ABSTRACT 9461235 Curlander Under this proposal, a UNIX workstation-based software package will be developed which is capable of automatically deriving surface topography from a Radarsat SAR stereo pairs and data. The software system will be capable of using available ground control information to refine the platform position and velocity, and thus the accuracy of the derived DEM (digital elevation maps). The system will feature a robust quality assurance subsystem to minimize errors in the DEM, and it will be capable of orthorectifying the source images using the derived DEM. ***