DGPS in Canada

DGPS (Differential Global Positioning Service) is a navigational system using the GPS system of satellites that circle the earth plus ground stations with limited signal range. The combination provides greater accuracy than GPS alone. DGPS requires receivers for both GPS and DGPS signals.

To learn more about GPS accuracy problems, read the GPS page.

DGPS is operated by the Canadian Coast Guard. 18 stations have been available for positioning and navigation since 1997 (in test mode). Refer to Radio Aids to Marine Naviation (RAMN) for coverage for each station (see station chart below).

Differential corrections are based on the NAD 83 datum position of the reference station antenna and positions obtained using DGPS should be referenced to this coordinate system only. DGPS receivers must be set to the WGS 84 datum in order to obtain optimum positioning accuracy.

Check the NOTMAR On-line Service, which distributes "Notice to Mariners" (chart updates) and "List of Lights, Buoys and Fog Signals". They also publish planned removal of aids to navigation in time for mariners to comment or make recommendations. Downgrading navigational aids is a direct result of planned reliance of commercial shipping on electronic navigation systems such as DGPS and electronic charts.

DGPS is being used for navigation on the Atlantic and Pacific coasts, most of the St. Lawrence River, Labrador, Georgian Bay, Riviere-du-Loup, and southern Nova Scota. The U.S. GPS system will continue to cover the remainder of the Great Lakes.

Table of Stage 1 DGPS Reference Stations

                    Id Nos     DGPS
                      of      Station                   Freq
Station Name        Stations    ID     Lat      Long   [kHz] Bits/sec
________________    ________   ____  _______  ________  ____  ____
Alert Bay BC         300,301   909   50 35 N  126 55 W   309  200
Amphitrite Pt BC     302,303   908   48 55 N  125 32 W   315  200
Cardinal ON          308,309   919   44 47 N   75 25 W   306  200
St.Jean Richelieu QC 312,313   929   45 19 N   73 18 W   296  200
Lauzon QC            316,317   927   46 48 N   71 09 W   309  200
Partridge Island NB  326,327   939   45 14 N   66 03 W   295  200
Pt. Escuminac NB     332,333   936   47 04 N   64 47 W   319  200
Fox Island NS        336,337   934   45 19 N   61 04 W   307  200
Cape Race NF         338,339   940   46 39 N   53 04 W   315  200
Cape Ray NF          340,341   942   47 34 N   59 09 W   290  200

To receive Notices to Mariners monthly editions, phone the Canadian Coast Guard Marine Navigation Services Directorate at (613)990-3037

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