Geometric inflight-calibration by block adjustment using MOMS-2P imagery of three intersecting stereo-strips

Abstract

Since May 1996 the German multi-line-scanner MOMS-2P (Modular Optoelectronic Multi-spectral Stereoscanner) is attached to the remote sensing module PRIRODA of the Russian space station MIR. Its stereo module with three differently oriented lenses allows for the acquisition of threefold along track stereoscopic imagery. After a long break in 1997, caused by the collision of MIR with a PROGRESS spacecraft, MOMS-2P is continously operating again since January 1998. The paper describes the geometric inflight-calibration and the simultaneous sensor orientation by photogrammetric block adjustment using imagery of the three intersecting MOMS-2P data takes T083C, T08C5 and T08FE, all covering parts of South Germany. Here, for the first time a block adjustment is applied to spaceborne 3-line-imagery of three different MOMS-2P data takes. The functional model for reconstruction of the exterior orientation is based on the principle of orientation images, the reconstruction of the interior orientation involves a set of 5 parameters per CCD-array and data take. The parameters and their changes are estimated in the block adjustment using 252 control points (inverse photogrammetry). Next, the accuracy of point determination with small subsets of control points is assessed using the remaining control points as independent checkpoints. In a further step a digital elevation model is derived from a dense cloud of homologous points, which is transformed into object space using the estimated interior orientation. The comparison with a reference DEM of superior accuracy showed unexpected systematic undulations in the MOMS-DEM. The major parts of the disturbances could be modelled, leading to a mean empirical height accuracy of 8 m for a 90 km x 50 km wide area. If all disturbances were eliminated, 7 m would be achieved. The results finally are summarized and conlusions are drawn.