MEMS Annular Rotating Sensor (MARS)

A MEMS Rotating Annular Sensor (MARS) is proposed which senses rotation velocities and accelerations in one discrete time sensor. Differential capacitance measured at various points about the annulus permit a single MARS to measure accelerations in threedegrees of freedom and rotational velocities in two, missing only the angular velocity about the local z axis. Two MARS systems can be used for full three axis inertial measurements and provide redundancy in all three accelerations and one rotationalvelocity measure. With built-in processing capability, the MARS system results in an extremely small, low-cost yet robust inertial measurement system. Output of the MARS system will be available in various digital serial formats.The MARS system has been designed to have four modes of operation: Storage, Start-up, Nominal Operation and Shut-down. To enable reliable use, each mode is operated in a controlled operation enabling the device to handle very large g loads withoutfailure. Sensing rotational rates up to 1000 degrees per second and accelerations up to 15,000 g are anticipated with the device. Due to the differential nature of the device, noise and temperature effects are expected to be minimal when compared toconventional MEMS devices.