Effect of structural anisotropy on anchor loss mismatch and predicted case drift in future micro-Hemispherical Resonator Gyros

The effect of structural anisotropy leading to anchor loss mismatch in micro-Hemispherical Resonator Gyros (micro-HRGs) is investigated by developing an anchor loss model based on finite element analysis. Worst-case lower bound estimates for the anchor loss component of the quality factor (Q) are found based on the computed frequency difference between a clamped support and a free support interface. The Young´s modulus of the finite element model is varied in a 4^th-harmonic pattern in the circumferential direction of the micro-HRG, resulting in splitting of the Q and resonance frequency of the otherwise degenerate gyro wineglass mode pair, allowing prediction of the case drift performance.