Research on a Wide-Bandwidth, High-Stability All-Quartz Resonant Accelerometer for Inertial Navigation

Accelerometers and gyroscopes are the core sensors that ensure precise measurements in inertial navigation systems (INSs). To enhance the dynamic range and stability of the accelerometer channels in INSs, this article proposes a new structure of an all-quartz resonant accelerometer. To improve environmental adaptability, the sensitive chip adopts a two-stage sealing design. The mass-flexible support structure incorporates stress isolation, and simulations of the temperature field demonstrate that the isolation structure reduces thermal stress interference by approximately 50% within the temperature range of - 55 °C to 80 °C. Mathematical models for the natural frequency of a resonant beam and the sensitivity of an accelerometer are established, with relative errors between simulations and mathematical models below 5%, validating the effectiveness of both analytical and numerical simulation approaches. Fused silica glass is employed as the material for the structure of mass-flexible support to concurrently improve sensitivity and natural frequency. Through the finite element analysis, the correlation between dimensions of flexible support and variations of sensitivity/natural frequency is revealed. Optimal parameters of flexible support are determined using a simulation-spectrum-fitting analysis method. Processing techniques of double-ended tuning fork (DETF) with high precision and accelerometer’s assembly methods are presented. Calibration experiments demonstrate a sensitivity of 88.3242 Hz/g and a natural frequency of 1307 Hz. The hermeticity reaches 9.7 × 10^-11 Pa · m³/s. Fixed-position stability tests show that the stability of 1 g is 7.18 µg and the stability of 0 g is 8.35 µg over 24 h. Short-term repeatability achieves better than 19.1 ppm for sensitivity and 15.4 µg for bias. Temperature coefficients are measured as 2.66 ppm/°C for sensitivity and 30.3 µg/°C for bias, the developed accelerometer features high sensitivity, wide bandwidth, and high stability, enhancing the dynamic range and control accuracy of the aircraft.