A rate hemispherical resonator gyroscope with bias stability of 0.0056°/h with compensation of phase delay

Abstract

This paper demonstrated a high accuracy rate hemispherical resonator gyroscope (HRG) with compensation of the phase delay induced by the front-end amplifier and the digital control circuit. Due to the existence of the phase delay, the output of the gyroscope is affected not only by the damping mismatch, but also by the frequency split of the resonator gyroscope, which is the main cause of the bias drift and the scale factor nonlinearity of rate resonator gyroscopes. Based on the results of theoretical analysis, a novel calibration method for the phase delay was proposed by monitoring the scale factor of the quadrature control loop. Detailed experimental results show that with phase delay compensation, the bias instability (BI) was improved from 0.0089°/h to 0.0027°/h, the angle random walk (ARW) was improved from 0.0047°/√h to 0.003°/√h, and the scale factor nonlinearity was decreased by 93.8 % from 734.8 ppm to 45.1 ppm. Measurement of one rate HRG after phase compensation at room temperature with duration of 7 hours shows a bias stability of better than 0.00658°/h and a bias repeatability of 0.0053°/h. The results show that the rate HRG with accurate phase delay compensation can achieve excellent accuracy and repeatability in long-time operation.