CN102466799A - Method for simulating interference SAR (Synthetic Aperture Radar) echo data based on POS (Posture) motion data - Google Patents

Abstract

The invention discloses a method for simulating interference SAR (Synthetic Aperture Radar) echo data based on POS (Posture) motion data, relating to an information acquiring and processing technology. POS data contain position information and posture information of an airborne platform of synthetic aperture radar (SAR). By using the method, airborne interference SAR original echo simulation based on actual motion data is realized through establishing a transformational relation between a POS coordinate system and a target scene coordinate system and fusing the motion information of the airborne platform into interference synthetic aperture radar echo calculation. The method comprises the following steps of: firstly, calculating the coordinate of a double-antenna phase center under a scene coordinate system by utilizing coordinate transformation; secondly, generating a correlation complex backscattering coefficient pair on the basis of real SAR image data; and thirdly, introducing DEM (Digital Elevation Model) topographic information, calculating two paths of original echo data according to an echo signal model, imaging and interfering to obtain an SAR image and an interference fringe.

Description

Interference SAR echo data emulation mode based on the POS exercise data

Technical field

The information of the present invention relates to is obtained and processing technology field, is a kind of interference SAR data simulation method based on POS (POSition&Orientation System) exercise data.

Background technology

Interference synthetic aperture radar (SAR) data simulation is for the checking of SAR imaging algorithm, and the research of aspects such as SAR Flame Image Process, interference disposal route has great significance.Interference SAR echo data emulation technology can be divided into time domain approach and frequency domain method at present; The maximum advantage of frequency domain method is that computing velocity is fast; Comparing shortcoming with Time-Domain algorithm is that the kinematic error model is difficult to introduce, and the phase calculation precision is lower, for the interference SAR echo simulation; Therefore phase accuracy has determined the precision of the interference SAR measurement of higher degree, adopts the method for frequency domain normally not satisfy simulation requirements.

Consider in the interference SAR data simulation of kinematic error that method commonly used at present is that the idealized kinematic error model of artificially setting up is incorporated into during echo calculates, for example single frequency sinusoidal model etc.Yet carry the influence that machine platform receives various factors in the reality, movement locus is complicated and changeable, and there is the movement locus skew of a plurality of frequencies usually in simply single-frequency shake of kinematic error.Therefore, the artificial kinematic error model of idealizing of setting up is introduced, and still can't realize the airborne interference SAR original echo emulation based on the actual motion data.

Summary of the invention

The objective of the invention is to solve the problem that exists in the prior art; A kind of interference SAR data simulation method based on the POS exercise data is provided; Year machine platform position and attitude information that movement measurement system is recorded are fused in the emulation of interference SAR echo data, are a kind of echo simulation methods based on the actual motion error information.

For achieving the above object, technical solution of the present invention is:

A kind of interference SAR echo data emulation mode based on the POS exercise data; It is through setting up the transformational relation of POS coordinate system and object scene coordinate system; The kinematic error of carrying machine platform is fused in the calculating of interference synthetic aperture radar (SAR) echo, to realize airborne interference SAR original echo emulation based on the actual motion data; May further comprise the steps: the first step, utilize coordinate transform to calculate double antenna phase center coordinate under the scene coordinate system; Second step was the basis with true SAR view data, and it is right to generate correlativity plural number backscattering coefficient; The 3rd step, introduce the DEM terrain information, calculate two-way original echo data according to echo signal model, obtain SAR image and interference fringe through forming images and interfering to handle.

Described interference SAR echo data emulation mode based on the POS exercise data, its said first step is through three coordinate system rotation, and positional information and attitude information are incorporated in the antenna phase center Coordinate Calculation, comprising:

A) actual the earth's core, the POS center rotating coordinate system coordinate conversion that comprises positional information is arrived the earth surface level coordinate system;

B) be transformed into the scene coordinate system from the earth surface level coordinate system again;

C) calculate antenna phase center at the platform coordinate system coordinate according to carrying the machine attitude information; Again it is transformed in the scene coordinate system; Obtain double antenna coordinate under the scene coordinate system; Set up the space geometry relation of radar and target, thereby in echo calculates, realized the introducing of positional information and attitude information kinematic error.

