Digital signal processing for a micromachined vibratory gyroscope based on a three dimensional adaptive filter demodulator

• A 3D adaptive filter demodulator eliminates common-mode noise of MEMS gyro.
• Selected LMS for its lower hardware resources through simulation comparison.
• Demonstrated the 3D AFD with improved in-phase and quadrature output results.

This paper reports a digital controller based on a three dimensional adaptive filter demodulator (AFD) for micromachined vibratory gyroscopes with the goal of eliminating common-mode noise and reducing hardware resources. The least mean square (LMS) adaptive filter, which has advantages of fast convergence speed, lower noise and fewer occupied hardware resources, is adopted to demodulate the vibration velocity of the gyroscope and detect its phase shift. A three dimensional AFD is proposed to eliminate the common-mode noise and quadrature coupling induced by the initial capacitance mismatch. Simulation and experimental results have verified the effectiveness of this method. The measurement results of the digital controlled gyroscope show a zero bias drift of 24.6 °/h and a nonlinearity of 0.1% with the measurement range of ±200°/s.