CN103630903B - The method of flow field, sea radial velocity is measured based on straight rail interference SAR - Google Patents

Abstract

The invention provides a kind of method measuring flow field, sea radial velocity based on straight rail interference SAR.The method utilizes the three width antennas arranged in straight rail direction to obtain the interferometric phase of three kinds of different interference times, thus the higher order term coefficient of interfering flow measurement medium velocity deviation can be estimated, and then interferometry velocity deviation can be corrected, obtain flow field, accurate sea radial velocity.

Description

The method of flow field, sea radial velocity is measured based on straight rail interference SAR

Technical field

The present invention relates to and interfere aperture radar (SyntheticApertureRadar is called for short SAR) technical field, particularly relate to a kind of method measuring flow field, sea radial velocity based on straight rail interference SAR.

Background technology

Synthetic-aperture radar (SyntheticApertureRadar is called for short SAR) is using the electromagnetic wave of microwave spectral coverage as carrier detection, realizes the technology for information acquisition to the high-precision two-dimensional imaging of object of observation by synthetic aperture.Compared with traditional optical imaging, SAR has early detection, round-the-clock, round-the-clock operational advantages.

Detecting target radial translational speed is one of important application of synthetic-aperture radar.Fig. 1 is that prior art measures based on straight rail interference SAR the schematic diagram that moving target moves radially speed.Please refer to Fig. 1, in straight rail interference SAR, before and after platform traffic direction, arrange two antennas, the base length between two antennas is B, one of them antenna transmission, and two antennas receive simultaneously.The mistiming of two receiving antenna Received signal strength is utilized to calculate the radial motion speed of moving target.

For same scene, two antennas respectively become once as, but there is a mistiming wherein V ₀for Platform movement speed.The radial velocity V of moving target in scene can be obtained by the phase differential comparing two width images _r, its expression formula is:

$V_r=\frac{\mathrm{\λ}}{4\mathrm{\π\τ}}\∠\underset{i=1}{\overset{M}{\mathrm{\Σ}}}{Q}_1^{{\left(i\right)}^{*}}{Q}_2^{\left(i\right)}---\left(1\right)$

Wherein, λ is radar electromagnetic wave wavelength, V ₀for Platform movement speed, ∠ represents phase term, M for look number more, be respectively that front and back two width antennas obtains i-th looks complex pattern information, and ∠ represents and gets phase term.

Straight rail interference SAR is not only widely used in the middle of the detection of rigid motion target, is also applied in the middle of the flow field survey of sea, is the important means of current ocean large area, high-resolution flow field survey.For rigid-object, formula (1) is exactly the unbiased esti-mator of speed, but for sea flow field survey, the Random Wave athletic meeting on sea causes (1) formula to there is velocity estimation deviation.

The two width sea complex patterns that straight rail interference SAR is measured can be expressed as:

$\left[\begin{array}{c}{Q}_1\\ Q_2\end{array}\right]={\mathrm{\σ}}_x\left[\begin{array}{cc}1& 0\\ 0& \mathrm{exp\; j}4\mathrm{\π}{V}_r\mathrm{\λ\τ}\end{array}\right]\left[\begin{array}{c}X\left(t\right)\\ X(t+\mathrm{\τ})\end{array}\right]+\left[\begin{array}{c}{N}_1\\ N_2\end{array}\right]---\left(2\right)$

Wherein, σ _xfor sea average scattering intensity, the sea normalization at random again scattered signal of X (t) for comprising phase place and amplitude random variation, for interfering time delay, N ₁, N ₂be respectively the thermonoise of two images.

In general Received signal strength Gaussian distributed, theoretical according to multiple gaussian probability, Q ₁, Q ₂probability density function be:

$f(Q_1,Q_2)={\mathrm{\π}}^{-2}{\left|R_Q\right|}^{-1}\exp \left(-[Q_1^{*},Q_2^{*}]R_Q^{-1}\left[\begin{array}{c}{Q}_1\\ Q_2\end{array}\right]\right)---\left(3\right)$

Wherein, R _qfor vector $\left[\begin{array}{c}{Q}_1\\ Q_2\end{array}\right]$ Covariance matrix:

$R_Q={\mathrm{\σ}}_X^2\left[\begin{array}{cc}1& 0\\ 0& \mathrm{exp\; j}4\mathrm{\π}{V}_r\mathrm{\λ\τ}\end{array}\right]R_X\left[\begin{array}{cc}1& 0\\ 0& \exp -j4\mathrm{\π}{V}_r\mathrm{\λ\τ}\end{array}\right]{\mathrm{\σ}}_N^2\left[\begin{array}{cc}1& 0\\ 0& 1\end{array}\right]---\left(4\right)$

Wherein for thermonoise average power, E [] represents statistical average, R _xfor vector $\left[\begin{array}{c}X\left(t\right)\\ X(t+\mathrm{\τ})\end{array}\right]$ Covariance matrix:

$R_X=\left[\begin{array}{cc}{R}_x\left(0\right)& R_x^{*}\left(\mathrm{\τ}\right)\\ R_x\left(\mathrm{\τ}\right)& R_x\left(0\right)\end{array}\right]---\left(5\right)$

Wherein, R _x(τ) be the autocorrelation function of X (t), namely R _x(τ)=E [X ^*(t) X (t+ τ)].

For when looking, namely adopt multiple probability to carry out velocity estimation with the adjacent image point of distribution, the joint probability density function of multiple like this picture point is more:

$f(Q_1^{\left(1\right)},Q_2^{\left(1\right)},\·\·\·,Q_1^{\left(M\right)},Q_2^{\left(M\right)})=\underset{i=1}{\overset{M}{\mathrm{\Π}}}{\mathrm{\π}}^{-2}{\left|R_Q\right|}^{-1}\exp (-[Q_1^{{\left(i\right)}^{*}},Q_2^{{\left(i\right)}^{*}}\left]R_Q^{-1}\left[\begin{array}{c}{Q}_1^{\left(i\right)}\\ Q_2^{\left(i\right)}\end{array}\right]\right)---\left(6\right)$

Wherein, $\left[\begin{array}{c}{Q}_1^{\left(i\right)}\\ Q_2^{\left(i\right)}\end{array}\right]$ Be i-th look in the multiple dispersion image that obtains of two antennas.

