Loran-C, an Overview

William J. Thrall

Abstract: In 1974 Loran-C was selected to be the government-provided radionavigation system for the U.S. Coastal Confluence Zone and the Great Lakes. Title 14, USC 81 states that the U.S. Coast Guard may establish and maintain electronic aids to operate marine navigation required to serve the needs of the military and commerce of the United Stares. Loran-C is a highly accurate positioning sys tern. It operates at: an assigned frequency of 100 kHz, and provides phase-coded pulses to develop hyperbolic time-difference lines-of-position (LOP'S). In addition to providing for radionavigation, Loran-C also provides precise time and time interval to within + 5 microseconds of UTC. The paper discusses the steps taken to plan, install, operate and maintain the Loran-C system up to the year 2000. The following topics are included in the discussion: theory of operation, timing, chain planning, group repetition interval, coding delay versus emission delay, chain calibration, chart: verification, system accuracy, signal reliability, and future developments. The opinions or assertions contained herein are lie private ones of the writer and are nut to be construed as official or reflecting the views of the Commandant or the Coast Guard at large.
Published in: Proceedings of the 13th Annual Precise Time and Time Interval Systems and Applications Meeting
December 1 - 3, 1981
Naval Research Laboratory
Washington, DC
Pages: 121 - 131
Cite this article: Thrall, William J., "Loran-C, an Overview," Proceedings of the 13th Annual Precise Time and Time Interval Systems and Applications Meeting, Washington, DC, December 1981, pp. 121-131.
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