Astrogeology Science Center

ISPRS 2003 Approaches for a Combined Adjustment of HRSC Image Data and MOLA Control Information

In this paper we focus on a detail concerning the estimation of exterior orientation parameters of the High Resolution Stereo Camera (HRSC) orbiting planet Mars during the European Mars Express mission. One of the challenges for the photogrammetric processing of HRSC images will be the low number of Ground Control Points (GCP’s) on Mars which can be identified and measured in the images in the usual way. Therefore, we want to use Mars Observer Laser Altimeter (MOLA)-data as control information in the photogrammetric bundle adjustment of HRSC images. Here, we discuss advantages and disadvantages of alternative approaches to improve exterior orientation parameters employing MOLA-data. The first approach assumes that each MOLA point lies in a plane defined by tree neighboring HRSC points. A similar approach could be applied, if there are less HRSC points than MOLA points. In this case we could take three MOLA points in the neighborhood of each HRSC point. The last approach we want to discuss uses a grid-based Digital Terrain Model (DTM) which has been derived from MOLA-data.