Preliminary metrological assessment for a field differential quantum gravimeter

The FIQUgS project aims at developing advanced field quantum gravimeters with enhanced resilience to temperature variations, reduced size, and lower power consumption. Two instruments are being developed within the project: a new version of Exail's Absolute Quantum Gravimeter (AQG) and a Differential Quantum Gravimeter (DQG) [1,2]. Both instruments have benefited from design improvements that eliminate the need for a power-intensive air-conditioning unit.

Here, we report on the first tests of the FIQUgS DQG conducted at LNE-OP/LTE laboratories in 2025. These tests follow similar ones carried out in 2022 with the DQG prototype [3] and include:

• A comparison of the absolute measurements of the DQG against AQG-B01* for gravity measurement and against a CG6* for vertical gravity gradients.
• A two weeks long measurement and a comparison with a superconducting gravimeter, see figure 1.
• An evaluation of the effect of temperature on measurement stability under varying temperature conditions.
• A comparison of the internal time and wavelength references against national standards.

Overall, the instrument performed well within an 18-35 °C range. Preliminary results for the comparison with AQG-B01 show an agreement within 100nm/s²  and gravity gradients measured using a CG6 show an agreement within 30E (1E=1nm/s²/m).

Further work will aim at robustifying the system and extend the thermal operating range. Nonetheless, these results provide a solid foundation for field surveys planned with FIQUgS in mid-2026.

Figure 1: 2 weeks long simultaneous gravity and vertical gravity gradient measurement of the FIQUgS DQG at LNE-OP/LTE.

 

The FIQUgS project is funded by the European Comission under the Horizon Europe program, grant number 101080144

*AQG-B01 and CG6 are instruments of INSU-CNRS French National Parc of Instruments PIN PGravi.

 

[1] https://www.fiqugs.eu/

[2] L. Antoni-Micollier et al., "Absolute Quantum Gravimeters and Gradiometers for Field Measurements," in IEEE Instrumentation & Measurement Magazine, vol. 27, no. 6, pp. 4-10, September 2024, doi: 10.1109/MIM.2024.10654720. 

[3] Janvier, C., Merlet, S., Rosenbusch, P., Ménoret, V., Landragin, A., Pereira dos Santos, F., and Desruelle, B.: Operational evaluation of an industrial differential quantum gravimeter, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-5171, https://doi.org/10.5194/egusphere-egu23-5171, 2023.