First Results on Shuttle Orbit Adjustment Using MOMS-02 Imagery.

Abstract

As part of the 2nd German Spacelab misssion (D2) the MOMS-02 scanner has collected high-resolution images with 5 m and 14 m ground pixel size. Based on a 3-line CCD-concept, direct and simultaneous stereo imaging is enabled through nadir, forward, and backward looking CCD lines, that allow to view terrestrial at different aspect angles. Given the known camera position and orientation, the ground position of object points can be determined from MOMS-02 images within the stereoscopic evaluation. In extension of current photogrammmetric algorithms a combined approach to orbit determination and photogrammmetric restitution has been developed, which allows the simultaneous adjustment of orbital parameters and ground coordinates.To this end, the spacecraft trajectory and the covariance matrix from the orbit determination process are incorporated into the photogrammetric processing with associated partial derivatives of spacecraft positionwith respect to epoch state and model parameters. Statistically the resulting estimation procedure is equivalent to a combination of orbit determination and photogrammetric restitution from radio tracking data, 3-line stereo image data and ground control point information. The first results of this combination applied to the MOMS-02 experi- ment are presented. To this end MOMS-02 images and a priori epoch state vector of the space shuttle are combined together with GPS- derived ground control points to estimate a consistent set of ground point coordinates and shuttle orbital parameters. The resulting epoch state vector, that reflects the navigational information content of the MOMS-02 imagery and GPS control points, is analyzed and compared to the original orbit solution. Conclusions regarding the benefit from the combination of orbit determination and photogrammetric image restitution are drawn.