JPL’s MEMS Gyroscope Fabrication,8-Electrode Tuning, and Performance Results

摘要

In this paper, we present JPL’s 8-electrode MEMSgyroscope, which allows for full electrostatic tuning of theresonant structure. It has shown a sufficient electrostatic tuningrange needed to fully correct the native frequency mismatches ofour current fabrication process. Test data shows that thisgyroscope design has Q’s averaging 30,000 (measured via ringdowntime method) and native frequency mismatch on the order of0.4%. The electrostatic tuning of the mismatched frequencies hassuccessfully demonstrated 0.02% matching for the test batch anddown to 0.003% (10mHz at 3000Hz) repeatable frequencymatching during specific tuning experiments. As a result, we canreport angle random walk (ARW) value of 0.1deg/rthr and 2°/hrbias instability (Allan variance 1/f floor estimated). A third party,Honeywell Inc., tested one of the earlier designed 4-electrodegyroscopes, which achieved frequency degeneracy through amechanical ion-milling of the springs, and reported 1°/hr biasinstability.