A direct comparison of five optical clocks and six atomic fountains, located at INRIM, LNE-SYRTE, NPL and PTB, was performed using two high-performance satellite techniques: broadband TWSTFT and GPS PPP. This was the first time that very wide band (20 Mchip/s) pseudo-random noise codes available on commercial TWSTFT modems were used for optical clock comparisons. This campaign represented the most comprehensive coordinated simultaneous operation of optical clocks to date.

More information : F Riedel et al 2020 Metrologia 57 045005

Contact : Joseph Achkar (joseph.achkar@observatoiredeparis.psl.eu) et Jérôme Lodewyck (jerome.lodewyck@obspm.fr)