Health Checking Autonomous Attitude Control System of Earth-Observing Miniature Satellite in Initial Orientation Modes

The problems of autonomous digital control of a spacecraft (SC) orientation and checking the operability of its attitude control system (ACS) in the initial orientation modes are considered. The developed methods, algorithms, and simulation results for a miniature Earth-surveying satellite in a Sun-synchronous orbit are presented. Autonomous angular guidance and modularly limited vector digital control using a vector of the modified Rodriguez parameters are applied to bring the SC's orientation from completely arbitrary to the required one. We briefly discuss the health check of the mini-satellite's ACS, as well as our discrete algorithms for onboard diagnostics of faults based on computer processing of available measurements and explicit relations.