Angular velocity calibration system with a self-calibratable rotary encoder

• A novel type of angular velocity calibration system for gyroscopes was developed.
• The system is equipped with a self-calibratable rotary encoder (SelfA).
• Angle deviation less than 10 arcseconds can be known by the system itself.
• Rotation rate of the system is sufficiently stable: within ±0.01%.
• As a demonstration, nonlinearity of a fiber-optic gyroscope was measured.

Gyroscopes are essential components of electronic stability control systems (ESC), which are currently incorporated in automobiles to reduce car accidents. To meet the traceability requirements of gyroscopes in ESC testing system, a novel type of angular velocity calibration system was developed at the National Metrology Institute of Japan. The system is equipped with a self-calibratable rotary encoder (SelfA), operating on the same self-calibration principle as the national angle standard in Japan. To evaluate the performance of the system, the stability of the measured angular velocity was examined in both time domain and in terms of Allan variance. The noise effect from the slip ring was also measured. The calibration procedure was demonstrated by monitoring the response of a fiber-optic gyroscope from −180°/s to 180°/s at 30°/s intervals. The results confirmed that the system performance satisfies the requirements for angular velocity calibration of mid-performance MEMS gyroscopes.