MEMS Gyroscope for Improved inertial navigation systems performance

High-performance MEMS gyroscopes are challenging and due to environmental noise and integration errors. Rate-integrating, or “whole angle,” mechanization improves the dynamic range by monitoring the precession of a freely oscillating mass over time periods in excess of 60-sec. Whole-angle mechanization requires significant efforts to increase Q by reducing viscous damping, anchor losses, and thermoelectric losses; however, the high-Q required for whole angle mechanization makes the instrument susceptible to structural vibrations. This problem is compounded by more austere flight environments seen in hypervelocity and highly maneuverable systems. As the velocity and maneuverability of aerial platforms increases, large shocks, exceeding 4000g, can be seen at frequencies in the 1-kHz to 15-kHz range. Various attenuation and mounting techniques can reduce g-levels to slightly less than 1000g (in that frequency range) but increasing device Q will counter the protection at the modal frequencies. Whole-angle gyros for austere flight environments must then be tuned to place the modes into safe vibration bands. This proposal will develop a MEMS gyroscope to address SWaP-C, dynamic range, and shock/vibration requirements of aerial platforms. The device will utilize whole-angle mechanization to address in-run bias stability, scale factor, and dynamic range requirements. The drive and sense modes will be designed to survive expected harmonic loading. The device will also make use of the Double U-Beam (DUB) suspension to take advantage of inherent symmetry in the suspension design. The proposed device includes a novel, but simple, fabrication approach to increase the inertial mass of the sensor and decouple the frequency design and the mass design.