Milli-Hertz Frequency Tuning Architecture Toward High Repeatable Micromachined Axi-Symmetry Gyroscopes
Chong Li, Yuchen Wang, Choon Ki Ahn, Chengxi Zhang, Bo Wang
Abstract
Axi-symmetry micro gyroscopes are increasingly popular for their ultrahigh measurement sensitivity. However, a side effect is the bias repeatability problem. In this article, we propose and demonstrate an ultraprecise frequency tuning solution to achieve state-of-the-art repeatability performance. The gyroscope dynamics are first analyzed and the major error source is confirmed as the frequency split. Then, an advanced frequency tracker and a precision tuning architecture are developed to improve the bias repeatability. The experimental results prove that the frequency tracker can identify the frequency splits at the mHz level. Consequently, a state-of-the-art turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> to turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> bias repeatability of 3.6°/h is conducted that shows orders of magnitude better than conventional solutions.