Monitoring And Analysis Of Surface Deformation In Mining Area Based On InSAR

China has abundant coal mine resources,and the damage caused by coal mining activities to land resources and the ecological environment due to surface deformation has attracted widespread attention.In this context,how to adopt a high-precision,low-cost,real-time and fast monitoring method to effectively monitor the occurrence and evolution trend of surface deformation in mining areas for a long time has become a hot research topic.Compared with traditional measurement techniques such as GPS,InSAR technology has the advantages of all-time,all-weather,large-scale,high precision,low cost,and high safety,making it an important technology for surface deformation monitoring.Using InSAR technology to monitor and analyze surface deformation in mining areas,in order to improve the applicability of InSAR technology in monitoring surface deformation in mining areas and provide theoretical and technical support for the safety and sustainable development of mining activities.The main contents include:(1)The basic principle of InSAR technology.This paper introduces the basic principles and processing flow of InSAR and DInSAR technologies,and provides overviews of the basic principles and processing flow of Stacking-InSAR,PS-InSAR,and SBAS-InSAR technologies in time-series InSAR.(2)An adaptive mean filtering method based on quality factor is proposed.Due to the complex terrain conditions in mining areas,the interferometric phase map contains a large amount of noise and requires filtering.The filtering effect is directly related to the accuracy of the phase unwrapping and deformation results.Therefore,it is necessary to use an appropriate filtering method to suppress phase noise and improve the reliability of phase information.In this paper,a mean filtering method based on quality factor is proposed to deal with the problems of noise removal and phase information retention of interference phase maps.The method uses three quality indexes,pseudo coherence coefficient,phase derivative variance and maximum phase gradient to form the quality factor,and assigns the mean filter window size according to the quality factor,so as to achieve effective noise suppression and phase information retention in different regions.Through the experimental verification and analysis of simulated data and real data,the results show that the proposed method can effectively suppress noise and maintain phase information,and improve the quality of interference phase map.(3)The fusion of DInSAR-PS-Stacking and SBAS-PS-InSAR methods was proposed to monitor surface deformation in mining areas.Taking a coal mine in Yijin Holuoqi,Ordos City,Inner Mongolia Autonomous Region as an example,this study uses Sentinel-1A data from January 2018 to October 2019 to select stable ground control points by using the PS three-threshold method(coherence coefficient threshold,amplitude dispersion index threshold,deformation velocity interval)based on permanent scatterers,which solves the problem of manually selecting ground control points during refinement and re-flattening.The DInSAR-PS-Stacking method and the SBAS-PS-InSAR method combined with the PS three-threshold method were proposed to obtain good deformation monitoring results,and the surface deformation results monitored by the two InSAR methods were compared,verified and analyzed.Considering the advantages of these two InSAR methods,the temporal deformation results obtained by these two InSAR methods were fused by the double threshold method(deformation threshold and average coherence threshold).The results show that the deformation information obtained by the comparison and fusion of multiple InSAR methods can better and more comprehensively monitor and analyze the surface deformation of mining areas,and provide scientific reference for mining subsidence control and disaster early warning.