CN104898098B - Multi-receiver deception jamming method aiming at circumferential SAR - Google Patents

Abstract

The invention discloses a multi-receiver deception jamming method aiming at a circumferential SAR. The method comprises the following steps of: arranging a jammer J in a circumferential SAR observation scene, calculating a circumferential SAR echo signal sJ(tr, ta) intercepted by the jammer, carrying out time-delay and phase modulation on the circumferential SAR echo signal, generating a false point target F, and calculating a false point target signal sF (tr, ta) according to an instant slope distance difference between the false point target and the jammer; (2) arranging I receivers in the circumferential SAR observation scene, determining the number of the receivers according to the instant slope distance difference between the No.i receiver and the jammer, constructing and solving a linear equation group, obtaining a coordinate actual value of the jammer and the instant slope distance actual value from the jammer to the circumferential SAR, and calculating a deception jamming signal of the false point target F; and (3) generating M false point targets in the circumferential SAR observation scene, solving and forwarding deception jamming signals of the M false point targets, and realizing the deception jamming to the circumferential SAR.

Description

Multi-receiver deception jamming method for circumferential SAR

Technical Field

The invention belongs to the technical field of radar signal processing, and particularly relates to a multi-receiver deception jamming method for a circular Synthetic Aperture Radar (SAR).

Background

The circumferential synthetic aperture radar (circumferential SAR) is a new working mode of the SAR, and plays an important role in the fields of island investigation, geological exploration, rescue and the like. The circular SAR has great significance for the detector; however, for the detected party, especially in the military field, the circular SAR can acquire more information of the detected party, thereby causing serious threat to the detected party, and therefore, the information of the detected party itself needs to be protected by some means. The method mainly comprises suppression type interference and deception type interference, wherein the suppression type interference has high requirement on the power of an interference machine; the power requirement of the deceptive jamming on the jamming machine is reduced, the SAR system is interfered in a mode of simulating radar echo or echo forwarding and the like, so that a false scene appears in an imaging result of the opposite side, and the jamming effect of 'falsely and falsely' is achieved, so that the information of the own side is protected, and the deceptive jamming gradually becomes an important direction in the research of the SAR system jamming method.

Scholars have achieved a number of valuable research efforts in terms of deceptive jamming. Considering the situation that a synthetic aperture radar platform has motion errors in the 'false scene SAR deception jamming technology and real-time analysis' (academic report of Western electronic technology university, 2009,36(5): 813-; in Leiwei, Lidianun and the like, the influence of radar positioning errors on interference effects is analyzed in the research of synthetic aperture radar interference methods based on false scenes (system engineering and electronic technology, 2005,27(10): 1741-; a high-efficiency deception jamming fast algorithm is provided in a 'fast algorithm for geometric target deception jamming of SAR' (modern radar, 2006,28(2):24-27) by the Gangrong and the Wangjian, and the calculation amount required for implementing the deception jamming is greatly reduced.

The existing deceptive interference research mainly aims at the interference protection of the strip SAR, the deceptive interference effect depends on the precision of a reconnaissance system to a great extent, the circular SAR is difficult to obtain due to track parameters (circle center, radius, motion error and the like), and the conventional method for obtaining the motion parameters through solving an analytic expression to carry out interference is no longer suitable for the interference of the circular SAR.

Disclosure of Invention

In view of the above disadvantages of the prior art, the present invention aims to provide a multi-receiver deception jamming method for a circular SAR, which directly solves the parameter integrity of the circular SAR system from the slant range difference of the multi-receiver without detecting the specific parameter information of the circular SAR, thereby achieving good deception jamming for the circular SAR.

In order to achieve the technical purpose, the invention adopts the following technical scheme.

