Timeseries InSAR Monitoring Method And Application For Wide-area Surface Deformation Information Extraction

Geological disasters refer to sudden disasters caused by slow changes in the regional geological environment,which pose a significant threat to the ecological environment and the safety of people’s property.According to data,in 2022,5659 small and medium-sized landslides,collapses,debris flows and other geological disasters occurred nationwide,causing huge economic losses and casualties.Therefore,strengthening regional real-time dynamic surface deformation monitoring and mastering the laws of geological environment change are of great significance for the prediction and early warning of geological disasters,ecological environment restoration,and geological disaster assessment.Synthetic Aperture Radar Interferometry(InSAR)technology can make up for the shortcomings of traditional measurement methods such as low efficiency and sparse measurement points.This technology has the advantages of high spatiotemporal resolution,all-weather,all-weather,and large-scale surface deformation monitoring,and can meet the needs of wide-area surface deformation monitoring.Time series InSAR technology is widely used in mining areas,cities,landslides,and other fields,which can weaken the impact of various errors and achieve millimeter level accuracy monitoring.However,due to the limitations of the width of the radar image,it is difficult for a single radar image to cover a large range of research areas,and it is necessary to fuse monitoring data from adjacent orbits or different strips of the same orbit to complete the extraction of wide-area surface deformation information.In addition,the impact of tropospheric atmospheric delay errors on the results should also be considered when using InSAR technology to monitor wide-area surface deformation in coastal areas.In response to the above issues,the thesis has carried out research on atmospheric delay correction methods based on wavelet changes and data fusion methods for multiple orbits,long strips,and time series,with the aim of reducing atmospheric delay phase errors and completing wide-area surface deformation monitoring with high accuracy.The main research content and results of this article are as follows:(1)This thesis summarizes the development history,research status,and application of InSAR technology,expounds the basic principles and data processing flow of D-InSAR technology,analyzes various phase components in the interferogram,and points out the limitations of D-InSAR technology.Subsequently,the basic principles of three commonly used timing InSAR technologies,PS-InSAR,SBAS,and Sta MPS,are introduced in detail.(2)A method of atmospheric delay correction based on wavelet transform is proposed.Using the characteristic that atmospheric delay error is independent of polarization mode,two polarization modes sensitive to different scattering mechanisms are selected.The differential interferograms obtained by the two polarization modes are subjected to wavelet multiresolution analysis,and the high-frequency coefficients of each decomposition scale are subjected to correlation analysis.The high-frequency coefficients with high correlation are subjected to weight reduction processing to weaken the impact of tropospheric atmospheric delay error.(3)The methods of multi orbit,long strip,and time series data fusion are studied.According to the different reference standards between different strips on the same track,the overall deviation between strips is used for long strip data fusion;Aiming at the differences between coordinate systems and reference datums between different orbits,the method of spatial weighted average of identical points in overlapping regions is used for data fusion;Aiming at the deviation of acquisition time of SAR images with different orbits and stripes in time series,the overall deviation between coherent target points is used for data fusion in time series to obtain accumulated ground deformation information after data fusion.(4)Taking the Shandong Peninsula as the research area,using the above atmospheric delay correction method based on wavelet transform and the data fusion method of multiple orbits,long strips,and time series,the SAR images covering five different orbits and different strips of seven prefecture-level cities in the Shandong Peninsula were processed using wide-area surface deformation time series InSAR,and the surface deformation information during 2021 was obtained.The results show that there are many obvious surface deformation areas in Shandong Peninsula,mainly concentrated in the Yellow River Delta region,near the Guangrao Economic Development Zone in the south of Guangrao County,Binzhou City,and at the junction of Guangrao Shouguang.Through field research and analysis,the main factors causing surface deformation are excessive exploitation of underground brine,overload exploitation of underground oil and gas resources,and extraction of underground industrial water.The thesis has 33 figures,5 tables,and 109 references.