Flat is not dead: Current and future performance of Si-MEMS Quad Mass Gyro (QMG) system

Abstract

This paper presents detailed performance status, modeling, and projections for the silicon MEMS Quadruple Mass Gyroscope (QMG) - a unique high Q, lumped mass, mode-symmetric Class II Coriolis Vibratory Gyroscope (CVG) with interchangeable whole angle, self-calibration, and force rebalance mechanizations. To support experimental work, a standalone CVG control and test suite was developed and implemented, comprising a packaged MEMS transducer, an analog buffer card, a digital control card, HRG-style real time closed loop control firmware, and a PC GUI for test control and data logging. Analysis of a QMG sealed without getter with a Q-factor of 1e3 reveals an Angle Random Walk (ARW) of 0.02 deg/rt-hr limited only by the fundamental Mechanical-Thermal Noise (MTN). Propagation of a detailed noise model to a QMG sealed with getter at a Q-factor of 1e6 (previously demonstrated) showed better than Navigation Grade ARW of 0.001 deg/rt-hr. Combination of the very low ARW with the mode-symmetry enabled self-calibration substantiates the navigation grade performance capacity of the Si-MEMS QMG.