Analysis and evaluation of coaxiality error of semi-strapdown micro inertial measurement system

The semi-strapdown micro inertial measurement method is a new solution to high precision attitude measurement of the high-speed rotation ammunition. The complex mechanical structure of semi-strapdown platform causes a non-ignorable coaxiality error. The basic structure and working principle of the system are introduced, and the analytical evaluation methods suitable for the coaxiality evaluation of the outer and inner cylinders of semi-strapdown system are proposed. The evaluation method of outer cylinder is based on the existing standard measurement method. A dynamic evaluation method for the inner cylinder coaxiality of semi-strapdown system is designed in detail based on the deduction of miniature inertial measurement unit (MIMU) output model in consideration of coaxiality error angle. The coaxiality error angle is calibrated using the component in the system, and makes the error compensation for the radial gyro output under the experiment condition. The analysis and evaluation of the coaxiality error of semi-strapdown micro inertial measurement system are performed. The results show that the proposed method is feasible.