SAR-GMTI composite phase modulation interference method based on phase-adjustable metasurface

Abstract

The invention discloses an SAR-GMTI composite phase modulation interference method based on a phase-adjustable metasurface, and relates to the technical field of microwave remote sensing, and the method comprises the steps: respectively obtaining a cosine phase modulation signal and a multi-phase segmented modulation signal through slow-time cosine phase modulation and slow-time multi-phase segmented modulation; multiplying the two modulation signals to obtain a composite phase modulation signal; due to the fact that the cosine phase modulation signal has good phase continuity and smoothness, the cosine phase modulation signal can show high robustness when facing noise and interference, and the integrity and identifiability of the signal can be kept in a complex environment. Meanwhile, the information of the multi-phase segmented modulation signal is transmitted in a segmented manner, so that the signal in each segment has high anti-noise capability, the anti-interference performance of the whole signal system is improved, the anti-interference capability of the formed composite phase interference signal is greatly enhanced, and the interference precision of the SAR-GMTI system is improved.

Description

Technical Field

[0001] The present invention relates to the field of microwave remote sensing technology, and in particular to a SAR-GMTI composite phase 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] In recent years, research on SAR-GMTI interference has mainly focused on two methods: active deception interference and passive interference. The interference identification algorithm of active deception interference mainly identifies or classifies several interference patterns. However, in actual battlefield environments, it is first necessary to identify whether it is subject to some kind of deception interference before taking corresponding countermeasures. Therefore, there are relatively few identification algorithms. Passive interference will increase the received noise level, thereby reducing the signal-to-noise ratio, affecting the signal quality and transmission reliability, which makes it impossible for communication or radar systems to accurately detect or identify target signals.

[0004] The emergence and development of electromagnetic metasurface technology has provided a new idea for improving SAR-GMTI interference technology, thanks to the ability of electromagnetic metasurface to flexibly control important parameters such as electromagnetic wave delay, amplitude, phase, and frequency. At present, the modulation of electromagnetic metasurface is mainly resonant phase modulation. The principle is to control the influence of each structure on the scattered light by changing the size of the unit structure, thereby changing the phase and wavefront of the scattered light. The resonant phase was originally realized in plasma metasurfaces. In metal nanostructures, when the frequency of the incident light matches the oscillation frequency of the electrons in the nanoparticles, the nanoparticles will have a strong absorption effect on the photon energy. This phenomenon is called localized surface plasmon resonance. However, the resonant phase modulation environment is highly sensitive. For example, factors such as temperature changes, humidity changes, or mechanical vibrations affect the resonance characteristics, resulting in poor anti-interference ability when modulating the incident electromagnetic waves, making it difficult to achieve high-precision interference with the SAR-GMTI system. Summary of the invention

[0005] The embodiment of the present invention provides a SAR-GMTI composite phase modulation interference method based on a phase-adjustable metasurface, which can solve the problem in the prior art that the current method has poor anti-interference ability when modulating the incident electromagnetic waves and is difficult to achieve high-precision interference on the SAR-GMTI system.

[0006] The embodiment of the present invention provides a SAR-GMTI composite phase 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. The phase-controlled metasurface performs slow-time cosine phase modulation and slow-time multi-phase segmented modulation on the transmission signals of the multiple regions, respectively, obtains cosine phase modulation signals and multi-phase segmented modulation signals, multiplies the cosine phase modulation signals and the multi-phase segmented modulation signals to obtain composite phase modulation signals, and forms composite phase modulation signals of multiple regions;

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

[0010] Preferably, the forming of the composite phase modulation signal comprises:

[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 cosine phase modulation and slow-time multi-phase segmented modulation, respectively, to obtain a cosine phase modulation signal and a multi-phase segmented modulation signal, respectively;

[0012] The cosine phase modulation signal is:

[0013] p1(t m )=exp[jβcos(2πf1t m )];

[0014] Where: p1(t m ) represents a cosine phase modulated signal; t m represents slow time; β and f1 represent the modulation index and modulation frequency of the cosine phase modulation signal respectively;

[0015] The multi-phase segmented modulation signal is:

[0016]

[0017] Where: p2(tm ) represents a multi-phase segmented modulation signal; * represents a convolution operation; τ,T,f2=1 / T,φ p ,P,N respectively represent the segment duration, modulation period, modulation frequency, modulation phase, number of phase segments within the pulse, and number of repetitions of the multi-phase segment modulation signal;

[0018] The cosine phase modulation signal and the multi-phase segmented modulation signal form a composite phase modulation signal, and the composite phase modulation signal is:

[0019] p(t m )=p1(t m )×p2(t m );

[0020] Where: p(t m ) represents a complex phase modulated signal.

