Garmin GPSMAP 496 - Manual (Page 147)

GPSMAP 496 Owner’s Manual 139
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eArnIng About
gPs
Learning About GPS
The Global Positioning System (GPS) is a satellite-based navigation
system made up of a network of 24 satellites placed into orbit by the
United States Department of Defense.
GPS was originally intended for military applications, but in the
1980s, the government made the system available for civilian use.
GPS works in any weather conditions, anywhere in the world, 24
hours a day. There are no subscription fees or setup charges to use
GPS. For more information refer to the Garmin Web site at
www.garmin.com and also read the GPS Guide for Beginners,
which can be found on the Web site at
.
What is EGNOS/WAAS/MSAS?
The European Geostationary Navigation Overlay System (EGNOS)
is European Space Agency developed service to improve the overall
integrity of the GPS signal and increase position accuracy for users
in Europe. In North America, EGNOS is referred to as WAAS.
The system is made up of satellites and network of ground reference
stations positioned across Europe that monitor GPS satellite data.
All SBAS systems use the same receiver frequency; therefore any
operational SBAS system should be capable of providing your GPS
unit with increased accuracy at any location in the world.
Currently, enabling EGNOS/WAAS on your Garmin GPSMAP 496
in regions that are not supported by ground stations may not improve
accuracy, even when receiving signals from an SBAS satellite. In
fact, it can degrade the accuracy to less than that provided by GPS
satellites alone. For this reason, when you enable EGNOS/WAAS
on your Garmin GPS receiver, the receiver automatically uses the
method that achieves the best accuracy. To enable EGNOS/WAAS,
refer to page 6 .