Comparisons of Absolute Gravimeters as a Key Component of the International Terrestrial Gravity Reference Frame (ITGRF) Shown on the Example of the WET-CAG2021 at Wettzell, Germany

Abstract

AbstractComparisons of absolute gravimeters are essential to guarantee their traceability to the International System of Units (SI) and their compatibility and will be a key component of the upcoming International Terrestrial Gravity Reference Frame (ITGRF) of IAG.The results of the regional comparison of absolute gravimeters WET-CAG2021 hosted at the Geodetic Observatory Wettzell, Germany, in autumn 2021 are presented. Seven FG5/X absolute gravimeters and—for the first time—two commercial AQG absolute quantum gravimeters took part. Temporal gravity variations during the comparison period of 12 weeks were monitored with the superconducting gravimeter GWR OSG-030. The equivalence of each absolute gravimeter is evaluated against a common reference level derived from the measurements during this comparison period. Although the comparison is outside the scope of CIPM MRA it is linked to the EURAMET.M.G-K3 2018 at the same site and the CM.G-K2.2017 in Beijing, China, which ensures the traceability.