Enhanced or eLoran for Time and Frequency Applications

G. Linn Roth, Ph.D., Paul Schick, James Jacoby, Chad Schweitzer, Dean Gervasi, Eric Wiley

Abstract:	The US Loran system is undergoing a modernization that will result in an enhanced or eLoran system. As a part of this modernization, three 5071A cesium clocks were installed at each transmitter, and state-of-the-art time and frequency clock measurement and control equipment was installed which uses GPS to steer the ensemble averaged Cs clocks to recover UTC (USNO) within 15 nanoseconds at each transmitter. When the conversion to eLoran is complete, the eLoran system will use time-of-transmission (TOT) control similar to GPS, and add a 9th pulse or Loran data channel (LDC) that will distribute UTC, leap second, and other information from each of the 29 transmitters in North America. eLoran provides performance comparable to GPS for numerous time and frequency applications, so eLoran can act as a traceable, infinite, and independent backup to GPS in these applications. This paper provides an overview of the eLoran modernization program and new eLoran antenna and receiver technology, and data from recent tests, including preliminary studies of Loran performance using H-field antennas located indoors.
Published in:	Proceedings of the 37th Annual Precise Time and Time Interval Systems and Applications Meeting August 29 - 31, 2005 Vancouver, Canada
Pages:	816 - 823
Cite this article:	Roth, G. Linn, Ph.D.,, Schick, Paul, Jacoby, James, Schweitzer, Chad, Gervasi, Dean, Wiley, Eric, "Enhanced or eLoran for Time and Frequency Applications," Proceedings of the 37th Annual Precise Time and Time Interval Systems and Applications Meeting, Vancouver, Canada, August 2005, pp. 816-823.
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