CN103630903A - Method for measuring radial velocity of sea surface flow field based on along-track interferometry SAR - Google Patents

Abstract

The invention provides a method for measuring the radial velocity of a sea surface flow field based on an along-track interferometry SAR. According to the method, three antennas arranged in the along-track direction are used for acquiring three interferometric phases different in interferometric time, then, a high-order coefficient of velocity deviation in interferometric flow measurement can be estimated, and interferometric measurement speed deviation can be corrected, thus obtaining the accurate radial velocity of the flow field.

Description

Based on straight rail interference SAR, measure the method for flow field, sea radial velocity

Technical field

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

Background technology

Synthetic-aperture radar (Synthetic Aperture Radar, be called for short SAR) is to using the electromagnetic wave of microwave spectral coverage as carrier detection, by synthetic aperture, realizes the technology for information acquisition to the high-precision two-dimensional imaging of object of observation.Compare 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, two antennas are set, the base length between two antennas is B, one of them antenna transmission, and two antennas receive simultaneously.The mistiming of utilizing two receiving antennas to receive signal is calculated the radial motion speed of moving target.

For same scene, two antennas each become once as, but there is a mistiming

v wherein ₀for platform movement velocity.By comparing the phase differential of two width images, can obtain the radial velocity V of moving target in scene _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 velocity, ∠ represents phase term, and M is for looking number more,

the i that before and after being respectively, two width antennas obtain looks complex pattern information, and ∠ represents to get 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) be exactly speed without inclined to one side estimation, but for sea flow field survey, the Random Wave athletic meeting on sea causes (1) formula to have velocity estimation deviation.

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

$\left[\begin{array}{c}{Q}_1\\ {\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2\end{array}\right]={\mathrm{\&sigma;}}_x\left[\begin{array}{cc}1& 0\\ 0& \mathrm{<figure-callout\; id="4"\; label="exp\; j"\; filenames="HDA00003663390600023.png"\; state="\{\{state\}\}">exp\; j</figure-callout>}4\mathrm{\&pi;}{V}_r\mathrm{\&lambda;\&tau;}\end{array}\right]\left[\begin{array}{c}X\left(t\right)\\ X(t+\mathrm{\&tau;})\end{array}\right]+\left[\begin{array}{c}{N}_1\\ N_2\end{array}\right]---\left(2\right)$

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

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

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

Wherein, R _qfor vector $\left[\begin{array}{c}{Q}_1\\ {\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2\end{array}\right]$ Covariance matrix:

$R_Q={\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">X</figure-callout>}}^2\left[\begin{array}{cc}1& 0\\ 0& \mathrm{<figure-callout\; id="4"\; label="exp\; j"\; filenames="HDA00003663390600023.png"\; state="\{\{state\}\}">exp\; j</figure-callout>}4\mathrm{\&pi;}{V}_r\mathrm{\&lambda;\&tau;}\end{array}\right]R_X\left[\begin{array}{cc}1& 0\\ 0& \exp -\mathrm{<figure-callout\; id="4"\; label="j"\; filenames="HDA00003663390600023.png"\; state="\{\{state\}\}">j</figure-callout>}4\mathrm{\&pi;}{V}_r\mathrm{\&lambda;\&tau;}\end{array}\right]{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">N</figure-callout>}}^2\left[\begin{array}{cc}1& 0\\ 0& 1\end{array}\right]---\left(4\right)$

Wherein

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

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

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

In the situation of looking more, namely adopt a plurality of probability to carry out velocity estimation with the adjacent image point distributing, the joint probability density function of a plurality of like this picture point is:

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

Wherein, $\left[\begin{array}{c}{Q}_1^{\left(i\right)}\\ Q_2^{\left(i\right)}\end{array}\right]$ Be i depending in two multiple dispersion images that antenna obtains.

V _rmaximal possibility estimation be:

$\frac{\&PartialD;\ln f(Q_1^{\left(1\right)},Q_2^{\left(1\right)},\&CenterDot;\&CenterDot;\&CenterDot;,Q_1^{\left(M\right)},Q_2^{\left(M\right)})}{\&PartialD;V_r}=0---\left(7\right)$

Through deriving, can obtain V _rthe expression formula of maximal possibility estimation be:

Wherein,

interferometric phase,

r _x(τ) phase term.

