Effect of EAM on Quality Factor and Noise in MEMS Vibratory Gyroscopes

This paper reports a study on contribution of electromechanical amplitude modulation (EAM) on performance of MEMS Coriolis vibratory gyroscopes (CVGs). We theoretically predicted and experimentally demonstrated the impact of EAM on both quality factor and output noise in MEMS CVGs operating in the open-loop rate mode. We demonstrated the effect on a dynamically amplified dual-mass gyroscope (DAG) improving the gyroscope performance from 0.04 deg/rt-hr in Angular Random Walk (ARW) and 0.52 deg/hr in bias instability to 0.0065 deg/rt-hr in ARW and 0.08 deg/hr in bias instability by changed the EAM setting from 3.5 to 1.2 V in amplitude and from 75 to 225 kHz in frequency. The optimized EAM parameters were derived by the noise prediction model presented in the paper.