A New Approach to Observability Analysis in the Alignment of Strapdown Inertial System with Moving Base

An error model was introduced for strapdown inertial system(SINS) whose navigation coordinate is inertial coordinate with moving base.According to piece-wise constant system analysis method,the observability during alignment of SINS with moving base was thoroughly studied and the influences by various base maneuvers on the observability were presented.The results show that during the alignment procedure of SINS with moving base,instead of conventionally using geographic coordinate as navigation coordinate,inertial coordinate referred in this paper can simplify the analysis and benefit determining orbit,and the observability of SINS can be enhanced whether the base is in line or rotating motion and furthermore,increasing the speed of convergence and accuracy of estimation.In the end,all of the conclusions are confirmed by computer simulation,which adopts the Kalman filtering,estimates the misalignment angle based on the idiographic experiment data,and gives the simulation diagrams.