Described interference SAR echo data emulation mode based on the POS exercise data, its said second step is to utilize true SAR picture amplitude data, the plural backscattering coefficient that generates correlativity is right, comprises step:

A) with the SAR picture amplitude as main antenna backscattering coefficient amplitude, be created between [π π] and obey equally distributed random phase;

B) on the linear combination basis of main antenna backscattering coefficient real part and imaginary part, add the random number of an independent normal distribution, in order to control the correlativity between the major-minor antenna backscattering coefficient, it is right to generate auxilliary antenna backscattering coefficient: real part and imaginary part.

Described interference SAR echo data emulation mode based on the POS exercise data, the real part and the imaginary part of the auxilliary antenna backscattering coefficient of its said generation, step is following:

Get main antenna backscattering coefficient γ ₁Real part x ₁With imaginary part y ₁, x then ₁y ₁Obeying average is 0, and variance is σ ²Normal distribution and separate; Then the real part and the imaginary part of auxilliary antenna backscattering coefficient are:

x ₂＝a _xx ₁+b _xy ₁+c _xz

y ₂＝a _yx ₁+b _yy ₁

a _x＝(2ρ-1)cos(ψ _ρ)

b _x＝(2ρ-1)sin(ψ _ρ)

Wherein, a _y=-sin (ψ _ρ)

b _y＝cos(ψ _ρ)

$c_x=2\sqrt{\mathrm{\ρ}(1-\mathrm{\ρ})}$

Wherein ρ, ψ _ρBe respectively backscattering coefficient related coefficient amplitude and phase place, z is that the obedience average is that 0 variance is σ ²Normal distribution random number, and and x ₁y ₁Separate.

Described interference SAR echo data emulation mode based on the POS exercise data, the auxilliary antenna backscattering coefficient real part x of its said generation ₂With imaginary part y ₂Satisfy following three conditions:

1) x ₂, y ₂Be that the obedience average is 0, variance is σ ²The stochastic variable of normal distribution;

2) x ₂, y ₂Between related coefficient be 0;

3) main antenna backscattering coefficient x ₁+ jy ₁With auxilliary antenna backscattering coefficient x ₂+ jy ₂Between related coefficient do

J and e are respectively imaginary unit and natural constant in the expression formula.

Described interference SAR echo data emulation mode based on the POS exercise data, its said the 3rd step is according to the radar of first and second step foundation and the model space geometric and the backscattering model of target, adopts the time domain echo signal model to produce original echoed signals; Time domain echo algorithm is on the basis of radar emission continuous impulse, along with the motion of Texas tower, generates the echoed signal of each pulse.

Described interference SAR echo data emulation mode based on the POS exercise data in its said the 3rd step, comprises that step is following:

A) for the orientation to moment t _s, target scattering unit in the compute beam irradiation area (i, oblique distance R j) _Ij, and definite R _IjThe range gate m at place;

B) the adjust the distance orientation echoed signal g of a m _aAdd from point (i, the contribution of j) doppler phase:

g _a=g _a+ σ _{I, j}w _aExp (j4 π R _Ij/ λ), wherein, λ is a wavelength, w _aBe the antenna radiation pattern gain, σ _{I, j}It is backscattering coefficient;

C) repeat the a-b step, travel through all scattering points that this orientation moment radar illumination arrives, obtain orientation t constantly _sOn the orientation echoed signal g that had a few _a

D) with g _aWith range transmission signal convolution, obtained the echoed signal of a pulse, travel through the echoed signal that each orientation obtains the whole simulation scene constantly.

E) according to a)-d) going on foot the echo data that calculates double antenna respectively, pass through CS (ChirpScaling) algorithm then and carry out the SAR imaging, compensation obtains interference fringe through kinematic error again.

The inventive method has realized based on the emulation of the airborne Interference synthetic aperture radar of actual motion data (SAR) original echo.

