The experience of a time Metrology Institute in the Galileo Navigation System: The time validation facility

The National Institute of Metrological Research (INRIM) in Italy has been deeply involved in the last 15 years in the development of the timing system of the European Satellite Navigation System Galileo, collaborating with the European metro-logical time laboratories, space industries, and the European Space Agency. In 2010–2013, INRIM designed, developed and operated the Time Validation Facility (TVF), a crucial timing element used for the In Orbit Validation (IOV) Galileo phase carried out with the first 4 satellites in 2013.