Self-calibration and compensation of residual gyro drifts for rotation inertial navigation system with fibre optic gyro

Fibre optic gyros (FOGs) are widely used in the rotation inertial navigation system (RINS). However, FOGs are sensitive to surrounding environments, and thus the drifts of FOGs would vary during the rotation of the gyros. This phenomenon may bring about residual gyro drifts, which are the primary cause for the accumulated navigation errors in the RINS. A recursion least square estimation method based on position errors is proposed to obtain residual drifts. A multi-position calibration method is presented to separate the residual drifts along the body axis. Static experiment results show that the positioning accuracy of a 12-h navigation is improved significantly from 2.24 to 0.54 n mile by compensating the residual drifts along the body axis. A vehicle-mounted motional experiment is conducted to verify the proposed calibration method, and the positioning accuracy is improved from 1.38 to 0.66 n mile.