[0021] Preferably, the extraction of the spectrum of the composite phase modulation signal comprises:

[0022] According to the modulation frequency f1 of the cosine phase modulation signal and the modulation frequency f2 of the multi-phase segmented modulation signal, the frequency domain of the composite phase modulation signal is obtained as:

[0023]

[0024] Among them: J n (β) represents the first-kind n-order Bessel function; B(m) is:

[0025]

[0026] Where: P represents the number of phase segments in the pulse; m represents the number of time points; j represents the imaginary part;

[0027] The spectrum of the complex phase modulated signal is calculated according to the first-kind n-order Bessel function J n (β) and B(m) are jointly weighted by amplitude.

[0028] Preferably, the formation of the multi-region composite phase interference signal includes:

[0029] The spectrum of the composite phase modulated signal in the frequency domain is extracted, and the spectrum of the composite phase modulated signal is shifted multiple times in the azimuth direction of the movement of the protected target, and the shifted multiple different spectra are used to replace the spectrum of the composite phase modulated signal in sequence to form multiple harmonic components of the composite phase modulated signal, and the multiple harmonic components are synthesized into a composite phase interference signal, thereby forming a multi-region composite phase interference signal.

[0030] Preferably, the composite phase interference signal is:

[0031]

[0032] Among them: J n (β) represents the first kind of n-th order Bessel function; f1 represents the modulation frequency of the cosine phase modulation signal; f2 represents the modulation frequency of the multi-phase segmented modulation signal; nf1+mf2 represents the spectrum offset of the composite phase interference signal.

[0033] Preferably, interfering with the SAR-GMTI system includes:

[0034] The SAR-GMTI system receives multi-region composite phase interference signals, and performs range matching filtering, range migration correction and clutter suppression on the interference signals, forming a multi-region array of false targets with different intervals along the azimuth of the protected target in the interference image, thus achieving interference with the SAR-GMTI system.

[0035] The offset of the nth false target in the azimuth dimension is:

[0036]

[0037] Wherein: nf1+mf2 represents the frequency spectrum offset of the composite phase interference signal; f1 represents the modulation frequency of the cosine phase modulation signal; f2 represents the modulation frequency of the multi-phase segmented modulation signal; γ represents the Doppler modulation frequency.

[0038] The embodiment of the present invention also provides a SAR-GMTI composite phase modulation jammer based on a phase-adjustable metasurface, comprising:

[0039] A design module, used to design a phase-controlled metasurface and install it on the target surface;

[0040] 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 cosine phase modulation and slow-time multi-phase segmented modulation on the transmission signals of the multiple regions, respectively, and obtains cosine phase modulation signals and multi-phase segmented modulation signals, respectively. The cosine phase modulation signal and the multi-phase segmented modulation signal are multiplied to obtain a composite phase modulation signal, and a composite phase modulation signal of multiple regions is formed;

[0041] The SAR-GMTI system interference module is used to generate a multi-region composite phase interference signal according to the frequency spectrum of the composite phase modulation signal, and interfere with the SAR-GMTI system through the multi-region composite phase interference signal.

[0042] An embodiment of the present invention further provides an electronic device, including a memory and a processor;

[0043] The memory is used to store computer programs;

[0044] The processor is used to implement the steps of the SAR-GMTI composite phase modulation interference method based on the phase-adjustable metasurface as described above when executing the computer program stored in the memory.

[0045] An embodiment of the present invention also provides a computer-readable storage medium for storing a computer program, which, when executed by a processor, implements the steps of the SAR-GMTI composite phase modulation interference method based on a phase-adjustable metasurface as described above.

[0046] The embodiment of the present invention provides a SAR-GMTI composite phase modulation interference method based on a phase-adjustable metasurface. Compared with the prior art, the beneficial effects thereof are as follows:

[0047] The present invention can obtain cosine phase modulation signals and multi-phase segmented modulation signals respectively through slow-time cosine phase modulation and slow-time multi-phase segmented modulation, and the two modulation signals are multiplied to obtain a composite phase modulation signal, and form a multi-region composite phase interference signal; since the cosine phase modulation signal has good phase continuity and smoothness, it can show strong robustness in the face of noise and interference, and can maintain signal integrity and recognizability in a complex environment; at the same time, the multi-phase segmented modulation signal transmits information by segmentation, so that the signal in each segment has strong anti-noise ability, thereby improving the anti-interference performance of the entire signal system, so that the anti-interference ability of the formed composite phase interference signal is greatly enhanced, so as to improve the interference accuracy of the SAR-GMTI system.

