Confirmation and analysis on the optimal multiposition alignment of strapdown inertial navigation system

To realize precise alignment, the optimal multiposition alignment conditions and methods of strapdown inertial navigation system(SINS) were investigated. Using an equivalent error model of SINS established by Lyapunov transform, the observability of SINS error states was quantificationally analyzed by rotating IMU around the orthogonal axes. Then, by research on the relationship between inertial instrument errors and IMU attitudes, the rotational modes by quantitative analysis of inertial measurement unit(IMU) were presented, and the IMU optimal rotating angular positions on which the optimum estimation of SINS error states were achieved. Finally, the simulation results verify the correctness of theoretical analysis.