Precise Point Positioning for timing

In recent years, many national timing laboratories have installed geodetic Global Positioning System receivers together with their traditional GPS/GLONASS Common View receivers and Two Way Satellite Time and Frequency Transfer equipments. Many of these geodetic receivers operate continuously within the International GNSS Service (IGS), and their data are regularly processed by IGS Analysis Centers. From its global network of over 350 stations and its Analysis Centers, the IGS generates precise combined GPS ephemerides and station and satellite clock time series referred to the IGS Time Scale. A processing method called Precise Point Positioning (PPP) is in use in the geodetic community allowing precise recovery of GPS antenna position, clock phase and atmospheric delays for GPS geodetic receivers which are not part of the IGS network, by taking advantage of IGS precise products without ensuring the effort of a formal belonging to the IGS federation. This article reports on the results of a collaborative work performed at the Istituto Nazionale di Ricerca Metrologica (INRiM) in Turin, Italy, and at the Natural Resources Canada (NRCan) in Ottawa to assess the time transfer potential of Precise Point Positioning.