Bias Thermal Stability Improvement of Mode-Matching MEMS Gyroscope Using Mode Deflection

This letter presents a novel strategy to eliminate the bias drift by using mode deflection. The bias of a mode-match gyroscope is mainly caused by the asymmetrical damping and its azimuth. Mode deflection is a method to deflect the drive mode to the direction of damping axis through the circuit configuration, thereby nulling the damping azimuth. After deflection, the bias is not sensitive to the drift of damping and its stability will be greatly improved. Experiments performed on a honeycomb disk resonator gyroscope have demonstrated the effect of this method. The compensation method yields a navigation-grade performance with the bias instability of 0.014 degrees/h. The bias variation overall temperature range from -40 degrees C to 60 degrees C is improved from 73.6 degrees/h to 1.15 degrees/h and the RMS of the bias is 0.26 degrees/h.