Calibration of a superconducting gravimeter with an absolute atom gravimeter

We present a 27-day-long common view measurement of an absolute cold atom gravimeter (CAG) and a relative iGrav superconducting gravimeter, which we use to calibrate the iGrav scale factor. This allowed us to push the CAG long-term stability down to the level of 0.5 nm s(-2). We investigate the impact of the duration of the measurement on the uncertainty in the determination of the correlation factor and show that it is limited to about 3 parts per thousand by the coloured noise of our cold atom gravimeter. A 3-day-long measurement session with an additional FG5X absolute gravimeter allows us to directly compare the calibration results obtained with two different absolute meters. Based on our analysis, we expect that with an improvement of its long-term stability, the CAG will allow to calibrate the iGrav scale factor to better than the per mille level (1 sigma level of confidence) after only 1 day of concurrent measurements for maximum tidal amplitudes.

Automated summary

In this study, a 27-day-long common view measurement of an absolute cold atom gravimeter (CAG) and a relative iGrav superconducting gravimeter was conducted to calibrate the iGrav scale factor. The long-term stability of CAG was improved to 0.5 nm s(-2), and the uncertainty in the determination of the correlation factor was limited to about 3 parts per thousand by the colored noise of the cold atom gravimeter. Additionally, a 3-day-long measurement session with an additional FG5X absolute gravimeter allowed for a direct comparison of calibration results obtained with two different absolute meters.