1 PPM precision self-calibration of scale factor in MEMS Coriolis vibratory gyroscopes

We report a scale factor self-calibration in MEMS Coriolis vibratory gyroscopes enabled by real time control of the sense-mode closed loop gain. Similarly to the closed loop scale factor employed in the Hemispherical Resonator Gyroscope (HRG), we measure and remove scale factor changes by injecting a known dither signal (virtual input rate) into the sense-mode dynamics during the normal operation of the gyroscope. The approach was validated using an inhouse developed sub-°/hr silicon MEMS Quad Mass Gyroscope (QMG) with HRG-like structural symmetry and low dissipation. We demonstrated a 350 ppm accuracy (limited by the setup) and a 1 ppm precision by simultaneously measuring the true and self-calibrated scale factors over a 10 °C dynamic temperature range.