Design of a Stationary Self-Alignment Algorithm for Strapdown Inertial Navigation Systems

This paper presents the design of a complete multi-rate self-alignment algorithm for strapdown inertial navigation systems (SINS), readily amenable to be implemented in a digital computer. The proposed algorithm is divided in two steps, the coarse and the fine self-alignments. As main contribution of this paper, one demonstrates that, for the particular case of stationary SINS, the fine alignment is not able to improve the orientation estimates derived from the coarse alignment. Instead, the main role of the fine alignment consists in estimating some of the uncompensated inertial sensor biases, which may be used for compensation into the navigation algorithms, greatly improving the accuracy of autonomous inertial navigators.