Searching for the Origin of Zero-Rate Offset and Scale-Factor Drift in Nems-Based Nav-Grade Gyroscope

Abstract

The paper researches on the origin of scale-factor (SF) and zero-rate-offset (ZRO) drift in gyroscopes based on NEMS resistive sensing, towards effective calibration and compensation for further performance improvement. It is shown that the SF drift is affected by the mode-split behaviour in temperature, induced by differences in the temperature coefficient of frequency (TCf) of the two modes, and further perturbed by softening/hardening in operation. Measuring the mode-split with 10-mHz accuracy enables to understand the behaviour and adjust the drive motion to reduce the mode-split drift by a factor 100. At the same time, it is shown how temperature tracking via the drive-mode resonance, and following output compensation, brings down stability to values below 0.01 °/hr.