Attitude planning and control method of low-orbit optical satellite along-track stereoscopic imaging

To improve the point accuracy of along-track stereoscopic imaging, a larger coverage area must be obtained；that is, the effective area for stereoscopic imaging must be improved. Herein, first, a method for attitude planning of along-track dual/triple perspective stereoscopic imaging is designed, which adopts the earth ellipsoid model and considers the earth rotation and satellite rolling direction maneuver. Next, to reduce the maneuver time and to increase the area that can be imaged by the satellite in a single shot, a method called path planning fast maneuver control is designed considering the actuator moment and angular momentum constraints, including two parts. According to a situation wherein the angular velocity of the satellite is limited owing to the torque and angular momentum constraints of the actuator, a three-axis maneuver attitude planner with the shortest path and continuous angular acceleration is designed based on the invariant rotation axis constraint. An attitude maneuver algorithm combining angular acceleration feed-forward and internal–external loop control is further designed to improve the dynamic performance of attitude tracking. Finally, a mathematical simulation is conducted with the parameters of the Jilin-1 satellite, whereby the control accuracy is better than 0. 02°, the stability is better than 0. 001（°）/s, and the imaging duration is no less than 10 s. During the in-orbit test, the stereo image pairs and digital surface models of Urumqi city are obtained, with an effective coverage area of 1600 km2 and an overlap rate of dual-view imaging exceeding 97%, which verifies the feasibility and effectiveness of the along-track dual-view stereo imaging planning and control method. © 2022 Chinese Academy of Sciences. All rights reserved.