Kalman smoothed estimates of GPS common-view data

A Kalman filter has been applied to two years of Global Positioning System (GPS) common-view data on a monthly basis for the time link between SP the Swedish National Testing and Research Institute, Sweden and the Observatoire de Paris, France. The Kalman estimates for the time link were compared to data extracted from the Circular T, issued by the Bureau International des Poids et Mesures (BIPM), France. The BIPM estimates are based on a Vondrak smoothing of the common-view data and values for the time link are available every fifth day, at standard dates. A third method, based on two-day averages around standard dates, was then compared to the above methods. It is shown that all three methods agree within 1 ns at standard dates, if the international GPS tracking schedule issued by the BIPM was routinely followed