Rapid alignment method of INS with large initial azimuth error under uncertain flexure disturbances

A new nonlinear initial alignment method was proposed for the rapid alignment of the ship-borne weapon INS with large initial azimuth attitude error under uncertain flexure deformation disturbances. Considering the flexure deformation of certain axis has the severest affection to the angular rate measurement, velocity and partial angular rate were used as the measurements in this method, in which the pitch rate is subtracted from the angular rate measurement. Simulation results show that comparing with the conventional solution, which compensates the flexure deformation by augmenting its model into the alignment filter, the proposed alignment method can accomplish the transfer alignment of a mooring ship's weapon INS with large heading error rapidly and accurately, and it is more reliable in the situation of flexure deformation uncertainty.