On-the Fly Merging of Attitude Solutions

Recent advances in autonomous attitude determination instrumentation enable even small satellites flying fully autonomous multi head star trackers providing full accurate and robust attitude information. Each sensor provides the full attitude information but for robustness and optimal usage of the available information, i.e. optimal accuracy, methods for merging such data should be investigated.

The need for and desirability of attitude merging depends on the mission objective and available resources. To enable real-time attitude control and reduce requirements on download budget, on-board merging of attitude data will often be advantageous. This should be weighted against the need for post observation reconstruction of attitudes, especially needed when end products are sensitive to optimal attitude reconstruction.

Instrument integrated merging algorithms will reduce the complexity of on-board AOCS. Methods for attitude merging are many. Two examples of merging methods taking into consideration anisotropic noise distributions are presented and discussed.