The Modeling of Hemispherical Resonator Gyro and Its Space Applications

The hemispherical resonator gyroscope (HRG) is a new vibration gyro, which first appeared in the 1960s. It has a feature of high accuracy, long life span, no wear-out and great reliability. With its excellent performances, the HRG can be used for spacecraft and satellite stabilization, precision pointing, aircraft navigation, strategic accuracy systems, oil borehole exploration and planetary exploration. Compared with traditional mechanical gyro and optical gyro, HRG has no rotators or movement parts. The resonator of HRG is made from quartz with low damping and stable temperature. The resonator Q factor exceeds 5,000,000 and it is placed under vacuum cap with residual pressure about 1x10(-6) atm. The principium of HRG sensing the rotation relies on a transverse stress wave in the solid resonator. The stable material character of resonator and simple structure make the gyro high reliability, long lifetime, anti-radiation, anti-shock and high accuracy. Two working modes of the HRG which is the whole angle mode and force to rebalance mode are respectively analyzed, besides, the control loops applied in the gyro are illuminated in the paper. The basic kinetic model of the HRG is investigated in the paper, from which the principle and exhibition of the error existing in the device could be obtained clearly. At last, the HRG space applications are displayed and the result of the 100% mission success has demonstrated it is the best candidate for critical and high value missions.