In-orbit geometric calibration of HaiYang-1C coastal zone imager with multiple fields.

The HaiYang-1C coastal zone imager (CZI) consists of two independent cameras with a total image swath of approximately 1000 km. In order to obtain precise imaging parameters of the CZI cameras, a feasible in-orbit geometric calibration approach with multiple fields is presented. First, the master CCD is calibrated with a calibration field. Then, the slave CCDs are respectively calibrated with different fields. Finally, the calibrated internal shift parameters of the slave CCDs are adjusted with tie points between adjacent sub-images. Seven HaiYang-1C CZI images were tested. The experimental results showed that the imaging parameters calibrated with the presented approach could perform as well as those calibrated with the conventional approach with a single field. However, the total swath of the calibration fields could be reduced from approximately 1000 km to 300 km. The application difficulties in collecting satisfactory calibration sub-images could be thereby significantly reduced in the geometric calibration.