Large-Scale Absolute Gravity Control in Brazil

Since 1986, IfE Hannover operates the absolute gravimeter JILAG-3. After laboratory and field experiments, hard- and software improvements, as well as comparative measurements at absolute and relative stations, the instrument has been employed for absolute gravity control in fundamental and geodynamic networks in central and northern Europe. At approximately 100 gravity determinations at about 60 different stations an average station precision of a few μgal (1 μgal = 10 nms -2) could be achieved by 500 to 2000 drops. Taking residual instrumental and local effects into account, the average accuracy is estimated to be 10 μgal.