V _rmaximal possibility estimation be:

$\frac{\∂\ln f(Q_1^{\left(1\right)},Q_2^{\left(1\right)},\·\·\·,Q_1^{\left(M\right)},Q_2^{\left(M\right)})}{\∂V_r}=0---\left(7\right)$

V can be obtained through derivation _rthe expression formula of maximal possibility estimation be:

Wherein, interferometric phase, r _x(τ) phase term.

For R rigid-object _x(τ) ≡ 1, its phase term be 0, so (8) formula can be reduced to (1) formula.But for sea random scatter, R _x(τ) be a complicated function determined by surface scattering doppler spectral, often simple by R in research in the past _x(τ) think the real number attenuation function of a Gaussian, ignore also adopt (1) formula to calculate flow field, sea, a velocity estimation deviation will be caused like this:

Γ (ω) is made to be R _x(τ) Fourier transform, Γ (ω) is in fact exactly the translation of surface scattering signal doppler spectral at frequency domain:

$\mathrm{\Γ}\left(\mathrm{\ω}\right)=P(\mathrm{\ω}+4\mathrm{\π}\frac{V_r}{\mathrm{\λ}})---(9-1)$

From the character of Fourier transform, when only occurring in Γ (ω) for even function.And Γ (ω) is not even function in most cases, unless radar incident direction is vertical with wind direction.Therefore in most cases, related function R is ignored _x(τ) phase term capital causes the deviation of velocity estimation.Relevant emulation and experiment show that this velocity deviation can reach the magnitude of 0.2m/s, can produce serious evaluated error, need to compensate to the accurate measurement of Sea Current.Realizing in process of the present invention, applicant finds that prior art is measured in the method for flow field, sea radial velocity, owing to have ignored the phase term of surface scattering related function based on straight rail interference SAR thus cause flow field, sea radial velocity measurement to occur error, and the many baselines straight rail interference technique be evolved further by the straight rail interference SAR technology of routine places multiple receiving antenna on Platform movement direction, the impact of the decoherence effect of system noise and scene further can be reduced like this.But traditional many baselines straight rail interference SAR is used for the phase term that have ignored surface scattering related function during Sea Current is measured equally this can bring evaluated error equally.

Summary of the invention

(1) technical matters that will solve

In view of above-mentioned technical matters, the invention provides a kind of method measuring flow field, sea radial velocity based on straight rail interference SAR, by considering that the impact of surface scattering related function reduces the measuring error of flow field, sea radial velocity.

(2) technical scheme

According to an aspect of the present invention, a kind of method measuring flow field, sea radial velocity based on straight rail interference SAR is provided.The method comprises:

Steps A, arrange N number of antenna in the below of flying platform along heading, base length is unequal mutually between two, and this base length is the distance between two antennas;

Step B, launch SAR signal by any antenna in N number of antenna, N number of antenna obtains N width SAR echo data to same Ocean Scenes simultaneously: Q ₁, Q ₂..., Q _n;

Step C, carries out interference treatment and multiple look processing between any two by N width SAR echo data, obtains and interferes delay time T _{i, j}corresponding interferometric phase data Φ _{i, j}, wherein:

${\mathrm{\τ}}_{i,j}=\frac{B_{i,j}}{2V_0}$

Wherein, B _{i, j}for the base length between antenna i and antenna j, V ₀for the flying speed of flying platform;

Step D, will interfere delay time T _{i, j}and the interferometric phase data Φ of correspondence _{i, j}substitute in N (N-1)-1 rank Taylor expansion of following interferometric phase Φ, solve sea ocean current radial velocity V _r:

$\left\{\begin{array}{c}{\mathrm{\Φ}}_{\mathrm{1,2}}=4\mathrm{\π}\frac{V_r}{\mathrm{\λ}}{\mathrm{\τ}}_{\mathrm{1,2}}+\underset{k=1}{\overset{N(N-1)/2-1}{\mathrm{\Σ}}}\frac{1}{(2k+1)!}{\mathrm{\φ}}^{(2k+1)}\left(0\right){\mathrm{\τ}}_{\mathrm{1,2}}^{2k+1}\\ {\mathrm{\Φ}}_{1,3}=4\mathrm{\π}\frac{V_r}{\mathrm{\λ}}{\mathrm{\τ}}_{\mathrm{1,3}}+\underset{k=1}{\overset{N(N-1)/2-1}{\mathrm{\Σ}}}\frac{1}{(2k+1)!}{\mathrm{\φ}}^{(2k+1)}\left(0\right){\mathrm{\τ}}_{\mathrm{1,3}}^{2k+1}\\ ......\\ {\mathrm{\Φ}}_{i,j}=4\mathrm{\π}\frac{V_r}{\mathrm{\λ}}{\mathrm{\τ}}_{i,j}+\underset{k=1}{\overset{N(N-1)/2-1}{\mathrm{\Σ}}}\frac{1}{(2k+1)!}{\mathrm{\φ}}^{(2k+1)}\left(0\right){\mathrm{\τ}}_{i,j}^{2k+1}\\ ......\\ {\mathrm{\Φ}}_{N-1,N}=4\mathrm{\π}\frac{V_r}{\mathrm{\λ}}{\mathrm{\τ}}_{N-1,N}+\underset{k=1}{\overset{N(N-1)/2-1}{\mathrm{\Σ}}}\frac{1}{(2k+1)!}{\mathrm{\φ}}^{(2k+1)}\left(0\right){\mathrm{\τ}}_{N-1,N}^{2k+1}\end{array}\right..$

(3) beneficial effect

As can be seen from technique scheme, the method that the present invention is based on straight rail interference SAR measurement flow field, sea radial velocity has following beneficial effect:

(1) by considering the impact of surface scattering related function, effective compensation conventional method can carry out in the flow field velocity measurement of sea deviation, improving the measuring accuracy of sea flow field velocity;

(2) developed further by the straight rail interference SAR technology of routine, only increase one or more receiving antenna, do not rely on complicated wave of the sea random motion model, computation process is simple, is easy to realize.