[0048] At the same time, the multi-region composite phase interference signal presents a more dispersed and unpredictable characteristic in the spectrum. The protected target can achieve better concealment effect under the detection of SAR-GMTI system. The existence of interference signal makes it difficult for the radar system to accurately extract target information from background noise, thereby improving the survivability and safety of the protected target. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of the overall process of the SAR-GMTI composite phase modulation interference method based on a phase-adjustable metasurface provided in an embodiment of the present invention;

[0050] Figure 2 A schematic diagram of a spatial interference model of a SAR-GMTI composite phase modulation interference method based on a phase-adjustable metasurface provided in an embodiment of the present invention;

[0051] Figure 3A schematic diagram of the design of a phase-adjustable metasurface for a SAR-GMTI composite phase modulation interference method based on a phase-adjustable metasurface provided in an embodiment of the present invention; (a) is a schematic diagram of a metasurface array formed, and (b) is a schematic diagram of a metasurface array test;

[0052] Figure 4 A schematic diagram of single-channel SAR imaging results without interference using the SAR-GMTI composite phase modulation interference method based on a phase-adjustable metasurface provided in an embodiment of the present invention;

[0053] Figure 5 A schematic diagram of single-channel SAR interference imaging results of the SAR-GMTI composite phase modulation interference method based on the phase-adjustable metasurface provided in an embodiment of the present invention;

[0054] Figure 6 A schematic diagram of clutter suppression results of the SAR-GMTI composite phase modulation jamming method based on the phase-adjustable metasurface provided in an embodiment of the present invention in the absence of interference;

[0055] Figure 7 A schematic diagram of clutter suppression results of the SAR-GMTI composite phase modulation jamming method based on a phase-adjustable metasurface provided in an embodiment of the present invention;

[0056] Figure 8 A schematic diagram of the moving target detection results in the absence of interference using the SAR-GMTI composite phase modulation interference method based on the phase-adjustable metasurface provided in an embodiment of the present invention;

[0057] Fig. 9 A schematic diagram of the moving target detection results of the SAR-GMTI composite phase modulation interference method based on the phase-adjustable metasurface provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0058] 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.

[0059] See also Figure 1 The embodiment of the present invention provides a SAR-GMTI composite phase modulation interference method based on a phase-adjustable metasurface, comprising the following steps:

[0060] Step 1: Design of phase-tunable metasurface.

[0061] Step 2: Establishment of a composite phase modulation signal model based on phase-adjustable metasurface.

[0062] Step 3: Construction of a multi-channel SAR-GMTI interference signal model based on phase-adjustable metasurface.

[0063] Step 4: Multi-channel SAR-GMTI processing and interference effect analysis.

[0064] The phase-adjustable metasurface design in step 1 is specifically as follows:

[0065] First, a gap metal branch structure is designed, and a lumped element, a varactor diode, is added between the metal gaps. The voltage on both sides of the varactor diode is adjusted to change the equivalent capacitance, so that the phase of the incident electromagnetic wave can be continuously changed. 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 to realize a complete two-dimensional electromagnetic metasurface array structure.

[0066] The establishment of the composite phase modulation signal model in step 2 is as follows:

[0067] Inspired by the superior interference effects of cosine phase modulation and multi-phase segmented modulation in traditional active interference methods, the present invention combines cosine phase modulation with multi-phase segmented modulation using a phase-adjustable metasurface to generate a composite phase modulation signal, the expression of which is:

[0068] p(t m )=p1(t m )×p2(t m );

[0069] Where: t m Indicates slow time; p1(t m ) and p2(t m ) represent the cosine phase modulation signal and the multi-phase segmented modulation signal, respectively:

[0070] p1(t m )=exp[jβcos(2πf1t m )];

[0071]

[0072] Where: β and f1 represent the modulation index and modulation frequency of the cosine phase modulated signal respectively; represents the convolution operation; τ,T,f2=1 / T,φ p ,P,N represent the segment duration, modulation period, modulation frequency, modulation phase, number of phase segments within the pulse, and number of repetitions of the multi-phase segment modulation signal respectively.

[0073] p(t m ) is expressed in the frequency domain as:

[0074]

[0075] Among them: J n (β) represents the first kind of n-order Bessel function, and B(m) is expressed as:

[0076]

[0077] It can be seen from the above formula that the spectrum of the composite phase modulated signal is composed of J n The “comb” spectrum is formed by jointly weighting the amplitudes of B(β) and B(m).

