masthead

Differential GPS Beacons

DGPS became operational on 1st July 2002 and consists of a network of 14 ground based reference stations providing transmissions with coverage of at least 50 miles around the coats of the UK and Ireland.

DGPS is an open system available to all mariners and is financed from the light dues paid by commercial shipping and other income paid into the general lighthouse fund.

DGPS beacons transmit correctional data to update positions derived from the Navstar Global Positioning System. The modulation used is MSK (Minimum Shift Keying) and the modulation rate is usually 100 or 200 bits per second.

In Europe the channel spacing is 500 KHz and the identification code is included in the transmitted data.

DGPS is referenced to WGS84

The frequencies for stations in the UK and Ireland are shown in the table below.

DGPS Station

Identification Number

Position

Frequency KHz

Sumburgh Head

685

59:51 N             01:16 W

291.5

Girdle Ness

686

57:08 N             02:03 W

297.0

Flamborough

687

54:07 N             00:05 W

290.5

North Foreland

688

51:23 N             01:27 E

299.5

St Catherine’s

680

50:35 N             01:18 W

307.5

Lizard

681

49:58 N             05:12 W

306.0

Nash Point

689

51:24 N             03:33 W

309.5

Mizen Head

660

51:27 N             09:48 W

284.0

Loop Head

665

52:33 N             09:55 W

293.0

Point Lynas

682

53:25 N             04:17 W

297.5

Tory Island

670

55:16 N             08:14 W

288.5

Butt of Lewis

684

58:31 N             06:16 W

295.5

Wormleighton

691

52:12 N             01:22 W

291.0

Stirling

693

56:04 N             04:03 W

285.5