A new silicon rate gyroscope

HSG-IMIT is developing a new silicon rate gyroscope of very small size, low cost, and high performance. The device is called MARS-RR, which means micromachined angular rate sensor with two rotary oscillation modes. First prototypes, MARS-RRI yielded random walk and bias stability as low as 0.27 deg//spl radic/h and 65 deg/h, respectively. The noise equivalent rate (3 /spl sigma/) corresponds to a resolution of 0.096 deg/s in a 50 Hz bandwidth. This performance is achieved by a new sensor design featuring decoupling of the actuation and the detection oscillation modes. Because of decoupling the modes mechanical and electromechanical crosstalk, one main error source of micromachined gyros, can be reduced and therefore the zero rate output (ZRO) almost disappears. Despite the small sensor area of 6 mm/sup 2/ the detection capacitance amounts to about 3 pF. Thus subatomic deflections are detectable and a high sensitivity is achieved. MARS-RR1 was manufactured within the Bosch Foundry process and therefore it was possible for us to reduce the development time considerably.

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