Self-Excitation Enabled Decoupling, Calibration, and Compensation of Errors for Whole-Angle Hemispherical Resonator Gyroscope

The precise calibration and compensation of detection, drive, system phase, and resonator errors in whole-angle (WA) hemispherical resonator gyroscope (HRG) are essential to improve performance. This article comprehensively considers the influences of four kinds of errors, including the gain mismatch and angle misalignment of detection and drive electrodes; the nonlinearity of capacitance detection and electrostatic drive; the phase delay of each module in the measurement and control system; and the anisodamping and anisoelasticity of resonator. A novel self-excitation enabled decoupling, calibration, and compensation (SE-DCC) process is proposed based on the analysis and modeling of these errors. The detection errors are first calibrated and compensated under high-speed turntable excitation. The drive and system phase errors are then self-calibrated and self-compensated under self-excitation operation. Finally, the characteristics of resonator appear, and the self-calibration and force compensation of anisodamping are completed. Experimental results demonstrate that the angle-dependent errors under high-speed rotation are effectively suppressed, the peak-to-peak value of angle-dependent bias (ADB) is reduced by more than two orders from 31.44°/h to 0.25°/h, the scale factor (SF) nonlinearity in ±500°/s range is reduced by 85 times from 74.6 to 0.879 ppm, the bias stability ( $1\sigma $ ) is reduced from 0.7740°/h to 0.0134°/h, and the bias instability (BI) is reduced by one order from 0.0991°/h to 0.0092°/h. The SE-DCC process is proven to push the accuracy of the tested WA HRG to inertial level and shows promise for expanding to all types of WA gyroscopes with high $Q$ factor and low-frequency spilt.