Self-Calibration Method for Phase Errors in Hemispherical Resonator Gyro Based on Virtual Precession

By adjusting the signal demodulation architecture and optimizing the control circuit configuration, the phase errors of the Coriolis gyroscope can be substantially mitigated. However, these approaches fail to account for the influence of phase asymmetry error on gyro performance. This article proposes a self-calibration method for phase errors based on virtual precession. First, a dynamic analysis model is established to examine the impact of x / y -channel phase errors and their asymmetry on the gyro control system. Second, the phase errors are decoupled from resonator structural errors via forward-reverse rotation modulation. Building on this, a real-time characterization method for phase errors that utilizes the evolution law of quadrature control voltage is developed. Finally, based on the identification results, a self-calibration method for phase errors is designed to offset the phase delay of the control system from the signal processing perspective. Experimental results demonstrate that after self-calibration, the second and fourth harmonics of the gyro output at different rotational speeds are reduced by 98.85% and 89.58%, respectively. Additionally, the scale factor nonlinearity (SFN) and circumferential drift instability are reduced by 95.40% and 97.52%, respectively. This method is not constrained by the gyro structure and the x / y -channel control strategy, making it broadly applicable to other axisymmetric Coriolis vibratory gyros.