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

A kind of multi-receiver cheating interference method for circumference SAR

Technical field

Circumferential synthetic aperture radar (SAR) is directed to the invention belongs to Radar Signal Processing Technology field, more particularly to one kind Multi-receiver cheating interference method.

Background technology

Circumferential synthetic aperture radar (circumference SAR) is a kind of emerging synthetic aperture radar mode of operation, island investigate, The fields such as geological prospecting, rescue played an important role.Circumference SAR is significant for investigation side；So And, for by investigation side, particularly in military field by investigation side, circumference SAR can obtain by investigation side more believe Breath, so as to causing serious threat by investigation side, it is therefore desirable to protected by the information of investigation side itself by certain means.Pin To general SAR system commonly use salvo be exactly implement interference, implement interference method mainly include pressing type interference and Deceiving interference, wherein, pressing type interference is very high to jamming power requirement；And Deceiving interference will to jamming power Reduction is asked, SAR system is disturbed by the mode such as guinea pig echo or echo forwarding, gone out in the imaging results for making other side Existing false scene, reaches the interference effect of " mixing the spurious with the genuine ", so as to protect the information of one's own side, therefore Deceiving interference gradually into It is the important directions in the research of SAR system interference method.

Scholars achieve many valuable achievements in research in terms of Deceiving interference.Sun Guangcai, all peaks etc. are " false Scene SAR Cheat Jamming Techniques and real time analysis " (Xian Electronics Science and Technology University's journal, 2009,36 (5):In 813-818) There is the situation of kinematic error in view of synthetic aperture radar platform, it is proposed that a kind of reality of false scene SAR Deceiving interferences When property method, obtains deception formula falseness scene more true to nature, while ensure that the real-time of false scene generation；Li Wei, beam Pasture agriculture etc. is in " the synthetic aperture radar interference method research based on false scene " (system engineering and electronic technology, 2005,27 (10):Influence of the radar fix error to interference effect is analyzed in 1741-1766), using the method for configuration of jammers, is solved The problem being likely encountered during false deceptive scene jamming；Gan Rongbing, Wang Jianguo are " to the fast of the geometry target cheating interference of SAR The short-cut counting method " (modern radar, 2006,28 (2):A kind of efficient cheating interference fast algorithm is proposed in 24-27), is greatly reduced Amount of calculation needed for implementing cheating interference.

Above-mentioned existing Deceiving interference studies the interference protection primarily directed to stripmap SAR, and cheating interference effect is very The precision of reconnaissance system is depended in big degree, and circumference SAR is difficult to because of its flight path parameter (center of circle, radius and kinematic error etc.) Obtain, conventional obtains exercise parameter by solving analytical expression so as to the method disturbed, the interference to circumference SAR No longer it is applicable.

The content of the invention

For the deficiency of above-mentioned prior art, it is an object of the invention to propose a kind of multi-receiver for circumference SAR Cheating interference method, the method need not scout the design parameter information of circumference SAR, directly be asked from the oblique distance difference of multi-receiver The parameter entirety of circumference SAR system is solved, good Deceiving interference is realized to circumference SAR.

To realize above-mentioned technical purpose, the present invention takes following technical scheme to be achieved.

A kind of multi-receiver cheating interference method for circumference SAR, it is characterised in that comprise the following steps：

Step 1, first, sets jammer J, and observed in circumference SAR according to jammer J in circumference SAR observation scenes Position in scene, sets up jammer to the instantaneous oblique distance R of circumference SAR_J(t_a)；Then, according to the wink of jammer to circumference SAR When oblique distance R_J(t_a) determine the circumference SAR echo signal s that jammer is intercepted and captured_J(t_r,t_a)；The circumference SAR that jammer is intercepted and captured is returned again Ripple signal s_J(t_r,t_a) enter line delay and phase-modulation, produce the false point target of the optional position in circumference SAR observation scenes F, and false point target to the instantaneous oblique distance R of circumference SAR is set up relative to the position of jammer according to false point target F_F(t_a), According to the instantaneous oblique distance R of false point target to circumference SAR_F(t_a) and jammer to circumference SAR instantaneous oblique distance R_J(t_a) calculate empty Instantaneous oblique distance difference Δ R between false point target and jammer_F(t_a)；Finally, according to the instantaneous oblique distance between false point target and jammer Difference Δ R_F(t_a) determine false point target signal s_F(t_r,t_a)；Wherein, t_rIt is fast time, t_aIt is the slow time；