Accompanying drawing explanation

Fig. 1 is that prior art measures based on straight rail interference SAR the schematic diagram that moving target moves radially speed method;

Fig. 2 is that the embodiment of the present invention measures based on straight rail interference SAR the process flow diagram that flow field, sea moves radially speed method;

Fig. 3 is the schematic diagram of triantennary putting position in method shown in Fig. 2;

Fig. 4 is that second embodiment of the invention measures based on straight rail interference SAR the schematic diagram that flow field, sea moves radially four antenna putting positions in speed method.

Embodiment

For making the object, technical solutions and advantages of the present invention clearly understand, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in more detail.It should be noted that, in accompanying drawing or instructions describe, similar or identical part all uses identical figure number.The implementation not illustrating in accompanying drawing or describe is form known to a person of ordinary skill in the art in art.In addition, although herein can providing package containing the demonstration of the parameter of particular value, should be appreciated that, parameter without the need to definitely equaling corresponding value, but can be similar to corresponding value in acceptable error margin or design constraint.

The invention provides a kind of method measuring flow field, sea radial velocity based on straight rail interference SAR.The method utilizes the three width antennas arranged in straight rail direction to obtain the interferometric phase of three kinds of different interference times, thus the higher order term coefficient of interfering flow measurement medium velocity deviation can be estimated, and then interferometry velocity deviation can be corrected, obtain flow field, accurate sea radial velocity.

In one exemplary embodiment of the present invention, provide a kind of method measuring flow field, sea radial velocity based on straight rail interference SAR.Fig. 2 is the embodiment of the present invention measures the method for flow field, sea radial velocity process flow diagram based on straight rail interference SAR.Fig. 3 is the schematic diagram of triantennary putting position in method shown in Fig. 2.

As shown in Figure 2, the method that the embodiment of the present invention measures flow field, sea radial velocity based on straight rail interference SAR comprises:

Steps A, arranges three antennas in the below of flying platform along heading, and between antenna 1,2, base length is B _1,2, between antenna 2,3, base length is B _2,3, meet B _1,2≠ B _2,3, and meet 0.4 < B _1,2/ B _2,3< 0.6 or 0.4 < B _2,3/ B _1,2< 0.6, as shown in Figure 3.

Step B, launch SAR signal by any antenna in triantennary, triantennary obtains three width SAR echo data: Q to same Ocean Scenes simultaneously ₁, Q ₂and Q ₃;

Step C, three width SAR echo datas carry out interference treatment and multiple look processing between any two, obtain corresponding interference delay time T respectively _1,2, τ _2,3, τ _1,3interferometric phase data Φ _1,2, Φ _2,3, Φ _1,3;

Please refer to Fig. 3, three antennas altogether can obtain three kinds and interfere time delay interfere the time delay of respective antenna 1 and antenna 2, antenna 2 and antenna 3 respectively for these three kinds, and the interferometric phase between antenna 1 and antenna 3.

Based on above-mentioned explanation, this step B comprises further:

Sub-step C1, three width SAR echo datas carry out interference treatment between any two, obtain 3 width conjugation and interfere complex image data: Q ₁ ^*q ₂, Q ₂ ^*q ₃and Q ₁ ^*q ₃;

In this sub-step, the interference treatment remnants comprised in conventional straight rail interference SAR hand over the operations such as the removal of rule component, spatial registration.By interference treatment, the impact of the factor such as antenna baseline cross rail component, three width antenna SAR image space dislocation can be removed, thus the error of interferometric phase can be reduced.

Sub-step C2, interferes complex image data Q to the conjugation of carrying out after interference treatment ₁ ^*q ₂, Q ₂ ^*q ₃and Q ₁ ^*q ₃carry out multiple look processing, obtain three interferometric phase data Φ _1,2, Φ _2,3, Φ _1,3:

${\mathrm{\&Phi;}}_{\mathrm{1,2}}=\&angle;\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{Q}_1^{{\left(i\right)}^{*}}{Q}_2^{\left(i\right)},$ ${\mathrm{\&Phi;}}_{\mathrm{2,3}}=\&angle;\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{Q}_2^{{\left(i\right)}^{*}}{Q}_3^{\left(i\right)},$ ${\mathrm{\&Phi;}}_{\mathrm{1,3}}=\&angle;\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{Q}_1^{{\left(i\right)}^{*}}{Q}_3^{\left(i\right)}---\left(10\right)$

Wherein, M for look number more, and ∠ represents phase term, represent that i-th in certain resolution element that the n-th antenna obtains looks data.The interference time that these three interferometric phases are corresponding is respectively:

${\mathrm{\&tau;}}_{\mathrm{1,2}}=\frac{B_{\mathrm{1,2}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{2,3}}=\frac{B_{\mathrm{2,3}}}{2V_0},$ ${\mathrm{\&tau;}}_{\mathrm{1,3}}=\frac{B_{\mathrm{1,2}}+B_{\mathrm{2,3}}}{{2V}_0}.$

Step D, will interfere delay time T _1,2, τ _2,3, τ _1,3and the interferometric phase Φ that difference is corresponding _1,2, Φ _2,3, Φ _1,3be updated in the 5 rank Taylor expansions of interferometric phase Φ, solve sea ocean current radial velocity V _r:

$\left\{\begin{array}{c}{\mathrm{\&Phi;}}_{\mathrm{1,2}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{1,2}}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,2}}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,2}}^5\\ {\mathrm{\&Phi;}}_{\mathrm{1,3}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{1,3}}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,3}}^5+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,3}}^5\\ {\mathrm{\&Phi;}}_{\mathrm{2,3}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{2,3}}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,3}}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,3}}^5\end{array}\right.---\left(11\right)$

Wherein, λ is SAR radar electromagnetic wave wavelength, φ ⁽³⁾and φ (0) ⁽⁵⁾(0) 3 rank term coefficient and the 5 rank term coefficient of the Taylor expansion of interferometric phase Φ are distinguished.

