Spinning Spacecraft Attitude Filtering with Spin Parameters: Performance Evaluation with Real Data

Söken, Halil Ersin
Sakai, Shin-İchiro
Van Der Ha, Jozef C.
Three-axis attitude estimation for spinning spacecraft is recently of considerable practical interest. In this scope, sequential filtering algorithms are also being studied recently. In this study, we extend our recent research for a nonlinear filtering algorithm for spinning spacecraft attitude estimation. In the filter the attitude of the spacecraft is represented using a set of spin parameters. These parameters consist of the spin-axis orientation unit vector in the inertial frame and the spin phase angle. As the system and measurement models are nonlinear an Unscented Kalman Filter (UKF) is implemented to estimate the spacecraft’s attitude. In this paper, we investigate the accuracy of the algorithm by using telemetry data gathered by the CONTOUR spacecraft in 2002. We discuss different methods for satisfying the spherical norm constraint for the spinaxis orientation unit vector terms. The filter works well and produces consistent results with those of the Tanygin-Shuster and TRIAD algorithms. Investigations on the norm constraint condition shows that unit vector normalization must be applied specifically in the presence of measurement biases.