3D Surface Deformation Monitoring Technology Based On Time Series InSAR

Since the advent of Interferometric synthetic aperture radar(InSAR)in the 1970 s,with its advantages of large-scale,high-precision,all-weather and all-time,InSAR has become an important method for human beings to understand the law of earth motion and prevent natural disasters in the field of remote sensing.As one of the emerging technologies to study surface deformation,time series differential interferometric synthetic aperture radar measurement technology has been widely used in many fields,such as land subsidence,mine deformation,landslide early warning and so on.Based on InSAR and high coherence points,this technology uses multiple SAR image data for time series analysis,so as to obtain the longtime deformation sequence of the surface,among which PS-InSAR and SBAS-InSAR are the most representative.However,the measurement results of time-series differential interferometry can only reflect the onedimensional projection of real three-dimensional deformation in the direction of radar line of sight,which is easy to affect the interpretation of deformation,which makes this technology have some limitations in practical application.By fusing multiple track data information of multiple platforms,the onedimensional deformation results can be extended to three-dimensional.In order to obtain high-precision one-dimensional deformation results and apply them to threedimensional deformation solution,based on interferometry,this paper makes an in-depth study on timeseries Interferometry Technology,and uses three-dimensional solution method to study urban settlement and landslide early warning.The main research contents and innovations are as follows:1.This thesis studies the principle of synthetic aperture radar interferometry and the process of sequential differential interferometry,focuses on the selection method of high coherence points in sequential InSAR technology,comprehensively applies PS scatters and DS scatters to sequential InSAR measurement,and uses the measured SAR data to identify high coherence points in mountainous areas,which proves that the joint recognition method of PS scatters and DS scatters has better effect in mountainous areas;The method of phase separation between atmosphere and nonlinear deformation in residual phase is studied.The effectiveness of filtering and EMD decomposition method in residual phase separation is proved by measured data and simulation experiments;2.Combining PS-InSAR method and SBAS-InSAR method,according to the principle of beamforming,a time series measurement method to remove atmosphere and reduce elevation error is designed.The original time series analysis process is improved,and a set of time series InSAR surface deformation monitoring process is designed and applied to the subsequent one-dimensional time series deformation calculation of cities;3.The three-dimensional surface deformation solution algorithm of multi satellite platform is studied.The one-dimensional deformation monitoring is carried out by using the 21 scene orbit lifting and 20 scene orbit lowering SAR data of sentinel-1a satellite in Kunming City,Yunnan Province from January2019 to September 2019.The urban settlement results are obtained by combining the three-dimensional solution method of multi platform,and the regional settlement trend is analyzed in combination with the actual Google Earth optical image,The experimental results show that the urban subsidence in Kunming is mainly caused by groundwater exploitation and engineering construction activities;4.A three-dimensional surface deformation solution method for mountainous areas is proposed.The landslide direction is determined by topographic gradient.According to the geometric relationship of radar imaging and the results of one-dimensional deformation solution,the three-dimensional deformation rate of the study area is obtained.Using 16 sentinel-1a satellite data,the three-dimensional deformation of a mountainous area in Qianxi County,Bijie City,Guizhou Province is calculated,and the east-west,north-south and vertical deformation rates in the study area are obtained.Combined with the actual Google Earth optical image,the regional landslide is compared and analyzed,and the results are consistent with the real landslide direction,which proves the effectiveness of this method.