CN1940594A - Reconstruction for three-dimensional non-sided view on-board interfere synthetic bore radar - Google Patents

Abstract

The invention relates to the technical field of information acquisition and processing, in particular to a three-dimensional reconstruction method of a non-front-looking airborne interferometric synthetic aperture radar. The method includes: the first step is to draw a schematic diagram; the second step is to define the physical meaning in the schematic diagram; the third step is to grasp the distance relationship and establish the first relationship chain; the fourth step is to grasp the phase relationship and establish the second The relationship chain; the fifth step is to grasp the Doppler frequency relationship and establish the third relationship chain; the sixth step is to define the coordinate system of the orthogonal base; the seventh step is to select the orthogonal base coordinate system; the eighth step is to From the first distance relationship, 3D reconstruction can be realized according to the obtained line-of-sight vector BD.

Description

A kind of reconstruction for three-dimensional non-sided view on-board interfere synthetic bore radar method

Technical field

The information of the present invention relates to is obtained and processing technology field, particularly a kind of reconstruction for three-dimensional non-sided view on-board interfere synthetic bore radar method.

Background technology

Interference synthetic aperture radar (SAR) technology is on traditional SAR remote sensing technology basis, in conjunction with differential GPS and inertia measurement technology and the new spatial remote sensing technology that grows up has round-the-clock, the round-the-clock characteristics of obtaining the digital elevation image.The interference SAR technology is measured traditional SAR and is extended to three dimensions from high-resolution object image two-dimensionally, is considered to the unprecedented earth observation from space technology that has potentiality.

The west area of China has wide area, and wherein major part belongs to traditional aerophotogrammetric area in hardship.Comprise the Qinghai-Tibet topographic mapping more than 5000m above sea level, the southwest is because the influence that cloud layer covers causes the mapping of no figure or few map-area, boundary line mapping etc.In these areas in hardship because the influence of factors such as geographical environment, weather, the drafting of the topomap that the traditional photography measuring method is difficult to realize that these are regional all the time.Certain areas can't obtain 1: 50000 or more large-scale topomap that satisfies certain accuracy requirement, and certain areas are basic or even do not have a map-area.Airborne interference SAR is owing to have round-the-clock, the round-the-clock characteristics of obtaining large tracts of land high accuracy number elevation map picture, and, thereby can solve 1: 50000 engineer's scale or more large-scale ground mapping of the area in hardship that traditional photography measures with certain side-looking incident angle earth observation.Therefore, develop the national task that the polarization sensitive synthetic aperture radar system with interference imaging function can be used for finishing 1: 50000 topomap surveying and drawing western about 500,000 square kilometres of territories, have profound significance.

Summary of the invention

The airborne Interference synthetic aperture radar three-dimensional rebuilding method is one of airborne Interference synthetic aperture radar core technology.The present invention's " a kind of reconstruction for three-dimensional non-sided view on-board interfere synthetic bore radar method " has novelty and novelty, can satisfy the airborne Interference synthetic aperture radar three-dimensional reconstruction under the general flight condition.

Wherein, the airborne Interference synthetic aperture radar three-dimensional rebuilding method is one of core technology of airborne Interference synthetic aperture radar." a kind of reconstruction for three-dimensional non-sided view on-board interfere synthetic bore radar method " that we propose has novelty and novelty, can satisfy the airborne Interference synthetic aperture radar three-dimensional reconstruction under the general flight condition.

Conventional airborne Interference synthetic aperture radar three-dimensional rebuilding method, its model is simple, realizes being merely able to satisfy the sided view on-board interfere synthetic bore radar three-dimensional reconstruction easily.And the airborne Interference synthetic aperture radar three-dimensional rebuilding method of our invention has generality, and model is complicated, can satisfy the reconstruction for three-dimensional non-sided view on-board interfere synthetic bore radar needs.

Content core of the present invention, the firstth, provided the spherical wave model of phase place; The secondth, the ingenious orthogonal basis coordinate system that defined; The 3rd is to have provided the airborne Interference synthetic aperture radar three-dimensional rebuilding method.

Description of drawings

Fig. 1 is a reconstruction for three-dimensional non-sided view on-board interfere synthetic bore radar method flow diagram of the present invention.

