Accuracy of geolocation and DEM for ASTER

Since the launch in December of 1999, ASTER (Advanced Thermal Emission and Reflection Radiometer) has collected more than 1,000,000 scenes of data and generated more than 10,000 DEM and ortho-rectified images (Level 3A) from them, covering 20% of the whole land. The relative and absolute accuracy of geolocation and DEM will be discussed by comparing GCPs (Ground Control Point), GIS (Geographic Information System) and other existing topographic map. ASTER has shown very high geometric accuracy even if any GCP is not available. Contributing factors to this high accuracy are the stability and knowledge of the space craft orbit and attitude, ASTER sensors geometry, information on the Earth movement, algorithm to calculate the line of site vectors, and so on. Discussion will also cover the applicability of the DEM and ortho-rectified image data, based on the accuracy, and the discussion on further improvement.