A new concept of time in geodesy

It is known that the synchronization of clocks on rotating platforms is not trivial. Accordingly, to set up a unique time scale on Earth is a challenging task. Exactly this is the main topic of a newly approved proposal for a DFG funded research group on a new approach to time in geodesy. This research group is a consortium consisting of the Technical University of Munich, University of Hannover, GFZ in Potsdam, University of Düsseldorf, PTB in Braunschweig, and the University of Bremen. We are contributing to this consortium with two research topics and groups: One topic is the theoretical modelling of synchronization in the framework of General Relativity where we will discuss and compare several synchrnonizations schemes (e.g., Einstein synchronization, one-way and two-way synchronization with satellites, VLBI). We also investigate whether new quantum technologies like entanglement may be used for a new scheme for synchronization. The second Bremen topic is the modelling of the influence of the Earth's atmosphere on the propagation of signals from ground to satellites. This research group has been apprved for four years; a prolongation for another four years is planned. One application will be to use our approach for synchroninization of clocks on Earth with the forthcoming PHARAO clock on the International Space Station.