Step 2, first, sets I receiver, jammer and I receiver composition deception in circumference SAR observation scenes EVAC, collaboration carries out cheating interference to circumference SAR, and sets up i-th receiver to the instantaneous oblique distance R of circumference SAR_i(t_a), I=1...I；Then, the instantaneous oblique distance difference defined between i-th receiver and jammer is Δ R_i(t_a), and according to i-th reception Instantaneous oblique distance difference Δ R between machine and jammer_i(t_a) number of known variables in expression formula determines the quantity of receiver；Finally, Quantity construction system of linear equations according to receiver, solves the system of linear equations, obtains reality of the jammer relative to circumference SAR Coordinate valueAnd jammer is to the instantaneous oblique distance actual value of circumference SAR

Step 3, first, according to actual coordinate value of the jammer relative to circumference SAR that step 2 is obtained And jammer is to the instantaneous oblique distance actual value of circumference SARCalculate instantaneous oblique distance of the falseness between point target F and jammer poor Actual valueThen, according to the actual value of the instantaneous oblique distance difference between false point target F and jammerReally The cheating interference signal of fixed falseness point target F

Step 4, with reference to step 1, optional position produces M false point target in circumference SAR observation scenes, constitutes false Scene；And actual coordinate value of the jammer relative to circumference SAR obtained according to step 2And jammer is arrived The instantaneous oblique distance actual value of circumference SARThe actual value of the instantaneous oblique distance difference between M false point target and jammer is calculated, and Determine the corresponding cheating interference signal of M false point target；The cheating interference signal to M false point target is forwarded again, Realize the Deceiving interference to circumference SAR.

Circumference SAR cheating interference methods based on multi-receiver of the invention, its advantage need not investigate circumference SAR Design parameter information, directly solves the parameter entirety of circumference SAR system from the oblique distance difference of multi-receiver, and then to circumference SAR realizes Deceiving interference；Parameters compared to direct measurement circumference SAR are disturbed it, and the inventive method has Certainty of measurement higher and algorithm stability；In the case where there is kinematic error in the carrier aircraft platform of circumference SAR, the inventive method Remain able to produce satisfied interference effect.

Brief description of the drawings

Explanation and specific embodiment are described in further detail to the present invention below in conjunction with the accompanying drawings.

Fig. 1 is flow chart of the invention；

Fig. 2 is the point target location map of emulation experiment；

Fig. 3 a are the imaging results figure of real scene point target；

Fig. 3 b are the imaging results figure of false scene point target；

Fig. 4 a are real scene when carrier aircraft does not exist kinematic error and false scene to point target P₁Along the resolving power pair of X-axis Than figure, abscissa is X-axis distance, and unit is rice, and the longitudinal axis is amplitude, and unit is (dB)；

Fig. 4 b are real scene when carrier aircraft does not exist kinematic error and false scene to point target P₁Along the resolving power pair of Y-axis Than figure, abscissa is Y-axis distance, and unit is rice, and the longitudinal axis is amplitude, and unit is (dB)；

Fig. 4 c are real scene when carrier aircraft does not exist kinematic error and false scene to point target P₁Along the resolving power pair of Z axis Than figure, abscissa is height, and unit is rice, and the longitudinal axis is amplitude, and unit is (dB)；

Fig. 4 d are real scene when carrier aircraft does not exist kinematic error and false scene to point target P₄Along the resolving power pair of X-axis Than figure, abscissa is X-axis distance, and unit is rice, and the longitudinal axis is amplitude, and unit is (dB)；

