利用Sentinel-1A/-1B升降轨SAR数据提取DEM与精度分析

DEM extraction and accuracy analysis by using Sentinel-1A/-1B SAR data

目前能免费获取的ASTER G DEM、SRTM DEM等产品,不能实时表达地表地形实际特征,尤其在矿区,使这些DEM应用具有一定的局限性。为此,本文利用InSAR技术提取DEM来更新研究区DEM。以鞍山市城区、郊区及矿区作为研究区,首先用In SAR技术处理Sentinel-1A/-1B卫星平台升降轨SAR数据并提取S1A DEM及S1B DEM,再用小波变换融合技术对提取的DEM进行融合,最后用交叉验证法、同名采样点高程差值统计分析法及高程差值剖面分析法对DEM进行分析。结果表明,利用Sentinel-1A/-1B升降轨SAR数据提取DEM并对其融合是可行的,在表达地形特征方面,提取DEM要优于参考DEM;采样点高程差值小于15m的比例达84. 5%,对提取DEM进行融合能使精度有所提高;地形平坦的城区及郊区,提取DEM精度要高于山区,差值较大区域主要分布在矿区,主要是因为矿产开采而导致地表高程降低。

At present,the elevation products,such as ASTER G DEM and SRTM DEM,can be obtained free of charge,which cannot show the surface topography in real time,especially in the mining area,so the application of these DEM has certain limitations.Therefore,this paper uses In SAR technology to extract DEM to update the DEM in the research area.In this paper,Anshan city,suburb and mining area,is taken as the research area.Firstly,the SAR data of Sentinel-1 A/-1 B are processed by InSAR technology to extract S1 A DEM and S1 B DEM,and then the extraction DEM is fused by wavelet transform fusion technology.Finally,the DEM is analyzed by cross validation,statistical analysis of height difference of sampling points of the same name and profile analysis of elevation difference.The results show that it is feasible to extract DEM from Sentinel-1 A/-1 B SAR data of ascending and descending orbits.In terms of terrain features,the obtained DEM is better than the reference DEM;the proportion of elevation difference of sampling points less than 15 m is 84.5%,and the accuracy of DEM extracted is improved by fusion ascending and descending orbit results.The accuracy of DEM extraction is higher in urban and suburban areas with flat terrain than in mountainous areas,and the areas with large difference are mainly distributed in mine area,which is mainly due to the mining activity resulting in the reduction of surface elevation.