On-Orbit Geometric Calibration of the Panchromatic/Multispectral Camera of the ZY-1 02C Satellite based on Public Geographic Data

摘要

This paper describes the theory and method of on-orbit geometric calibration of the panchromatic/multispectral (P/MS) camera of the ZY-1 02C satellite. Instead of using a high quality test field specifically designed for camera calibration purpose, this study intends to make a use of readily available, public geographic data as the reference. Such public data may include Google Earth (TM) images, Bing Map images, SRTM DEM, and ASTER GDEM. For comparison purpose, the standard national digital orthophoto maps (Dom) and digital elevation models (DEm) are also utilized. To carry out the calibration, ground control points (GcPs) are selected by matching the satellite images to the reference data. It is shown that the calibration corrects large amounts of systematic errors caused by significant lens distortion and poor direct georeferencing. After calibration, the interior accuracy of the images is improved from a range of six to eight pixels to sub-pixel level, and the direct georeferencing accuracy is increased from 1.8 km to 115 m. The study demonstrates the necessity of camera calibration and the value of public geographic data for this need.