Simulation, state determination, and control design for a small imaging spacecraft

This paper presents the design of the Attitude Determination and Control System (ADCS) for the SCOUT imaging spacecraft being developed by Andrews Space. The unique performance constraints of low-cost space vehicles present control and estimation challenges in terms of processor throughput and sensor noise. We discuss the implementation of an ADCS able to achieve sub 100m accuracy (at 450km altitude while pointing 30° off nadir) by making use of steady-state Kalman filtering for attitude determination, low-order gravity models for orbit propagation, and an LQR-based control system. We discuss the impact of various noise sources on the satellites knowledge error as well as how processor-in-the-loop testing was performed to prove out the feasibility of running the ADCS system on the target embedded platform.