A major effort is under way to develop highly portable absolute gravimeters having an ultimate accuracy of 3-5 μGal, an accuracy which translates into a height sensitivity of several centimeters. We are just finishing the construction of six such units. Measurements at the Joint Institute for Laboratory Astrophysics with one of these new instruments agree well with the earlier measurements made in 1981 and 1982 with a previous generation instrument. Recent measurements at the International Bureau of Weights and Measures in Sevres, France, as a part of an international intercomparison of absolute gravimeters, also show good agreement with the other instruments. |