TY - JOUR
T1 - A Highly Stable and Sensitive MEMS-based Gravimeter for Long-term Earth Tides Observations
AU - Yang, Lujia
AU - Xu, Xiaochao
AU - Wang, Qian
AU - Tian, Ji'ao
AU - Fang, Yanyan
AU - Zhao, Chun
AU - Hu, Fangjing
AU - Tu, Liangcheng
N1 - © 2022 IEEE. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details
PY - 2022/9/30
Y1 - 2022/9/30
N2 - Precision measurements of local gravitational acceleration variations are of great importance in geophysical surveys. With advantages such as cost-effectiveness and portability, Micro-Electro-Mechanical system (MEMS)-based gravimeters have shown the potential for long-term gravity measurements. In this paper, aiming to further improve the stability of the instrument, the design considerations and system evaluations of a MEMS gravimeter are presented. With a linear spring design for the silicon proof-mass, a low natural frequency of ~14 Hz and a large linear range of ~10300 mGal are achieved with an ultra-low self-noise floor of 1.2 μGal/√Hz@1 Hz. By implementing a vacuum chamber system, the pressure variation is reduced from hundreds of Pa/day in atmosphere to a linear variation of ~6 Pa/day. In addition, an active temperature control system can suppress temperature fluctuations by 2 to 3 orders of magnitude within the band from 1×10 -4 Hz to 1×10 -2 Hz. The stability of the proposed MEMS gravimeter is demonstrated via long-term Earth tides observations within a 30-day time span, giving a correlation coefficient of 0.957 with the reference. An excellent bias instability of ≤4 μGal is demonstrated within the 8-3000 s averaging time range, representing one of the best performances to date in terms of stability for MEMS gravimeters. This shows the potential of high-performance MEMS gravimeters for petroleum and mineral prospecting, seismology and other geophysical applications.
AB - Precision measurements of local gravitational acceleration variations are of great importance in geophysical surveys. With advantages such as cost-effectiveness and portability, Micro-Electro-Mechanical system (MEMS)-based gravimeters have shown the potential for long-term gravity measurements. In this paper, aiming to further improve the stability of the instrument, the design considerations and system evaluations of a MEMS gravimeter are presented. With a linear spring design for the silicon proof-mass, a low natural frequency of ~14 Hz and a large linear range of ~10300 mGal are achieved with an ultra-low self-noise floor of 1.2 μGal/√Hz@1 Hz. By implementing a vacuum chamber system, the pressure variation is reduced from hundreds of Pa/day in atmosphere to a linear variation of ~6 Pa/day. In addition, an active temperature control system can suppress temperature fluctuations by 2 to 3 orders of magnitude within the band from 1×10 -4 Hz to 1×10 -2 Hz. The stability of the proposed MEMS gravimeter is demonstrated via long-term Earth tides observations within a 30-day time span, giving a correlation coefficient of 0.957 with the reference. An excellent bias instability of ≤4 μGal is demonstrated within the 8-3000 s averaging time range, representing one of the best performances to date in terms of stability for MEMS gravimeters. This shows the potential of high-performance MEMS gravimeters for petroleum and mineral prospecting, seismology and other geophysical applications.
U2 - 10.1109/TIM.2022.3210969
DO - 10.1109/TIM.2022.3210969
M3 - Article
SN - 0018-9456
JO - IEEE Transactions on Instrumentation and Measurement
JF - IEEE Transactions on Instrumentation and Measurement
ER -