Simultaneous exploitation of the fundamental and higher order wineglass modes in a vibratory gyro

This paper reports the first step towards simultaneously operating the n = 2 and n = 3 pairs of modes in a disk resonator for two independent measurements of angular rate. A model based approach is adopted to estimate the resonator imbalance parameters and an iterative mass perturbation technique is developed to simultaneously reduce the frequency mismatch of the n = 2 mode pair as well as the n = 3 mode pair. At the termination of mass deposition process, each pair of modes exhibits a residual frequency mismatch of approximately 100 mHz.