A multi-receiver spoofing interference method for circular SAR, comprising the steps of:

step 1, firstly, an interference machine J is arranged in a circumferential SAR observation scene, and the transient from the interference machine to the circumferential SAR is established according to the position of the interference machine J in the circumferential SAR observation sceneTime slope distance R_J(t_a) (ii) a Then, according to the instantaneous slope distance R from the jammer to the circumference SAR_J(t_a) Determining a circumferential SAR echo signal s intercepted by a jammer_J(t_r,t_a) (ii) a Then intercepting the circumferential SAR echo signal s by the jammer_J(t_r,t_a) Carrying out time delay and phase modulation to generate a false point target F at any position in a circumferential SAR observation scene, and establishing an instantaneous slope distance R from the false point target to the circumferential SAR according to the position of the false point target F relative to an interference machine_F(t_a) According to the instantaneous slope distance R from the false point target to the circumference SAR_F(t_a) And instantaneous slope distance R from jammer to circumference SAR_J(t_a) Calculating the instantaneous slope distance difference Delta R between the false point target and the jammer_F(t_a) (ii) a Finally, according to the instantaneous slope distance difference delta R between the false point target and the jammer_F(t_a) Determining a false point target signal s_F(t_r,t_a) (ii) a Wherein, t_rFor a fast time, t_aIs a slow time;

step 2, firstly, I receivers are arranged in a circumferential SAR observation scene, a deception jamming system is formed by the jammer and the I receivers, deception jamming is carried out on the circumferential SAR in a cooperative mode, and the instantaneous slope distance R from the ith receiver to the circumferential SAR is established_i(t_a) I1.. I; then, defining the instantaneous slope distance difference between the ith receiver and the jammer as DeltaR_i(t_a) And based on the instantaneous slope difference DeltaR between the ith receiver and the jammer_i(t_a) Determining the number of receivers by the number of unknown variables in the expression; finally, a linear equation set is constructed according to the number of the receivers, the linear equation set is solved, and the actual coordinate value of the interference machine relative to the circular SAR is obtainedAnd actual value of instantaneous slope distance from jammer to circumference SAR

Step 3, firstly, obtaining the actual coordinate value of the interference machine relative to the circular SAR according to the step 2And actual value of instantaneous slope distance from jammer to circumference SARCalculating the actual value of the instantaneous slope distance difference between the false point target F and the jammerThen, according to the actual value of the instantaneous slope distance difference between the false point target F and the jammerDetermining spurious point target F spoofing interference signals

Step 4, referring to the step 1, generating M false point targets at any position in the circumferential SAR observation scene to form a false scene; and obtaining the actual coordinate value of the interference machine relative to the circular SAR according to the step 2And actual value of instantaneous slope distance from jammer to circumference SARCalculating actual values of instantaneous slope distance differences between the M false point targets and the jammers, and determining deception jamming signals corresponding to the M false point targets; and then, transmitting the deception jamming signals of the M false point targets to realize deception jamming of the circumferential SAR.

The circumference SAR deception jamming method based on the multi-receiver has the advantages that the specific parameter information of the circumference SAR does not need to be detected, the parameter integrity of the circumference SAR system is directly solved from the slant range difference of the multi-receiver, and then the deception jamming is realized on the circumference SAR; compared with the method for directly measuring the interference of various parameters of the circular SAR on the circular SAR, the method has higher measurement precision and algorithm stability; under the condition that the circular SAR carrier platform has motion errors, the method can still generate satisfactory interference effect.

Drawings

The invention is described in further detail below with reference to the following description of the drawings and the detailed description.

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a plot of a point target location distribution for a simulation experiment;

FIG. 3a is a diagram of the imaging result of a real scene point target;

FIG. 3b is a diagram of the imaging result of a false scene point target;

FIG. 4a is a point-to-point target P of a real scene and a false scene when there is no motion error in the carrier₁A resolution contrast plot along the X-axis with X-axis distance in meters on the abscissa and amplitude (dB) on the ordinate;

FIG. 4b is a point-to-point target P of a real scene and a false scene when there is no motion error in the carrier₁A resolution contrast plot along the Y-axis with the abscissa as the Y-axis distance in meters and the ordinate as the amplitude in (dB);

FIG. 4c is a point-to-point target P of a real scene and a false scene when there is no motion error in the carrier₁A resolution contrast plot along the Z-axis with height in meters on the abscissa and amplitude (dB) on the ordinate;

FIG. 4d is a point-to-point target P of a real scene and a false scene when there is no motion error in the carrier₄A resolution contrast plot along the X-axis with X-axis distance in meters on the abscissa and amplitude (dB) on the ordinate;

