Self-Calibration Adjustment of CBERS-02B Long-Strip Imagery

Due to hardware limitations, such as the poor accuracy of its onboard Global Positioning System receiver and star tracks, the direct georeferencing accuracy of the China and Brazil Earth Resource Satellite 02B (CBERS-02B) by its onboard position and attitude measurements is less than 1000 m at times. Thus, the image data cannot be directly used in surveying applications. This paper presents a self-calibration bundle adjustment strategy to improve the georeferencing accuracy of the onboard high-resolution camera (HRC). An adequate number of automatically matched ground control points (GCPs) are used to perform the bundle adjustment. Both the systematic error compensation model and the orientation image model along with the interior self-calibration parameters are used in the bundle adjustment to eliminate the systematic errors. A self-calibration strategy is used to compensate for the time delay and integrated charge-coupled device translation and rotation errors by introducing a total of ten interior orientation parameters. The preliminary results show that the accuracy of self-calibration bundle adjustment is two pixels better than that of bundle adjustment without self-calibration, and the planimetric accuracy of the check points is about 10 m. The unusual variations of the exterior orientation parameters in some cases are eliminated after enlarging the orientation image intervals and increasing the weights of the onboard position and attitude observations.