Improved method for measuring gyro constant drift on line in SINS

Gyro constant drift that changes with time is one of the main factors of navigation error in strapdown inertial navigation system (SINS). An improved method based on existing all-monitor method for measuring gyro constant drift on line is proposed. The characteristic that gyro constant drift changes slowly in short time is used to improve the rotation scheme of the monitor gyro. The rotation times of the monitor gyro are decreased and the measurement precision is ensured at the same time. The principle and error analysis of this method are presented in detail. All-monitor of gyro and inertial navigation semi-physical simulation were carried out. Simulation results show that this method can reduce the complexity of monitor effectively, the error of gyro drift is decreased by one order of magnitude (RMS) and the inertial navigation position accuracy is improved almost by five times.