Noise analysis of closed-Loop vibratory rate gyros

This paper presents detailed noise analysis of closed-loop MEMS vibratory gyros whose noise characteristics are dominated by the mechanical-thermal noise of the sensor´s vibrating structure as well as the electrical noise associated with the pickoff signal conditioning electronics in the sense channel. The mechanical-thermal noise and the electrical noise are represented as uncorrelated additive wideband disturbances dominant at the sensor´s input and output, respectively. A comprehensive spectral density model of the closed-loop rate-equivalent noise is derived to explain the effects of various sensor parameters including the resonator quality factor, the closed-loop bandwidth, and the modal frequency split. Experimental results with a Disk Resonator Gyro (DRG) are presented to support the analysis.