Description of drawings

Fig. 1 is based on the geometric simulation scheme synoptic diagram of POS data;

Fig. 2 is a time domain echo generating algorithm process flow diagram;

Fig. 3 is major-minor Antenna Correlation backscattering coefficient figure, wherein:

Fig. 3 a is a main antenna backscattering coefficient map of magnitudes;

Fig. 3 b produces the auxilliary antenna backscattering coefficient amplitude that principle produces according to correlativity;

Fig. 4 is the corresponding target landform (DEM) of simulating scenes;

Fig. 5 is two passage original echo data, wherein:

Fig. 5 a is the main antenna original echo data that emulation obtains;

Fig. 5 b is auxilliary antenna echo data;

Fig. 6 handles back SAR image to echo data, wherein:

Fig. 6 a is through main antenna SAR picture amplitude figure after the CS imaging processing;

Fig. 6 b is the auxilliary antenna picture amplitude figure that obtains after handling;

The interferometric phase image that Fig. 7 emulation obtains, wherein:

Fig. 7 a is desirable interference fringe picture;

Fig. 7 b is that emulated data is not carried out the interference fringe that motion compensation obtains through imaging processing;

Fig. 7 c is the interference fringe picture through obtaining after the motion compensation;

Fig. 8 is based on the interference SAR echo data simulation flow figure of POS exercise data.

Embodiment

A kind of interference SAR data simulation method of the present invention based on the POS exercise data; Being that year machine platform position and attitude information that movement measurement system records are fused in the emulation of interference SAR echo data, is a kind of echo simulation method based on the actual motion error information.Concrete performing step is following: 1) consider to calculate the double antenna phase centre location under the condition of motion excursion and attitude disturbance.

As shown in Figure 1, can positional information and attitude information be incorporated in the antenna phase center Coordinate Calculation through three coordinate system rotation.

Several important coordinate system definition at first are described.The earth's core rotating coordinate system definition: true origin is positioned at the earth's core, and the Z axle points to earth's axis, and the X axle points to the zero degree meridian, Y axle and X, and the Z axle constitutes right-handed system; The definition of the earth surface level coordinate system: coordinate origin is the scene center of observed object early, the X axle point to geographical south to, the XY plane is the earth surface level, so the Y axle points to the due east direction, Z axle vertical ground upwards; The definition of scene coordinate system: coordinate origin is the scene center of observed object early, and the X axle points to and carries machine platform ideal flying direction, and the XY plane is the earth surface level, and Z axle vertical ground upwards.

The earth's core rotating coordinate system and the earth surface level coordinate system transformational relation can be expressed as:

E _p＝A _pg(E _g-A _pg0)

$A_{\mathrm{pg}}=\left(\begin{array}{ccc}\cos (\mathrm{\π}/2-{\mathrm{\Φ}}_0)& 0& -\sin (\mathrm{\π}/2-{\mathrm{\Φ}}_0)\\ 0& 1& 0\\ \sin (\mathrm{\π}/2-{\mathrm{\Φ}}_0)& 0& \cos (\mathrm{\π}/2-{\mathrm{\Φ}}_0)\end{array}\right)\left(\begin{array}{ccc}\cos {\mathrm{\Λ}}_0& {\sin \mathrm{\Λ}}_0& 0\\ {-\sin \mathrm{\Λ}}_0& {\cos \mathrm{\Λ}}_0& 0\\ 0& 0& 1\end{array}\right)$

E wherein _gE _pBe respectively the earth's core rotating coordinate system and the earth surface level coordinate system coordinate, A _Pg0Be the coordinate of the earth surface level coordinate system true origin under the rotating coordinate system of the earth's core.Φ ₀And Λ ₀Be respectively the geodetic latitude and the geodetic longitude of the earth surface level coordinate system true origin.The earth surface level coordinate system and scene coordinate system transformational relation can be expressed as:

E _c＝A _cp.E _p

Wherein $A_{\mathrm{Cp}}=\left(\begin{array}{ccc}{\mathrm{Cos}\mathrm{\θ}}_{\mathrm{Pc}}& {\mathrm{Sin}\mathrm{\θ}}_{\mathrm{Pc}}& 0\\ {-\mathrm{Sin}\mathrm{\θ}}_{\mathrm{Pc}}& {\mathrm{Cos}\mathrm{\θ}}_{\mathrm{Pc}}& 0\\ 0& 0& 1\end{array}\right)$

E wherein _cBe coordinate under the scene coordinate system, θ _PcBe carry machine flying platform direction and Due South to angle.Through above-mentioned coordinate transform, can calculate POS center scene coordinate system coordinate E _C0:

E _c0＝A _cpA _pg(E _g-A _pg0)

Attitude information causes the shake of antenna sway brace, thereby influences the position of double antenna phase center.Double antenna coordinate under the POS platform coordinate system can be expressed as:

