Utilization of mechanical quadrature in silicon MEMS vibratory gyroscope to increase and expand the long term in-run bias stability

We report a new approach for improvement of the long term in-run bias stability of Coriolis vibratory gyroscopes. The approach is based on utilization of the mechanical quadrature error in gyroscopes to compensate for variation in system parameters. The proposed approach was validated by a silicon Quadruple Mass Gyroscope, with the natural frequency of 3 kHz, frequency mismatch of <;0.5 Hz, and isotropic quality factor of 950, packaged without getter. The algorithm is described and experimentally demonstrated in this paper, showing a bias stability of 0.1 deg/hr after 300 seconds, and importantly, retaining that value for over 3 hours of the integration time.