Geometric in-flight calibration of the stereoscopic line-CCD scanner MOMS-2P

This paper describes the geometric in-flight calibration of the Modular Opt oelectronic Multispectral Scanner MOMS-2P, which has collected digital mult ispectral and threefold along-track stereoscopic imagery of the earth's sur face from the PRIRODA module of the Russian space station MIR from October 1996 to August 1999. The goal is the verification and, if necessary, the up date of the calibration data, which were estimated from the geometric labor atory calibration. The paper is subdivided into two parts, describing two d ifferent procedures of geometric in-flight calibration. The first method is based on DLR matching software and is restricted to nadir looking channels , which are read out simultaneously. From a high number of individual point matches between the images of the same area taken by the different CCD arr ays, the most reliable ones are selected and used to calculate shifts with components in and across flight direction between the CCD arrays. These act ual shifts are compared to the nominal shifts, derived from the results of the laboratory calibration, and parameters of the valid camera model are es timated from both data sets by least squares adjustment. A special case of band-to-band registration are the two optically combined CCD-arrays of the nadir high-resolution channel. They are read out simultaneously with a nomi nal 10 pixel overlap in stereoscopic imaging mode A. The DLR matching softw are is applied to calculate the displacement vector between the two CCD-arr ays. The second method is based on combined photogrammetric bundle adjustme nt using an adapted functional model for the reconstruction of the interior orientation. It requires precise and reliable ground control information a s well as navigation data of the navigation-package MOMS-NAV. Nine contiguo us image scenes of MOMS-2P data-take T083C building an about 550-km-long st rip over southern Germany and Austria taken in March 1997 were evaluated. F rom both procedures calibration data are estimated, which are presented and compared to the lab-calibration results. (C) 2000 Elsevier Science B.V. Al l rights reserved.