E _pos1＝A _re.[0?-Bcosα/2?-Bsinα/2] ^T

E _pos2＝A _re.[0?Bcosα/2?Bsinα/2] ^T

Wherein: $A_{\mathrm{Re}}=\left[\begin{array}{ccc}1& 0& 0\\ 0& {\mathrm{Cos}\mathrm{\θ}}_r& {-\mathrm{Sin}\mathrm{\θ}}_r\\ 0& {\mathrm{Sin}\mathrm{\θ}}_r& {\mathrm{Cos}\mathrm{\θ}}_r\end{array}\right]\left[\begin{array}{ccc}{\mathrm{Cos}\mathrm{\θ}}_p& 0& {\mathrm{Sin}\mathrm{\θ}}_p\\ 0& 1& 0\\ {-\mathrm{Sin}\mathrm{\θ}}_p& 0& {\mathrm{Cos}\mathrm{\θ}}_p\end{array}\right]\left[\begin{array}{ccc}{\mathrm{Cos}\mathrm{\θ}}_y& {-\mathrm{Sin}\mathrm{\θ}}_y& 0\\ {\mathrm{Sin}\mathrm{\θ}}_y& {\mathrm{Cos}\mathrm{\θ}}_y& 0\\ 0& 0& 1\end{array}\right]$

θ _rθ _pθ _yBe respectively the three-axis attitude angle: roll angle, the angle of pitch and crab angle, B is a base length, and α is the baseline inclination angle, and POS is positioned at the center of baseline.Again with the platform coordinate system coordinate transformation in the scene coordinate system:

E _c1＝E _pos1+E _c0

E _c2＝E _pos2+E _c0

So far obtain double antenna scene coordinate system coordinate, thereby set up the spatial relation of radar and target.

2) utilize true SAR picture amplitude data, the plural backscattering coefficient that generates correlativity is right.

Backscattering coefficient comprises amplitude and phase place, the sharp keen distribution of whose amplitude obeys, and phase place is obeyed evenly and is distributed.Yet can not directly simply generate two groups of independently equally distributed random phases, binary channels backscattering coefficient phase place has correlativity.Here combine actual SAR picture amplitude data, a kind of correlativity backscattering coefficient production method is provided, method step is following:

A) with the SAR picture amplitude as main antenna backscattering coefficient amplitude, be created between [π π] and obey equally distributed random phase.

B) provide the auxilliary antenna backscattering coefficient of a kind of correlativity to generate scheme here.Basic thought is the random number through an independent normal distribution of interpolation on the linear combination basis of main antenna backscattering coefficient real part and imaginary part, and in order to control the correlativity between the major-minor antenna backscattering coefficient, it is following to generate step:

Get main antenna backscattering coefficient γ ₁Real part x ₁With imaginary part y ₁, x then ₁y ₁Obeying average is 0, and variance is σ ²Normal distribution and separate.We can set up the real part and the imaginary part of auxilliary antenna backscattering coefficient so:

x ₂＝a _xx ₁+b _xy ₁+c _xz

y ₂＝a _yx ₁+b _yy ₁

a _x＝(2ρ-1)cos(ψ _ρ)

b _x＝(2ρ-1)sin(ψ _ρ)

Wherein, a _y=-sin (ψ _ρ)

b _y＝cos(ψ _ρ)

$c_x=2\sqrt{\mathrm{\ρ}(1-\mathrm{\ρ})}$

Wherein ρ, ψ _ρBe respectively backscattering coefficient related coefficient amplitude and phase place, z is that the obedience average is that 0 variance is σ ²Normal distribution random number, and and x ₁y ₁Separate.Can verify the auxilliary antenna backscattering coefficient real part x that generates through following formula ₂With imaginary part y ₂Satisfy following three conditions:

(1) x ₂, y ₂Be that the obedience average is 0, variance is σ ²The stochastic variable of normal distribution.

(2) x ₂, y ₂Between related coefficient be 0.

(3) main antenna backscattering coefficient x ₁+ jy ₁With auxilliary antenna backscattering coefficient x ₂+ jy ₂Between related coefficient do

J and e are respectively imaginary unit and natural constant in the expression formula.

3) introduce DEM information, generate the two-way original echoed signals according to echo signal model.

