Initial Alignment of Swing Base Based on Parameter Identification Method without Latitude

In order to meet the actual motion situation and improve the dynamic performance of inertial navigation equipment, the initial posture alignment needs to be completed under the moving base, and velocity and position information are generally provided directly by GPS. However, there is difficult to get precise position information-especially latitude in some complex conditions. This paper use INS to give latitude estimation during the initial alignment. First, use the dual vector attitude determination principle based on the solidified inertial coordinate system to obtain attitude matrix. Then, through the integration of the specific force on body coordinate to determine the sign of latitude and correct attitude matrix. Last, got precise initial attitude and velocity performing the parameter identification fine alignment within the alignment time period. Relying on ship mooring alignment test, the horizontal velocity solution value was reduced to a maximum of 0.6m/s, which was in line with the actual situation of ship mooring swing. Latitude estimation can not only improve the autonomy of the INS, but also compare it with the initial value of latitude input, a warning will be given to the user if the discrepancy is too large.