The Extraction Of Three Dimensional Deformation Field Of Time Series Differential Interference SAR

For a long time, the surface activity is often dynamic change process from quantitative to qualitative change. As a coherent imaging system, the spaceborne SAR can not only provide amplitude, phase and frequency of a variety of features related to the large amounts of object information, but also by all-weather data acquisition capability and to revisit period of fixed to a surface area of temporal variation in long time continuous, stable observations, for scholars to reveal the learning phenomenon provides a great help.At present, In SAR technology is one of the representative technologies to obtain high precision elevation information. As its extension, D-In SAR technology has a great application prospect in the field of micro deformation monitoring and prediction of geological disasters. But it is influenced by time, space, and atmospheric delay. In view of this question, in the end of twentieth Century, the Italian professor Ferretti’s research group proposed the permanent body of the scattering body technology, can overcome the bottleneck problem which restricts the development of D-In SAR technology. In addition, compared with the traditional D-In SAR technology, the monitoring ability of the radar interferometry based on permanent scatter to the terrain deformation can reach the millimeter level accuracy.Firstly, this paper discusses the development of the theory and method of time series In SAR, and also analyzes and forecasts the development trend and Prospect of the technology. Then for PS-In SAR technology, analyzes the related principle and gives the data processing flow, do experiment on the key technology, and has carried on the analysis, mainly including SAR image registration, using coherent point target recognition method for detection of PS, PS network solution wrapped and linear parameter solution of the steps; at last, based on the measured data, using the technology to achieve the deformation rate of earthquake monitoring, combined with the side looking SAR imaging geometry, rough study area three-dimensional deformation rate field. The main research contents are as follows:1 SAR image registration. Using real ENVISAT SAR image, and select the center point of the image as a point of the same name, using basic parameters of SAR image header files, realize image coarse registration and registration results with In SAR processing software Doris software processing results are compared, the correctness of the algorithm is verified; Then, the sub pixel level registration algorithm based on the coherent coefficient method is studied, and the results of the track parameters rough registration are performed by comparing and analyzing the experimental results;2 Selection of coherent points. Of amplitude dispersion difference method, visual method two coherent point target extraction method, and the use of real ALOS satellite three pieces of the SAR image, respectively by amplitude from difference method, depending on the correlation method to extract coherent point, combining the two methods with the results of the study area of Google Maps, the correctness of the algorithm is verified and the results of two methods are compared and analyzed, analysis of their respective characteristics;3 PS network solution and the solution of linear parameters. After extraction of PS, PS network construction based on Delaunay triangulation method and PS network based on the construction of establishment phase difference model, and the parameters were estimated, finally, the least square adjustment method to solve linear parameters, the PS point on the deformation rate value and the elevation correction value is obtained; in order to draw the entire region of deformation velocity field, the Kriging interpolation method, interpolation model is chosen as the Gaussian model, obtained the entire region of deformation velocity field. The interpolation results with pre-set deformation rate field for comparative analysis and verify the algorithm’s correctness;4 Application example of PS-In SAR technology based on the measured data. The spaceborne satellite in 2008 November 10, 2009 to September 21, time taken in L’Aquila, Italy, area of the image is firstly, the eight pieces provided by ESA real satellite ENVIST SAR image and the area in April 2009 06 occurred an earthquake with a magnitude of 6.3, combined with NASA provided for the high precision SRTM digital elevation DEM, open-source In SAR processing Doris software platform based on selected on February 23, 2009 image based image, achieve 8 pieces of image registration to the differential interference pattern between the generation of all processes. Then, the time series In SAR processing software is used to realize the extraction of PS points and the solution of the winding steps. Finally, it is concluded that the shape variable rate. Finally based on the side looking SAR imaging geometry and angle relation, access to the area of L’Aquila in Italy in the period of three dimensional conformal transmission rate field.