Garmin 3200 Manual De Usuario

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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 (see “DGPS” below).  At 
this time the system is still in the developmental stage with a goal of 
providing reliable signals with an accuracy of 7 meters (21–22 ft.) both 
horizontally and vertically 95% of the time.  Current tests have shown 
the actual accuracy to be on the order of 2–3 meters.  For more informa-
tion, go to http://gps.faa.gov/Programs/WAAS/waas.htm.

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.  

In addition to compensating for errors in the position, these correc-

tions signals can also correct for deliberate degradation of the accuracy of 
GPS  by the U.S. Department of Defense under their Selective Availability 
(SA) program.  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.