FIG. 4e shows the absence of movement of the carrierReal scene and false scene are to point target P when error₄A resolution contrast plot along the Y-axis with the abscissa as the Y-axis distance in meters and the ordinate as the amplitude in (dB);

FIG. 4f is a point-to-point target P of a real scene and a false scene when there is no motion error in the carrier₄A resolution contrast plot along the Z-axis with height in meters on the abscissa and amplitude (dB) on the ordinate;

FIG. 5a shows a real scene point-to-point target P when there is motion error in the carrier₁A resolution contrast plot along the X-axis with X-axis distance in meters on the abscissa and amplitude (dB) on the ordinate;

FIG. 5b is a false scene point-to-point target P when there is motion error in the carrier₁A resolution contrast plot along the X-axis with X-axis distance in meters on the abscissa and amplitude (dB) on the ordinate;

FIG. 5c shows the real scene to point target P when there is motion error in the carrier₁A resolution contrast plot along the Y-axis with the abscissa as the Y-axis distance in meters and the ordinate as the amplitude in (dB);

FIG. 5d is a point-to-point target P of a false scene when there is motion error in the carrier₁A resolution contrast plot along the Y-axis with the abscissa as the Y-axis distance in meters and the ordinate as the amplitude in (dB);

FIG. 5e is the real scene point-to-point target P when there is motion error in the carrier₁A resolution contrast plot along the Z-axis with height in meters on the abscissa and amplitude (dB) on the ordinate;

FIG. 5f is a point-to-point target P of a false scene when there is motion error in the carrier₁A resolution contrast plot along the Z-axis with height in meters on the abscissa and amplitude (dB) on the ordinate;

Detailed Description

Referring to fig. 1, a multi-receiver spoofing interference method for a circular SAR of the present invention includes the following steps:

step 1, firstly, an interference machine J is arranged in a circumferential SAR observation scene, and an instantaneous slant distance R from the interference machine to a circumferential SAR is established according to the position of the interference machine J in the circumferential SAR observation scene_J(t_a) (ii) a Then, according to the instantaneous slope distance R from the jammer to the circumference SAR_J(t_a) Determining a circumferential SAR echo signal s intercepted by a jammer_J(t_r,t_a) (ii) a Then intercepting the circumferential SAR echo signal s by the jammer_J(t_r,t_a) Carrying out time delay and phase modulation to generate a false point target F at any position in a circumferential SAR observation scene, and establishing an instantaneous slope distance R from the false point target to the circumferential SAR according to the position of the false point target F relative to an interference machine_F(t_a) According to the instantaneous slope distance R from the false point target to the circumference SAR_F(t_a) And instantaneous slope distance R from jammer to circumference SAR_J(t_a) Calculating the instantaneous slope distance difference Delta R between the false point target and the jammer_F(t_a) (ii) a Finally, according to the instantaneous slope distance difference delta R between the false point target and the jammer_F(t_a) Determining a false point target signal s_F(t_r,t_a)。

The specific substeps of step 1 are:

1.1 setting a circular SAR carrier platform to do uniform circular motion on a plane with the height of H, wherein the radius of the uniform circular motion is r, and the angular speed of the uniform circular motion is omega; setting an interference machine J in a circumferential SAR observation scene, wherein the coordinate of the interference machine J relative to the circumferential SAR is (x)_J,y_J,z_J) Then the instantaneous slant distance R from the jammer to the circumference SAR_J(t_a) Is composed of

Wherein, t_aIs a slow time;

1.2 instantaneous slope distance R from jammer to circumference SAR_J(t_a) Determining the circular SAR echo signal intercepted by the jammer as s_J(t_r,t_a) The expression is as follows:

wherein, t_rFor fast time, σ is the scattering coefficient of the point target, c denotes the speed of light, f_cIs the carrier frequency, gamma is the frequency modulation rate of the linear frequency modulation signal; a (-) is the distance envelope of the chirp signal, expressed as:

wherein, T_pIs the pulse width of the chirp signal;

1.3 pairs of circumferential SAR echo signals s intercepted by jammers_J(t_r,t_a) Carrying out time delay and phase modulation to generate a false point target F at any position in a circumferential SAR observation scene, wherein the coordinate of the false point target F relative to the jammer is (x)_F,y_F,z_F) Then the instantaneous slope distance from the false point target to the circular SAR is according to R_F(t_a) Comprises the following steps:

definition of Δ R_F(t_a) Is the instantaneous slope distance difference, Δ R, between the false point target and the jammer_F(t_a)＝R_F(t_a)-R_J(t_a) The specific expression is as follows:

1.4 based on the instantaneous slope distance difference Delta R between the false point target and the jammer_F(t_a) Determining a false point target signal s_F(t_r,t_a) The expression is as follows:

wherein σ_Fλ is the signal wavelength, and (·) represents the impulse function, which is the scattering coefficient of the decoy point target.