R for 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 being determined by surface scattering doppler spectral, in research in the past often simply by R _x(τ) think the real number attenuation function of a Gaussian, ignore

also adopt (1) formula to calculate flow field, sea, will cause like this velocity estimation deviation:

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

$\mathrm{\&Gamma;}\left(\mathrm{\&omega;}\right)=P(\mathrm{\&omega;}+4\mathrm{\&pi;}\frac{V_r}{\mathrm{\&lambda;}})---(9-1)$

From the character of Fourier transform,

only occur in the situation that Γ (ω) is even function.And Γ (ω) is not even function in most of situation, unless radar incident direction is vertical with wind direction.Therefore in most of situation, ignore related function R _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, to the accurate measurement of Sea Current, can produce serious evaluated error, need to compensate.In realizing process of the present invention, applicant finds in the method for prior art based on straight rail interference SAR measurement flow field, sea radial velocity, owing to having ignored the phase term of surface scattering related function

thereby cause flow field, sea radial velocity measurement to occur error, and the many baselines straight rail interference technique being further evolved by conventional straight rail interference SAR technology is to place a plurality of receiving antennas in platform direction of motion, can further reduce like this impact of the decoherence effect of system noise and scene.But traditional many baselines straight rail interference SAR is measured the phase term of having ignored equally surface scattering related function for Sea Current 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 of 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, provide a kind of method of measuring flow field, sea radial velocity based on straight rail interference SAR.The method comprises:

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

Step B, arbitrary antenna transmission SAR signal in N antenna, N antenna obtains N width SAR echo data: Q to same Ocean Scenes simultaneously ₁, Q ₂..., Q _n;

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

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

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

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

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

(3) beneficial effect

From technique scheme, can find out, 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, can by conventional method, carry out the deviation in the flow field velocity measurement of sea by effective compensation, improve the measuring accuracy of sea flow field velocity;

(2) by conventional straight rail interference SAR technology, further developed, just increased one or more receiving antennas, 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 clearer, 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 description, similar or identical part is all used identical figure number.The implementation that does not illustrate in accompanying drawing or describe is form known to a person of ordinary skill in the art in affiliated technical field.In addition, although the demonstration of the parameter that comprises particular value can be provided herein, should be appreciated that, parameter is without definitely equaling corresponding value, but can in acceptable error margin or design constraint, be similar to corresponding value.

The invention provides a kind of method of measuring flow field, sea radial velocity based on straight rail interference SAR.The method utilization is obtained the interferometric phase of three kinds of different interference times at three width antennas of straight rail direction setting, thereby can estimate the higher order term coefficient of interfering flow measurement medium velocity deviation, and then can proofread and correct interferometry velocity deviation, obtain flow field, accurate sea radial velocity.

In one exemplary embodiment of the present invention, provide a kind of method of measuring flow field, sea radial velocity based on straight rail interference SAR.Fig. 2 is that the embodiment of the present invention is measured the process flow diagram of the method for flow field, sea radial velocity 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 is measured flow field, sea radial velocity based on straight rail interference SAR comprises:

Steps A arranges three antennas along heading below flying platform, 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, arbitrary antenna transmission SAR signal 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 are interfered between any two processing and are looked processing more, obtain the corresponding delay time T of interfering 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 distinguish respective antenna 1 and antenna 2, antenna 2 and antenna 3 time delay for these three kinds, and the interferometric phase between antenna 1 and antenna 3.

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

Sub-step C1, three width SAR echo datas are interfered processing between any two, obtain 3 width conjugation and interfere complex pattern data: Q ₁ ^*q ₂, Q ₂ ^*q ₃and Q ₁ ^*q ₃;

In this sub-step, interfere processing to comprise that the remnants in conventional straight rail interference SAR hand over the operations such as the removal of rule component, spatial registration.By interference, process, can remove the impact of the factors such as antenna baseline cross rail component, three width antenna SAR image space dislocation, thereby can reduce the error of interferometric phase.

Sub-step C2, to interfering the conjugation after processing to interfere complex pattern data Q ₁ ^*q ₂, Q ₂ ^*q ₃and Q ₁ ^*q ₃carry out looking processing more, 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 looking number more, and ∠ represents phase term,

represent that the i in certain resolution element that n antenna obtain looks data.The interference time that these three interferometric phases are corresponding is respectively:

${\mathrm{\&tau;}}_{\mathrm{1,2}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>}}_{\mathrm{1,2}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{2,3}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{2,3}}}{2V_0},$ ${\mathrm{\&tau;}}_{\mathrm{1,3}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>}}_{\mathrm{1,2}}+{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{2,3}}}{{2V}_0}.$

Step D, will interfere delay time T _1,2, τ _2,3, τ _1,3and interferometric phase Φ corresponding to difference _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 item coefficients and the 5 rank item coefficients of the Taylor expansion of difference interferometric phase Φ.

