A gyro includes a rotatable hub with a flexing member centrally supporting a rotor. The rotor is further supported by a pair of piezoelectric force transducers angularly separated by 90 degrees. The rotor turns with the hub. Oscillators drive the transducers and, as the gyro undergoes angular displacement,...http://www.google.de/patents/US4386535?utm_source=gb-gplus-sharePatent US4386535 - Resonator restrained gyro
