Ground Deformation Monitoring Of Shenzhen Urban Area With Interferometric Point Target Analysis

Land Subsidence is a vertical surface deformation phenomena formed from natural factors and human factors. Serious land subsidence would become a geological disaster. In China, more than96cities and regions have occurred land subsidence in different degrees, causing economic losses over hundred billion Yuan. Land subsidence has been one of the major geological disasters to constrain regional environmental and social economic sustainable development.Synthetic Aperture Radar differential interferometry (DInSAR) has the advantages of wide coverage, all-weather, high-precision monitoring of land subsidence. It has become a new, economic earth observation technologies in land subsidence monitoring field. However, the spatio-temporal decorrelation and atmospheric delay seriously restrict the application of DInSAR techniques. PSInSAR technology can overcome the effects of decorrelation and atmospheric delay indirectly, with stable scatter properties of PS point to obtain time series analysis of phase information, access to the surface deformation. But PSInSAR technology requires a larger amount of data, generally at least30.In this thesis, adopting a new PSInSAR technique Interferometry Point Target Analysis (IPTA), short-term land subsidence monitoring test for small data sets, acquired the conclusion of the reference value. The study is divided into the following aspects:1、IPTA technology is used to deal with small data ASAR images. The key issues in IPTA processing is analyzed. Based on the spectral properties of individual SLC and based on a low intensity variability to select the candidate point target. Considering the correctness and the distribution density of the candidate point target, optimization of key parameters and extracting the candidate point target. IPTA processing is based on two-dimensional linear phase model to Regression analysis, and by iterative regression analysis of the gradual elevation to correct the value of the candidate point target and the relative linear deformation rate, and ultimately acquire for the average deformation rate image. 2、Analyzing land subsidence of the study area. The results showed that the deformation rate in satellite line of sight (LOS) is-14.4mm/a～8.6mm/a, indicating that the Shenzhen City has different degrees of surface subsidence, and the most serious ground subsidence is occurred in Bao’an District and reclamation District. On the basis of the information of land subsidence in Shenzhen urban, land subsidence along the Shenzhen Metro is extracted. A large area of reclamation and subway construction is the main reason of land subsidence for the Shenzhen City.