Scintrex CG5 used for superconducting gravimeter calibration

Abstract

The scale factor accuracy of superconducting gravimeters (SG) can be largely improved by a high repetition rate of calibration experiments. At stations where the availability of absolute gravimeters is limited, carefully calibrated spring gravimeters can be used for providing the reference signal assuming the irregular drift is properly adjusted. The temporal stability of the SG scale factor is assessable by comparing the temporal variations of M2 tidal parameters observed at neighboring SG sites or from synthetic tide models. Combining these methods reduces the SG scale factor error to a few 0.1‰. The paper addresses the particular procedure required for evaluating the calibration experiments based on spring gravimeters and presents results obtained at Conrad observatory (Austria). Comparing the M2 amplitude factor modulation helped to reveal a SG scale factor offset of about 0.2‰ due to re-installation. Keywords: Superconducting gravimeter, CG-5 Scintrex gravimeter, Scale factor, Calibration accuracy, M2 tidal parameter variation