Time Metrology

Contribution to European Projects of Radionavigation Satellites (EGNOS, Galileo)

EGNOS: Our laboratory is involved in the operational activities within the EGNOS satellite radionavigation system of ESA. EGNOS is the European augmentation system, equivalent to the WAAS American system or to the MSAS Japanese system. In its navigation message, EGNOS will propose to the users, the civil aviation in particular, the link of their reference timescale ENT(EGNOS Network Time) to UTC through UTC (OP) which drives the ground station installed at the Observatoire de Paris, under the control of CNES.

GALILEO: LNE-SYRTE is member of the Fidelity consortium who signed the contract with the Galileo Joint Undertaking in June 2005 for the realization of the Galileo Time Service Provider prototype (GTSP). Fidelity has started the construction of and will operate the GTSP to deliver Coordinated Universal Time (UTC) services to the Galileo satellite system in time for its In-Orbit Validation expected in 2008. The role of the GTSP is to provide parameters for steering Galileo System Time (GST), as realized at the Galileo Precise Timing Facility (PTF), to UTC (modulo 1 s). LNE-SYRTE is involved in the following tasks: prototype definition and design, contribution to GTSP by providing daily clock data and time transfer data and participating to calibration campaigns by GPS and TWSTFT, use of Galileo in time metrology and the relation with EGNOS.

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