Error propagation model for rhumb-line attitude maneuvers

The attitude control of a spin-stabilized spacecraft is performed by a forced precession of the spin axis produced by a series of pulsed thrust actuations. Thruster performance characteristics (i.e., the thrust pulse's integrated magnitude and its effective centroid time) constitute the principal error sources governing the accuracy of an attitude control maneuver. These errors affect the maneuver evolution in terms of the total maneuver path-length and in its heading direction in inertial space, i.e. the rhumb angle. Inertial directional offsets of the thrust pulse caused by timing errors caused by spin rate deviations also contribute to the rhumb angle error. An analytical model is constructed for describing the propagation of path-length and rhumb angle errors into the resulting attitude at the conclusion of the maneuver. Detailed simulations with relevance to actual spacecraft applications have been performed to arrive at an understanding of the expected error magnification for different maneuver input parameters and initial conditions. Finally, also a model is presented for the propagation of the statistical characteristics of the input errors into the statistics of the resulting error in the final attitude.