MEMS inertial sensor toward higher accuracy & multi-axis sensing

This paper reports MEMS inertial sensor which is based on the principle of a rotational gyroscope can detect both 3-axis acceleration and 2-axis angular rate at a time by electrostatically suspending and rotating rotor in the shape of a ring made from silicon. The device has several advantages: the levitation of the rotor in a vacuum eliminates a mechanical friction resulting in high sensitivity; the position control for the levitation allows to sense accelerations in tri-axis. Latest measurements yield noise level of gyro and that of accelerometer as low as 0.002deg/s/Hz^frac12 and 20 muG/Hz^frac12, with 1.5mm diameter rotor at 74,000rpm