Fig. 4 e are real scene when carrier aircraft does not exist kinematic error and false scene to point target P₄Along the resolving power pair of Y-axis Than figure, abscissa is Y-axis distance, and unit is rice, and the longitudinal axis is amplitude, and unit is (dB)；

Fig. 4 f are real scene when carrier aircraft does not exist kinematic error and false scene to point target P₄Along the resolving power pair of Z axis Than figure, abscissa is height, and unit is rice, and the longitudinal axis is amplitude, and unit is (dB)；

Fig. 5 a for when there is kinematic error in carrier aircraft real scene to point target P₁Along the resolving power comparison diagram of X-axis, abscissa It is X-axis distance, unit is rice, and the longitudinal axis is amplitude, and unit is (dB)；

Fig. 5 b for when there is kinematic error in carrier aircraft false scene to point target P₁Along the resolving power comparison diagram of X-axis, abscissa It is X-axis distance, unit is rice, and the longitudinal axis is amplitude, and unit is (dB)；

Fig. 5 c for when there is kinematic error in carrier aircraft real scene to point target P₁Along the resolving power comparison diagram of Y-axis, abscissa It is Y-axis distance, unit is rice, and the longitudinal axis is amplitude, and unit is (dB)；

Fig. 5 d for when there is kinematic error in carrier aircraft false scene to point target P₁Along the resolving power comparison diagram of Y-axis, abscissa It is Y-axis distance, unit is rice, and the longitudinal axis is amplitude, and unit is (dB)；

Fig. 5 e for when there is kinematic error in carrier aircraft real scene to point target P₁Along the resolving power comparison diagram of Z axis, abscissa It is height, unit is rice, and the longitudinal axis is amplitude, and unit is (dB)；

Fig. 5 f for when there is kinematic error in carrier aircraft false scene to point target P₁Along the resolving power comparison diagram of Z axis, abscissa It is height, unit is rice, and the longitudinal axis is amplitude, and unit is (dB)；

Specific embodiment

A kind of reference picture 1, multi-receiver cheating interference method for circumference SAR of the invention, comprises the following steps：

Step 1, first, sets jammer J, and observed in circumference SAR according to jammer J in circumference SAR observation scenes Position in scene, sets up jammer to the instantaneous oblique distance R of circumference SAR_J(t_a)；Then, according to the wink of jammer to circumference SAR When oblique distance R_J(t_a) determine the circumference SAR echo signal s that jammer is intercepted and captured_J(t_r,t_a)；The circumference SAR that jammer is intercepted and captured is returned again Ripple signal s_J(t_r,t_a) enter line delay and phase-modulation, produce the false point target of the optional position in circumference SAR observation scenes F, and false point target to the instantaneous oblique distance R of circumference SAR is set up relative to the position of jammer according to false point target F_F(t_a), According to the instantaneous oblique distance R of false point target to circumference SAR_F(t_a) and jammer to circumference SAR instantaneous oblique distance R_J(t_a) calculate empty Instantaneous oblique distance difference Δ R between false point target and jammer_F(t_a)；Finally, according to the instantaneous oblique distance between false point target and jammer Difference Δ R_F(t_a) determine false point target signal s_F(t_r,t_a)。

The specific sub-step of step 1 is：

The carrier aircraft platform of 1.1 setting circumference SAR makees uniform circular motion, uniform circular motion in the plane that height is H Radius is r, and the angular speed of uniform circular motion is ω；Circumference SAR observation scene in set jammer J, jammer J relative to The coordinate of circumference SAR is (x_J,y_J,z_J), then instantaneous oblique distance R of the jammer to circumference SAR_J(t_a) be

Wherein, t_aIt is the slow time；

1.2 according to the instantaneous oblique distance R of jammer to circumference SAR_J(t_a), determine the circumference SAR echoes letter that jammer is intercepted and captured Number be s_J(t_r,t_a), its expression formula is：

