Results from a new interferometric ballistic differential gravity meter

Recently Micro-G Solutions developed an interferometric ballistic differential gravity meter and commenced data collection and analysis. Target accuracies are ±1 μGal/m or 10 EU. The instrument uses ballistic laser interferometer concepts proven on the commercial FG5 absolute gravimeter, with modifications made to accommodate fiber optic interferometer technology. Design principles are explained, with emphasis placed on the advantages of a differential gravity instrument versus a gradiometer. Results from initial experiments conducted with a prototype instrument represent the first time absolute interferometric differential gravity data has been collected and processed. Achieved single drop precision is ±7 μGal, while five minute precision drops to ±1.7 μGal. These statistics are comparable to the current generation FG5 absolute gravity meters. Conclusions regarding the implications of the data to the geosciences community are made and future research plans are discussed.