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 at place, τ=0 order derivative

According to the definition of autocorrelation function,

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

So

must be odd function, and we know that the even derivative of odd function must be 0, in addition delay time T be not more than in surface scattering situation correlation time, can ignore formula (12) formula in higher than the higher order term on 5 rank, so (12) formula can be written as:

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

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 calculate by sea random motion is carried out to modeling, but this need to accurately know the stormy waves information on sea, and this is difficult to accomplish in actual flow field survey.

In formula (14) formula, there are three unknown number (V _r, φ ⁽³⁾(0), φ ⁽⁵⁾(0)), need three times independently interferometry just can resolve.And just obtained three independent interferometries at 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 to simultaneous can be obtained:

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

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, can guarantee τ _1,2, τ _2,3, τ _1,3between unequal mutually, so just can guarantee that three interference are separate interferometries.System of equations (11) must have solution, solves the V of gained _rbe the sea radial velocity that does not contain deviation.

The resolution error of system of equations (11) depends on the conditional number of the matrix of coefficients of system of equations (11).For the conditional number of reduction ratio matrix, select the time delay of optimization to meet 0.4 < τ _1,2/ τ _2,3< 0.6 or 0.4 < τ _2,3/ τ _1,2< 0.6, and this is also to require base length to meet 0.4 < B above _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 is measured flow field, sea radial velocity based on straight rail interference SAR is introduced complete.

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

Steps A arranges four antennas along heading below flying platform, 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, arbitrary antenna transmission SAR signal 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 are interfered between any two processing and are looked processing more, obtain the corresponding delay time T of interfering 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

${\mathrm{\&tau;}}_{\mathrm{1,3}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>}}_{\mathrm{1,2}}+{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{2,3}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{1,4}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>}}_{\mathrm{1,2}}+{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{2,3}}+{\mathrm{<figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="4"\; label="B"\; filenames="HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{3,4}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{2,3}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{2,3}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{2,4}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{2,3}}+{\mathrm{<figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="4"\; label="B"\; filenames="HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{3,4}}}{2V_0},$ ${\mathrm{\&tau;}}_{\mathrm{3,4}}=\frac{{\mathrm{<figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="4"\; label="B"\; filenames="HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{3,4}}}{{2V}_0},$ Interfere for these six kinds and distinguish respective antenna 1 and antenna 2, antenna 1 and antenna 3, the interferometric phase between antenna 1 and antenna 4, antenna 2 and antenna 3, antenna 2 and antenna 4, antenna 3 and antenna 4 time delay.

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

Sub-step C1, four width SAR echo datas are interfered processing between any two, obtain six width conjugation and interfere complex pattern 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, interfere processing to comprise that the remnants in conventional straight rail interference SAR hand over the operations such as the removal of rule component, spatial registration.By interference, process, can remove the impact of the factors such as antenna baseline cross rail component, four width antenna SAR image space dislocation, thereby can reduce the error of interferometric phase.

Sub-step C2, to interfering the conjugation after processing to interfere complex pattern data Q ₁ ^*q ₂, Q ₁ ^*q ₃, Q ₁ ^*q ₄, Q ₂ ^*q ₃, Q ₂ ^*q ₄, Q ₃ ^*q ₄carry out looking processing more, 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 looking number more, and ∠ represents phase term,

represent that the i in certain resolution element that n antenna obtain looks data.The interference time that these six interferometric phases are corresponding is respectively:

${\mathrm{\&tau;}}_{\mathrm{1,2}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>}}_{\mathrm{1,2}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{1,3}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>}}_{\mathrm{1,2}}+{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{2,3}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{1,4}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>}}_{\mathrm{1,2}}+{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{2,3}}+{\mathrm{<figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="4"\; label="B"\; filenames="HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{3,4}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{2,3}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{2,3}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{2,4}}=\frac{{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{2,3}}+{\mathrm{<figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="4"\; label="B"\; filenames="HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{3,4}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{3,4}}=\frac{{\mathrm{<figure-callout\; id="3"\; label="B"\; filenames="HDA00003663390600022.png,HDA00003663390600023.png"\; state="\{\{state\}\}">\; <figure-callout\; id="4"\; label="B"\; filenames="HDA00003663390600023.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}}_{\mathrm{3,4}}}{{2V}_0}.$

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 interferometric phase Φ corresponding to difference _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, 5 rank, 7 rank, 9 rank, the 11 rank item coefficients of the Taylor expansion of difference interferometric phase Φ.

