Spacecraft attitude estimation based on magnetometer measurements and the covariance intersection algorithm [nanosatellites]

This paper describes the design of an autonomous attitude determination and estimation system based only on magnetometer measurements. Initial angle determination is performed through averaging of a large pool of measurements which eliminates the large error in the theoretical field model. Attitude estimation is undertaken using a so-called covariance intersection method which guarantees consistent estimates even if the correlation level between the predictions and measurements is not known. Test results show that this averaging approach is capable of providing very accurate initial attitude determination and that the covariance intersection estimator is capable of maintaining this property. Overall, we conclude that the system developed here is feasible for obtaining and maintaining high accuracy attitude estimation using only magnetometer measurements.