Analysis and compensation of residual gyro drifts on azimuth alignment accuracy in the RINS

The rotational inertial navigation system (INS) uses rotational alignment to improve azimuth alignment accuracy significantly. However, due to the existence of magnetic drifts in the fiber optic gyro, under the comprehensive influence of outside conditions, there will be residual drifts that cannot be averaged out along the body frame or the geographic frame, which will have a significant impact on azimuth alignment accuracy. An innovative and effective calibration compensation strategy is proposed by analyzing the generation mechanism of residual drifts and their influence on alignment accuracy, which can significantly improve azimuth alignment accuracy. With the aid of a high-precision total station, the experimental results of initial alignment in four directions show that the accuracy of azimuth alignment is improved from 16.47 ''(1u sigma) to 10.34 '' (1 sigma) by compensating residual drifts, which has significant theoretical significance and practical value in engineering applications for improving the overall performance of the INS.