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GPSMAP 2206/2210 Owner’s Manual
A
PPENDIX
>
W
HAT
IS
WAAS/EGNOS?
What is WAAS/EGNOS?
The Wide Area Augmentation System (WAAS) is an FAA-funded service to
improve the overall integrity of the GPS signal for users in North America. In
Europe, WAAS is referred to as EGNOS.
The system is made up of satellites and approximately 25 ground reference
stations positioned across the United States that monitor GPS satellite data. Two
master stations, located on either coast, collect data from the reference stations
and create a GPS data correction message.
According to the FAA’s Web site, testing of WAAS in September 2002 confirmed
an accuracy performance of 1–2 meters horizontal and 2–3 meters vertical
throughout the majority of the continental United States and portions of Alaska.
WAAS is just one service provider that adheres to the Minimum Operational
Performance Standard (MOPS) for global Satellite Based Augmentation Systems
(SBAS). Eventually there will be several services of worldwide geostationary
communication satellites that broadcast integrity information and differential
correction data as transmitted by ground reference stations.
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 WAAS on your GPSMAP 2206/2210 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 WAAS
on your Garmin GPS receiver, the receiver automatically uses the method that
achieves the best accuracy.
For more information, go to
http://gps.faa.gov
.
WAAS Capability
The GPSMAP 2206/2210 is capable of receiving WAAS satellite signals.
Effective use of the WAAS satellite signal may be limited by your geographic
location in relation to those satellites, now in developmental service. WAAS
satellite signal reception requires an absolute clear view of the sky and works best
when there are no nearby obstructions such as buildings or mountains.
WAAS satellites are numbered 33 or higher when viewing the sky view on your
GPSMAP 2206/2210. Initial reception of the WAAS signal may take up to 15-20
minutes, then 1–2 minutes afterwards. When WAAS differential correction has
been received for GPS satellites (numbers 32 or below), a “D” appears in the
signal bar of the sky view and “Ready For Navigation with WAAS” appears in
the Status field. To learn more about the WAAS system, its satellite locations
and current state of development, visit the FAA web site (
).
Because WAAS requires CPU resources of the GPSMAP 2206/2210 to search
for and track the satellites, you can disable the WAAS feature to improve unit
performance if WAAS reception is not available in your area.
To disable or enable WAAS capability:
1. On the
GPS
tab, highlight the
Setup
sub tab.
2. Use the
ROCKER
to highlight the
WAAS
field, and press
ENTER
.
3. Highlight
On
or
Off
, and press
ENTER
.
