Resolution 6 of the 20th CGPM (1995)

Clock comparison by satellite laser techniques

The 20th Conférence Générale des Poids et Mesures,


  • the need for long distance time transfer at the highest possible level of accuracy,
  • that successful time transfer with a precision of 100 ps has been achieved between Western Europe and North America using the LASSO (Laser Synchronization from Satellite Orbit) experiment on a geostationary satellite,
  • that time transfer techniques, such as GPS (Global Positioning System), GLONASS (Global Navigation Satellite System) and two-way satellite time transfer, need an independent means of assessment of their accuracy,
  • that solutions have been proposed that may lead to clock synchronization by laser techniques using non-geostationary satellites,

recalling Resolution 4 of the 18th Conférence Générale in 1987, which also concerns clock comparison by satellite techniques,

recommends that the space agencies consider the installation on their satellites of appropriate equipment for clock comparison by satellite laser techniques.

DOI : 10.59161/CGPM1995RES6E

The reader should note that the official version of this Resolution is the French text

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