Garmin 3200 Application Manual

Also see for iQue 3200: Operating instructions Specifications

Contents

Garmin 3200 Application Manual Manual pdf 62 page image

50AppendixWAAS and DGPSWhat is WAAS?The Wide Area Augmentation System (WAAS) is an F.A.A. fundedproject to improve the overall integrity of the GPS signal. It is a space-based system that broadcasts integrity information and correction dataas determined by ground reference stations (see “DGPS” below). Atthis time the system is still in the developmental stage with a goal ofproviding reliable signals with an accuracy of 7 meters (21–22 ft.) bothhorizontally and vertically 95% of the time. Current tests have shownthe 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 upDifferential GPS (DGPS) stations to transmit correction signals. They areoperational in coastal areas and on many navigable river systems. TheDGPS 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 ofGPS 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.