Strapdown inertial navigation system (SINS) swinging base self-aligning method based on Lie group optimal estimation

The invention discloses a strapdown inertial navigation system (SINS) swinging base self-aligning method based on Lie group optimal estimation. Lie group description is adopted instead of traditionalquaternion description to realize the calculation of SINS attitude transformation; a linear initial self-aligning filtering model based on the Lie group description is established by using a Lie groupdifferential equation; and a Lie group optimal estimation method is designed to determine an initial attitude matrix required by navigation. According to the method, the optimal estimation is directly performed on the initial attitude matrix by a Lie group optimal estimation algorithm, so that the initial attitude estimation problem is transformed into the optimal estimation problem of a SO(3) group; one-step direct self-alignment of the SINS is realized; the aligning time is shortened greatly; the problems of non-uniqueness and non-linearity generated by the traditional quaternion description of the initial attitude