Schwereregistrierungen mit dem Micro-g LaCoste gPhone-98 und dem ZLS Burris Gravity Meter B-64

Modern spring gravimeters offer - e.g. compared to superconducting gravimeters - a fiexible, simpler and economical solution for the long term acquisition of gravity data, but are limited by instrumental drift. We investigate the accuracy of the Micro-g LaCoste gPhone-98 (g-98) and the ZLS Burris Gravity Meter B-64 (B-64) of the Institut für Erdmessung (IfE). Both instruments conducted recordings for several months on stations with low to high seismic noise. At one station g-98 and B-64 recorded in parallel. Additionally, the B-64 recorded simultaneously with the GWR Instruments OSG-054 superconducting gravimeter in Onsala (Sweden). The tidal analysis of timeseries from these two instruments shows an agreement of 0.3 ‰ (O1, K1, M2) to 1.7 ‰ (S2) for diurnal- and semidiurnal amplitude factors. The linear calibration factor of g-98 and B-64 was found to be stable at the level of 3 · 10^-4.The instrumental drift of a gPhone is generally linear after an initial run-in phase. The magnitude as well as the variation of g-98's drift has decreased over time with each new setup of the instrument at a new location. Currently, the drift is approximately 90 nm/s² per day. The drift of B-64, on the other hand, does currently not show a linear behaviour.