Localized thermal tuning in fused silica inductive vibrating ring gyroscopes

Inductive vibrating ring gyroscopes (IVRGs) present superior shock tolerance and reliability compared to conventional capacitive gyroscopes, making them ideal for inertial measurements in harsh environments. However, their operation in high-precision whole-angle mode requires real-time minimization of the frequency split between degenerate modes to prevent bias drift and measurement errors. Traditional electrostatic tuning methods are unsuitable for electromagnetic configurations, necessitating an alternative approach. In this paper, we propose and experimentally validate a localized thermal tuning technique to generate spatially controlled Joule heating at modal antinodes through specially patterned electrodes. This method utilizes the temperature-dependent increase of Young's modulus in fused silica to achieve reversible and real-time frequency adjustment, with minimal thermal coupling between the degenerate modes. Finite element simulations demonstrated that optimized electrode designs reduced thermal coupling coefficient and improved split tuning efficiency. Prototypes incorporating localized thermal electrodes were fabricated and characterized, achieving efficient frequency split suppression (reducing split to 14 mHz), substantial reductions in angle-dependent bias (from 0.928°/s to 0.146°/s), significant scale factor nonlinearity improvements (from 4321 ppm to 61.3 ppm), and enhanced bias instability (from 4.8°/h to 0.67°/h), all with negligible impact on quality factor and robust temperature adaptability across -40 °C to 60 °C. These results confirm that localized thermal tuning is an available and effective strategy for inductive vibrating ring gyroscopes, paving the way for enhancing the precision in harsh environment applications.