Wherein, t_rIt it is the fast time, σ is the scattering coefficient of point target, and c represents the light velocity, f_cIt is carrier frequency, γ believes for linear frequency modulation Number frequency modulation rate；A () for linear FM signal distance to envelope, its expression formula is：

Wherein, T_pIt is the pulse width of linear FM signal；

The circumference SAR echo signal s that 1.3 pairs of jammers are intercepted and captured_J(t_r,t_a) enter line delay and phase-modulation, produce in circle The false point target F of optional position in all SAR observations scenes, false point target F is (x relative to the coordinate of jammer_F,y_F, z_F), then false point target to the instantaneous oblique distance of circumference SAR according to R_F(t_a) be：

Define Δ R_F(t_a) it is poor instantaneous oblique distance between false point target and jammer, Δ R_F(t_a)=R_F(t_a)-R_J(t_a), Its expression is：

1.4 according to the instantaneous oblique distance difference Δ R between false point target and jammer_F(t_a), it is determined that false point target signal s_F (t_r,t_a), its expression formula is：

Wherein, σ_FIt is the scattering coefficient of false point target, λ is signal wavelength, and δ () represents impulse function.

Step 2, first, sets I receiver, jammer and I receiver composition deception in circumference SAR observation scenes EVAC, collaboration carries out cheating interference to circumference SAR, and sets up i-th receiver to the instantaneous oblique distance R of circumference SAR_i(t_a), I=1...I；Then, the instantaneous oblique distance difference defined between i-th receiver and jammer is Δ R_i(t_a), and according to i-th reception Instantaneous oblique distance difference Δ R between machine and jammer_i(t_a) number of known variables in expression formula determines the quantity of receiver；Finally, Quantity construction system of linear equations according to receiver, solves the system of linear equations, obtains the coordinate actual value of jammerAnd jammer is to the instantaneous oblique distance actual value of circumference SAR

The specific sub-step of step 2 is：

2.1 set I receiver in circumference SAR observation scenes, and i-th receiver is relative to the coordinate of jammer (Δx_i,Δy_i,Δz_i), the coordinate is, it is known that setting up i-th receiver to the instantaneous oblique distance R of circumference SAR_i(t_a), its expression formula For：

2.2 define Δ R_i(t_a) it is poor instantaneous oblique distance between i-th receiver and jammer, Δ R_i(t_a)=R_i(t_a)-R_J (t_a), its expression is：

Make rcos ω t_a-x_J=x₀, rsin ω t_a-y_J=y₀, H-z_J=z₀, and by the instantaneous oblique distance of jammer to circumference SAR R_J(t_a) be abbreviated as R_J, the instantaneous oblique distance difference Δ R between i-th receiver and jammer_i(t_a) it is abbreviated as Δ R_i, then connect for i-th Instantaneous oblique distance difference Δ R between receipts machine and jammer_i(t_a) expression arrange be：

Wherein,

It is rightBoth members it is squared, arrangement be with Lower expression formula：

Wherein, x₀、y₀、z₀、R_JIt is 4 known variables, then 4 receivers is set in circumference SAR observation scenes；

2.3 set 4 receivers in circumference SAR observation scenes, according to step 2.2, then construct system of linear equations such as Under：

Wherein, (Δ x_i,Δy_i,Δz_i) represent coordinate of i-th receiver relative to jammer, Δ R_iRepresent i-th and connect Instantaneous oblique distance between receipts machine and jammer is poor, R_JIt is the instantaneous oblique distance of jammer to circumference SAR；

System of linear equations in step 2.3 is reduced to AC=Δs by 2.4, wherein, A is coefficient matrix, and C is 4 unknown changes Measure composition column vector, Δ oblique distance difference measurements matrix, then the solution of system of linear equations AC=Δs be expressed as：

C^*=A^-1Δ

Wherein, A^-1The inverse matrix of coefficient matrices A is represented,It is the solution of system of linear equations, then does Disturb machine is to the instantaneous oblique distance actual value of circumference SARAnd actual coordinate value of the jammer relative to circumference SAR is

