Integrated high precision identification and compensation for thermal effect error of fiber-optic inertial navigation system

To improve the utilizing accuracy of fiber-optic inertial navigation systems in the thermal changing environment, an integrated high precision identification and compensation method is investigated for the thermal effect error of inertial instruments. Firstly, system-level calibration within the full temperature range is implemented to establish the high accurate calibration parameter reference. The thermal coefficients of gyro and accelerometers' scale factors and the bias of accelerometers is obtained. Then, the relationship between the instrument misalignments and the object coordinate frame with the temperature change is determined. Accordingly, the thermally induced coordinate pointing error is corrected by means of the direction transformation between the instrument coordinate frame under the working temperature and the object coordinate frame under the reference temperature. Afterwards, the gyro thermal bias drift separation method is explored and the drift error is compensated from the gyro output during the static temperature chamber experiments. Finally, the static and dynamic navigation experiments in the normal temperature and the thermal changing environment are conducted. Results illustrate that the location error of the prior is reduced from 2 093 to 442 m while the positioning accuracy of the post is improved by nearly 5 times, which considerably strengthen the adaptability of navigation systems to temperature changing. © 2018, Science Press. All right reserved.