Step 2, firstly, I receivers are arranged in a circumferential SAR observation scene, a deception jamming system is formed by the jammer and the I receivers, deception jamming is carried out on the circumferential SAR in a cooperative mode, and the instantaneous slope distance R from the ith receiver to the circumferential SAR is established_i(t_a) I1.. I; then, defining the instantaneous slope distance difference between the ith receiver and the jammer as DeltaR_i(t_a) And based on the instantaneous slope difference DeltaR between the ith receiver and the jammer_i(t_a) Determining the number of receivers by the number of unknown variables in the expression; finally, a linear equation set is constructed according to the number of the receivers, the linear equation set is solved, and the coordinate actual value of the jammer is obtainedAnd actual value of instantaneous slope distance from jammer to circumference SAR

The specific substeps of step 2 are:

2.1 set I receivers in the circumferential SAR observation scene, the coordinate of the ith receiver relative to the jammer is (delta x)_i,Δy_i,Δz_i) The coordinates of which are known, establishing the instantaneous slope R of the ith receiver to the circumferential SAR_i(t_a) The expression is as follows:

2.2 Definitions of Δ R_i(t_a) Is the instantaneous slope difference, Δ R, between the ith receiver and the jammer_i(t_a)＝R_i(t_a)-R_J(t_a) The specific expression is as follows:

let rcos ω t_a-x_J＝x₀，rsinωt_a-y_J＝y₀，H-z_J＝z₀And the instantaneous slope distance R from the jammer to the circumference SAR_J(t_a) And is abbreviated as R_JInstantaneous slope difference Δ R between the ith receiver and jammer_i(t_a) Abbreviated as Δ R_iThen the instantaneous slope distance difference Δ R between the ith receiver and the jammer_i(t_a) The specific expression of (A) is summarized as follows:

wherein,

to pairThe two sides of the equation (a) are squared and are arranged into the following expression:

wherein x is₀、y₀、z₀、R_JIf the number of the unknown variables is 4, 4 receivers are arranged in the circumferential SAR observation scene;

2.3 set 4 receivers in the circumferential SAR observation scene, according to step 2.2, construct the linear equation system as follows:

wherein (Δ x)_i,Δy_i,Δz_i) Representing the coordinates of the ith receiver relative to the jammer, Δ R_iRepresenting the instantaneous slope difference, R, between the ith receiver and the jammer_JThe instantaneous slant range from the jammer to the circumferential SAR;

2.4, the system of linear equations in step 2.3 is simplified to AC ═ Δ, where a is the coefficient matrix, C is the column vector consisting of 4 unknown variables, and Δ skew measurement matrix, then the solution of the system of linear equations AC ═ Δ is expressed as:

C^*＝A^-1Δ

wherein A is^-1Represents the inverse of the coefficient matrix a,the actual value of the instantaneous slope distance from the jammer to the circular SAR isAnd the actual coordinate value of the interference machine relative to the circular SAR is

Step 3, first, the rootThe actual coordinate value of the interference machine relative to the circular SAR obtained according to the step 2And actual value of instantaneous slope distance from jammer to circumference SARCalculating the actual value of the instantaneous slope distance difference between the false point target F and the jammerThen, according to the actual value of the instantaneous slope distance difference between the false point target F and the jammerDetermining spurious point target F spoofing interference signals

The specific substeps of step 3 are:

3.1 obtaining the actual coordinate value of the interference machine relative to the circular SAR according to the step 2And actual value of instantaneous slope distance from jammer to circumference SARCalculating the actual value of the instantaneous slope distance difference between the false point target F and the jammerComprises the following steps:

wherein (x)_F,y_F,z_F) Coordinates of the target F of the false point relative to the jammer;

3.2 actual value based on instantaneous slope difference between false point target F and jammerDetermining spurious point target F spoofing interference signalsComprises the following steps:

wherein,is the actual value of the instantaneous slope difference between the false point target F and the jammer.

