Recomputation of the Global Mars Control-Point Network (original) (raw)

2000, Photogrammetric Engineering and Remote Sensing

This paper deals with the recomputation of the global controlpoint network of the planet Mars. The existing Mars control point net is based on Viking data and consists of a large number of ground points, which can be easily identifed in the imagery and whose three-dimensional (30) object coordinates (e.g., latitude p , longitude A, and height h with respect to a reference ellipsoid) are known. These coordinates were redetermined in order to eliminate several disadvantages of the former computations and to include the currently best available input data such as improved Viking trajectory information, the Viking occultation data, present rotational parameters, and the Mars Pathfinder lander data. Within a simultaneous 30 bundle block triangulation, seven interior orientation parameters, the position and attitude pammeters of 1140 images, and the ground coordinates of 3739 tie points and one control point were estimated. The RMS values CLJ~, , q , J. Q of the theoretical standard deviations of the adjusted object coordinates amount to 750 m, 770 m, and 710 m, respectively, which is a significant improvement compared with former results (1 to 5 km). The accuracy of the ground point coordinates is close to the theoretical accuracy limit of 520 m in X, Y, and Z, where error-free orientation parameters are assumed. This new set of orientation parameters and ground points may now be used for local, regional, and global DTM genemtion; for the determination of reference bodies; for mapping purposes; as well as for current (Mars Global Surveyor 1996) and future (e.g.