Experimental Galileo System Time (E-GST): one year of real-time experiment

Abstract : The Galileo System Test Bed (GSTB) V1 is the first experimental phase in the Galileo project supported by the European Space Agency (ESA). The aim is testing the Galileo algorithms in a mixed configuration where the space segment is given by the existing GPS constellation, while the ground segment is an experimental setup as close as possible to the Galileo architecture. In the framework of the GSTB V1, Alenia Spazio, in collaboration with the Istituto Elettrotecnico Nazionale (IEN), had the responsibility to design and realize an infrastructure able to generate the Experimental Galileo System Time (E-GST), which is the reference time for all the GSTB V1. The infrastructure that allows the realization of E-GST is the Experimental Precise Timing Station (E-PTS), which is implemented at the IEN facilities, Turin, Italy. The paper reports the main results of the E-PTS experimentation carried out during the whole of 2004, addressing the E-GST overall performance with respect to the demanding GSTB V1 goals. The lessons learned from the experiment are also pointed out in the paper, together with some recommendations to be taken into account in the design of the Precise Timing Facilities (PTF) of the Galileo ground segment.

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