Step 4, referring to the step 1, generating M false point targets at any position in the circumferential SAR observation scene to form a false scene; and obtaining the actual coordinate value of the interference machine relative to the circular SAR according to the step 2And actual value of instantaneous slope distance from jammer to circumference SARCalculating actual values of instantaneous slope distance differences between the M false point targets and the jammers, and determining deception jamming signals corresponding to the M false point targets; and then, transmitting the deception jamming signals of the M false point targets to realize deception jamming of the circumferential SAR.

The effects of the present invention can be further explained by the following simulation experiments.

1) Simulation conditions are as follows:

the radar working mode is a circular positive side SAR mode, the carrier frequency is 9.6GHz, the transmission signal bandwidth is 150MHz, the pulse width is 1e-6s, the angular velocity is 1.25rad/s, the pulse repetition frequency is 100Hz, the azimuth aperture is 1m, the flying height is 300m, the uniform circular motion radius is 400m, the coordinates of the jammer are (0,0,0), and four receivers A₁To A₄Are (1,2,0), (-1,3,4), (0,1,1) and (2, -3,1), respectively, in meters.

2) Simulation content and analysis:

FIG. 2 is a point target position distribution diagram of a simulation experiment, in which 4 point targets P are set in a simulation scene₁-P₄Coordinates (0,4, -4), (-4, -2, -4), (4, -2, -4) and (0,0,4), respectively, in meters; for the convenience of comparative analysis, the position of the false scene point target is set to be the same as the position of the circumferential SAR observation scene (real scene) point target.

Fig. 3a and 3b are an imaging result diagram of a real scene point object and an imaging result diagram of a false scene point object, respectively. As can be seen from fig. 3a and 3b, jammers can generate realistic false objects.

FIGS. 4 a-4 c are diagrams of the point-to-point target P of the real scene and the false scene when there is no motion error in the carrier₁Contrast plots of resolution along different directions; 4 d-4 f are point-to-point targets P for real scene and false scene when there is no motion error in the carrier₄Contrast plots of resolution along different directions; in fig. 4 a-4 f, the solid line represents the real scene and the dashed line represents the dummy scene. As can be seen from fig. 4 a-4 f, the imaging quality of the false scene point object is good.

The invention is still applicable to the situation that the carrier has motion errors, and the point target P is aligned to the real scene and the false scene when the carrier does not have motion errors as shown in FIGS. 5a to 5f₁Contrast plots of resolution along different directions; in fig. 5a, 5c and 5e, the solid line represents the real scene; in figures 5b, 5d and 5f,the dashed line represents a false scene. As can be seen from fig. 5 a-5 f, the presence of carrier motion errors leads to a degradation of the imaging quality of real scene point objects, and at the same time to a degradation of the imaging quality of false scene point objects; real scene and false scene are to point target P₁Imaging results along different directions are almost completely consistent, which shows that imaging effects of a false scene and a real scene on the point target are highly consistent, and deception jamming realized by the method has higher fidelity.

Claims (4)

1. A multi-receiver spoofing interference method for circular SAR, comprising the steps of:

step 1, firstly, an interference machine J is arranged in a circumferential SAR observation scene, and an instantaneous slant distance R from the interference machine to a circumferential SAR is established according to the position of the interference machine J in the circumferential SAR observation scene_J(t_a) (ii) a Then, according to the instantaneous slope distance R from the jammer to the circumference SAR_J(t_a) Determining a circumferential SAR echo signal s intercepted by a jammer_J(t_r，t_a) (ii) a Circumferential SAR echo signal intercepted by interference machineNumber s_J(t_r，t_a) Carrying out time delay and phase modulation to generate a false point target F at any position in a circumferential SAR observation scene, and establishing an instantaneous slope distance R from the false point target to the circumferential SAR according to the position of the false point target F relative to an interference machine_F(t_a) According to the instantaneous slope distance R from the false point target to the circumference SAR_F(t_a) And instantaneous slope distance R from jammer to circumference SAR_J(t_a) Calculating the instantaneous slope distance difference Delta R between the false point target and the jammer_F(t_a) (ii) a Finally, according to the instantaneous slope distance difference delta R between the false point target and the jammer_F(t_a) Determining a false point target signal s_F(t_r，t_a) (ii) a Wherein, t_rFor a fast time, t_aIs a slow time;

