Modeling, Characterization, and Compensation of Detection Errors for Differential Frequency Modulation Whole-Angle Hemispherical Resonator Gyroscope

Differential frequency modulation whole-angle (DFM-WA) hemispherical resonator gyroscope (HRG) has lower angular velocity output noise (AVON) than amplitude modulation whole-angle (AM-WA) HRG, which allows its performance potential to be fully exploited. However, the detection errors comprehensively affect the frequency tracking, amplitude control, and output accuracies of the clockwise (CW) and counter clockwise (CCW) traveling waves, seriously damaging the performance of the DFM-WA HRG. In this paper, the detection errors are effectively modelled and characterized in the parametric equations of the two traveling waves as well as the synthesized standing wave, and the accurate identification and compensation of the detection errors are then accomplished based on the angular velocity output (AVO) with low noise. Experimental results strongly indicate that the AVON, the bias instability, and the angle random walk of the DFM-WA HRG are reduced by over one magnitude, 3 times, and 5 times relative to the AM-WA HRG with the same resonator. The DFM-WA scheme gives the HRG an effective scale factor (SF) of 3.057mHz/°/s. The SF nonlinearity of the DFM-WA HRG is reduced by 69.19% from 2.678 ppm to 0.825 ppm, and its SF stability is enhanced by 74.99% from 59.8848 ppm to 14.9792 ppm in the range of -40 °Cto 60 °C. The AVO of the DFM-WA HRG is unaffected by ∼ 1mHzfrequency mismatch and the changes in the CW and CCW traveling wave frequencies within the range of 5003.8Hzto 5032Hz. The DFM-WA scheme is a promising path for the development of HRG with large dynamics, high precision, low noise, and excellent temperature stability.