A dual-mode gyroscope architecture with in-run mode-matching capability and inherent bias cancellation

This paper introduces a novel dual-mode actuation and sensing scheme for readout and calibration of axisymmetric Coriolis resonant gyroscopes. The proposed scheme actuates both gyroscope modes simultaneously with the same in-phase excitation, senses both modes concurrently, and utilizes the sum and difference of the sense signals to demonstrate complete cancellation of the gyroscope bias terms, and provide automatic in-run mode-matching capability. Moreover, the architecture provides twofold enhancement of angular rate sensitivity and signal-to-noise performance, as compared to conventional single-mode excitation of the same gyroscope. We demonstrate, for the first time 45× reduction in temperature drift of bias of a 2.6 MHz 650 μm diameter substrate-decoupled BAW gyroscope and a bias stability of 5.4 °/hr, paving the way towards near-zero-drift gyroscopes.