A sensitive micromachined resonant accelerometer for moving-base gravimetry

Abstract

A sensitive micromachined resonant accelerometer that exhibits extremely low noise floor and excellent bias stability is presented for future application of moving-base gravimetry. An overall structure optimization is presented for large scale factor and low noise, which is significant for measuring variations in the gravitational field of the Earth. The experimental results show that the MEMS accelerometer has a scale factor up to 876 Hz/g and a noise floor down to 75ng/Hz by setting a relatively low full-scale range of ±5 g. The experimental results of the resonant accelerometer with ±0.01°C temperature control show that the averaged bias stability for one day duration is 0.197 μg and the bias repeatability within about 3 months is 1.56 μg. Furthermore, a six-day measurement duration of the accelerometer with its sensitive axis perpendicular to the ground shows a sensitive measurement synchronously with the Earth's tidal gravity, which demonstrates that the resonant accelerometer has the capability for high-performance applications such as moving-base gravimeters and shipborne inertial navigation systems.