gravity difference at ~120 cm sensor height from absolute and relative gravity measurements between two pillars at Metsähovi, Onsala and Bad Homburg Instrumental precision Metsähovi AB-AC Onsala AS-AN Bad Homburg BA-AA dg(rel) ±0.5 µGal 1.97.734.9 Difference dg(abs) – dg(rel) [µGal] 1.91.4-2.6 -1.61.1 0.1 2.7 1.7 1.9 0.2 Onsala ±1…±2 µGal  several setups to minimize the instumental uncertainties (Floor-recoil, azimuth (Coriolis/attrition), setup,…)