A MEMS Gyro-Rebalanced Accelerometer for High Performance

MEMS accelerometers typically use force/torque rebalance applied by subcomponent actuators which, although well-understood, are seriously limited in performance by fundamental material stability issues. These deficiencies can be overcome by the introduction of "gyro-rebalance", which substitutes inertial force balancing (the use of gyro torque to counterbalance pendulum torque) for the actuators. The best example of a gyro-rebalance accelerometer is the ultra-high performance Pendulous Integrating Gyro Accelerometer (the "PIGA"), which is used in all U.S. strategic ballistic missile guidance systems. This proposal begins with the design of existing MEMS gyros and MEMS accelerometers under development at MSSA, and makes the necessary modifications to make a gyro-rebalance accelerometer. These instruments are being developed as components of an Integrated MEMS IMU under a Phase II SBIR contract from the Air Force. The gyro-rebalance mechanization is expected to improve both the scale factor and bias stability to achieve performance levels that are orders of magnitude better than currently available from MEMS accelerometers.