A new silicon rate gyroscope

Abstract A new silicon rate gyroscope of small size, low cost, and high performance is described. The device is called MARS-RR, which means M icromachined A ngular R ate S ensor with two R otary oscillation modes. First prototypes, MARS-RR1 yielded random walk and bias stability as low as 0.14 deg/h and 65 deg/h, respectively. The rate equivalent rms noise corresponds to a resolution of 0.05 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 2 , the detection capacitance amounts to approximately 3 pF. Thus, subatomic deflections are detectable and a high sensitivity is achieved. MARS-RR1 was manufactured within the Bosch Foundry process [M. Illing, Micromachining Foundry Designrules, Version 1.0, Bosch Mikroelektronik; M. Offenberg, H. Munzel, D. Schubert, B. Maihofer, F. Larmer, E. Muller, O. Schatz, J. Marek, SAE Technical Paper Series, 960758, SAE 96, The Engineering Society for Advancing Mobility Land Sea Air and Space, 1996, reprinted from Sensors and Actuators, 1996 (SP-1133), p. 35; M. Offenberg, F. Larmer, B. Elsner, H. Munzel, W. Riethmuller, Novel Process for a Monolithical Integrated Accelerometer, Transducer '95, Eurosensor IX, 148-C4, pp. 589–592] and therefore it was possible for us to reduce the development time considerably.