Calibration of laser inertial navigator with dual-axis rotation

The calibration of inertial measurement units (IMU) is required to determine the coefficients in the input/output models of inertial sensors. High accuracy turntables and information on the north direction and the local level are usually required in traditional calibration methods. But for a laser inertial navigator with dual-axis rotation, in which the IMU is usually compactly designed, it is usually not convenient to remove the IMU from the navigator to high precision turntable for calibration. To improve the affordability, a simple calibration method is proposed using the dual-axis rotation function of the navigator itself. The method relaxes the orthogonality requirement of the rotation axes and eliminates the need of north information. Rough knowledge of the local plumb-line direction is enough to determine the signs of accelerometer calibration parameters. No re-installation of the IMU is required during the calibration and thus it makes automatic calibration easy to implement. Simulations show that the proposed method is feasible. The proposed method is also tested on an experimental laser inertial navigator with dual-axis rotation, and the navigation results show that the calibration accuracy meets the requirements of high performance inertial navigations.