Below introduce the derivation of formula (11):

By the phase term in velocity estimation deviation formula (9) expansion in Taylor series, and notice velocity deviation can be expressed as:

$V_b=\frac{\mathrm{\&lambda;}}{4\mathrm{\&pi;}}\underset{n=2}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{1}{n!}{\mathrm{\&phi;}}^{\left(n\right)}\left(0\right){\mathrm{\&tau;}}^{n-1},n=\mathrm{2,3},...---\left(12\right)$

Wherein, φ ⁽ⁿ⁾(0) be at the n order derivative at τ=0 place

According to the definition of autocorrelation function,

$R_x\left(\mathrm{\&tau;}\right)=R_x^{*}(-\mathrm{\&tau;})---\left(13\right)$

So necessarily odd function, and our even derivative necessarily 0 of knowing odd function, the higher order term higher than 5 rank in formula (12) formula can be ignored in addition, so (12) formula can be written as under delay time T is not more than surface scattering situation correlation time:

$V_b\&ap;\frac{\mathrm{\&lambda;}}{4\mathrm{\&pi;}}[\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}^2+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}^4]---\left(14\right)$

According to formula (8), obtain the Taylor expansion of interferometric phase:

$\mathrm{\&Phi;}\&ap;4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}\mathrm{\&tau;}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}^5---\left(15\right)$

φ in theory ⁽³⁾and φ (0) ⁽⁵⁾(0) can by carrying out modeling to calculate to sea random motion, but this needs the stormy waves information accurately knowing sea, and this is difficult to accomplish in the flow field survey of reality.

Three unknown number (V are had in formula (14) formula _r, φ ⁽³⁾(0), φ ⁽⁵⁾(0)), need three times independently interferometry just can resolve.And just obtain three independent interferometries in step B, and the interference time of interfering for three times is not identical, therefore can resolve this three unknown numbers.The equation of three interferometries is carried out simultaneous can obtain:

$\left\{\begin{array}{c}{\mathrm{\&Phi;}}_{\mathrm{1,2}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{1,2}}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,2}}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,2}}^5\\ {\mathrm{\&Phi;}}_{\mathrm{1,3}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{1,3}}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,3}}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,3}}^5\\ {\mathrm{\&Phi;}}_{\mathrm{2,3}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{2,3}}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,3}}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,3}}^5\end{array}\right.---\left(11\right)$

Because base length meets 0.4 < B _1,2/ B _2,3< 0.6 or 0.4 < B _2,3/ B _1,2< 0.6, then can ensure τ _1,2, τ _2,3, τ _1,3between unequal mutually, so just can ensure that three interference are separate interferometries.Then system of equations (11) must have solution, solves the V of gained _rbe not containing the sea radial velocity of deviation.

The resolution error of system of equations (11) depends on the conditional number of the matrix of coefficients of system of equations (11).In order to the conditional number of reduction ratio matrix, the time delay of optimization is selected to meet 0.4 < τ _1,2/ τ _2,3< 0.6 or 0.4 < τ _2,3/ τ _1,2< 0.6, this is also that signature requirement base length meets 0.4 < B _1,2/ B _2,3< 0.6 or 0.4 < B _2,3/ B _1,2the reason of < 0.6.

So far, the method that first embodiment of the invention measures flow field, sea radial velocity based on straight rail interference SAR is introduced complete.

In another exemplary embodiment of the present invention, additionally provide a kind of method measuring flow field, sea radial velocity based on straight rail interference SAR utilizing 4 antennas.The method that the present embodiment measures flow field, sea radial velocity based on straight rail interference SAR comprises:

Steps A, arranges four antennas in the below of flying platform along heading, and between antenna 1,2, base length is B _1,2, between antenna 2,3, base length is B _2,3, between antenna 3,4, base length is B _3,4.Meet B _1,2≠ B _2,3≠ B _3,4, and meet 0.4 < B _1,2/ B _2,3< 0.6,0.4 < B _2,3/ B _3,4< 0.6 or 0.4 < B _2,3/ B _1,2< 0.6,0.4 < B _3,4/ B _2,3< 0.6, as shown in Figure 4.

Step B, launch SAR signal by any antenna in four antennas, four antennas obtain four width SAR echo data: Q to same Ocean Scenes simultaneously ₁, Q ₂, Q ₃and Q ₄;

Step C, four width SAR echo datas carry out interference treatment and multiple look processing between any two, obtain corresponding interference delay time T respectively _1,2, τ _1,3, τ _{isosorbide-5-Nitrae}, τ _2,3, τ _2,4, τ _3,4interferometric phase data Φ _1,2, Φ _1,3, Φ _{isosorbide-5-Nitrae}, Φ _2,3, Φ _2,4, Φ _3,4;

Please refer to Fig. 4, four antennas altogether can obtain six kinds and interfere time delay ${\mathrm{\&tau;}}_{\mathrm{1,3}}=\frac{B_{\mathrm{1,2}}+B_{\mathrm{2,3}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{1,4}}=\frac{B_{\mathrm{1,2}}+B_{\mathrm{2,3}}+B_{\mathrm{3,4}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{2,3}}=\frac{B_{\mathrm{2,3}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{2,4}}=\frac{B_{\mathrm{2,3}}+B_{\mathrm{3,4}}}{2V_0},$ ${\mathrm{\&tau;}}_{\mathrm{3,4}}=\frac{B_{\mathrm{3,4}}}{{2V}_0},$ Interfere respectively respective antenna 1 and antenna 2, antenna 1 and antennas 3 time delay for these six kinds, antenna 1 and antenna 4, antenna 2 and antenna 3, antenna 2 and antenna 4, interferometric phase between antenna 3 and antenna 4.

Based on above-mentioned explanation, this step B comprises further:

Sub-step C1, four width SAR echo datas carry out interference treatment between any two, obtain six width conjugation and interfere complex image data: Q ₁ ^*q ₂, Q ₁ ^*q ₃, Q ₁ ^*q ₄, Q ₂ ^*q ₃, Q ₂ ^*q ₄and Q ₃ ^*q ₄;

In this sub-step, the interference treatment remnants comprised in conventional straight rail interference SAR hand over the operations such as the removal of rule component, spatial registration.By interference treatment, the impact of the factor such as antenna baseline cross rail component, four width antenna SAR image space dislocation can be removed, thus the error of interferometric phase can be reduced.

