Accuracy estimation of the IfE gravimeters Micro-g LaCoste gPhone-98 and ZLS Burris Gravity Meter B-64

Presently, modern spring gravimeters are the most flexible, technically simple, and comparatively cheap solution for recordings over extended time periods in contrast to superconducting gravimeters. We investigate the accuracy of the state-of-the-art spring gravimeters Micro-g LaCoste gPhone-98 and ZLS Burris Gravity Meter B-64 of the Institut fur Erdmessung (IfE). With both instruments gravity was recorded for periods of several months at five stations with high and low microseismic noise. Simultaneous measurements with both instruments as well as the parallel recording of the ZLS Burris gravimeter with the GWR Instruments Observatory Superconducting Gravimeter OSG-054 in Onsala (Sweden) are investigated. Tidal analysis is used to assess the quality of the time series. Diurnal and semi-diurnal amplitude factors agree at the level of 1 Open image in new window and better from recordings of Burris and OSG gravimeters in Onsala. In addition to gravity recordings a number of calibration experiments were carried out to test the long-term stability of the meters. The linear calibration factor of both gravimeters is stable to 3 × 10−4. The drift of the gPhone-98 decreased over time and is currently reduced with a linear factor of \(\approx 90\) nm/s2 per day. The instrumental drift of Burris B-64 on the other hand can currently not be reduced with a linear factor.