Nonlinear measurement based SINS initial alignment algorithm under large misalignment angle

Aiming at the problem of strapdown inertial navigation (SINS) initial alignment with large misalignment angles for land vehicles, an initial alignment algorithm is proposed based on the second order Taylor series expansion of second order nonlinear measurements. Firstly, the nonlinear alignment is transformed into a filtering problem with linear system equation and second order nonlinear measurement equation. Then, a filtering scheme is designed based on the exact Taylor series expansion of the measurement equation. Under arbitrary attitude and without initial value, the initial alignment and parameter estimation can be attained by using the linear Kalman Filtering scheme. Finally, the alignment experiments are performed on a land vehicle, and the results indicate that the new algorithm has an equal alignment precision with respect to the traditional two-phase alignment method within 300 seconds. © 2016, Editorial Dept. of JA. All right reserved.