The Seventh International Comparison of Absolute Gravimeters ICAG-2005 at the BIPM. Organization and preliminary results

Abstract

ICAG-2005, an international comparison of absolute gravimeters, was held in September 2005 at the Bureau International des Poids et Mesures (BIPM), Sèvres, France. Nineteen absolute gravimeters performed measurements of free-fall acceleration g at eleven sites of the BIPM gravity network. Fifteen relative gravimeters were used to measure the vertical gravity gradients and to provide gravity ties between the sites. The maximum g-difference was about 9 mGal. The status of a pilot study was agreed for this comparison by the Consultative Committee for Mass and Related Quantities. For the first time in the ICAG series, a technical protocol specifying the organization, measurement strategy, data processing, calculation of the uncertainties and presentation of the results, was developed for the ICAG 2005. The unweighted mean value of the results of absolute measurements referred to the site A is presented and compared with the similar values obtained in ICAG-1997 and ICAG-2001