step 2, firstly, I receivers are arranged in a circumferential SAR observation scene, a deception jamming system is formed by the jammer and the I receivers, deception jamming is carried out on the circumferential SAR in a cooperative mode, and the instantaneous slope distance R from the ith receiver to the circumferential SAR is established_i(t_a) I1.. I; then, defining the instantaneous slope distance difference between the ith receiver and the jammer as DeltaR_i(t_a) And based on the instantaneous slope difference DeltaR between the ith receiver and the jammer_i(t_a) Determining the number of receivers by the number of unknown variables in the expression; finally, a linear equation set is constructed according to the number of the receivers, the linear equation set is solved, and the actual coordinate value of the interference machine relative to the circular SAR is obtainedAnd actual value of instantaneous slope distance from jammer to circumference SAR

Step 3, firstly, obtaining the actual coordinate value of the interference machine relative to the circular SAR according to the step 2And instantaneous skewing of jammers to circumferential SARFrom the actual valueCalculating the actual value of the instantaneous slope distance difference between the false point target F and the jammerThen, according to the actual value of the instantaneous slope distance difference between the false point target F and the jammerDetermining spurious point target F spoofing interference signals

Step 4, referring to the step 1, generating M false point targets at any position in the circumferential SAR observation scene to form a false scene; and obtaining the actual coordinate value of the interference machine relative to the circular SAR according to the step 2And actual value of instantaneous slope distance from jammer to circumference SARCalculating actual values of instantaneous slope distance differences between the M false point targets and the jammers, and determining deception jamming signals corresponding to the M false point targets; and then, transmitting the deception jamming signals of the M false point targets to realize deception jamming of the circumferential SAR.

2. The method for multi-receiver spoofing interference for circular SAR as claimed in claim 1, wherein said specific sub-step of step 1 is:

1.1 setting a circular SAR carrier platform to do uniform circular motion on a plane with the height of H, wherein the radius of the uniform circular motion is r, and the angular speed of the uniform circular motion is omega; setting an interference machine J in a circumferential SAR observation scene, wherein the interference machine J is opposite to a circleThe coordinate of the peripheral SAR is (x)_J，y_J，z_J) Then the instantaneous slant distance R from the jammer to the circumference SAR_J(t_a) Is composed of

$R_J\left(t_a\right)=\sqrt{{(r{\mathrm{cos\ωt}}_a-x_J)}^2+{(r{\mathrm{sin\ωt}}_a-y_J)}^2+{(H-z_J)}^2}$

Wherein, t_aIs a slow time;

1.2 instantaneous slope distance R from jammer to circumference SAR_J(t_a) Determining the circular SAR echo signal intercepted by the jammer as s_J(t_r，t_a) The expression is as follows:

$s_J(t_r,t_a)=\mathrm{\σ}a(t_r-\frac{2R_J\left(t_a\right)}{c})\exp \left\{j2{\mathrm{\πf}}_c(t_r-\frac{2R_J\left(t_a\right)}{c})\right\}\exp \left\{j\mathrm{\π}\mathrm{\γ}{(t_r-\frac{2R_J\left(t_a\right)}{c})}^2\right\}$

wherein, t_rFor fast time, σ is the scattering coefficient of the point target, c denotes the speed of light, f_cIs the carrier frequency, gamma is the frequency modulation rate of the linear frequency modulation signal; a (-) is the distance envelope of the chirp signal, expressed as:

$a\left(t_r\right)=\left\{\begin{array}{cc}1,& \left|t_r\right|\≤T_p/2\\ 0,& \left|t_r\right|>T_p/2\end{array}\right.,$

wherein, T_pIs the pulse width of the chirp signal;

1.3 pairs of circumferential SAR echo signals s intercepted by jammers_J(t_r，t_a) Carrying out time delay and phase modulation to generate a false point target F at any position in a circumferential SAR observation sceneThe coordinates of the point target F relative to the jammer are (x)_F，y_F，z_F) Then the instantaneous slope distance R of the false point target to the circular SAR_F(t_a) Comprises the following steps:

