High performance structurally decoupled micromachined gyroscope

In order to suppress the quadrature error in micromachined gyroscopes, various decoupled structures have been designed employing independent suspension beams for the drive and sense modes. The new decoupled structure presented in this paper employs a vibration isolation frame and independent inertial masses for the drive and sense modes. This frame can not only prevent the oscillation of the drive masses coupling to the sense masses, but also pass the Coriolis forces on the drive masses to the sense masses. A gyroscope sample and its read-out circuit are fabricated. The quality factors of the drive and sense modes in atmosphere are measured as 800 and 34, and the resonance frequencies of the drive and sense modes are 2.981 kHz and 2.813 kHz. The scale factor of this gyroscope is 38 mV/(deg/sec) with a nonlinearity better than 0.8% in a measurement range of plusmn100deg/sec, and the short-term bias stability in half an hour is 0.28deg/sec.