Insar Key Technology & Application In Deformation Monitoring

As an new space geodetic technology,Interferometric synthetic aperture radar (InSAR) had been testified a high potential means of earth observation providing a method for large range digital elevation model(DEM) and surface deformation monitoring of high precision.Registration algorithm and atmospheric especially the water vapor correction of interferogram is analysised and researched emphatically based on the principle of InSAR and data process in this dissertation.The correlation coefficient of image co-registration is based on the probability statistics,inseading statistic frequency average by space average to get the image matched on assumption.The matrix similarity degree is made as an index of image co-registration based on the discussion of similarity degree,and it presents a new view studying mechanism of image co-registration.The variable delay of the radar signal propagating through the atmosphere represents a major limitation to accuracy,it is not generally possible to separate out phase distortions caused by water vapor from topographic and deformation information using InSAR images alone.Most existing researches tried to reduce the atmospheric effects on repeat-pass InSAR using independent external datasets such as GPS and MODIS,but this is usually restricted by the the limited spatial resolution of GPS stations and the low resolution of MODIS which is asynchronous with InSAR data.The primary researching contributions of this dissertation are as as follows:(1) The matrix similarity degree based on the similarity is discussed,then the matrix similarity degree is made as an index of image co-registration analysising the correlation of interferometric images from the view of matrix similarity,which is much terser and more clarifies meaning than correlation coefficient grasping the mechanism of image co-registration.On this basis,a method computing the orient weighting matrix similarity degree is proposed based on the robust weighting function, useful for detecting and rejecting the the noises,precision and reliability of the algorithm is tested by the stimulant data.(2) Data process modules of Doris software are studied,and a detailed description about composition and parameter setting of each module especially for registration is given.Then ENVISAT ASAR data are used to obtain the surface deformation of bam post-earthquake by Two-pass Differential with Doris.The profiles and the isoline map for the maximal deformation areas caused by the fault zone are generated in order to carry out detailed interpretation and analysis,finally the crustal movement after earthquake is analyzed according to the existing research.(3) Comparative study on the water vapor estimation results derived from MODIS/MERIS and land based GPS stations at single point and time-space is given, and the corrected MODIS/MERIS water vapor by linear model based on GPS water vapor shows a better consistency with GPS water vapor.Then the comparison between Differential MERIS water vapor and Differential GPS water vapor verified that uncorrected MERIS water vapor can meet the demand for interferogram water vapor correction(4) A case study of applying Differential MERIS PWV to correct ASAR interferogram over Southern California is given,which shows that the standard deviation(STD) of interferogram is improved by 23%after the water vapor correction.Then the further comparison of the deformation results from uncorrected/corrected interferograms with GPS observation shows the deformation from the corrected interferogram is agree well with GPS,also verifies the effectiveness of the correction,the reliability of InSAR results is improved by 3% after water vapor correction.