Time Distribution Capabilities of the Wide Area Augmentation System (WAAS)

William J. Klepczynski, Pat Fenton, Ed Powers

Abstract:	Because of the role of time as a secondary mission of the Wide Area Augmentation System (WAAS), the FAA has been interested in developing the use of the WAAS for time distribution. An economical, evolutionary approach to the development of the WAAS for time distribution has been pursued. Several groups have been participating in a program to develop a Time Distribution System (TDS). Data presented to date indicate that the WAAS is probably not at the same level as GPS for time distribution. Recent WAAS data indicate that the daily average values of the differences between UTC (USNO) and WAAS Network Time (WNT) range between +20 ns and -25 ns. Recent GPS data from USNO obtained with a single frequency GPS Time Transfer Unit indicate that 2-day average values of the differences between UTC (USNO) and GPS Time range between +6 ns and -15 ns. Because of foreseeable improvements in the not-too-distant future, it seems reasonable to expect that the WAAS will soon exceed the performance of GPS for time distribution. Among these improvements are operational improvements within the WAAS as it matures, and improved orbits for the geostationary satellites as more stations inaugurate satellite-based augmentation system (SBAS) observations for time.
Published in:	Proceedings of the 33th Annual Precise Time and Time Interval Systems and Applications Meeting November 27 - 27, 2001 Hyatt Regency Long Beach Long Beach, California
Pages:	111 - 120
Cite this article:	Klepczynski, William J., Fenton, Pat, Powers, Ed, "Time Distribution Capabilities of the Wide Area Augmentation System (WAAS)," Proceedings of the 33th Annual Precise Time and Time Interval Systems and Applications Meeting, Long Beach, California, November 2001, pp. 111-120.
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