DEM RECONSTRUCTION USING SHORT BASELINE ERS-1/2 TANDEM DATA AND SRTM DEM

摘要

Considering the geometry formula of synthetic aperture radar interferometry (InSAR), interferogram with short baseline is rarely used for Digital Elevation Model (DEM) generation. However, in some areas, high fringe frequency and geometry decorrelation caused by long baseline make phase unwrapping difficult. A new approach is presented in this paper to produce DEM in mountainous areas with a steep slope using interferogram with short baseline. Instead of ground control points (GCPs), an external DEM such as that from Shuttle Radar Topography Mission (SRTM) is used in this approach. Facilitated by SRTM DEM, systematic phase errors and unreliable height points are removed respectively. The application of this approach to an ERS Tandem interferogram with baseline of 16 m over the Three Gorges region in China shows that the resultant DEM agrees to a 1:50,000 DEM from National Center for Geomatics of China within about 50m.