A novel high sensitivity MEMS acoustic gyroscope by measuring phase shift

This paper presents a novel acoustic gyroscope based on phase difference measurement of two ultrasonic waves traveling in opposite directions. The device can potentially outperform fiber optic gyroscopes in device size and sensitivity owing to significantly lower speed of sound compared to light. It also has big advantages over vibratory MEMS gyroscopes in terms of stability and reliability, as the unique design and mechanism eliminate undesired coupling from mechanical stress and parasitic capacitance. We have carried out simulations and experiments to evaluate the performance of the acoustic gyroscope. The preliminary test results were in very good agreement with theoretical analysis, and predicted that a 3 mm diameter device could achieve a sensitivity of approximately 2.8 mrad/(rad/s), corresponding to a time difference of 0.23 ns at the working frequency of 12 MHz.