$R_F\left(t_a\right)=\sqrt{{(r{\mathrm{cos\ωt}}_a-x_J-x_F)}^2+{(r{\mathrm{sin\ωt}}_a-y_J-y_F)}^2+{(H-z_J-z_F)}^2};$

definition of Δ R_F(t_a) Is falseInstantaneous slope distance difference, Δ R, between point target and jammer_F(t_a)＝R_F(t_a)-R_J(t_a) The specific expression is as follows:

${\mathrm{\ΔR}}_F\left(t_a\right)=\sqrt{{(r{\mathrm{cos\ωt}}_a-x_J-x_F)}^2+{(r{\mathrm{sin\ωt}}_a-y_J-y_F)}^2+{(H-z_J-z_F)}^2}-R_J\left(t_a\right);$

1.4 based on the instantaneous slope distance difference Delta R between the false point target and the jammer_F(t_a) Determining a false point target signal s_F(t_r，t_a) The expression is as follows:

$s_F(t_r,t_a)=s_J(t_r,t_a)\[{\mathrm{\σ}}_F\mathrm{\δ}(t_r-\frac{2{\mathrm{\ΔR}}_F\left(t_a\right)}{c})\exp \left\{j\frac{4\mathrm{\π}}{\mathrm{\λ}}{\mathrm{\ΔR}}_F\left(t_a\right)\right\}\]$

wherein σ_Fλ is the signal wavelength, and (·) represents the impulse function, which is the scattering coefficient of the decoy point target.

3. The method for multi-receiver spoofing interference for circular SAR as claimed in claim 2, wherein said step 2 is specifically sub-steps of:

2.1 set I receivers in the circumferential SAR observation scene, the coordinate of the ith receiver relative to the jammer is (delta x)_i，Δy_i，Δz_i) The coordinates of which are known, establishing the instantaneous slope R of the ith receiver to the circumferential SAR_i(t_a) The expression is as follows:

$R_i\left(t_a\right)=\sqrt{{(r{\mathrm{cos\ωt}}_a-x_J-{\mathrm{\Δx}}_i)}^2+{(r{\mathrm{sin\ωt}}_a-y_J-{\mathrm{\Δy}}_i)}^2+{(H-z_J-{\mathrm{\Δz}}_i)}^2};$

2.2 Definitions of Δ R_i(t_a) Is the instantaneous slope difference, Δ R, between the ith receiver and the jammer_i(t_a)＝R_i(t_a)-R_J(t_a) The specific expression is as follows:

${\mathrm{\ΔR}}_i\left(t_a\right)=\sqrt{{(r{\mathrm{cos\ωt}}_a-x_J-{\mathrm{\Δx}}_i)}^2+{(r{\mathrm{sin\ωt}}_a-y_J-{\mathrm{\Δy}}_i)}^2+{(H-z_J-{\mathrm{\Δz}}_i)}^2}-R_J\left(t_a\right);$

let rcos ω t_a-x_J＝x₀，rsinωt_a-y_J＝y₀，H-z_J＝z₀And the instantaneous slope distance R from the jammer to the circumference SAR_J(t_a) And is abbreviated as R_JInstantaneous slope difference Δ R between the ith receiver and jammer_i(t_a) Abbreviated as Δ R_iThen the instantaneous slope distance difference Δ R between the ith receiver and the jammer_i(t_a) The specific expression of (A) is summarized as follows:

${\mathrm{\ΔR}}_i+R_J=\sqrt{{(x_0-{\mathrm{\Δx}}_i)}^2+{(y_0-{\mathrm{\Δy}}_i)}^2+{(z_0-{\mathrm{\Δz}}_i)}^2},$

wherein,

to pairThe two sides of the equation (a) are squared and are arranged into the following expression:

${\mathrm{\Δx}}_i{x}_0+{\mathrm{\Δy}}_i{y}_0+{\mathrm{\Δz}}_i{z}_0+{\mathrm{\ΔR}}_i{R}_J=\frac{{\mathrm{\Δx}}_i^2+{\mathrm{\Δy}}_i^2+{\mathrm{\Δz}}_i^2-{\mathrm{\ΔR}}_i^2}{2}$

wherein x is₀、y₀、z₀、R_JIf the number of the unknown variables is 4, 4 receivers are arranged in the circumferential SAR observation scene;

