An internally damped inertial platform for marine gravimetry and a test case 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 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816-829,共14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);supported by the Key Special Projects of the Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(for Introduced Talents Team)(Nos.GML2021GD0810,GML2019ZD0602)。

摘　　要：To dampen periodic off-levelling motions within an inertial platform while undergoing horizontal accelerations of the same period and to achieve a levelling accuracy of a few tens of arcseconds with that system,an internally damped inertial platform for a marine scalar gravity system was the developed.Methods for attenuating horizontal acceleration and reducing off-levelling error by a satisfactory gyro-levelling loop,which are fundamental to the internally damped inertial platform,were designed and implemented.In addition,phase delays are introduced by the levelling loop.The resulting off-levelling gravity errors were analyzed and modeled.A series of tests on a motion simulator were performed in laboratory for a variety of simulated sea conditions.We found that the motion of the platform is a function of the amplitude and period of the simulated ship motions and ranges between 10 and 40 arcseconds.In addition,the phase lag between platform motion and ship motion is not constant but ranges 180°-270°,depending on the period and amplitude of the motion.Then,the platform,on which a gravimeter was mounted,was installed on the R/V Shiyan 2 to conduct a gravity survey in the South China Sea.Despite rough sea conditions,it was shown that in short periods of 2-30 s,the off-levelling angle was less than 30 arcseconds,and the phase lagged the horizontal acceleration by 230°-260°.From a repeated survey line and intersecting survey points,the estimated errors of gravity measurements were between 1.3 and 1.7 mGal.The marine measurements results were compared with those of satellite altimetry data and show a mean value of 0.5 mGal in a standard deviation of 1.5 mGal.

关 键 词：internally damped platform gyro-levelling loop marine gravimetry 

分 类 号：P714[天文地球—海洋科学]