Use of an Integrated GPS/Loran Tracking System in the Urban Environment

James Carroll, Henry Wychorski, Kam Chin, David Phinney, and Bryan Long

Abstract:	"The rapidly increasing use of satellite navigation encompasses a broad range of civilian users, not all of whom are sufficiently aware of important operational risks to using, say, the Global Positioning System (GPS) for positioning, navigation and timing (PNT). The Volpe Center has recently installed vessel tracking and surveillance systems in several waterways worldwide. This includes systems that provide important navigation and tracking information for commercial and personal users. Volpe also has been developing systems that enhance maritime security by providing increased situational awareness. A new generation of transponder equipment is being developed for use by harbor protection forces in both domestic and foreign ports. This paper discusses another extension of this technology to land applications in urban areas, using positioning and timing information provided by an integrated GPS/Loran- C system. The original Loran-C, now about 60 years old, is nearing completion of a significant upgrade and enhancement effort funded by the FAA. Enhanced Loran (e-Loran) is a very complementary system to GPS. Its signals are much less susceptible to the interference that can impair GPS, and its broadcast frequency has minimal line-of-sight issues. E-Loran has recently been shown to be an adequate backup system to GPS for many applications. An important issue for the integrated GPS/Loran system is how well Loran can supplement GPS when the GPS signal is not usable. This paper describes the design and uses of the integrated GPS/Loran surveillance system, presents results from performance evaluations conducted in the Boston and New York City areas, and under GPSband jamming in New Mexico. Preliminary conclusions are that Loran can be a valuable surveillance supplement to GPS in spectrum denial situations and in some urban applications. However, more technology development of Loran receivers may be necessary before integrated GPS/Loran systems can compete with dead reckoning supplements to GPS in the urban environment."
Published in:	Proceedings of the 61st Annual Meeting of The Institute of Navigation (2005) June 27 - 29, 2005 Royal Sonesta Hotel Cambridge, MA
Pages:	354 - 361
Cite this article:	Carroll, James, Wychorski, Henry, Chin, Kam, Phinney, David, Long, Bryan, "Use of an Integrated GPS/Loran Tracking System in the Urban Environment," Proceedings of the 61st Annual Meeting of The Institute of Navigation (2005), Cambridge, MA, June 2005, pp. 354-361.
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