The Application Of Permanent Scatters Insar Technique To Monitoring Three Gorges Landslide

Synthetic Aperture Radar Interferometry (InSAR) has been developed to a new geodetic technique over the past decades. It has made great efforts on topography and surface deformation measurement. On the measurement of surface deformation , its precision can reach mm level. Now many units in and out country apply InSAR to the research of surface deformation caused by landslide,city sedimentation and so on , the results of which have demonstrated that InSAR technique has huge potentials on detecting surface deformation . If the baseline both of time and space between two imagings, it will bring decorrelation .Such decorrelation and atmospheric effects bring difficulties to InSAR processing and affect accuracy of its results . To solve this problem , the doctor A. Ferretti of Italy put forward a new technique ofInSAR------Permanent Scatterers D-InSAR. This technique needs at least 25 images. It needschoosing one as master image , others as slave images . After gaining the differential interferometry graph , the points without any changes during long time can be picked out . Then analyze these points to get surface deformation.This thesis studies the area of Wanzhou in Chongqing city , which is in the center of Three Gorges reservoir area with many geological hazards such as landslide,rock-fall etc. Whether the building of Three Gorges dam can change the geologic surroundings of the area to make it occur landslide or not becomes the problem people careThe main part of this thesis is to apply PS InSAR technique to detecting the landslide in Wanzhou area . It introduces at first the basic principles of InSAR processing , then expounds PS InSAR theory and analyzes the key work of PS InSAR processing : the identification of PS and the subtraction of atmospheric effects . At last we use EV-InSAR software to process the 11 images of the studied area , obtaining the deformation of 8 PS points .The results of the processing show that the subsidence of most of the points achieve 10mm along the line of sight(LOS). In addition , using D-InSAR, we process two images of 2003/12 and 2004/01 .The results reveal that the studied area went down 0.1 -0.2mm along the LOS. It shows that the deformation directions of them are identical.