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

In addition, the above-mentioned definition to each element is not limited in various concrete structures or the shape of mentioning in embodiment, and those of ordinary skill in the art can know simply and replace it, for example:

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

For example, along N antenna of heading, the base length complementation between antenna is between two identical, thereby guarantees between the two corresponding interference times unequal mutually.Between antenna, interfere and can obtain between two

plant interferometric phase: Φ _{i, j}.Wherein, i=1,2 ..., N; J=1,2 ..., N; And i < j.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}substitution (15) Shi Ke get

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

By solving equation group (17), can obtain flow field, more accurate sea radial velocity V _r, preferably, N=3,4,5, in general as long as N < 30 can adopt, but the complexity of the larger system of N is just higher;

(2) (for example the Optimality Criteria of N=3 is 0.4 < B to the Optimality Criteria that the satisfied optimization the present invention of antenna baseline provides _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 still can be so that system of equations (11) or (16) meet condition, thereby 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 adopting with platform flying speed, must meet following rule:

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

L-band: 5～30 meters;

C-band: 1～6 meter;

X-band: 0.5～3 meter;

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

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 measures the method for flow field, sea radial velocity and introduces many antennas straight rail interference SAR pattern and resolve the high-order coefficient in interferometric phase, reduce interferometry velocity deviation, improved 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; institute is 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 modification of making, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (10)

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

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

Step B, arbitrary antenna transmission SAR signal in a described N antenna, N antenna obtains N width SAR echo data: Q to same Ocean Scenes simultaneously ₁, Q ₂..., Q _n;

Step C, interferes described N width SAR echo data between any two and processes and look processing more, obtains interference delay time T _{i, j}corresponding interferometric phase data Φ _{i, j}, wherein:

${\mathrm{\&tau;}}_{i,j}=\frac{B_{i,j}}{{2V}_0}$

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

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

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

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 item 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:

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

Wherein, φ ⁽³⁾and φ (0) ⁽⁵⁾(0) be respectively 3 rank item coefficients and the 5 rank item coefficients of the Taylor expansion of interferometric phase Φ.

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, interferes processing between any two to three width SAR echo datas, obtains 3 width conjugation and interferes complex pattern data: Q ₁ ^*q ₂, Q ₂ ^*q ₃and Q ₁ ^*q ₃;

Sub-step C2, to interfering the conjugation after processing to interfere complex pattern data Q ₁ ^*q ₂, Q ₂ ^*q ₃and Q ₁ ^*q ₃carry out looking processing more, obtain three interferometric phase data Φ _1,2, Φ _2,3, Φ _1,3:

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

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

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

6. method according to claim 5, is characterized in that, described interference is processed the remnants that comprise in straight rail interference SAR and handed 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;}}_{\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.$

Wherein, described φ ⁽³⁾(0), φ ⁽⁵⁾(0), φ ⁽⁷⁾(0), φ ⁽⁹⁾and φ (0) ⁽¹¹⁾(0) 3 rank, 5 rank, 7 rank, 9 rank, the 11 rank item coefficients of the Taylor expansion of difference interferometric phase Φ.

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, interferes processing between any two to four width SAR echo datas, obtains six width conjugation and interferes complex pattern 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, to interfering the conjugation after processing to interfere complex pattern 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; 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 looking number more, and ∠ represents phase term,

represent that the i in certain resolution element that n antenna obtain looks data, the interference time that these six interferometric phases are corresponding is respectively:

${\mathrm{\&tau;}}_{\mathrm{1,2}}=\frac{B_{\mathrm{1,2}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{1,3}}=\frac{B_{\mathrm{1,2}}+B_{\mathrm{2,3}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{1,4}}=\frac{B_{\mathrm{1,2}}+B_{\mathrm{2,3}}+B_{\mathrm{3,4}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{2,3}}=\frac{B_{\mathrm{2,3}}}{{2V}_0},$ ${\mathrm{\&tau;}}_{\mathrm{2,4}}=\frac{B_{\mathrm{2,3}}+B_{\mathrm{3,4}}}{2V_0},$ ${\mathrm{\&tau;}}_{\mathrm{3,4}}=\frac{B_{\mathrm{3,4}}}{{2V}_0}.$

10. according to the method described in any one in claim 1 to 9, it 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: wave band: 200～1500 meters; C-band: 50～200 meters; X-band: 15～100 meters.

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