A Frequency Calculation and Temperature Compensation System for Quartz Resonant Accelerometer Sensors

Acceleration sensors determine the accuracy and reliability of the inertial measurement system. In quartz acceleration sensors, the frequency calculation method directly affects their performance. The current research focuses on improving the signal processing algorithm, optimizing the sensor hardware design and its frequency calculation method as well as temperature compensation. However, there are still some limitations in stability and accuracy. To address these challenges, this paper introduces an optimized frequency calculation module based on a Field-Programmable Gate Array (FPGA). The resonant acceleration sensor calculates the acceleration by measuring the resonant frequency difference between the upper and lower beams. The optimization module utilizes the equal precision sampling technology to effectively reduce the ±1 error of the frequency measurement signal, and by optimizing the gating time, improve the speed and accuracy of frequency measurement. The system clock subdivision techniques are employed to reduce system errors further. The frequency characteristics of quartz resonators are investigated in this paper. The optimal polynomial order for compensation is determined by polynomial fitting using the least square method. Based on the above, this paper builds a complete hardware-software system. The system uses FPGA to construct a Programmable Chip (SOPC) and its duties involve frequency monitoring, data interaction, frequency calculation, and temperature compensation. System measurement results showed an accuracy of 46.98 mHz at 400 Hz and 2.96 mHz at 1 Hz. The frequency temperature adjustment method decreased the maximum offset of zero deviation dynamic frequency from 26.0192Hz to 0.3836Hz over the entire temperature range (- 40 to 80°C).