A marine gravimeter based on electromagnetic damping and its tests in the South China Sea  

作　　者：Pengfei WU Lin WU Lifeng BAO Long WANG Bo WANG Danling TANG 

机构地区：[1]State Key Laboratory of Geodesy and Earth’s Dynamics,Innovation Academy for Precision Measurement Science and Technology,Chinese Academy of Sciences,Wuhan 430077,China [2]University of the Chinese Academy of Sciences,Beijing 100049,China [3]Guangdong Remote Sensing Center for Marine Ecology and Environment(GDRS),Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 511458,China [4]School of Geography and Information Engineering,China University of Geosciences,Wuhan 430074,China

出　　处：《Journal of Oceanology and Limnology》2023年第2期792-803,共12页海洋湖沼学报（英文）

基　　金：Supported by the National Natural Science Foundation of China(Nos.42192535,41876136);the Guangdong Special Support Program(No.2019BT02H594)。

摘　　要：A new gravity sensor based on electromagnetic damping for the JMGrav marine gravimeter is presented.The new gravity sensor considered the advanced construction methods of the electromagnetic damping system of the gravimeter.The design features of the new system are discussed and the research survey data in the South China Sea are shown.Numerical simulations are applied to model the magnetic and mechanical characteristics of the system using finite element analysis and to evaluate the force distribution and the resulting damping effects.The performance characteristics of the system were tested on a motion simulator in laboratory,and the gravimeter was subjected to vertical accelerations of up to 100 Gal in 1-1000 s.It was found that the amplitude reduction of vertical accelerations in 3-15 s is 30-45 dB,with a time lag of 2-5 s,while the effect on gravity in period greater than 600 s is less than 0.5 dB,with a time lag of less than 100 s.The accelerations cause discrepancies of approximately only 1 mGal between the static value and the mean dynamic value.The sea tests were conducted in September 2020.Gravity measurements were taken with a JMGrav marine gravimeter onboard the R/V Dongfanghong 3,and the effective survey line exceeded 2000 km.Completely irregular accelerations with peaks up to 100 Gal yielded a reduction of approximately 40 dB in amplitude.The survey data were evaluated using ocean gravity field models and grid line tests.The results show that the accuracy of the gravity measurements is better than 2 mGal.

关 键 词：electromagnetic damping JMGrav marine gravimeter marine gravity survey 

分 类 号：P716.81[天文地球—海洋科学]