In‐Orbit Geometric Calibration And Validation Of Zy‐3 Linear Array Sensors

Abstract The ZiYuan‐3 surveying satellite ( ZY ‐3), launched on 9th January 2012, is China's first civilian high‐resolution stereo mapping satellite. To ensure the mapping accuracy of ZY ‐3, considerable research has been conducted since its launch on the calibration and validation of its three‐line array charge‐coupled device ( CCD ) sensors ( TLC sensors). Its dynamic exterior systematic errors (such as camera installation errors) and static interior distortion were eliminated using 1:2000 digital orthophotomaps and digital elevation models ( DEM s) of the Dengfeng (Henan) and Tianjin areas of China as control data. Various CCD alignment calibration models were compared, on the basis of their geometric accuracy after calibration, to determine the optimal model. Finally, validation experiments were performed using ZY ‐3 TLC images and ground control points ( GCP s) collected over Anping in Hebei Province, Zhaodong in Heilongjiang Province and the Taihang Mountain area in China. The positioning accuracy attained its theoretical value over the Anping and Zhaodong areas. Using GCP s whose image coordinates were obtained manually, the plan and height accuracy were found to be better than 3 m and 2 m, respectively.