A new electronic feedback compensation method for rate integrating gyroscopes

Abstract

Towards the objective of a rate integrating gyroscope (RIG) without a minimum rate threshold and performance limited only by electrical and mechanical thermal noise, we present our progress on a new, generalized electronic feedback method for the compensation of resonator damping asymmetry (anisodamping) and stiffness asymmetry (anisoelasticity) with a new method of RIG operation using self-precession. This enables overcoming the precession angle-dependent bias error and minimum rate threshold, two issues identified by Lynch for a MEMS RIG [1]. To correct angle-dependent bias, we augment the electronic feedback force of the amplitude regulator with a non-unity gain output distribution matrix selected to correct for anisodamping. Using this method, we have decreased the angle dependent bias error by a factor of 30, resulting a minimum rate threshold of 3.5 dps. To further improve RIG performance, an electronically-induced self-precession rate is incorporated and successfully demonstrated to lower the rate threshold. The RIG's output noise is also evaluated, demonstrating an ARW of 11 mdps/√Hz, similar to rate gyro operation at same amplitude.