Research On Surface Deformation Detecting By D-InSAR

Based on the phase information extracted from Synthetic Aperture Radar,Differential Interferometric SAR can measure the deformation form earthquake,volcano,glacier movements,land subsidence and landslide with a centimeter to millimetre accuracy.also, D-InSAR possesses many prominent merits, including the capability to work on all-of-day and atmospheric conditions, speediness high accuracy and large area observations.etc.In this thesis,detaild researches are done about the key processing arithmetic of D-InSAR.The main works are list as follows:1. The application and research actuality were summerised.The predominance was listed compared with other deformation detecting methods.Combinning with the imaging modes and basic theories of InSAR,the principles and common processing flow charts of D-InSAR were analyzed,so as to its differential mode and error sources.2. The SAR image registration methods in common use and its characters were introduced. For the sub-pixel precision,the multilevel registration strategy was adopt for SAR registration.The coherent coefficient method was used for coarse registration first,then the fine-registration was implemented with the coherent coefficient interpolation methodthe result indicated its feasibility and practicability.3.Several algorithms for interferogram filtering were achieved and the residue numbers was used for estimating their effect.The experiment show that:The traditional mean and median filter were not adapt for interferogram filtering.The periodic pivoting filter keeped the Periodic pivoting characteristic of interferogram better.The gradient-based adaptive filtering method has good performance in preserving the profile of the interference fringe.The improved Goldstein adaptive filter get rid of phase noise maximumly at a low loss of phase information.4.The direct phase integral method,branch-cutting method,quality map region growing method and least squares method were studied for phase unwrapping.The branch-cutting method was used for experiment with ERS-SAR data,The unwrapped phase was consistent with the result of Doris.It shows that the branch-cutting method can assure high efficiency if the interferogram has a good quantity.5.With ENVISAT ASAR data,the differential interferogram of巴姆area were obtained by D-InSAR technology. Then, preliminary interpretation was seted and deformation up to centimeter was detected, also,the suitability of D-Insar was analyzed.