Issue Date: Sunday 1 January 2012
The General Lighthouse Authorities (GLA) provide a MF Radio Beacon Differential GPS (DGPS) service on the Coasts of Great Britain and Ireland.
DGPS is provided as a marine aid to navigation, giving 24 hour-a-day, all-year-round service with overlapping signal coverage up to 50 nautical miles offshore around the coasts of the United Kingdom and the Republic of Ireland. The differential signals are transmitted using a terrestrial network of medium frequency marine radio beacons in the 283.5-315 kHz band. Mariners are encouraged to equip themselves with a suitable receiver as the signal provides both real time integrity monitoring of GPS derived positions and the capability of fixing their positions to better than 5 metres accuracy (95% probability) in moving applications. Greater accuracy can be achieved in stationary applications.
All mariners are advised that: