Triple linear-array image geometry model of ZiYuan-3 surveying satellite and its validation

ZiYuan-3 (ZY-3) surveying satellite is China's first civilian high-resolution stereo mapping satellite. The satellite's objective is oriented towards plotting 1: 50,000 and 1: 25,000 topographic maps. Compared with plotting using foreign commercial mapping satellite imagery, establishment of the image geometry model is the core technical problem for different products and various applications of ZY-3 surveying satellite. This article analyses key problems of high-precision geometry processing based on the overall design, and proposes ZY-3 surveying satellite image geometry model with the technology of virtual CCD line-array imaging. In addition, this article utilises the first orbit imagery of ZY-3 satellite with coverage of Dalian region in Liaoning Province, and produces forward, backward and nadir camera calibrated products. Different ground control points are selected for the block adjustment experiment and the digital surface model (DSM), digital ortho-map (DOM) are generated. The accuracy is validated by check points. The experiment reveals that the planar accuracy of DOM and vertical accuracy of DSM are better than 3 m and 2 m, respectively. The experiment demonstrates the effectiveness of ZY-3 surveying satellite image geometry model.