Influence of external DEM and multi-look on deformation detection in coalfield

CHENG Xiaoqian; MA Chao; MA Wei

doi:10.16186/j.cnki.1673-9787.2018.02.008

Abstract：By using two-pass DInSAR technology,the ability of surface deformation was discussed based on high resolution SAR image.Multi look SAR and external DEM are key information sources of the two-pass DInSAR.Therefore,the quality of data affects the differential interference directly.Four interferometric image pairs of high resolution RDARSAT-2 with different external DEM (SRTM DEM,ASTER GDEM) and multiviews were used to investigate the influence of different external DEM and multi-view on deformation detection in mining area.Combined with the working face,the deformation was obtained by DInSAR and were analyzed along the profile.In order to explore the influence of the different external DEM and multi-view,the profile curve of deformation and the edge of the basin were fitted by Orign8.5 software.The results show that (1) in the condition of good coherence,both two external DEM can obtain the mining subsidence deformation areas and the deformation curve of subsidence profile is consistent with the mining subsidence.(2) SRTM DEM and ASTER GDEM obtain the similar deformations with the same multi-view of high resolution SAR images,which is because the large difference of resolution exists in DEM and SAR image.(3) multi-view affects the differential interference greatly with the same external DEM.The increasing multi-view smooth the noises,However,the detection ability of details are reduced.Therefore,selecting small multi-view maintains the advantage of high resolution SAR and improves the monitoring capacity of DInSAR in mining deformation detection.A high-er resolution of external DEM should be selected in order to make full use of the high resolution information of SAR and smaller multi-view to ensure the details.