LAUSR

ABSTRACT In-orbit calibration of satellite optical sensors is of crucial importance for improving the accuracy and stability of high-resolution satellite stereo mapping and positioning. For the in-orbit calibration of Ziyuan 3 (ZY-3), the first Chinese three-line stereo mapping satellite, a rigorous imaging geometric model of the three-line sensors is established and the internal systematic error is modelled during analysis of the satellite structure and charge-coupled device (CCD) array. To improve the accuracy and stability of the in-orbit calibration, a new trajectory model, piece-point with weight polynomial model, is used and compared with models in current use. In addition, an attitude constant error model is constructed and applied to reduce attitude errors and provide a more accurate initial attitude value, thus increasing the accuracy and stability of the in-orbit calibration. In addition, ground control point (GCP) stripes, established by partitioning GCPs into stripes, are proposed and used to eliminate random errors during in-orbit calibration. Finally, in-orbit calibration is performed for single and multiple sensors and the result of the calibration is assessed using GCPs and checkpoints. Based on the calibration result, variations of the three-line CCD array on ZY-3 are calculated and analysed in the along- and cross-track directions.