Abstract:

According to the basic principle of the modulated strapdown inertial navigation system (MSINS), the design principle of on-line calibration trajectory is improved. Firstly, the system error model is established based on the inertial navigation unit (IMU) output error model. And then, the system observability is analyzed in the case of no accelerated motion and no turntable rotating. The results show that half of the state amounts are unobserved. In order to solve the problem, the unobserved state amounts are selected by observability decomposition. And the IMU movement principle, which makes the observability decomposition matrix full rank, is derived. The principle of the on-line calibration trajectory is improved on the basis. Finally, its effectiveness is demonstrated by simulations and turntable experiments. The results show that this design principle can further compensate for the IMU errors and improve the MSINS accuracy.