On orbit identification of mass characteristic parameters for spacecraft

Considering that high-accuracy control of spacecraft attitude and orbit requires accurate knowledge of mass characteristic parameters of a spacecraft, two approaches-the least square method based on parameter decoupling and the non-linear system optimization based on the particle swarm optimization(P S O), are proposed to identify the mass, inertia tensor and center of mass position of the spacecraft. The former decouples the inertia tensor and the mass and centroid position, and identify them separately. The latter transforms the parameter identification problem into a non-linear system global optimization problem, and uses the PSO to identify all the parameters simultaneously. The proposed methods do not assume that the spacecraft moves slowly enough, and overcome the shortcoming of previous methods which break the coupling relationship between the parameters forcibly. The identified parameters are adopted to evidently improve the performance of the spacecraft's attitude and orbit control. Simulation results verify the proposed approaches.