Sub-step C2, interferes complex image data Q to the conjugation of carrying out after interference treatment ₁ ^*q ₂, Q ₁ ^*q ₃, Q ₁ ^*q ₄, Q ₂ ^*q ₃, Q ₂ ^*q ₄, Q ₃ ^*q ₄carry out multiple look processing, obtain six interferometric phase data Φ _1,2, Φ _1,3, Φ _{isosorbide-5-Nitrae}, Φ _2,3, Φ _2,4, Φ _3,4:

${\mathrm{\&Phi;}}_{\mathrm{1,2}}=\&angle;\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{Q}_1^{{\left(i\right)}^{*}}{Q}_2^{\left(i\right)},$ ${\mathrm{\&Phi;}}_{\mathrm{1,3}}=\&angle;\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{Q}_1^{{\left(i\right)}^{*}}{Q}_3^{\left(i\right)},$ ${\mathrm{\&Phi;}}_{\mathrm{1,4}}=\&angle;\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{Q}_1^{{\left(i\right)}^{*}}{Q}_4^{\left(i\right)},$ ${\mathrm{\&Phi;}}_{\mathrm{2,3}}=\&angle;\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{Q}_2^{{\left(i\right)}^{*}}{Q}_3^{\left(i\right)},$ ${\mathrm{\&Phi;}}_{\mathrm{2,4}}=\&angle;\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{Q}_2^{{\left(i\right)}^{*}}{Q}_4^{\left(i\right)},$ ${\mathrm{\&Phi;}}_{\mathrm{3,4}}=\&angle;\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{Q}_3^{{\left(i\right)}^{*}}{Q}_4^{\left(i\right)}$

Wherein, M for look number more, and ∠ represents phase term, represent that i-th in certain resolution element that the n-th antenna obtains looks data.The interference time that these six interferometric phases are corresponding is respectively:

${\mathrm{\&tau;}}_{\mathrm{1,2}}=\frac{B_{\mathrm{1,2}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{1,3}}=\frac{B_{\mathrm{1,2}}+B_{\mathrm{2,3}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{1,4}}=\frac{B_{\mathrm{1,2}}+B_{\mathrm{2,3}}+B_{\mathrm{3,4}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{2,3}}=\frac{B_{\mathrm{2,3}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{2,4}}=\frac{B_{\mathrm{2,3}}+B_{\mathrm{3,4}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{3,4}}=\frac{B_{\mathrm{3,4}}}{{2V}_0}.$

Step D, will interfere delay time T _1,2, τ _1,3, τ _{isosorbide-5-Nitrae}, τ _2,3, τ _2,4, τ _3,4and the interferometric phase Φ that difference is corresponding _1,2, Φ _1,3, Φ _{isosorbide-5-Nitrae}, Φ _2,3, Φ _2,4, Φ _3,4be updated in the 11 rank Taylor expansions of interferometric phase Φ, solve sea ocean current radial velocity V _r:

$\left\{\begin{array}{c}{\mathrm{\&Phi;}}_{\mathrm{1,2}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{1,2}}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,2}}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,2}}^5+\frac{1}{7!}{\mathrm{\&phi;}}^{\left(7\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,2}}^7+\frac{1}{9!}{\mathrm{\&phi;}}^{\left(9\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,2}}^9+\frac{1}{11!}{\mathrm{\&phi;}}^{\left(11\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,2}}^{11}\\ {\mathrm{\&Phi;}}_{\mathrm{1,3}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{1,3}}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,3}}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,3}}^5+\frac{1}{7!}{\mathrm{\&phi;}}^{\left(7\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,3}}^7+\frac{1}{9!}{\mathrm{\&phi;}}^{\left(9\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,3}}^9+\frac{1}{11!}{\mathrm{\&phi;}}^{\left(11\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,3}}^{11}\\ {\mathrm{\&Phi;}}_{\mathrm{1,4}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{1,4}}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,4}}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,4}}^5+\frac{1}{7!}{\mathrm{\&phi;}}^{\left(7\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,4}}^7+\frac{1}{9!}{\mathrm{\&phi;}}^{\left(9\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,4}}^9+\frac{1}{11!}{\mathrm{\&phi;}}^{\left(11\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,4}}^{11}\\ {\mathrm{\&Phi;}}_{\mathrm{2,3}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{2,3}}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,3}}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,3}}^5+\frac{1}{7!}{\mathrm{\&phi;}}^{\left(7\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,3}}^7+\frac{1}{9!}{\mathrm{\&phi;}}^{\left(9\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,3}}^9+\frac{1}{11!}{\mathrm{\&phi;}}^{\left(11\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,3}}^{11}\\ {\mathrm{\&Phi;}}_{\mathrm{2,4}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{2,4}}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,4}}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,4}}^5+\frac{1}{7!}{\mathrm{\&phi;}}^{\left(7\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,4}}^7+\frac{1}{9!}{\mathrm{\&phi;}}^{\left(9\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,4}}^9+\frac{1}{11!}{\mathrm{\&phi;}}^{\left(11\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{2,4}}^{11}\\ {\mathrm{\&Phi;}}_{\mathrm{3,4}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{3,4}}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{3,4}}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{3,4}}^5+\frac{1}{7!}{\mathrm{\&phi;}}^{\left(7\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{3,4}}^7+\frac{1}{9!}{\mathrm{\&phi;}}^{\left(9\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{3,4}}^9+\frac{1}{11!}{\mathrm{\&phi;}}^{\left(11\right)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{3,4}}^{11}\end{array}\right.---\left(16\right)$

Wherein, λ is SAR radar electromagnetic wave wavelength, φ ⁽³⁾(0), φ ⁽⁵⁾(0), φ ⁽⁷⁾(0), φ ⁽⁹⁾and φ (0) ⁽¹¹⁾(0) 3 rank of the Taylor expansion of interferometric phase Φ, 5 rank, 7 rank, 9 rank, 11 rank term coefficient are distinguished.

So far, by reference to the accompanying drawings the present invention two embodiment has been described in detail.Describe according to above, those skilled in the art should have the method that the present invention is based on straight rail interference SAR and measure flow field, sea radial velocity and have clearly been familiar with.

