Improved Alignment Method for a SINS Using Two Vector Measurements

The attitude of the strap down inertial navigation system (SINS) in static base with respect to the Earth can be obtained directly using the TRIAD algorithm given two vector measurements. This is usually called analytic coarse alignment method in which all six outputs from the SINS are used to compute the attitude. In this study, we present a novel analytic alignment method called selective alignment. This method uses only three outputs of the SINS and some limited information from the remaining outputs to calculate the attitude. Simulations and experimental results demonstrate the validity of this method, and the precision of yaw is improved using the selective alignment method compared to the traditional analytic coarse alignment method in the vehicle experiment.