Real-time Time and Frequency Transfer Using Gps Carrier Phase Observations

A client-server based data communication scheme was developed in order to establish a permanent and dynamic real-time GPS network for relative time and frequency transfer. The Kalman-filter-based real-time processor uses station pairwise common-view phase observations for estimating the receiver clock and tropospheric parameters. Orbit determination is based on real-time broadcast ephemerides and station coordinates are fixed and known. Real-time estimates were compared with clock solutions from postprocessed data resulting in standard deviation values in the order of 50 ps for short baselines.