Mutual Benefits of Timekeeping and Positioning
Dr.Patrizia TAVELLA, UTC,
The international standard time, called Coordinated Universal Time UTC, is computed at the “Bureau International des Poids et Mesures” in Paris based on about 450 atomic clocks maintained in time laboratories all over the world. Clocks located in remote laboratories need to be compared and measured and this is usually achieved by using the signals of the different GNSS systems. GNSS system in fact do not only offer position to the user, but also the possibility to compare local clocks.
On the other hand, atomic clocks and timekeeping systems are the heart of GNSS systems as the fundamental measures in the use of GNSS, the pseudorange, is a measures of time of flight of the signal and hence the capacity to have good clocks, good synchronization techniques, coordination, and signal processing is fundamental in navigation systems, as in national and international timekeeping. In addition, the different GNSS systems disseminate UTC as important service to the user requesting time synchronization. To this aim, GNSS systems are connected to the UTC community, usually through one or more national time laboratories.
Navigation and timing are strongly connected and the development in one field is often stimulating new ideas in the other field allowing a cross-fertilization with important mutual benefit in timekeeping and positioning.
Patrizia TAVELLA,
Degree in Physics and Ph.D. in Metrology, she is now Director of the Time Department of the “Bureau International des Poids et Mesures” in Paris, after 30 years at the Italian Metrology Institute, INRIM, Torino, Italy. Her main interests are mathematical and statistical models applied to atomic time scale algorithms. She collaborated to the development of the European Navigation System Galileo.
