Notices to Mariners

Enhanced Loran (eLoran) Project Update

13 - 2012

Issue Date: Wednesday 3 October 2012

Aid: eLoran

Area:

Further to CIL Notice 2 of 2008 the Commissioners of Irish Lights wish to update mariners on eLoran transmissions from the General Lighthouse Authority (GLA) transmitter at Anthorn in Cumbria.

The GLA for the UK and Ireland have a trial Enhanced Loran (eLoran) transmitter station in Anthorn (coordinates: Latitude 54° 54.673' N. Longitude 03° 17.237 W)*.  The station has been transmitting consistently since Jan 2008, providing coverage to the UK and Ireland.  Existing Loran receivers may require software upgrades from their equipment suppliers to use this station.

The GLA are now preparing to move to an Initial Operating Capability stage for their eLoran transmitter. Differential Loran and improved Additional Secondary Factor (ASF) data will be included in the Anthorn eLoran digital message. The differential data will be acquired from monitoring equipment to be installed at 7 major UK East Coast ports during 2012/13. The selected ports are Dover, Harwich/Felixstowe, Medway/Tilbury, Immingham, Middlesbrough, Grangemouth and Aberdeen. Accuracy of better than 20 metres can be expected in the selected areas.

All radio navigation systems are susceptible to interference (including jamming) and environmental effects, which can adversely affect their availability.  The General Lighthouse Authorities strongly advise that no single Aids to Navigation system should be used in isolation and that users should use all alternative means available to cross check the information received.

Maritime Users are strongly encouraged to use eLoran as a navigational input system to back-up and complement the widespread use of GPS. The General Lighthouse Authorities would welcome feedback from the user community on the performance of eLoran.

* The signals from Anthorn are transmitted with a Group Repetition Interval (GRI) of 67,310 microseconds and an Emission Delay (ED) of 27300 microseconds, broadcasting as station 'Y' of chain 6731.  The signals are modulated with Eurofix data messages, with the facility to broadcast differential Loran, improved Additional Secondary Factor (ASF) data, differential GPS, integrity information and UTC (Co-ordinated Universal Time) parameters.  Eurofix data messages can be received when using an appropriate eLoran receiver.

By Order, Yvonne Shields Chief Executive.