T2L2 : Ground to ground Time Transfer

Abstract

T2L2 (Time Transfer by Laser Link), developed by both CNES and OCA permits the synchronization of remote ultra stable clocks over intercontinental distances. The principle is derived from laser telemetry technology with a dedicated space equipment deigned to record arrival times of laser pulses at the satellite. Using laser pulses instead of radio frequency signals used in classical time transfer techniques (GPS, TWSTFT), T2L2 permits to realize some links between distant clocks with time stability of a few picoseconds and accuracy better than 100 ps.