Boeing Disc Resonator Gyroscope

Abstract

As microelectromechanical system (MEMS) gyros were being developed for automotive safety and military tactical applications, in 1994 Boeing selected a conventionally-machined hemispherical resonator gyroscope (HRG) for high performance, continuous space pointing applications. In that same year research was begun into high performance MEMS gyros for compact, low-cost space pointing applications. Collaboration with several national MEMS research labs and operational experience with the HRG led to an understanding of the benefits of high Q, symmetrical resonator designs in MEMS. Early post resonator designs led to closed loop, tuned, low-noise electronics design and operation with capacitive sensing but required undesirable 3D assembly of the post onto the micro-machined flexures. High dynamic loading and imprecision of the bonded joints led to gyro bias that was not stable over the long run. This led to the conception of the Disc Resonator Gyroscope (DRG) which yielded a compact planar micro-machined design with central support and carrying no critical loads. Successive optimization of the layout, scale, material selection and fabrication design as well as the operational electronics has led to progressively more stable performance. A recent fixed orientation laboratory run demonstrated a stable rate within 0.01 o /h over a week of continual measurement, believed to be a record for a MEMS gyroscope. This research background behind the DRG and its principle of operation will be presented along with the latest test results which promise high performance, as well as compact, low-cost MEMS gyroscopes for space applications.