Development of a robust attitude determination system for a nano-satellite

In this paper, robust attitude determination based on the indirect extended Kalman filter is proposed. For the nano-satellite, there are only two vectors of magnetic vector and sun vector for vector measurement without redundant sensors. Accordingly, the three-axis attitude determination using conventional algorithm is impossible when one of the vectors is not available. The proposed attitude determination method uses propagation based on satellite attitude dynamics. The gyro measurements are used for a measurement, and angular rates are estimated by measurements and control inputs. Thus the attitude propagation shows much smaller error than conventional attitude update in the simulation results.