Fig. 2 is an airborne Interference synthetic aperture radar three-dimensional rebuilding method vector correlation synoptic diagram.

Embodiment

The reconstruction for three-dimensional non-sided view on-board interfere synthetic bore radar method of Fig. 1, step is as follows:

The first step is drawn synoptic diagram;

Second step, the physical significance in the definition synoptic diagram;

In radar interference is measured, two slave antennas must be arranged, therefore, establish vector

Be the position of antenna 1, vector

Be baseline, i.e. the connecting line of two antennas, vector

And vector Be respectively the distance of echo, then vector to antenna 1 and antenna 2

Being the three-dimensional position that will obtain, is the problem that will solve;

The 3rd step, catch distance relation, to set up first and close tethers, the radar return that returns from ground must be to satisfy equidistant relation, this is a sphere relation, i.e. AD=AB+BD=AB+|BD|A, wherein, vector

Be vector

Unit vector, be called and look vector;

The 4th step, catch phase relation, set up second and close tethers, in the radar video that two width of cloth antennas obtain, include phase information, the phase differential of two images of two width of cloth antenna correspondences satisfies certain relation, promptly satisfies hyperbolic relation;

$\mathrm{\Φ}=\frac{2\mathrm{\π}\left|\stackrel{\→}{\mathrm{BD}}\right|}{\mathrm{\λ}}[\sqrt{1-\frac{2\stackrel{\→}{\mathrm{BD}}\·\stackrel{\→}{\mathrm{BC}}}{{\left|\stackrel{\→}{\mathrm{BD}}\right|}^2}+{\left(\frac{\stackrel{\→}{\mathrm{BC}}}{\stackrel{\→}{\mathrm{BD}}}\right)}^2}-1]$

The 5th step, catch doppler frequency relation, set up the 3rd and close tethers, radar return includes phase information, along with the orientation to distribution, have frequency change, i.e. doppler frequency, multispectral rein in the speed that implied in the centre frequency an amount of with the relation of looking vector, promptly $f_d=\frac{2}{\mathrm{\λ}}\stackrel{\→}{A}\·\stackrel{\→}{V},$ This is a tapered relation;

The 6th step, the coordinate system of definition orthogonal basis, this is a most crucial step of the present invention, in the above-mentioned physical relation formula, the antenna of radar changes in time and moves.Therefore, look vector and change in time and change, the correct suitable coordinate system of ingenious selection is crucial, and the connecting line vector that we choose two antennas is first base, promptly $\stackrel{\→}{n_b=\frac{\stackrel{\→}{B}C}{\left|\stackrel{\→}{\mathrm{BC}}\right|}},$ Second base is positioned at velocity plane, promptly ${\stackrel{\→}{n}}_c=\frac{\stackrel{\→}{V}-(\stackrel{\→}{V}\·{\stackrel{\→}{n}}_b){\stackrel{\→}{n}}_b}{|\stackrel{\→}{V}-(\stackrel{\→}{V}\·{\stackrel{\→}{n}}_b){\stackrel{\→}{n}}_b|},$ The 3rd base satisfies right-hand rule, promptly ${\stackrel{\→}{n}}_d={\stackrel{\→}{n}}_c\×{\stackrel{\→}{n}}_b;$

In the 7th step,, make the sight line vector because the ingenious of above-mentioned orthogonal basis coordinate system choose

Problem solve and to become very direct, definition $\mathrm{BD}=\left|\mathrm{BD}\right|(a_1{n}_b+a_2{n}_c+a_3{n}_d),$ According to second phase relation formula, can get a ₁According to the 3rd doppler frequency relational expression, can get a ₂According to orthogonality, can get a ₃

The 8th step is by first distance relation, according to the sight line vector that obtains

Can realize three-dimensional reconstruction.

Fig. 2 is an airborne Interference synthetic aperture radar three-dimensional rebuilding method vector correlation synoptic diagram.Wherein, A is a true origin, i.e. the O of coordinate point.B, C are two antennas, i.e. antenna 1 and antenna 2.D is the position of any point of being asked.Promptly realize the some position of three-dimensional reconstruction.V is a speed.

