A minimum model error approach for attitude estimation

In this paper, an optimal batch estimator and filter based on the Minimum Model Error (MME) approach is developed for three-axis stabilized spacecraft. This robust algorithm accurately estimates the attitude of a spacecraft with or without the utilization of angular rate measurements from gyros. The absence of rate data may be a result of intentional design or from unexpected failure of existing gyros. The formulation described in this paper is shown using only attitude sensors (e.g., three-axis magnetometers, sun sensors, star trackers, etc). The functional form of the optimal estimation approach involves a gradient search and a linearization technique with a linear Riccati transformation. This algorithm is computationally efficient and provides accurate state estimates. Results using this new algorithm indicate that an MME-based approach accurately estimates the attitude of an actual spacecraft with the use of only magnetometer sensor measurements.