Model Parameters Identification and Motion Estimation of Spacecraft with Flexible Appendages Using Various Sensors Sets

This paper studies the accuracy characteristics of algorithms for the flexible spacecraft structural elements oscillatory motion determination using various sensor sets. The spacecraft body is considered as a rigid body to which flexible elements are attached using cantilever fastenings. Algorithms based on the nonlinear least-squares method for model parameters identification are developed, as well as algorithms based on the extended Kalman filter for real-time estimation of the state vector, which includes the parameters of the angular motion of the spacecraft body, as well as current deviations of the equilibrium position of flexible elements and their velocities in normal coordinates for a set of modes with the lowest frequencies. For flexible motion estimation, the use of a number of measurement sources is considered: attitude sensors mounted on the spacecraft body; accelerometers attached to non-rigid structural elements; and measurements obtained as a result of processing video images from a camera mounted on the satellite body, whose field of view includes the flexible structural elements. The paper provides a comparative analysis of the algorithms' performance using various measurement sources.