High accuracy continuous time transfer with GPS IPPP and T2L2

We present a comparison of time transfer results over European baselines obtained with two space-based techniques: Precise Point Positioning with integer ambiguity resolution (IPPP) using GPS satellites and Time Transfer by Laser Link (T2L2) using the low orbiting satellite Jason-2. The data was obtained in a 3-month experiment in Autumn 2013 for baselines between Paris, Herstmonceux and Grasse. We find that the difference between the 30-s IPPP link results and the closest 1-s T2L2 data points has a standard deviation below 100 ps for all three baselines. These results provide the basis for a continuous time transfer technique with accuracy at the 100 ps level for baselines over which T2L2 can operate in CV. Occasional T2L2 measurements provide the absolute time difference with a high accuracy and a continuous IPPP link maintains the accuracy for weeks to months between calibrations.