Waas/Egnos; Sources Of Errors - Garmin nuvi 215 Owner's Manual

WAAS/EGNOS

The Wide Area Augmentation System (WAAS) is a system of satellites and
ground stations that provides even better position accuracy than the already
highly accurate GPS. Europe's version of this system is the European
Geostationary Navigation Overlay Service (EGNOS).
The Federal Aviation Administration (FAA) developed the WAAS program. It
makes more airspace usable to pilots, provides more direct en route paths, and
provides new precision approach services to runways, resulting in safety and
capacity improvements in all weather conditions at all locations throughout the
U.S. National Airspace System (NAS).
Although it was designed for aviation users, WAAS supports a wide variety
of other uses, for example, more precise marine navigation. To take advantage
of WAAS technology, you must have a WAAS-capable GPS receiver in an
area where WAAS satellite coverage is available such as North America. No
additional equipment or fees are required to take advantage of WAAS.

Sources of Errors

Errors can affect the accuracy of the GPS signal. Take your GPS receiver to an
area with a wide and unobstructed view of the sky to reduce the possibility and
impact of some errors. Here are some of the most common GPS errors.
• ionosphere and troposphere Delays
as it passes through the atmosphere. The system uses a built-in model that
nüvi 215 owner's manual
How Accurate Is GPS?
—the satellite signal slows down
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