| With the development of the city, the damage of the land subsidence in Xi’an becamemore and more severe, which great restrict the development of the city and harm to people’slife. So it has great significance to monitor the land subsidence. differential InSAR is adeveloped microwave technology. This paper analyzed the main processes, and algorithms inthe D-InSAR data processing, and calculated the ground subsidence information of Xi’an.The main results obtained as follows:1. This paper analyzed the basic method of InSAR and D-InSAR, builded themathematical models and data processing, the effect of the corresponding parameters waspresented, and introduced the elevation changes in sensitivity and deformation sensitivity.2. The model and forming principle of speckle were analyzed. We used the mean filteralgorithm and Goldstein adaptive filter algorithm, and combined with ERS SAR data tocalculation and analysis, after the mean filter algorithm, the interference fringe had many loss,and there are still many noises; after the Goldstein adaptive filter algorithm, the moreinformation in the edge could be saved, it is a better filter algorithm. In order to monitor theland subsidence, we had better to select the Goldstein adaptive filter algorithm.3. Branch-cut method and minimum cost flow method were compared and demonstratedby the phase data. Branch-cut method can preserved the edge information of the area betterthan minimum cost flow method. And the minimum cost flow method can also get morereasonable result, even through in regions of low coherence. Both of methods can’t solve thephase unwrapping of ground subsidence, so we should choose the method of phaseunwrapping according to the actual situation in the actual processing.4. This paper collected8scenes ERS-1/2SAR SLC images and3scenes ENVISATASAR images from1992to2006about Xi’an to make data processing, and get thesubsidence information of corresponding period. It can monitor the land subsidenceinformation by D-InSAR technology. |
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