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NIM’s Changping Campus was recommended as the gravimetric site for Global International Comparison of Absolute Gravimeter (ICAG) in 2017


Absolute gravimeters have been compared every four years in international campaigns since more than 30 years ago at BIPM in a cooperation of metrological and geosciences institutions. In 2010, it was decided that future ICAGs would not be hosted by the BIPM.Working groups of gravimetry in CCM (CCM-WGG) and IAG came together to discuss the possibilities of continuing the comparisons.The plans of the metrology community in the future to use alternating comparison sites and to integrate the results of the Key Comparisons in the CIPM Key comparison database correspond to the aim of the geodesy community to realize a new International Gravity Refernce System.

World institutions have been asked if they are able to support the establishment of the decentralized system of the sites for the comparisons of absolute gravimeters and repeated absolute measurements which then could be used as the basis for the real reference system.

Three institution (NIM-China, LNE-France, VNIIM-Russia) proposed to host ICAG-2017 in 2010. During the last two years, many efforts and progresses have been made in NIM, including:rebuilding laboratory, pushing ahead of purchase of superconducting gravimeter (GWR-iGrav) and absolute gravimeter (FG-5X), equipping the laboratory with special multilevel tripod, using relative gravimeter (CG-5) to measure gravtiy gradient, organizing the precision leveling measurement, asking for the support from custom by Chinese government,etc. 

In 2011, CCM-WGG meeting recognized NIM's Changping Campus as the most probably site for hosting ICAG-2017. In 2012, after two circles electronic vote by all CCM-WGG members, NIM's Changping Campus won 80% members support and was recommended as the gravimetric site for ICAG-2017. ICAG which is the important Global International Key Comparison can support the watt-balance type experiments for the realization of proposed new definition of kilogram will be moved out from Europe firstly since more than 30 years. 

In 2012. Bi-Comparison of absolute gravimeters between NIM and KRISS have been conducted in NIM's Changping Campus.Additionally, NIM will host the first Asian-Pacific Regional ICAG within APMP in 2015.