Surface Deformation Monitoring Based On Polarimetric Timeseries InSAR Technology

Time-series Interferometric Synthetic Aperture Radar(TS-InSAR)technology has been widely used in deformation monitoring of many kinds of surface since its appearance.Compared with the traditional geodetic methods,the time-series InSAR technology can provide a wide range of deformation monitoring results.However,poor monitoring results often occur when the technique is applied in low coherence areas.It has been shown that multipolarimetric data can improve the deformation monitoring results of time-series InSAR technology.Therefore,from the perspective of how to effectively combine multi-polarimetric data and the TS-InSAR technology,this thesis studies the processing method of polarimetric TS-InSAR.The main research work of this thesis is as follows:(1)Aiming at the low computational efficiency of polarimetric phase optimization model based on pixel scattering mechanism,an improvement is proposed in this thesis.Through the comparison and parameter debugging of various optimization algorithms,the genetic algorithm with the best effect in the comparison result replaces the exhaustive algorithm in the original model.A best Scattering Mechanism model based on Genetic Algorithm(GA-BS)is proposed,and the validity and reliability of the model are verified.This paper takes Gaolan Port Economic Zone of Zhuhai city as the experimental area,and uses Sentinel-1A dualpolarimetric satellite image data to test the model.Compared with traditional singlepolarimetric processing method and polarimetric phase optimization model based on Trace Moment(TM)statistical characteristics and Total Power interferogram(TP),it is proved that GA-BS model can effectively improve the quality of deformation monitoring results.The experimental results obtained by this model are superior to the polarimetric phase optimization model based on the statistical characteristics of trace moment and total power interferogram.At the same time,the experimental results of the model are compared with the leveling data in the study area,which proves the reliability of the method.(2)In this thesis,a polarimetric distributed scatterer interferometry(PolDSI)model is proposed,which uses multi-polarimetric intensity data for homogeneous pixel identification and optimizes the interferometry phase based on the total power interferogram.In the experiment,the feasibility and reliability of the model method were explored by using the same research area and image data mentioned above.The experimental model is proved to be effective in increasing the number of DS measuring points by comparing with the singlepolarimetric DSI treatment.Meanwhile,compared with the processing results of singlepolarimetric DSI,the processing results of this model show more deformation details.By comparing the model processing results with the above leveling data,the reliability of the model method proposed in this thesis is proved.(3)In this thesis,the GA-BS model of polarimetric Persistent Scatterer Interferometry(PolPSI)is combined with the TP-based PolDSI model.The data processing model integrating PolDSI and PolPSI is established.The feasibility and reliability tests of the model were carried out in Gaolan Port Economic Zone of Zhuhai city and Chaoshan area of Guangdong Province,and the ground deformation in two areas was investigated and analyzed.In the experimental results of the two regions,the number of measuring points in the results of the model is far more than that of the single-polarimetric DSI+PSI treatment.Compared with the singlepolarimetric method,this model can obtain more deformation details in the study area and improve the deformation monitoring effect.In order to prove the reliability of the model,the method of horizontal data comparison and cross validation is used to prove that the model can obtain reliable deformation results.(4)In view of the surface deformation phenomenon in Gaolan Port Economic Zone and Chaoshan area,this thesis carries out time series analysis based on relevant local data.Analysis shows that the main reasons for the serious settlement in Gaolan Port area are the land reclamation project and the soft soil with high porosity ratio.The main reasons for the serious ground uplift and subsidence in Chaoshan area are the local groundwater pumping and the relevant policies adopted by the local government,as well as the local geological conditions of quaternary sediments.