Parametric drive of a toroidal MEMS rate integrating gyroscope demonstrating < 20 PPM scale factor stability

In this paper, we report parametric drive of a MEMS rate integrating gyroscope for reduction of drifts induced by drive electronics. A Toroidal Ring Gyroscope (TRG) with 100k Q-factor at 1760 μm diameter was fabricated in epitaxial silicon encapsulation (EpiSeal) process. Device was operated in rate integrating mode using a FPGA based control system. In contrast to the conventional amplitude control architecture, the central star electrode of the gyroscope, connected to a single drive channel was utilized for amplitude control of both modes. Due to the parametric pumping effect, energy added to each (x and y) mode is proportional to the existing amplitude of the respective mode. As a result, errors associated with finding the orientation of the standing wave and x-y drive gain drift are bypassed. Compared to conventional x-y drive architecture, as high as 14× improvement in scale factor stability was observed with parametric pumping, resulting in better than 20 ppm scale factor stability without any compensation or temperature stabilization.