2.3 set 4 receivers in the circumferential SAR observation scene, according to step 2.2, construct the linear equation system as follows:

$\left[\begin{array}{cccc}{\mathrm{\Δx}}_1& {\mathrm{\Δy}}_1& {\mathrm{\Δz}}_1& {\mathrm{\ΔR}}_1\\ {\mathrm{\Δx}}_2& {\mathrm{\Δy}}_2& {\mathrm{\Δz}}_2& {\mathrm{\ΔR}}_2\\ {\mathrm{\Δx}}_3& {\mathrm{\Δy}}_3& {\mathrm{\Δz}}_3& {\mathrm{\ΔR}}_3\\ {\mathrm{\Δx}}_4& {\mathrm{\Δy}}_4& {\mathrm{\Δz}}_4& {\mathrm{\ΔR}}_4\end{array}\right]\left[\begin{array}{c}{x}_0\\ y_0\\ z_0\\ R_J\end{array}\right]=\left[\begin{array}{c}({\mathrm{\Δx}}_1^2+{\mathrm{\Δy}}_1^2+{\mathrm{\Δz}}_1^2-{\mathrm{\ΔR}}_1^2)/2\\ ({\mathrm{\Δx}}_2^2+{\mathrm{\Δy}}_2^2+{\mathrm{\Δz}}_2^2-{\mathrm{\ΔR}}_2^2)/2\\ ({\mathrm{\Δx}}_3^2+{\mathrm{\Δy}}_3^2+{\mathrm{\Δz}}_3^2-{\mathrm{\ΔR}}_3^2)/2\\ ({\mathrm{\Δx}}_4^2+{\mathrm{\Δy}}_4^2+{\mathrm{\Δz}}_4^2-{\mathrm{\ΔR}}_4^2)/2\end{array}\right]$

wherein (Δ x)_i，Δy_i，Δz_i) Representing the coordinates of the ith receiver relative to the jammer, Δ R_iRepresenting the instantaneous slope difference, R, between the ith receiver and the jammer_JThe instantaneous slant range from the jammer to the circumferential SAR;

2.4, the system of linear equations in step 2.3 is simplified to AC ═ Δ, where a is the coefficient matrix, C is the column vector of 4 unknown variables, and Δ is the skew measurement matrix, then the solution of the system of linear equations AC ═ Δ is expressed as:

C^*＝A^-1Δ

wherein A is^-1Represents the inverse of the coefficient matrix a,the actual value of the instantaneous slope distance from the jammer to the circular SAR isAnd the actual coordinate value of the interference machine relative to the circular SAR is

4. The method for multi-receiver spoofing interference for circular SAR as claimed in claim 2, wherein said step 3 is specifically sub-steps of:

3.1 obtaining the actual coordinate value of the interference machine relative to the circular SAR according to the step 2And actual value of instantaneous slope distance from jammer to circumference SARCalculating the actual value of the instantaneous slope distance difference between the false point target F and the jammerComprises the following steps:

${\mathrm{\ΔR}}_F^{*}\left(t_a\right)=\sqrt{{(x_0^{*}-x_F)}^2+{(y_0^{*}-y_F)}^2+{(z_0^{*}-z_F)}^2}-R_J^{*}$

wherein (x)_F，y_F，z_F) Coordinates of the target F of the false point relative to the jammer;

3.2 actual value based on instantaneous slope difference between false point target F and jammerDetermining spurious point target F spoofing interference signalsComprises the following steps:

$s_F^{*}(t_r,t_a)=s_J(t_r,t_a)\[{\mathrm{\σ}}_F\mathrm{\δ}(t_r-\frac{2{\mathrm{\ΔR}}_F^{*}\left(t_a\right)}{c})\exp \left\{j\frac{4\mathrm{\π}}{\mathrm{\λ}}{\mathrm{\ΔR}}_F^{*}\left(t_a\right)\right\}\]$

wherein,targeting F and interference for false pointsActual value of instantaneous slope difference between machines.