Geometric inflight calibration of the stereoscopic CCD linescanner MOMS-2P

Abstract

This paper describes the geometric inflight calibration of the Modular Optoelectronic Multispectral Scanner MOMS-2P, which is collecting digital multispectral and threefold along track stereoscopic imagery of the earth´s surface from the PRIRODA module of the Russian space station MIR since October 1996. Goal is the verification and, if necessary, the update of the calibration data, which were deduced from the geometric laboratory calibration. The paper is subdivided into two parts, describing two different procedures of geometric inflight calibration: The first method is based on DLR matching software and is restricted to nadir looking channels, which are read out simultaneously. From very many individual point matches between the images of the same area taken by the different CCD arrays the most reliable ones are specially subselected and used to calculate shifts with components in and across flight direction between the CCD arrays. These actual shifts are compared to the nominal shifts, derived from the results of the laboratory calibration, and parameters of the valid camera model are estimated 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 high resolution channels. They are read out simultaneously with a nominal 10 pixel overlap in stereoscopic imaging mode A. The DLR matching software is applied to calculate the displacement vector between the two CCD-arrays. The second method is based on combined photogrammetric bundle adjustment using an adapted functional model for the reconstruction of the interior orientation. It requires precise and reliable ground control information as well as navigation data of the navigation-package MOMSNAV. 11 subsequent image scenes of MOMS-2P data take T083C are evaluated, which were taken in March 1997 building an about 550 km long strip over southern Germany and Austria. From both procedures calibration data are deduced, which are presented and compared to the lab-calibration results.