Radargrammetry for DEM generation using minimal control points

The erroneous satellite orbit causes significant distortions to the result of DEM (Digital Elevation Model) generated by radargrammetry. If accurate ephemeris data of satellite are available, satellite orbit parameters can be exactly determined without CPs (control points). If not, it must be refined by using the well defined CPs. For the refinement of orbit parameters, the acquisition of sufficient CPs is the most tedious and time consuming step and obstacle to near real time applications, especially for SAR (Synthetic Aperture Radar) imagery. This paper describes orbit parameters refinement method for radargrammetry using ephemeris data and only a single control point to resolve the CPs problem. The proposed method is applied to RADARSAT-1 SGF images of which ephemeris information is not accurate to directly use for accurate geometric modeling. The RMSE of the DEM generated by using a single CP (Control Point) is 43.86m, while that of the DEM generated by traditional method using 10 CPs is 45.79m in comparison with reference DEM that is generated from 1:5, 000 digital topographic maps.