Observability of self-calibration and self-alignment for inertially stabilized platform

The observability of the self-calibration and self-alignment system for an inertially stabilized platform is of vital importance, because it determines the solution existence of the system states. This article provides a straightforward and comprehensible method to investigate the observability of the nonlinear inertially stabilized platform’s self-calibration and self-alignment system. The proposed method is based on a principle that a parameter is observable only if it has a unique solution from the system outputs. The effect of the platform coordinates frame on the system observability is discussed in detail. The demonstration results indicate that the system is completely observable if the platform frame is defined based on the input axes of accelerometer triad. Besides, the analysis processes show that a high performance self-calibration and self-alignment can be accomplished if the inertially stabilized platform is kept stationary with the Earth at different positions and alternately rotated around its each axis. The validation of those results is checked by simulations, and the achieved conclusions make outstanding contributions to the development of the optimal torqueing schemes for the inertially stabilized platform’s self-calibration and self-alignment system.