Expert Advice - The Case for eLORAN
June 1, 2006 By: Sally Basker GPS WorldThe 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.
The UK government has championed the new e-Navigation concept based GNSS that is intended to set international standards to make safe navigation easier and cheaper. e-Navigation is the cost-effective collection, integration, and display of maritime information onboard and ashore by electronic means, to enhance berth-to-berth navigation and related services for safety and security at sea, and to protect the marine environment.
Physical aids to navigation (AtoN), principally buoys and lights, will always be needed to provide a reversionary capability because of the inevitable vulnerabilities of GNSS. However, reverting from e-Navigation based solely on GNSS to physical AtoN will become less straightforward over time because mariners will become less familiar with the traditional skills needed to navigate using physical aids. In some cases, safety might actually worsen.
Enhanced Loran (eLORAN) is needed both to ensure safety in a higher risk environment and to deliver a radionavigation dividend — cost savings that result from the introduction of radionavigation services and their take-up in the maritime sector. eLORAN is a low-frequency, terrestrial navigation system operating at 100 kHz and synchronized to Coordinated Universal Time (UTC). It is intended to meet the required navigation performance parameters for a range of transport and timing applications including marine general navigation.
Initial differential eLORAN trials conducted 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.
On May 10, the General Lighthouse Authorities (GLAs) of the United Kingdom and Ireland released “The Case for eLORAN,” a document identifying how eLORAN will secure the safe, low-risk, and cost-effective mix of AtoN needed for the benefit and safety of all mariners around the British Isles. The document shows how the GLAs will develop the UK’s lead role in e-Navigation. This work will follow the adoption by the IMO Maritime Safety Committee of e-Navigation as a key part of the work programme for its Navigation sub-committee. “The Case for eLORAN” is available for download in PDF format.
Sally Basker is the director of Research and Radionavigation for the General Lighthouse Authorities of the United Kingdom and Ireland , and a member of GPS World’s Editorial Advisory Board.
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