Step 3, first, according to actual coordinate value of the jammer relative to circumference SAR that step 2 is obtained And jammer is to the instantaneous oblique distance actual value of circumference SARCalculate instantaneous oblique distance of the falseness between point target F and jammer poor Actual valueThen, according to the actual value of the instantaneous oblique distance difference between false point target F and jammerIt is determined that The cheating interference signal of false point target F

The specific sub-step of step 3 is：

3.1 actual coordinate values of the jammer relative to circumference SAR obtained according to step 2And interference Instantaneous oblique distance actual value of the machine to circumference SARCalculate the actual value of instantaneous oblique distance difference of the falseness between point target F and jammerFor：

Wherein, (x_F,y_F,z_F) it is coordinates of the false point target F relative to jammer；

3.2 according to the poor actual value of the instantaneous oblique distance between false point target F and jammerDetermine False Intersection Points mesh Mark the cheating interference signal of FFor：

Wherein,It is the actual value of the instantaneous oblique distance difference between false point target F and jammer.

Step 4, with reference to step 1, optional position produces M false point target in circumference SAR observation scenes, constitutes false Scene；And actual coordinate value of the jammer relative to circumference SAR obtained according to step 2And jammer is arrived The instantaneous oblique distance actual value of circumference SARThe actual value of the instantaneous oblique distance difference between M false point target and jammer is calculated, and Determine the corresponding cheating interference signal of M false point target；The cheating interference signal to M false point target is forwarded again, Realize the Deceiving interference to circumference SAR.

Effect of the invention can be further described by following emulation experiment.

1) simulated conditions：

Radar operation mode is circumference positive side SAR patterns, and carrier frequency is 9.6GHz, and transmitted signal bandwidth is 150MHz, pulse Width is 1e-6s, and angular speed is 1.25rad/s, and pulse recurrence frequency is 100Hz, and azimuth aperture is 1m, flying height 300m, Uniform circular motion radius is 400m, and the coordinate of jammer is (0,0,0), four receiver A₁To A₄Coordinate be respectively (1,2, 0), (- 1,3,4), (0,1,1) and (2, -3,1), unit is rice.

2) emulation content and analysis：

Fig. 2 is the point target location map of emulation experiment, and 4 point target P are set in simulating scenes₁-P₄, coordinate point Not Wei (0,4, -4), (- 4, -2, -4), (4, -2, -4) and (0,0,4), unit is rice；For ease of being analyzed, setting is empty The position of false scene point target is identical with the position of circumference SAR observation scene (real scene) point targets.

Fig. 3 a and Fig. 3 b are respectively the imaging results figure of real scene point target and the imaging results of false scene point target Figure.From Fig. 3 a and Fig. 3 b, jammer can produce false target true to nature.

Fig. 4 a- Fig. 4 c are real scene when carrier aircraft does not exist kinematic error and false scene to point target P₁Along different directions Resolving power comparison diagram；Fig. 4 d- Fig. 4 f are real scene when carrier aircraft does not exist kinematic error and false scene to point target P₄Edge The resolving power comparison diagram of different directions；In Fig. 4 a- Fig. 4 f, solid line represents real scene, and dotted line represents false scene.From Fig. 4 a- As can be seen that the image quality of false scene point target is good in Fig. 4 f.

The situation that the present invention has kinematic error in carrier aircraft stands good, and Fig. 5 a- Fig. 5 f are that carrier aircraft does not exist kinematic error When real scene and false scene to point target P₁Along the resolving power comparison diagram of different directions；In Fig. 5 a, Fig. 5 c and Fig. 5 e, solid line Represent real scene；In Fig. 5 b, Fig. 5 d and Fig. 5 f, dotted line represents false scene.As can be seen that carrier aircraft fortune from Fig. 5 a- Fig. 5 f The presence of dynamic error causes the image quality of real scene point target to decline, and also results in the image quality of false scene point target Decline；Real scene and false scene are to point target P₁Imaging results along different directions are almost completely the same, illustrate false field Scape and real scene are highly consistent to the imaging effect of point target, and the cheating interference that the inventive method is realized has higher true to nature Degree.

