Calibration of accelerometer triad of an IMU with drifting Z -accelerometer bias

A method has been developed for solving the problem of the drift of Z-accelerometer bias during the multiposition calibration of the accelerometer triad of an inertial measurement unit IMU. The method makes use of the deterministic correlation between the drifting accelerometer bias and other parameters, and also makes use of the fact that the uncertainty in nonorthogonality of the triad is negligible. If knowledge of the characteristics of the drifting bias is adequately known, excellent identification of triad parameters can be obtained. The method does not require additional measurement beyond the normal measurement data collected in the multiposition calibration test. In addition, the method has a good sensitivity property with respect to the inaccuracy of the bias model. Computer simulation demonstrates the effectiveness of the method