Satellite Information - Garmin GPSMAP 580 Owner's Manual

Satellite Information

90°
45°
Satellite Sky View
Satellite Location
The location of each available satellite is shown over two location rings
on the Satellite Information Page. The outer ring represents the horizon,
the inner ring represents 45° above the horizon, and the c
directly overhead. When the unit is using a satellite for navigation, the
satellite number is highlighted on the location rings. The unit can show
satellite location with either North or your current heading at the top of the
screen.
Satellite Strength Indicator Bars
The Satellite Strength Indicator Bars show the strength of the signal being
received and the status of the signal. The bars are either shaded or filled. A
hollow gray bar means the unit is in the process of storing orbital data it is
receiving from the satellite signal. When the bar turns solid green, the unit
is using the satellite signal for navigation. A "D" in or above the bar means
GPSMAP 580/585 Owner's Manual
Center dot - 90°
above the horizon
Inner ring- 45°
above the horizon
Outer ring -
the horizon
enter
represents
differential corrections (WAAS) are being applied to that satellite.
Differential Field
Differential receiver status is indicated in the lower-left field of the
GPS tab and shows one of the following conditions:
• None—no optional beacon receiver is attached or enabled in
the Interface sub tab on the Main menu—Setup tab or WAAS
is disabled.
• Searching for WAAS—WAAS is enabled and the receiver is
searching for WAAS signal.
• Using WAAS—WAAS capability is enabled and the unit is
receiving WAAS corrections.
What is WAAS?
The Wide Area Augmentation System (WAAS) is an FAA-funded
project to improve the overall integrity of the GPS signal and
increase position accuracy for users in North America.
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 in
September 2002 of WAAS confirmed an accuracy performance
of 1–2 meters horizontal and 2–3 meters vertical throughout the
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