Claims (4)

1. a kind of multi-receiver cheating interference method for circumference SAR, it is characterised in that comprise the following steps：

Step 1, first, sets jammer J, and observe scene in circumference SAR according to jammer J in circumference SAR observation scenes In position, set up jammer to the instantaneous oblique distance R of circumference SAR_J(t_a)；Then, according to the instantaneous oblique of jammer to circumference SAR Away from R_J(t_a) determine the circumference SAR echo signal s that jammer is intercepted and captured_J(t_r, t_a)；The circumference SAR echoes letter intercepted and captured to jammer again Number s_J(t_r, t_a) enter line delay and phase-modulation, the false point target F of the optional position in circumference SAR observation scenes is produced, and False point target to the instantaneous oblique distance R of circumference SAR is set up relative to the position of jammer according to false point target F_F(t_a), according to Instantaneous oblique distance R of the false point target to circumference SAR_F(t_a) and jammer to circumference SAR instantaneous oblique distance R_J(t_a) calculate False Intersection Points Instantaneous oblique distance difference Δ R between target and jammer_F(t_a)；Finally, according to the instantaneous oblique distance difference Δ between false point target and jammer R_F(t_a) determine false point target signal s_F(t_r, t_a)；Wherein, t_rIt is fast time, t_aIt is the slow time；

Step 2, first, sets I receiver, jammer and I receiver composition cheating interference in circumference SAR observation scenes System, collaboration carries out cheating interference to circumference SAR, and sets up i-th receiver to the instantaneous oblique distance R of circumference SAR_i(t_a), i= 1...I；Then, the instantaneous oblique distance difference defined between i-th receiver and jammer is Δ R_i(t_a), and according to i-th receiver with Instantaneous oblique distance difference Δ R between jammer_i(t_a) number of known variables in expression formula determines the quantity of receiver；Finally, according to The quantity construction system of linear equations of receiver, solves the system of linear equations, obtains actual coordinate of the jammer relative to circumference SAR ValueAnd jammer is to the instantaneous oblique distance actual value of circumference SAR

Step 3, first, according to actual coordinate value of the jammer relative to circumference SAR that step 2 is obtainedAnd it is dry Disturb machine to the instantaneous oblique distance actual value of circumference SARCalculate the actual value of instantaneous oblique distance difference of the falseness between point target F and jammerThen, according to the actual value of the instantaneous oblique distance difference between false point target F and jammerDetermine False Intersection Points mesh Mark the cheating interference signal of F

Step 4, with reference to step 1, optional position produces M false point target in circumference SAR observation scenes, constitutes false field Scape；And actual coordinate value of the jammer relative to circumference SAR obtained according to step 2And jammer is to circumference The instantaneous oblique distance actual value of SARThe actual value of the instantaneous oblique distance difference between M false point target and jammer is calculated, and determines M The corresponding cheating interference signal of individual false point target；The cheating interference signal to M false point target is forwarded again, and it is right to realize The Deceiving interference of circumference SAR.

2. a kind of multi-receiver cheating interference method for circumference SAR as claimed in claim 1, it is characterised in that described The specific sub-step of step 1 is：

The carrier aircraft platform of 1.1 setting circumference SAR makees uniform circular motion, uniform circular motion radius in the plane that height is H It is r, the angular speed of uniform circular motion is ω；Jammer J is set in circumference SAR observation scenes, jammer J is relative to circumference The coordinate of SAR is (x_J, y_J, z_J), then instantaneous oblique distance R of the jammer to circumference SAR_J(t_a) be

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

Wherein, t_aIt is the slow time；

1.2 according to the instantaneous oblique distance R of jammer to circumference SAR_J(t_a), determine that the circumference SAR echo signal that jammer is intercepted and captured is s_J (t_r, t_a), its expression formula is：

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

Wherein, t_rIt it is the fast time, σ is the scattering coefficient of point target, and c represents the light velocity, f_cIt is carrier frequency, γ is linear FM signal Frequency modulation rate；A () for linear FM signal distance to envelope, its expression formula is：

