ANALYSIS OF ONE YEAR OF GPS AND TWO-WAY TIME TRANSFER RESULTS BETWEEN PTB, NPL, AND VSL

摘要

As part of the Galileo project of Early Trials on Time Synchronization Techniques and Calibration Issues, the GPS Common-View and Two-Way Satellite Frequency and Time Transfer (TWSTFT) results between the time scales of PTB, NPL, and VSL during 2001 were analyzed. This was done to identify the obtainable uncertainty levels with these techniques. These will be used for the future connection between the Galileo System Time (GST) and TAI and UTC. The results of the analysis are presented. The baseline of the stations is 400 to 900 km. The uncertainties from statistical origin (Type A evaluation) were determined by means of MDEV and TDEV. The uncertainties from other sources (Type B evaluation) were determined from calibration trips. The stabilities of the clocks dominate at averaging times > 5 days; at shorter averaging times TWSTFT shows better TDEV and MDEV. In the combined uncertainty, the contribution of the uncertainty in the calibration results dominates in both the GPS and TWSTFT results.