The integrated fine alignment method considering DVL error

A fine alignment method suitable for marine strapdown inertial navigation system is proposed. In this method, DVL (Doppler velocity log) is applied to give velocity reference. System error equation is deduced to obtain fine alignment model. And the measurement equation corresponded to Doppler velocity log is given in this paper. Here in the measurement equation we consider the DVL speed measuring error equations. By this means, DVL velocity information complements to SINS and we can acquire higher precision and reliability for alignment at sea. It can satisfy the requirements for independence and accuracy. In order to validate this method, we carry the simulation tests out under several marine conditions, including movement with constant velocity and direction, three-axis sway and acceleration. The simulation results show that the proposed method has appropriate duration and great accuracy.