According to the radar of front foundation and the model space geometric and the backscattering model of target, adopt the time domain echo signal model to produce original echoed signals.Time domain echo basic idea is on the basis of radar emission continuous impulse, along with the motion of Texas tower, generates the echoed signal of each pulse.The step of algorithm is (like Fig. 2) as follows:

A) for the orientation to moment t _s, target scattering unit in the compute beam irradiation area (i, oblique distance R j) _Ij, and definite R _IjThe range gate m at place.

B) the adjust the distance orientation echoed signal g of a m _aAdd from point (i, the contribution of j) doppler phase:

g _a=g _a+ σ _{I, j}w _aExp (j4 π R _Ij/ λ), wherein λ is a wavelength, w _aBe the antenna radiation pattern gain, σ _{I, j}It is backscattering coefficient.

C) repeat the a-b step, travel through all scattering points that this orientation moment radar illumination arrives.Obtain orientation t constantly _sOn the orientation echoed signal g that had a few _a

D) with g _aWith range transmission signal convolution, obtained the echoed signal of a pulse, travel through the echoed signal that each orientation obtains the whole simulation scene constantly.

E) according to a)-d) going on foot the echo data that calculates double antenna respectively, pass through CS (ChirpScaling) algorithm then and carry out the SAR imaging, compensation obtains interference fringe through kinematic error again.

Among Fig. 1, the positional information that comprises in the POS data (latitude, longitude and height) through the earth's core rotating coordinate system and the coordinate transform of the earth surface level coordinate system, is transformed in the scene coordinate system, obtains the coordinate of POS center in the scene coordinate system.Because POS is positioned at the center of baseline sway brace, therefore can merge attitude information in the POS data, resolve the major-minor antenna phase center in baseline two ends coordinate under the scene coordinate system.

Fig. 2 is a time domain echo algorithm flow, and basic thought is on the basis of radar emission continuous impulse, along with the motion of Texas tower, generates the echoed signal of each pulse.

Fig. 3 a is a main antenna backscattering coefficient map of magnitudes, and Fig. 3 b produces the auxilliary antenna backscattering coefficient amplitude that principle produces according to correlativity, and the corresponding related coefficient of the corresponding backscattering coefficient of major-minor antenna is 0.98.

Fig. 4 is the simulating scenes altitude figures, and the scene border district shape that keeps left is comparatively smooth, and rising and falling then appears in the right side landform.

Fig. 5 a is the main antenna original echo data that emulation obtains, and Fig. 5 b is auxilliary antenna echo data.

Fig. 6 a is through main antenna SAR picture amplitude figure after the CS imaging processing, and Fig. 6 b is the auxilliary antenna picture amplitude figure that obtains after handling, and echo data has obtained focusing on preferably.

Fig. 7 a is desirable interference fringe picture, and Fig. 7 b is that emulated data is not carried out the interference fringe that motion compensation obtains through imaging processing, and Fig. 7 c is through the interference fringe picture that obtains after the motion compensation, conforms to desirable striped.

Fig. 8 is based on the flow process of POS exercise data interference SAR echo data emulation mode, and its step is following:

Interference SAR echo simulation scheme is divided into three parts, and first utilizes coordinate transform to calculate double antenna phase center coordinate under the scene coordinate system; Second portion is to be the basis with true SAR view data, and it is right to generate correlativity plural number backscattering coefficient; Third part is introduced the DEM terrain information exactly, calculate two-way original echo data according to echo signal model, thereby emulation obtains SAR image and interference fringe.

Claims (7)

1. interference SAR echo data emulation mode based on the POS exercise data; It is characterized in that: through setting up the transformational relation of POS coordinate system and object scene coordinate system; The kinematic error of carrying machine platform is fused in the calculating of interference synthetic aperture radar echo, to realize airborne interference SAR original echo emulation based on the actual motion data; May further comprise the steps: the first step, utilize coordinate transform to calculate double antenna phase center coordinate under the scene coordinate system; Second step was the basis with true SAR view data, and it is right to generate correlativity plural number backscattering coefficient; The 3rd step, introduce the DEM terrain information, calculate two-way original echo data according to echo signal model, obtain SAR image and interference fringe through forming images and interfering to handle.

