Design and simulation of a nano-satellite attitude determination system

Abstract

Earth imaging satellites have typically been large systems with highly accurate and expensive sensors. With the recent push for Operationally Responsive Space, Earth imaging has potentially achievable with small and reletively inexpensive satellites. This has led to the research currently underway to develop very small, low-cost imaging satellites that can produce useful Operational-level and Tactical-level imagery products. This thesis contributes to that effort by developing a detailed design for the attitude determination for a tactically useful earth-imaging nano-satellite. Tactical Imaging Nano-sat Yielding Small-Cost Operations and Persistent Earth-coverage (TINYSCOPE) is an ongoing investigation at NPS, concerning using a nano-satellite, based on the CubeSat standard, to achieve Earth imaging from LEO orbit. A detailed design of the attitude determination system includes sensor selection ahd characterization, as well as high fidelity simulation via MATLAB/Simulink. The attitude determination system is based on an Extended Kalman Filter using multiple sensor types and data rates. The sensors include a star tracker, sun sensor, gyroscope and magnetometer.