Contributing to TAI with a Secondary Representation of the SI Second

Understand

We report the first contribution to the international atomic time (TAI) based on a secondary representation of the SI second.

• This work is done with the LNE-SYRTE FO2-Rb fountain frequency standard using the $^{87}$Rb ground state hyperfine transition.
• We describe FO2-Rb and how it is connected to local and international time scales.
• We report on local measurements of this frequency standard in the SI system, i.e.