Analytical method for moving base initial alignment based on gravity measurement

Aiming at that the traditional analytical method for coarse alignment is not applicable for moving base, a new analytical method for moving base initial alignment based on gravity measurement was proposed. Firstly, a mid-frame was built in an inertial coordinate frame at the middle point of navigation time. Then gravity vectors in carrier frame and navigation frame were projected into the mid-frame, Sum and cross-product operations were done for projections at both sides of the mid-frame. Two 3D spaces obtained were corresponding to the initial navigation frame and the initial carrier frame. Finally, several alignment processes were simulated and compared under different operation conditions. Results showed that the proposed method can be applied in moving base alignment, it is easy to realize in engineering, and it provides a certain guidance for alignment in motion of vehicle navigation systems.