A MEM vibratory gyro with mode-matching achieved by resonator mass loading

This paper presents preliminary performance results for a vibratory rate gyro based on a novel MEM resonator whose design facilitates frequency mismatch reduction via mass loading. A model-based systematic tuning algorithm was implemented to reduce the n=2 modal frequency mismatch without impacting the quality factors. Mass loading the resonator eliminates the need for electrostatic tuning and only a single bias voltage to the resonator is required for operation as a rate sensor. Force-to-rebalance operation with a 10Hz bandwidth yielded a minimum rate bias instability of 0.11deg/hr and an estimated angle random walk of 0.02 deg/root-hr. A decrease in rate noise was also demonstrated as the sensor´s cross-channel coupling was reduced by aligning the forcer/pick-off frame with the anti-nodes of the modes.