Error Modulation Scheme for Dual RINS Based on Device Time-Sequence Fusion

The rotational inertial navigation system (RINS) mitigates system errors through periodic rotation, with the effectiveness of compensation contingent upon the inertial measurement unit (IMU) rotation scheme employed. In conventional rotational modulation, the rotation of the IMU introduces additional errors resulting from rotational angular motion coupled with scale factor and installation error, particularly exacerbating asymmetric scale factor error. An optimal rotation scheme should eliminate inertial sensor errors without introducing new ones. Building upon the maximum rotatable angle of the IMU, a rotation modulation scheme based on time-sequence fusion (TSF) of dual RINS is proposed for the traditional single-axis two-position rotation–stop (with identical stopping durations) and single-axis four-position rotation–stop (with identical stopping durations only at symmetric positions) schemes. The proposed scheme ensures that the dual RINS is precisely timed to rotate and stop, utilizing solely the stop data derived from TSF for calculation. While modulating constant error, the rotation-induced coupling errors are effectively mitigated, and the oscillations in attitude and velocity are reduced. Simulation results show that the system positioning error based on TSF is reduced from 6.13 n mile/72 h for a single system to 1.48 n mile/72 h. Experimental results indicate that, relative to the single system, TSF reduces the latitude error root-mean-square error (RMSE) by 64.44% and the longitude error RMSE by 62.89% in 36 h.