Claims (1)

1. A non-side-looking airborne interferometric synthetic aperture radar three-dimensional reconstruction method, its steps are as follows: The first step is to draw a schematic diagram; The second step is to define the physical meaning in the schematic diagram; In radar interferometry, there must be two antennas, therefore, let the vector

is the position of antenna 1, the vector

is the baseline, that is, the connecting line of the two antennas, the vector

and vector

are the distances from the echo to antenna 1 and antenna 2 respectively, then the vector is the three-dimensional position to be obtained; The third step is to grasp the distance relationship and establish the first relationship chain. The radar echo returned from the ground must satisfy the equidistance relationship, which is a spherical relationship, that is, AD=AB+BD=AB+|BD|A, Among them, the vector as a vector

The unit vector of is called the view vector; The fourth step is to grasp the phase relationship and establish the second relationship chain. The radar images obtained by the two antennas contain phase information, and the phase difference between the two images corresponding to the two antennas satisfies a certain relationship, that is, the two curve relationship; $\mathrm{<span\; class="notranslate">\; \&Phi;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; |</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; BD</span>}}<span\; class="notranslate">\; |</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}<span\; class="notranslate">\; [</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; BD</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; BC</span>}}}{{<span\; class="notranslate">\; |</span>\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; BD</span>}}<span\; class="notranslate">\; |</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>\frac{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; BC</span>}}}{\stackrel{<span\; class="notranslate">\; \&Right\; Arrow;</span>}{\mathrm{<span\; class="notranslate">\; BD</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ]</span>$ The fifth step is to grasp the Doppler frequency relationship and establish the third relationship chain. The radar echo contains phase information. With the azimuth distribution, there is a frequency change, that is, the Doppler frequency, and the Doppler center frequency The relationship between the appropriate amount of velocity and the view vector is implied, that is, $f_d=\frac{2}{\mathrm{\&lambda;}}\stackrel{\&Right\; Arrow;}{A}\&Center\; Dot;\stackrel{\&Right\; Arrow;}{V},$ This is a cone relationship; The sixth step is to define the coordinate system of the orthogonal base, which is the core step of the present invention. In the above physical relation, the antenna of the radar moves with time, therefore, the view vector changes with time, and the correct choice A suitable coordinate system is the key, and the connecting line vector of the two antennas is selected as the first basis, namely $\stackrel{\&Right\; Arrow;}{{\mathrm{no}}_b}=\frac{\stackrel{\&Right\; Arrow;}{\mathrm{BC}}}{\left|\stackrel{\&Right\; Arrow;}{\mathrm{BC}}\right|},$ The second basis lies in the velocity plane, namely ${\stackrel{\&Right\; Arrow;}{\mathrm{no}}}_c=\frac{\stackrel{\&Right\; Arrow;}{V}-(\stackrel{\&Right\; Arrow;}{V}\&CenterDot;\stackrel{\&Right\; Arrow;}{{\mathrm{no}}_b}){\stackrel{\&Right\; Arrow;}{\mathrm{no}}}_b}{|\stackrel{\&Right\; Arrow;}{V}-(\stackrel{\&Right\; Arrow;}{V}\&Center\; Dot;\stackrel{\&Right\; Arrow;}{{\mathrm{no}}_b}){\stackrel{\&Right\; Arrow;}{\mathrm{no}}}_b|},$ The third basis satisfies the right-hand rule, that is, ${\stackrel{\&Right\; Arrow;}{\mathrm{no}}}_d=\stackrel{\&Right\; Arrow;}{{\mathrm{no}}_c}\&times;\stackrel{\&Right\; Arrow;}{{\mathrm{no}}_b};$ In the seventh step, due to the selection of the above-mentioned orthogonal base coordinate system, the line-of-sight vector

problem solving becomes quite straightforward, defining $\mathrm{BD}=\left|\mathrm{BD}\right|(a_1{\mathrm{no}}_b+a_2{\mathrm{no}}_c+a_3{\mathrm{no}}_d),$ According to the second phase relational expression, a ₁ can be obtained; according to the third Doppler frequency relational expression, a ₂ can be obtained; according to the orthogonality, a ₃ can be obtained; The eighth step, according to the first distance relationship, according to the obtained line of sight vector Three-dimensional reconstruction can be realized.

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