Differential eLoran Trials in Harwich Harbour

Gerard Offermans, Arthur Helwig, Paul Williams, and Wouter Pelgrum

Abstract:	“A prudent navigator should not rely on a single source of navigational information.” Although GPS and the future European Galileo seem to be able to provide inexpensive, highly accurate navigation information, it has become clear in the last decade that neither system, nor the two together will be sufficient to guarantee safe navigation in the most demanding circumstances. Alternate or back-up systems are desirable. From a maritime perspective, the world’s shipping industry is experiencing a period of strong growth with seaborne trade at record levels and increasing 4 percent per year. Ships are larger and faster, sea-lanes more crowded, and crews are less experienced. New concepts, such as e-Navigation should make safe navigation easier and less expensive. However, the reliance on the correctness and availability of navigation and timing information for these systems becomes much stronger, thus increasing the operational risks when systems fail. In these cases a back-up system is a necessity. Initial differential eLoran trials conducted by UK’s General Lighthouse Authorities at Harwich in April 2006 and using a test transmitter at Rugby have demonstrated horizontal positioning accuracies better than 9 meters with 95 percent confidence using modern, miniaturized eLoran receivers. This puts eLoran on the same basis as single-frequency GPS or Galileo: each requires differential corrections to guarantee meeting the International Maritime Organisation’s (IMO) future accuracy requirements for port approach and restricted waters. IMO Resolution A.915(22) presents the revised maritime policy and requirements for a future GNSS. The paper describes the concept of differential eLoran positioning, the trial set-up and the results.
Published in:	Proceedings of the 2007 National Technical Meeting of The Institute of Navigation January 22 - 24, 2007 The Catamaran Resort Hotel San Diego, CA
Pages:	1167 - 1178
Cite this article:	Offermans, Gerard, Helwig, Arthur, Williams, Paul, Pelgrum, Wouter, "Differential eLoran Trials in Harwich Harbour," Proceedings of the 2007 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2007, pp. 1167-1178.
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