Half-a-month stable 0.2 degree-per-hour mode-matched MEMS gyroscope

We experimentally demonstrate a mode-matched MEMS gyroscope capable of measuring rates as low as 0.2 °/hr stable on a time scale of half-a-month without ovenization or stress isolation - a long-term performance unprecedented for traditional micromachined sensors. The offset stability is attributed to the active mode-matching loop reducing adverse effects of real-world environment by maintaining zero frequency split, resulting in an almost two orders of magnitude improvement to in-run bias instability. We explore and compare the ability of electrostatic spring softening and mechanical hardening effects to tune frequencies for active mode-matching. The presented approach may enable commercialization of mode-matched MEMS gyroscopes.