Long Time-series InSAR Surface Deformation Monitoring With Distributed Scatterers In Mining Area

With the increase of orbital SAR satellites,the accumulation of SAR datasets,and the increasing requirements for surface deformation monitoring,the conventional timeseries InSAR analysis techniques mainly focused on the analysis of high coherence point targets and has the problem of insufficient measurement points and low distribution density in mining area,causing the difficult to visually reflect the influence range of surface deformation of the mining area in practical application.In order to fully exploit the potential of multi-temporal SAR data in surface deformation monitoring,to overcome the limitation of the natural environment of the mining area on the current time-series InSAR analysis technology,it is possible to explore the distributed targets for ground deformation monitoring according to the different scattering characteristics of the ground targets.Based on the conventional PS-InSAR technology,this paper researches on method of monitoring the deformation by using the time-series InSAR technology with distributed targets,which had then been applied to monitor and analyzes the surface deformation of Peibei mining area,making its temporal and spatial evolution characteristics more clearer.Therefore,the main research work and concusions of the study are as follows:(1)The principle and data processing of InSAR and D-InSAR were briefly explained,and point out the limitations of InSAR technology;three kinds of Time-series InSAR analysis technology system--PS-InSAR technology with Single master image,SBAS technology with Multi master image and hybrid Time-series InSAR analysis technology were then presented;(2)The statistical properties of distributed targets are briefly described,and the second statistical moments of statistical characteristics of distributed targets--Sample Covariance/Coherence matrix are described in detail;Then,a variety of Non-Parametric hypothesis test and Parametric hypothesis test methods used for Statistically Homogeneous Pixels(SHPs)selection have been explained and summarized,systematically;(3)The basic concept of interferometric phase consistency is elaborated,and as a basic constraint condition,the phase optimization function model of Distributed target is proposed.Then,from the statistical properties and the multi-scattering mechanism of distributed target,the Maximum Likelihood Estimation(MLE)method,the sample Covariance matrix and Coherent matrix eigenvalue decomposition(C/T-EVD)method are used to implement the distributed target based on the phase optimization function model,and a unified form of phase optimization function is introduced.In terms of optimize efficiency,the sample Covariance/Coherence matrix eigenvalue decomposition does not need iterative analysis,and has the advantage of high computational efficiency.(4)The conventional PS-InSAR technology and the DS-InSAR method by integrating distributed targets had been utilized to monitor the surface deformation of the Peibei mining area,the mining(2007.02-2011.03)and at the present stage(2017.01-2018.12)of long-term surface deformation of the Peibei mining area was obtained by using SAR data from different periods.First,combined with the type of land cover in mining area,we demonstrate the advantages of integrating distributed targets for surface deformation monitoring,and analyze the deformation of major subsidence areas.Compared with conventional PS-InSAR result,the reliability of distributed target monitoring results was illustrated in a cross-validated way.The research shows that:(1)the DS-InSAR deformation results are basically consistent with PS-InSAR results,in spatial distribution trend;the DS-InSAR deformation results obtained by different phase optimization methods for distributed targets keep well,and the deformation rate difference is small.(2)DS-InSAR method combinded with Distributed targets can improve the continuity and integrity of deformation information by increasing the number of measurement points(MPs)and spatial distribution density,which help to locate the location of land subsidence and delineate the influence extent of surface subsidence caused by coal mining,and also helps to increase the probability of detecting surface deformation areas in mining areas.(3)Compared with the conventional PS-InSAR results,the DS-InSAR method based on the distributed target increase the number of Measurement Points(MPs)and spatial distribution density,which can make phase unwrapping more accurately to a certain degree,leading to improve the reliability of deformation estimation.Moreover,its can improve the consistency of deformation phase in spatial domain,which is beneficial to the extraction of significant surface deformation information.