Robust Double Mass Mems Gyroscope with Large Drive Amplitude for North-Finding

A double mass MEMS gyroscope (DMG) with a large drive amplitude for north-finding is proposed, which is robust to fabrication imperfections and 1/f noise in its polarization voltage. Its drive amplitude is increased to 18μm to compensate for the gain loss in split mode, and we prove it's superior to narrow the frequency split for low 1/f noise consideration. The gyro's drive and sense motions are decoupled via specifically designed coupling beams. Fabricated in a 6-inch SOI process with a wafer-level vacuum package, the number of dies with a quadrature error <80°/s is up to 70%. Even without a quadrature nulling loop, the proposed MEMS gyro could realize a bias-instability (BIS) <0.1°/h with high yield interfaced with a customized ASIC. Utilizing “short-term but repeated” Maytagging, the proposed gyro realizes 0.23° (4 milliradians) azimuth accuracy (1σ) within 5min.