Stephan Gehrke

HRSC on Mars Express - Photogrammetric and Cartographic Research

The High Resolution Stereo Camera (HRSC) on the European spacecraft Mars Express is the first camera on a planetary mission especially designed for photogrammetric and cartographic purposes. Since January 2004 the camera has been taking image data from the Martian surface, characterized by high-resolution, stereo capability and color. These data provide an enormous potential for the generation of 3D surface models, color orthoimages, topographic and thematic maps, and additional products. The image data acquired undergo calibration and systematic processing to orthoimages and 3D data products. Within the international HRSC Science Team the members of the Photogrammetric/Cartographic Working Group are concerned with further refinements in order to achieve highest quality data products. These activities comprise improvements of the exterior orientation of the camera, various approaches to enhance DTM quality, and the generation of maps in the standard scale of 1:200 000 and larger scales as well. The paper reports on these activities and the results achieved so far.

The Mapping Performance of the HRSC/SRC in Mars Orbit

The images obtained by the HRSC (High Resolution Stereo Camera) on Mars Express show excellent potential for topographic mapping of the planet. The derived stereo models agree with topographic data obtained earlier by MOLA (Mars Orbiter Laser Altimeter) on the Mars Global Surveyor: For the image scenes from the Mars Express commissioning phase that were studies, we find absolute difference in heights as small as 50 m and laterial positional differences along MOLA tracks of about 100 m. We show that HRSC effectively fills the gap between the MOLA tracks. SRC (Super Resolution Channel) images as well placed at their nominal geometric positions and reveal further detail within the HRSC context images. However, many of the images, fall short of the expected image quality for reasons to be examined.