In addition, the above-mentioned definition to each element is not limited in the various concrete structure or shape mentioned in embodiment, and those of ordinary skill in the art can replace it with knowing simply, such as:

(1) more antenna is adopted to obtain more interferometric phase, higher order term coefficient in (15) formula is retained more high-order, then resolve more higher order term coefficient with more interferometric phase of interfering, thus obtain flow field, more accurate sea radial component;

Such as along N number of antenna of heading, the base length complementation between two between antenna is identical, thus ensures between the two corresponding interference times unequal mutually.Interfere between antenna between two and can obtain plant interferometric phase: Φ _{i, j}.Wherein, i=1,2 ..., N; J=1,2 ..., N; And i < j.Then the higher order term coefficient in formula (15) can be remained into N (N-1)-1 rank, by Φ _{1, N}, Φ _{2, N}, Φ _{n-1, N}and τ _{1, N}, τ _{2, N}, τ _{n-1, N}substitute into (15) Shi Ke get

$\left\{\begin{array}{c}{\mathrm{\&Phi;}}_{\mathrm{1,2}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{1,2}}+\underset{k=1}{\overset{N(N-1)/2-1}{\mathrm{\&Sigma;}}}\frac{1}{(2k+1)!}{\mathrm{\&phi;}}^{(2k+1)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,2}}^{2k+1}\\ {\mathrm{\&Phi;}}_{\mathrm{1,3}}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{\mathrm{1,3}}+\underset{k=1}{\overset{N(N-1)/2-1}{\mathrm{\&Sigma;}}}\frac{1}{(2k+1)!}{\mathrm{\&phi;}}^{(2k+1)}\left(0\right){\mathrm{\&tau;}}_{\mathrm{1,3}}^{2k+1}\\ ......\\ {\mathrm{\&Phi;}}_{i,j}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{i,j}+\underset{k=1}{\overset{N(N-1)/2-1}{\mathrm{\&Sigma;}}}\frac{1}{(2k+1)!}{\mathrm{\&phi;}}^{(2k+1)}\left(0\right){\mathrm{\&tau;}}_{i,j}^{2k+1}\\ ......\\ {\mathrm{\&Phi;}}_{N-1,N}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{N-1,N}+\underset{k=1}{\overset{N(N-1)/2-1}{\mathrm{\&Sigma;}}}\frac{1}{(2k+1)!}{\mathrm{\&phi;}}^{(2k+1)}\left(0\right){\mathrm{\&tau;}}_{N-1,N}^{2k+1}\end{array}\right.---\left(17\right)$

More accurate sea flow field radial velocity V can be obtained by solving equation group (17) _r, preferably, N=3,4,5, as long as in general N < 30 can adopt, but the complexity of N more Iarge-scale system is higher;

(2) antenna baseline does not meet and optimizes the Optimality Criteria that provides of the present invention (Optimality Criteria of such as N=3 is 0.4 < B _1,2/ B _2,3< 0.6 or 0.4 < B _2,3/ B _1,2< 0.6; The Optimality Criteria of N=4 is 0.4 < B _1,2/ B _2,3< 0.6,0.4 < B _2,3/ B _3,4< 0.6 or 0.4 < B _2,3/ B _1,2< 0.6,0.4 < B _3,4/ B _2,3< 0.6), but system of equations (11) or (16) still can be made to meet condition, thus obtain flow field, the sea radial velocity after deviation compensation, just its error may be larger;

(3) described aircraft is aircraft, dirigible or satellite, and base length is relevant with the radar band adopted with platform flying speed, must meet following rule:

3.1 for the span of several conventional remote sensing radar band base length airborne platform (flying speed 100-200m/s) are:

L-band: 5 ~ 30 meters;

C-band: 1 ~ 6 meter;

X-band: 0.5 ~ 3 meter;

3.2 for the span of several conventional remote sensing radar band base length Space-borne (flying speed is about 7500m/s) are:

L-band: 200 ~ 1500 meters;

C-band: 50 ~ 200 meters;

X-band: 15 ~ 100 meters;

In sum, the present invention is based on straight rail interference SAR and measure the method introducing multiple antennas straight rail interference SAR pattern of flow field, sea radial velocity to resolve the higher order coefficient in interferometric phase, reduce interferometry velocity deviation, improve the accuracy of flow field, sea radial velocity measurement.

Above-described specific embodiment; object of the present invention, technical scheme and beneficial effect are further described; be understood that; the foregoing is only specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any amendment made, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (10)

1. measure a method for flow field, sea radial velocity based on straight rail interference SAR, it is characterized in that, comprising:

Steps A, arrange N number of antenna in the below of flying platform along heading, base length is unequal mutually between two, and this base length is the distance between two antennas;

Step B, launch SAR signal by any antenna in described N number of antenna, N number of antenna obtains N width SAR echo data to same Ocean Scenes simultaneously: Q ₁, Q ₂..., Q _n;

Step C, carries out interference treatment and multiple look processing between any two by described N width SAR echo data, obtains and interferes delay time T _i,jcorresponding interferometric phase data Φ _i,j, wherein:

${\mathrm{\&tau;}}_{i,j}=\frac{B_{i,j}}{2V_0}$

Wherein, B _i,jfor the base length between antenna i and antenna j, V ₀for the flying speed of flying platform;

Step D, will interfere delay time T _i,jand the interferometric phase data Φ of correspondence _i,jsubstitute in N (N-1)-1 rank Taylor expansion of following interferometric phase Φ, solve sea ocean current radial velocity V _r:

$\left\{\begin{array}{c}{\mathrm{\&Phi;}}_{1,2}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{1,2}+\underset{k=1}{\overset{N(N-1)/2-1}{\&Sigma;}}\frac{1}{(2k+1)!}{\mathrm{\&phi;}}^{(2k+1)}\left(0\right){\mathrm{\&tau;}}_{1,2}^{2k+1}\\ {\mathrm{\&Phi;}}_{1,3}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{1,3}+\underset{k=1}{\overset{N(N-1)/2-1}{\&Sigma;}}\frac{1}{(2k+1)!}{\mathrm{\&phi;}}^{(2k+1)}\left(0\right){\mathrm{\&tau;}}_{1,3}^{2k+1}\\ \mathrm{......}\\ {\mathrm{\&Phi;}}_{i,j}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{i,j}+\underset{k=1}{\overset{N(N-1)/2-1}{\&Sigma;}}\frac{1}{(2k+1)!}{\mathrm{\&phi;}}^{(2k+1)}\left(0\right){\mathrm{\&tau;}}_{i,j}^{2k+1}\\ \mathrm{......}\\ {\mathrm{\&Phi;}}_{N-1,N}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{N-1,N}+\underset{k=1}{\overset{N(N-1)/2-1}{\&Sigma;}}\frac{1}{(2k+1)!}{\mathrm{\&phi;}}^{(2k+1)}\left(0\right){\mathrm{\&tau;}}_{N-1,N}^{2k+1}\end{array}\right.$

Wherein, in described step C and step D, i=1,2 ..., N; J=1,2 ..., N; And i < j; λ is SAR radar electromagnetic wave wavelength, φ ^(2k+1)(0) be the 2k+1 rank term coefficient of the Taylor expansion of interferometric phase Φ.

