Attitude Reconstruction for Freja, a Magnetometer Based Approach

摘要

An attitude estimation algorithm has been developed and tested based on magnetometer data from the Freja spacecraft. The attitude has previously been determined once or twice per orbit using single point algorithms. Thermally induced inertiavariations, however, prevent simple interpolation. The approach presented here, model thermal effects and preserve angular momentum, variations in the moments of inertia. Perturbations to the field measurements axe avoided in the filter update. Thealgorithm allow attitude determination during eclipse, where no reliable attitude was previously available, thereby increasing the value of the science observations.