[0078] The construction of the multi-channel SAR-GMTI interference signal model in step 3 is as follows:

[0079] 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 height of the radar platform from the ground is H, and it flies along the 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 represents 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 at the same time; 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; in the range of 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.

[0080] The instantaneous slant range R between the i-th (i=1,2) equivalent antenna and the moving target i (t m ) is expressed as:

[0081]

[0082] Assume that the LFM signal transmitted by the SAR-GMTI system is expressed as:

[0083]

[0084] 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.

[0085] 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:

[0086]

[0087] in: represents the unmodulated moving target echo signal received by antenna i, which is expressed as:

[0088]

[0089] 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. The interference signal can be expressed in the Doppler frequency domain as:

[0090]

[0091] It can be seen that the spectrum of the interference signal is a multiple shift of the spectrum of the original echo signal in the azimuth direction, and the spectrum offset is nf1+mf2; at the same time, the amplitude of each harmonic component is affected by J n (β) and B(m) are jointly modulated; in addition to the above interference signals, the total echo signal received by the radar Also includes the echo signal generated by background clutter and system noise Echo signal It is expressed as:

[0092]

[0093] 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.

[0094] The multi-channel SAR-GMTI processing and interference effect analysis in step 4 are as follows:

[0095] 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:

[0096]

[0097] Among them: B r Indicates the transmit signal bandwidth.

[0098] 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:

[0099]

[0100] Where: γ c =-2V 2 / (λR B );Δt=d / V;B a Represents the signal Doppler bandwidth.

[0101] The relationship between the interference signals received by the two antennas can be expressed as:

[0102]

[0103] 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 the formula is:

[0104]

[0105] in: Represents residual clutter and noise caused by non-ideal factors.

[0106] The echo signal after clutter suppression is processed by azimuth matched filtering to obtain the final interference SAR-GMTI image, and its formula is:

[0107]

[0108] in:

[0109] Among them: B a represents the signal Doppler bandwidth; γ represents the Doppler modulation frequency.

[0110] It can be seen that multiple false targets are generated along the azimuth direction in the jamming SAR-GMTI image, and the offset of the mnth false target in the azimuth dimension is:

[0111]

[0112] Finally, the constant false alarm rate (CFAR) detector is used to detect moving targets.

[0113] The specific tests are:

[0114] A reference moving target RT and three protected moving targets MT1-3 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 composite phase modulated using the phase-adjustable metasurface, and the modulation parameters are set as β=1, f1=10Hz, f2=37.5Hz, φ p =0, 0.2π, 0.35π, 0.8π; the five echo signals and interference signals are processed by range-Doppler SAR imaging to obtain the unmodulated single-channel SAR imaging results and the single-channel interference imaging results, respectively. 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.

[0115] After dual-channel DPCA processing, the non-interference clutter suppression results and the modulation interference clutter suppression results are obtained, as shown in the figure. Figure 6 and Figure 7 As shown in the figure, it can be seen that after the composite phase modulation processing based on the phase-adjustable metasurface, the protected moving target MTi, (i = 1, 2, 3) can generate a string of false moving targets in the azimuth direction, and the distance and azimuth offset of each false moving target are proportional to the modulation frequency; 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. Figure 8 and Fig. 9 As shown, the interference image obtained by the present invention through composite phase modulation processing contains a false moving target string, thereby interfering with the detection and recognition of the moving target, achieving the purpose of deception interference.

[0116] The present invention utilizes a phase-adjustable metasurface to perform slow-time phase modulation on radar signals to generate multi-channel SAR composite phase interference signals; by performing range-Doppler imaging and clutter suppression processing on the multi-channel SAR composite phase interference signals, theoretical analysis and experimental results show that the present invention generates a string of false moving targets with flexibly controllable azimuth positions and amplitudes in the azimuth direction, has a highly flexible, high-fidelity, low-cost SAR-GMTI interference effect, and has strong practical application value.

[0117] 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. SAR-GMTI composite phase modulation jamming method based on phase-adjustable metasurface, characterized in that: The following steps are involved: 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. The phase-controlled metasurface performs slow-time cosine phase modulation and slow-time multi-phase segmented modulation on the transmission signals of the multiple regions, respectively, obtains cosine phase modulation signals and multi-phase segmented modulation signals, multiplies the cosine phase modulation signals and the multi-phase segmented modulation signals to obtain composite phase modulation signals, and forms composite phase modulation signals of multiple regions; A multi-region composite phase interference signal is generated according to the frequency spectrum of the composite phase modulation signal, and the SAR-GMTI system is interfered by the multi-region composite phase interference signal.