2. method according to claim 1, is characterized in that, described N=3,4 or 5.

3. method according to claim 2, is characterized in that, described N=3;

Described step C comprises: obtain interference time τ _1,2corresponding interferometric phase data Φ _1,2; Interference time τ _1,3corresponding interferometric phase data Φ _1,3with interference time τ _2,3corresponding interferometric phase data Φ _2,3;

In described step D, the 5 rank Taylor expansions of described interferometric phase Φ are as follows:

$\left\{\begin{array}{c}{\mathrm{\&Phi;}}_{1,2}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{1,2}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{1,2}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{1,2}^5\\ {\mathrm{\&Phi;}}_{1,3}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{1,3}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{1,3}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{1,3}^5\\ {\mathrm{\&Phi;}}_{2,3}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{2,3}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{2,3}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{2,3}^5\end{array}\right.$

Wherein, φ ⁽³⁾and φ (0) ⁽⁵⁾(0) 3 rank term coefficient and the 5 rank term coefficient of the Taylor expansion of interferometric phase Φ are respectively.

4. method according to claim 3, is characterized in that, the setting position of described three antennas meets:

0.4<B _1,2/ B _2,3<0.6 or 0.4<B _2,3/ B _1,2<0.6

Wherein, B _1,2for the base length between antenna 1 and antenna 2; B _2,3for the base length between antenna 2 and antenna 3.

5. method according to claim 3, is characterized in that, described step C comprises:

Sub-step C1, carries out interference treatment between any two to three width SAR echo datas, obtains 3 width conjugation and interferes complex image data: Q ₁ ^*q ₂, Q ₂ ^*q ₃and Q ₁ ^*q ₃;

Sub-step C2, interferes complex image data Q to the conjugation of carrying out after interference treatment ₁ ^*q ₂, Q ₂ ^*q ₃and Q ₁ ^*q ₃carry out multiple look processing, obtain three interferometric phase data Φ _1,2, Φ _2,3, Φ _1,3:

${\mathrm{\&Phi;}}_{1,2}=\&angle;\underset{i=1}{\overset{M}{\&Sigma;}}{Q}_1^{\left(i\right)*}{Q}_2^{\left(i\right)},{\mathrm{\&Phi;}}_{2,3}=\&angle;\underset{i=1}{\overset{M}{\&Sigma;}}{Q}_2^{\left(i\right)*}{Q}_3^{\left(i\right)},{\mathrm{\&Phi;}}_{1,3}=\&angle;\underset{i=1}{\overset{M}{\&Sigma;}}{Q}_1^{\left(i\right)*}{Q}_3^{\left(i\right)}$

Wherein, M for look number more, and ∠ represents phase term, represent that i-th in certain resolution element that the n-th antenna obtains looks data, the interference time that these three interferometric phases are corresponding is respectively: ${\mathrm{\&tau;}}_{1,2}=\frac{B_{1,2}}{2V_0},{\mathrm{\&tau;}}_{2,3}=\frac{B_{2,3}}{2V_0},{\mathrm{\&tau;}}_{1,3}=\frac{B_{1,2}+B_{2,3}}{2V_0}.$

6. method according to claim 5, is characterized in that, the described interference treatment remnants comprised in straight rail interference SAR hand over the removal of rule component, spatial registration operation.

7. method according to claim 2, is characterized in that, described N=4;

Described step C comprises: obtain interference time τ _1,2corresponding interferometric phase data Φ _1,2; Interference time τ _1,3corresponding interferometric phase data Φ _1,3; Interference time τ _{isosorbide-5-Nitrae}corresponding interferometric phase data Φ _{isosorbide-5-Nitrae}; Interference time τ _2,3corresponding interferometric phase data Φ _2,3; Interference time τ _2,4corresponding interferometric phase data Φ _2,4; Interference time τ _3,4corresponding interferometric phase data Φ _3,4;

In described step D, the 11 rank Taylor expansions of described interferometric phase Φ are as follows:

