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What is waas, What is differential gps (dgps) – Garmin GPSMAP 76 User Manual

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GPSMAP 76 Owner’s Manual

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WAAs

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dGps

What is WAAS?

The Wide Area Augmentation System (WAAS) is an

F.A.A. funded project to improve the overall integrity

of the GPS signal. It is a space-based system that

broadcasts integrity information and correction data

as determined by ground reference stations. WAAS

testing completed in September of 2003 confirmed

an accuracy of 2 to 3 vertical meters throughout the

majority of the continental U.S. and portions of Alaska.

For more information, go to

http://gps.faa.gov/Programs/WAAS/waas.htm

Note: If you are using the GPSMAP 76 outside

of the U.S., it is recommended that you turn off

WAAS for the most accurate location fix.

What is Differential GPS (DGPS)?

The U.S. and Canadian governments (among others)

have set up Differential GPS (DGPS) stations to

transmit correction signals. They are operational in

coastal areas and on many navigable river systems. The

DGPS system is available for use without a fee.
Please refer to the U.S. Coast Guard’s Web site

http://www.navcen.uscg.gov/ for locations and the

status of the differential sites. Using DGPS requires

additional equipment.