A high-sensitivity MEMS gravimeter with a large dynamic range

Abstract

Precise measurement of variations in the local gravitational acceleration is valuable for natural hazard forecasting, prospecting, and geophysical studies. Common issues of the present gravimetry technologies include their high cost, high mass, and large volume, which can potentially be solved by micro-electromechanical-system (MEMS) technology. However, the reported MEMS gravimeter does not have a high sensitivity and a large dynamic range comparable with those of the present commercial gravimeters, lowering its practicability and ruling out worldwide deployment. In this paper, we introduce a more practical MEMS gravimeter that has a higher sensitivity of 8 μGal/√Hz and a larger dynamic range of 8000 mGal by using an advanced suspension design and a customized optical displacement transducer. The proposed MEMS gravimeter has performed the co-site earth tides measurement with a commercial superconducting gravimeter GWR iGrav with the results showing a correlation coefficient of 0.91.

Sensors: A MEMS gravimeter combines high precision with portability

Researchers in China have developed a small, portable gravimeter based on micro-electromechanical-system (MEMS) technology with a sensitivity and dynamic range comparable with larger, commercially available gravimeters. The new device was created by a team led by Liangcheng Tu at Huazhong University of Science and Technology. The MEMS mechanism consists of a spring-mass system designed around a combination of curved and folded beams. Together, these ensure that the system is stiff under low loads but flexible at loads around 1 g. An optical component measures the displacement of the proof mass to measure gravitational acceleration. The team tested their design alongside a commercial gravimeter and found a 90% correlation in the measurements of Earth tides, demonstrating its utility for applications from oil and gas exploration to hazard detection.