$\left\{\begin{array}{c}{\mathrm{\&Phi;}}_{1,2}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{1,2}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{1,2}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{1,2}^5+\frac{1}{7!}{\mathrm{\&phi;}}^{\left(7\right)}\left(0\right){\mathrm{\&tau;}}_{1,2}^7+\frac{1}{9!}{\mathrm{\&phi;}}^{\left(9\right)}\left(0\right){\mathrm{\&tau;}}_{1,2}^9+\frac{1}{11!}{\mathrm{\&phi;}}^{\left(11\right)}\left(0\right){\mathrm{\&tau;}}_{1,2}^{11}\\ {\mathrm{\&Phi;}}_{1,3}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{1,3}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{1,3}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{1,3}^5+\frac{1}{7!}{\mathrm{\&phi;}}^{\left(7\right)}\left(0\right){\mathrm{\&tau;}}_{1,3}^7+\frac{1}{9!}{\mathrm{\&phi;}}^{\left(9\right)}\left(0\right){\mathrm{\&tau;}}_{1,2}^9+\frac{1}{11!}{\mathrm{\&phi;}}^{\left(11\right)}\left(0\right){\mathrm{\&tau;}}_{1,3}^{11}\\ {\mathrm{\&Phi;}}_{1,4}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{1,4}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{1,4}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{1,4}^5+\frac{1}{7!}{\mathrm{\&phi;}}^{\left(7\right)}\left(0\right){\mathrm{\&tau;}}_{1,4}^7+\frac{1}{9!}{\mathrm{\&phi;}}^{\left(9\right)}\left(0\right){\mathrm{\&tau;}}_{1,4}^9+\frac{1}{11!}{\mathrm{\&phi;}}^{\left(11\right)}\left(0\right){\mathrm{\&tau;}}_{1,4}^{11}\\ {\mathrm{\&Phi;}}_{2,3}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{2,3}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{2,3}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{2,3}^5+\frac{1}{7!}{\mathrm{\&phi;}}^{\left(7\right)}\left(0\right){\mathrm{\&tau;}}_{2,3}^7+\frac{1}{9!}{\mathrm{\&phi;}}^{\left(9\right)}\left(0\right){\mathrm{\&tau;}}_{2,3}^9+\frac{1}{11!}{\mathrm{\&phi;}}^{\left(11\right)}\left(0\right){\mathrm{\&tau;}}_{2,3}^{11}\\ {\mathrm{\&Phi;}}_{2,4}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{2,4}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{2,4}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{2,4}^5+\frac{1}{7!}{\mathrm{\&phi;}}^{\left(7\right)}\left(0\right){\mathrm{\&tau;}}_{2,4}^7+\frac{1}{9!}{\mathrm{\&phi;}}^{\left(9\right)}\left(0\right){\mathrm{\&tau;}}_{2,4}^9+\frac{1}{11!}{\mathrm{\&phi;}}^{\left(11\right)}\left(0\right){\mathrm{\&tau;}}_{2,4}^{11}\\ {\mathrm{\&Phi;}}_{3,4}=4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}}{\mathrm{\&tau;}}_{3,4}+\frac{1}{3!}{\mathrm{\&phi;}}^{\left(3\right)}\left(0\right){\mathrm{\&tau;}}_{3,4}^3+\frac{1}{5!}{\mathrm{\&phi;}}^{\left(5\right)}\left(0\right){\mathrm{\&tau;}}_{3,4}^5+\frac{1}{7!}{\mathrm{\&phi;}}^{\left(7\right)}\left(0\right){\mathrm{\&tau;}}_{3,4}^7+\frac{1}{9!}{\mathrm{\&phi;}}^{\left(9\right)}\left(0\right){\mathrm{\&tau;}}_{3,4}^9+\frac{1}{11!}{\mathrm{\&phi;}}^{\left(11\right)}\left(0\right){\mathrm{\&tau;}}_{3,4}^{11}\end{array}\right.$

Wherein, described φ ⁽³⁾(0), φ ⁽⁵⁾(0), φ ⁽⁷⁾(0), φ ⁽⁹⁾and φ (0) ⁽¹¹⁾(0) 3 rank of the Taylor expansion of interferometric phase Φ, 5 rank, 7 rank, 9 rank, 11 rank term coefficient are distinguished.

8. method according to claim 7, is characterized in that, the setting position of described four antennas meets:

0.4<B _1,2/B _2,3<0.6，0.4<B _2,3/B _3,4<0.6

Or 0.4<B _2,3/ B _1,2<0.6,0.4<B _3,4/ B _2,3<0.6 wherein, B _1,2for the base length between antenna 1 and antenna 2; B _2,3for the base length between antenna 2 and antenna 3; B _3,4for the base length between antenna 3 and antenna 4.

9. method according to claim 7, is characterized in that, described step C comprises:

Sub-step C1, carries out interference treatment between any two to four width SAR echo datas, obtains six width conjugation and interferes complex image data: Q ₁ ^*q ₂, Q ₁ ^*q ₃, Q ₁ ^*q ₄, Q ₂ ^*q ₃, Q ₂ ^*q ₄and Q ₃ ^*q ₄;

Sub-step C2, interferes complex image data Q to the conjugation of carrying out after interference treatment ₁ ^*q ₂, Q ₁ ^*q ₃, Q ₁ ^*q ₄, Q ₂ ^*q ₃, Q ₂ ^*q ₄and Q ₃ ^*q ₄; Obtain six interferometric phase data Φ _1,2, Φ _1,3, Φ _{isosorbide-5-Nitrae}, Φ _2,3, Φ _2,4, Φ _3,4:

${\mathrm{\&Phi;}}_{1,2}=\&angle;\underset{i=1}{\overset{M}{\&Sigma;}}{Q}_1^{\left(i\right)*}{Q}_2^{\left(i\right)},{\mathrm{\&Phi;}}_{1,3}=\&angle;\underset{i=1}{\overset{M}{\&Sigma;}}{Q}_1^{\left(i\right)*}{Q}_3^{\left(i\right)},{\mathrm{\&Phi;}}_{1,4}=\&angle;\underset{i=1}{\overset{M}{\&Sigma;}}{Q}_1^{\left(i\right)*}{Q}_4^{\left(i\right)},{\mathrm{\&Phi;}}_{2,3}=\&angle;\underset{i=1}{\overset{M}{\&Sigma;}}{Q}_2^{\left(i\right)*}{Q}_3^{\left(i\right)},$ ${\mathrm{\&Phi;}}_{2,4}=\&angle;\underset{i=1}{\overset{M}{\&Sigma;}}{Q}_2^{\left(i\right)*}{Q}_4^{\left(i\right)},{\mathrm{\&Phi;}}_{3,4}=\&angle;\underset{i=1}{\overset{M}{\&Sigma;}}{Q}_3^{\left(i\right)*}{Q}_4^{\left(i\right)}$

Wherein, M for look number more, and ∠ represents phase term, represent that i-th in certain resolution element that the n-th antenna obtains looks data, the interference time that these six interferometric phases are corresponding is respectively: ${\mathrm{\&tau;}}_{1,2}=\frac{B_{1,2}}{2V_0},{\mathrm{\&tau;}}_{1,3}=\frac{B_{1,2}+B_{2,3}}{2V_0},{\mathrm{\&tau;}}_{1,4}=\frac{B_{1,2}+B_{2,3}+B_{3,4}}{2V_0},{\mathrm{\&tau;}}_{2,3}=\frac{B_{2,3}}{2V_0},{\mathrm{\&tau;}}_{2,4}=\frac{B_{2,3}+B_{3,4}}{2V_0},{\mathrm{\&tau;}}_{3,4}=\frac{B_{3,4}}{2V_0}.$

10. method according to any one of claim 1 to 9, is characterized in that:

Described flying platform is aircraft or dirigible, and the span of described base length is: L-band: 5 ~ 30 meters; C-band: 1 ~ 6 meter; X-band: 0.5 ~ 3 meter; Or

Described flying platform is satellite, and the span of described base length is: L-band: 200 ~ 1500 meters; C-band: 50 ~ 200 meters; X-band: 15 ~ 100 meters.