Modified hybrid calibration method for IMU without orientation

In classical dynamic-static hybrid calibration of strapdown inertial navigation system (SINS), test equipment, such as turntable, must perform north-seeking to determine the nominal input of SINS. A modified hybrid calibration method without orientation is proposed in this paper. Firstly, the error model including 33 error coefficients of IMU is established through rotating experiments in six positions. The calibrated coefficients include scale factor, constant error, misalignment and g compliance error and etc. Then, the new calibration method without orientation for SINS is presented in detail. Finally, the experiments based on this modified calibration method and classical hybrid calibration method are carried out individually. Experiment results indicate that the modified hybrid calibration method can accurately determine 33 error coefficients of IMU, and the accuracy of this method is equivalent to that of the classical hybrid calibration method in which the test equipment must perform north-seeking. The process of the modified hybrid calibration method is much simpler than that of the classical one, which improves the efficiency of the calibration of SINS.