Results of relative gravimeter measurements at the ICAG97 intercomparison

In Sevres the fifth International Absolute Gravimeter Intercomparison was conducted in November 1997. In order to support the absolute measurements, the BGI Working Group 8: Relative Networks at Absolute Gravimeter Comparison ICAG97 conducted a relative gravimeter campaign as well. Twelve LaCoste and Romberg and one Scintrex gravimeters measured the connections between absolute points and vertical gravity gradients at each point. In addition the calibration baseline installed in 1994 was re-measured as well to check or provide calibration factors for all gravimeters. The results show that the accuracy for single instruments is in the range of 3 to 8 μGal 1 for a gravity difference, for both the Scintrex and the LaCoste gravimeters. The campaign was also used to intercompare different ways of calibrating the gravimeter electrostatic feedback systems. The calibration platform of BKG, Frankfurt, was installed in Sevres and the results can be compared to that of the calibration line. This paper gives results for the 1997 campaign.