Abstract:

During approximate stationary alignment, observability of strapdown inertial navigation systems (SINS) is so weak that the long duration is needed to accomplish initial alignment. In order to solve this problem, a SINS rapid alignment method based on augmented measurements is proposed. Velocity error and earth angular rate are considered as measurements without changing state equations. Measurement equations are deduced according to the augmented measurements. An extended Kalman filter (EKF) is also used for SINS initial alignment. Vehicular test results show that the new method not only converges more quickly but has the similar accuracy, compared with the conventional Kalman filter method.