Abstract: The microsatellite has low accuracy of attitude and position measuring equipment, due to the limitations of platform volume, weight and energy, which results in large direct positioning error. Through the calibration of the constant angular error of the multi-view images in the Songshan area, we found that the system error of attitude angle varies linearly with time. This paper proposes an on-orbit geometry calibration model based on two-dimensional direction angle of detector and offset matrix with attitude linearity error to improve the positioning accuracy. Compared with the traditional constant angular model, this paper considers the law of linear variation of attitude angle system with time. The experimental results show that after the internal and external orientation elements are calibrated, the positioning accuracy of the satellite is increased from tens of kilometers to less than ten meters. The proposed calibration model effectively eliminates the system error of attitude angle varying linearly with time compared with the traditional constant angular model.

Key words: microsatellite, rigorous geometric model, calibration of parameter, linear angular error model, two-dimensional direction angle of detector