2. the interference SAR echo data emulation mode based on the POS exercise data according to claim 1; It is characterized in that the said first step is through three coordinate system rotation; Positional information and attitude information are incorporated in the antenna phase center Coordinate Calculation, comprise:

1) actual the earth's core, the POS center rotating coordinate system coordinate conversion that comprises positional information is arrived the earth surface level coordinate system;

2) be transformed into the scene coordinate system from the earth surface level coordinate system again;

3) calculate antenna phase center at the platform coordinate system coordinate according to carrying the machine attitude information; Again it is transformed in the scene coordinate system; Obtain double antenna coordinate under the scene coordinate system; Set up the space geometry relation of radar and target, thereby in echo calculates, realized the introducing of positional information and attitude information kinematic error.

3. the interference SAR echo data emulation mode based on the POS exercise data according to claim 1 is characterized in that, said second step is to utilize true SAR picture amplitude data, and the plural backscattering coefficient that generates correlativity is right, comprises step:

A) with the SAR picture amplitude as main antenna backscattering coefficient amplitude, be created between [π π] and obey equally distributed random phase;

B) on the linear combination basis of main antenna backscattering coefficient real part and imaginary part, add the random number of an independent normal distribution, in order to control the correlativity between the major-minor antenna backscattering coefficient, it is right to generate auxilliary antenna backscattering coefficient: real part and imaginary part.

4. the interference SAR echo data emulation mode based on the POS exercise data according to claim 3 is characterized in that, the real part and the imaginary part of the auxilliary antenna backscattering coefficient of said generation, and step is following:

Get main antenna backscattering coefficient γ ₁Real part x ₁With imaginary part y ₁, x then ₁y ₁Obeying average is 0, and variance is σ ²Normal distribution and separate; Then the real part and the imaginary part of auxilliary antenna backscattering coefficient are:

x ₂＝a _xx ₁+b _xy ₁+c _xz

y ₂＝a _yx ₁+b _yy ₁

a _x＝(2ρ-1)cos(ψ _ρ)

b _x＝(2ρ-1)cos(ψ _ρ)

Wherein, a _y=-sin (ψ _ρ)

b _y＝cos(ψ _ρ)

$c_x=2\sqrt{\mathrm{\ρ}(1-\mathrm{\ρ})}$

Wherein ρ, ψ _ρBe respectively backscattering coefficient related coefficient amplitude and phase place, z is that the obedience average is that 0 variance is σ ²Normal distribution random number, and and x ₁y ₁Separate.

5. according to claim 3 or 4 described interference SAR echo data emulation modes, it is characterized in that the auxilliary antenna backscattering coefficient real part x of said generation based on the POS exercise data ₂With imaginary part y ₂Satisfy following three conditions:

1) x ₂, y ₂Be that the obedience average is 0, variance is σ ²The stochastic variable of normal distribution;

2) x ₂, y ₂Between related coefficient be 0;

3) main antenna backscattering coefficient x ₁+ jy ₁With auxilliary antenna backscattering coefficient x ₂+ jy ₂Between related coefficient do J and e are respectively imaginary unit and natural constant in the expression formula.

6. the interference SAR echo data emulation mode based on the POS exercise data according to claim 1; It is characterized in that; Said the 3rd step; Be according to the radar of first and second step foundation and the model space geometric and the backscattering model of target, adopt the time domain echo signal model to produce original echoed signals; Time domain echo algorithm is on the basis of radar emission continuous impulse, along with the motion of Texas tower, generates the echoed signal of each pulse.

7. according to claim 1 or 6 described interference SAR echo data emulation modes, it is characterized in that, in said the 3rd step, comprise that step is following based on the POS exercise data:

A) for the orientation to moment t _s, target scattering unit in the compute beam irradiation area (i, oblique distance R j) _Ij, and definite R _IjThe range gate m at place;

B) the adjust the distance orientation echoed signal g of a m _aAdd from point (i, the contribution of j) doppler phase:

g _a=g _a+ σ _{I, j}w _aExp (j4 π R _Ij/ λ), wherein, λ is a wavelength, w _aBe the antenna radiation pattern gain, σ _{I, j}It is backscattering coefficient;

C) repeat the a-b step, travel through all scattering points that this orientation moment radar illumination arrives, obtain orientation t constantly _sOn the orientation echoed signal g that had a few _a

D) with g _aWith range transmission signal convolution, obtained the echoed signal of a pulse, travel through the echoed signal that each orientation obtains the whole simulation scene constantly.

E) according to a)-d) going on foot the echo data that calculates double antenna respectively, pass through CS (ChirpScaling) algorithm then and carry out the SAR imaging, compensation obtains interference fringe through kinematic error again.

Images