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 |