Initial evaluation of the "bottoms up" time recovery technique

This paper describes a new time transfer methodology and evaluates the performance of a number of globally distributed timing systems that utilize the technique. Active steering of high performance atomic clocks based on one-way GPS broadcasts is implemented automatically at remote sites. Data flows "up" to a central node where a series of processing and analysis steps provide after-the-fact calibration data. Using this technique, the widely separated sites can be inter-calibrated and their individual UTC time recovery performance can be monitored, managed and maintained. Relative synchronization between sites is as low as 2.5 ns over a 4000 mile baseline, and UTC(USNO) time recovery system wide is below 10 ns.<>