Improved lever arm compensation algorithm for initial alignment of SINS/odometer

Aiming at the initial alignment problem of vehicle based strapdown inertial navigation system (SINS), an odometer aided SINS initial alignment in-motion algorithmis proposed, and an improved lever arm model according to the characteristics of odometer output isput forward. Based on the observability analysis, a two-step on-line initial alignment method is proposed at first, in which the odometer scale factor error and the SINS installation error are calibrated in step 1, and then the attitude, inertial sensor biases and odometer's lever arm are estimated in step 2. Then, the error equation of SINS/ odometer algorithm is derived and Kalman filter is designed to achieve initial alignment. Finally, the computer simulation and vehicle test are carried out. The simulation results show that the estimate error of the lever arm is reduced by 10% or more, which improves the estimation precision of attitude, and the vehicle test verify the efficiency of the algorithm.