Fast and high-accuracy systematic calibration of inertial devices based on IMU off-axis transposition

Abstract

In the traditional systematic calibration of inertial devices, the calibration path is designed by the reclosing of the IMU sensitive axis and the turntable rotation axis. The rotation axis is 1 times per rotation, and only 2 sensitive axis positions are changed. In order to effectively motivate the error items of inertial devices, an IMU off-axis installation structure is designed. The rotation axis of the turntable is 1 times per rotation, and 3 sensitive axis positions can be changed at the same time. On this basis, a systematic calibration scheme for inertial devices based on IMU off-axis transposition is designed. A 30 dimensional system errors model including 24 error terms, such as gyro and accelerometer constant errors, installation errors and scale factor errors, is set up. The observability of each state in each calibration path is analyzed by piece-wise constant system (PWCS) and singular value decomposition (SVD) method. Compared with the traditional classical systematic calibration scheme, the proposed scheme can not only realize the full dimensional observation of the state, but also the observability of each state is higher on the whole than that of the traditional scheme. In the process of using filter to calibrate inertial devices, the calibration time is shorter and the precision is higher, and the number of turntable axes required for the proposed scheme is changed from three axis to double axis, which reduces the requirements for hardware conditions.