2. The SAR-GMTI composite phase modulation interference method based on phase-adjustable metasurface according to claim 1 is characterized in that: The formation of the composite phase modulated signal comprises: 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 cosine phase modulation and slow-time multi-phase segmented modulation, respectively, to obtain a cosine phase modulation signal and a multi-phase segmented modulation signal, respectively; The cosine phase modulation signal is: p1(t m )=exp[jβcos(2πf1t m )]; Where: p1(t m ) represents a cosine phase modulated signal; t m represents slow time; β and f1 represent the modulation index and modulation frequency of the cosine phase modulation signal respectively; The multi-phase segmented modulation signal is: Where: p2(t m ) represents a multi-phase segmented modulation signal; * represents a convolution operation; τ,T,f2=1 / T,φ p ,P,N respectively represent the segment duration, modulation period, modulation frequency, modulation phase, number of phase segments within the pulse, and number of repetitions of the multi-phase segment modulation signal; The cosine phase modulation signal and the multi-phase segmented modulation signal form a composite phase modulation signal, and the composite phase modulation signal is: p(t m )=p1(t m )×p2(t m ); Where: p(t m ) represents a complex phase modulated signal.

3. The SAR-GMTI composite phase modulation interference method based on phase-adjustable metasurface according to claim 2 is characterized in that: Extracting the spectrum of the composite phase modulated signal comprises: According to the modulation frequency f1 of the cosine phase modulation signal and the modulation frequency f2 of the multi-phase segmented modulation signal, the frequency domain of the composite phase modulation signal is obtained as: Among them: J n (β) represents the first-kind n-order Bessel function; B(m) is: Where: P represents the number of phase segments in the pulse; m represents the number of time points; j represents the imaginary part; The spectrum of the complex phase modulated signal is calculated according to the first-kind n-order Bessel function J n (β) and B(m) are jointly weighted by amplitude.

4. The SAR-GMTI composite phase modulation interference method based on phase-adjustable metasurface according to claim 3 is characterized in that: The formation of the multi-region composite phase interference signal includes: The spectrum of the composite phase modulated signal in the frequency domain is extracted, and the spectrum of the composite phase modulated signal is shifted multiple times in the azimuth direction of the movement of the protected target, and the shifted multiple different spectra are used to replace the spectrum of the composite phase modulated signal in sequence to form multiple harmonic components of the composite phase modulated signal, and the multiple harmonic components are synthesized into a composite phase interference signal, thereby forming a multi-region composite phase interference signal.

5. The SAR-GMTI composite phase modulation interference method based on phase-adjustable metasurface according to claim 4 is characterized in that: The composite phase interference signal is: Among them: J n (β) represents the first kind of n-th order Bessel function; f1 represents the modulation frequency of the cosine phase modulation signal; f2 represents the modulation frequency of the multi-phase segmented modulation signal; nf1+mf2 represents the spectrum offset of the composite phase interference signal.

6. The SAR-GMTI composite phase modulation interference method based on phase-adjustable metasurface according to claim 5 is characterized in that: The interference to the SAR-GMTI system includes: The SAR-GMTI system receives multi-region composite phase interference signals, and performs range matching filtering, range migration correction and clutter suppression on the interference signals, forming a multi-region array of false targets with different intervals in the azimuth direction of the protected target in the interference image, thereby achieving interference with the SAR-GMTI system. The offset of the nth false target in the azimuth dimension is: Wherein: nf1+mf2 represents the frequency spectrum offset of the composite phase interference signal; f1 represents the modulation frequency of the cosine phase modulation signal; f2 represents the modulation frequency of the multi-phase segmented modulation signal; γ represents the Doppler modulation frequency.

7. SAR-GMTI composite phase 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 cosine phase modulation and slow-time multi-phase segmented modulation on the transmission signals of the multiple regions, respectively, and obtains cosine phase modulation signals and multi-phase segmented modulation signals, respectively. The cosine phase modulation signal and the multi-phase segmented modulation signal are multiplied to obtain a composite phase modulation signal, and a composite phase modulation signal of multiple regions is formed; The SAR-GMTI system interference module is used to generate a multi-region composite phase interference signal according to the frequency spectrum of the composite phase modulation signal, and interfere with the SAR-GMTI system through the multi-region composite phase interference signal.

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 composite phase 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 composite phase modulation interference method based on a phase-adjustable metasurface as described in any one of claims 1 to 6.

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