Rapid coarse alignment for marching vehicle based on GPS and odometer

Aimed at vehicle-mounted strap-down inertial navigation system (SINS), a rapid coarse alignment method for marching vehicle is proposed. The matrix between navigation frame and body frame is decomposed into three parts. The problem to solve the matrix between navigation frame and body frame is attributed to solving the matrix between initial body frame and inertial frame, which can be obtained by the non-colinear vectors constructed with the vehicle's velocity from GPS in navigation frame and that from odometer in body frame. The only requirement of this alignment method for marching vehicle is a turning movement in the alignment stage. Compared with the existing alignment methods, this method does not use the measurement information of accelerometers. The simulation results show that the coarse alignment can be fulfilled in 1 minute, and the alignment error is less than 0.3° with low accuracy gyros whose zero bias is 0.1(°)/h.