to the SAR-GMTI system includes: The SAR-GMTI system receives multi-region segmented frequency-shifted jamming signals, and performs range-direction matched filtering, range migration correction, and clutter suppression on the jamming signals, thereby forming a multi-region array of false targets at different intervals along the azimuth of the protected target in the jamming image, thereby jamming the SAR-GMTI system. The number of false targets is determined by the number of segments N of the segmented frequency shift modulation signal, and the offset of the false target relative to the protected target in azimuth is: Where: f n It represents the frequency shift of the segmented frequency shift modulation signal; γ represents the Doppler modulation frequency.

6. The SAR-GMTI segmented frequency shift modulation jamming method based on phase-adjustable metasurface according to claim 5 is characterized in that: The echo signal generated by the segmented frequency-shifted interference signal and background clutter is expressed as follows after range-matched filtering and range migration correction: Where: A represents the complex reflection coefficient of the target; T a represents synthetic aperture time; λ represents wavelength; c represents the speed of light; B r represents the bandwidth of the transmitted signal; j represents the imaginary part; The dual-channel offset phase center antenna (DPCA) method is used to suppress clutter and obtain the final segmented frequency shift interference signal.

7. SAR-GMTI segmented frequency shift modulation jammer based on phase-adjustable metasurface, characterized in that: include: A design module, used to design a phase-controlled metasurface and install it on the target surface; Modulation module: When the protected target is moving, the phase-controlled metasurface designed on the surface receives the radar transmission signal of the SAR-GMTI system in the form of multiple regions. The phase-controlled metasurface performs slow-time frequency shift modulation and slow-time multi-phase segmented modulation on the transmission signals of the multiple regions, respectively, obtains frequency shift modulation signals and multi-phase segmented modulation signals, generates segmented frequency shift modulation signals according to the frequency shift modulation signals and the multi-phase segmented modulation signals, and forms segmented frequency shift modulation signals in multiple regions; The SAR-GMTI system interference module generates multi-region segmented frequency shift interference signals according to the spectrum of the segmented frequency shift modulation signal, and interferes with the SAR-GMTI system through the multi-region segmented frequency shift interference signals.

8. An electronic device, characterized in that: include: Memory and processor; The memory is used to store computer programs; The processor is used to implement the steps of the SAR-GMTI segmented frequency shift modulation interference method based on a phase-adjustable metasurface as described in any one of claims 1 to 6 when executing the computer program stored in the memory.

9. A computer-readable storage medium, characterized in that: Used to store a computer program, which, when executed by a processor, implements the steps of the SAR-GMTI segmented frequency shift modulation interference method based on a phase-adjustable metasurface as described in any one of claims 1 to 6.

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