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

Wherein, T_pIt is the pulse width of linear FM signal；

The circumference SAR echo signal s that 1.3 pairs of jammers are intercepted and captured_J(t_r, t_a) enter line delay and phase-modulation, produce in circumference SAR The false point target F of optional position in observation scene, false point target F are (x relative to the coordinate of jammer_F, y_F, z_F), then it is empty Instantaneous oblique distance R of the false point target to circumference SAR_F(t_a) be：

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

Define Δ R_F(t_a) it is poor instantaneous oblique distance between false point target and jammer, Δ R_F(t_a)=R_F(t_a)-R_J(t_a), its tool Body expression formula is：

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

1.4 according to the instantaneous oblique distance difference Δ R between false point target and jammer_F(t_a), it is determined that false point target signal s_F(t_r, t_a), its expression formula is：

$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_FIt is the scattering coefficient of false point target, λ is signal wavelength, and δ () represents impulse function.

3. a kind of multi-receiver cheating interference method for circumference SAR as claimed in claim 2, it is characterised in that described The specific sub-step of step 2 is：

2.1 set I receiver in circumference SAR observation scenes, and i-th receiver is (Δ x relative to the coordinate of jammer_i, Δy_i, Δ z_i), the coordinate is, it is known that setting up i-th receiver to the instantaneous oblique distance R of circumference SAR_i(t_a), its expression formula is：

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

2.2 define Δ R_i(t_a) it is poor instantaneous oblique distance between i-th receiver and jammer, Δ R_i(t_a)=R_i(t_a)-R_J(t_a), Its expression is：

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

Make rcos ω t_a-x_J=x₀, rsin ω t_a-y_J=y₀, H-z_J=z₀, and by the instantaneous oblique distance R of jammer to circumference SAR_J (t_a) be abbreviated as R_J, the instantaneous oblique distance difference Δ R between i-th receiver and jammer_i(t_a) it is abbreviated as Δ R_i, then i-th reception Instantaneous oblique distance difference Δ R between machine and jammer_i(t_a) expression arrange be：

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

Wherein,

It is rightBoth members it is squared, arrange as following table reaches Formula：

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

Wherein, x₀、y₀、z₀、R_JIt is 4 known variables, then 4 receivers is set in circumference SAR observation scenes；

2.3 set 4 receivers in circumference SAR observation scenes, according to step 2.2, then construct system of linear equations 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, Δ y_i, Δ z_i) represent coordinate of i-th receiver relative to jammer, Δ R_iRepresent i-th receiver Instantaneous oblique distance between jammer is poor, R_JIt is the instantaneous oblique distance of jammer to circumference SAR；

System of linear equations in step 2.3 is reduced to AC=Δs by 2.4, wherein, A is coefficient matrix, and C is 4 known variables groups Into column vector, Δ be oblique distance difference measurements matrix, then the solution of system of linear equations AC=Δs be expressed as：

C^*=A^-1Δ

Wherein, A^-1The inverse matrix of coefficient matrices A is represented,Be the solution of system of linear equations, then jammer Instantaneous oblique distance actual value to circumference SAR isAnd actual coordinate value of the jammer relative to circumference SAR is

4. a kind of multi-receiver cheating interference method for circumference SAR as claimed in claim 2, it is characterised in that described The specific sub-step of step 3 is：

3.1 actual coordinate values of the jammer relative to circumference SAR obtained according to step 2And jammer to circle The instantaneous oblique distance actual value of all SARCalculate the actual value of instantaneous oblique distance difference of the falseness between point target F and jammer For：

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

Wherein, (x_F, y_F, z_F) it is coordinates of the false point target F relative to jammer；

3.2 according to the poor actual value of the instantaneous oblique distance between false point target F and jammerIt is determined that falseness point target F's takes advantage of Deceive interference signalFor：

$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,It is the actual value of the instantaneous oblique distance difference between false point target F and jammer.