A method for the initial alignment of the strap-down inertial navigation system of land vehicle on stationary base is presented.The extended Kalman filter (EKF) is used as the standard technique for the initial alignment of SINS.However,it is based on a sub-optimal im- plementation of the recursive Bayesian estimation framework applying Gaussian random variables.It requires analytic Jacobians.To overcome these shortages,a new extension method of Kalman filters-Sigma point Kalman filters (SPKF) is proposed.C...