The Use of the Wide Area Augmentation System (WAAS) as a Time Transfer System

Pat Fenton, William J. Klepczynski, Edward Powers and Robert Douglas

Abstract:	This paper extends the program (Ref. 1) to evaluate the WAAS potential as a time transfer and a time distribution system. This paper reviews the performance of using dual frequency GPS satellite measurements corrected by the WAAS broadcast data. In our previous work (Ref. 1) we found that the code and carrier measurements made on the signal coming from the WAAS Geostationary satellite were at least a magnitude noisier than GPS. We attributed most of this error to multipath errors and to the fact that the WAAS signal is narrow band (2MHz) and cannot be improved by modern multipath-resistant correlation techniques. This paper examines the use of a directional antenna focused on the WAAS satellite. The directional antenna should eliminate the effects of multipath and could potentially provide a very clean continuous signal for time and frequency transfer. A feed Hornand directional parabolic dish antennas were tested over a short baseline at USNO. The directional dish antenna was found to produce 25% cleaner data than the feed horn. Because of the very high signal to noise ratio level attained by using the high gain dish antenna, we found that the receiver maintained phase lock for days. Data from the directional dish antenna was collected at USNO and NRC. Results from this 700Km base line revealed ns level performance for time transfer and 1E-15 level frequency transfer after only 8 hours of observation.
Published in:	Proceedings of the 2000 National Technical Meeting of The Institute of Navigation January 26 - 28, 2000 Pacific Hotel Disneyland Anaheim, CA
Pages:	375 - 380
Cite this article:	Fenton, Pat, Klepczynski, William J., Powers, Edward, Douglas, Robert, "The Use of the Wide Area Augmentation System (WAAS) as a Time Transfer System," Proceedings of the 2000 National Technical Meeting of The Institute of Navigation, Anaheim, CA, January 2000, pp. 375-380.
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