Mobile Field Measurements with a Quantum Gravimeter: Technical Setup and Performance

Terrestrial gravimetry serves for many geophysical and environmental applications by observing gravity variations that are caused by mass variations in the subsurface, such as water storage changes. Recent advances in quantum technology led to the first commercially available absolute quantum gravimeter (AQG) from the company Exail that is designed for deployment in field surveys. In this paper, we present a technical setup including instrument transport, power supply and site design for mobile AQG field surveys on a regional gravimetric network. We discuss the technical and operational feasibility of the setup and assess the measured gravity data in terms of sensitivity, accuracy and repeatability for a 6-day field survey with an AQG of the B-series with serial number 02 (AQG#B02) in the vicinity of the Geodetic Observatory Wettzell (Bavarian Forest, Germany). This is the first mobile AQG survey of its kind to have been carried out. The repeatability of the absolute gravity value at the same site was 54 or 75 nm s⁻² on average, depending on its definition. When compared with measurements from an A10 absolute field gravimeter on the same network sites, the accuracy of the AQG was 64 nm s⁻² on average. While mobile AQG field campaigns were shown to be technically feasible, the overall AQG performance did not yet meet the requirements for typical hydrological applications to assess water storage changes. Meanwhile, the AQG-B series was developed further by the manufacturer, improving the stability of the gravimeter.