AstroStart 60Cx Benutzerhandbuch

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. The 

European Geostationary Navigation Overlay Service 

(EGNOS) is the European version of WAAS and 

operates in the same manner.
WAAS is made up of satellites and ground reference 

stations positioned across the United States that 

monitor GPS satellite data. Master stations, located on 

either coast, collect data from the reference stations 

and create a GPS data correction message. Master 

station uplinks the correction message to the WAAS 

GEO satellites using a ground uplink station. Then 

WAAS GEO satellites broadcast the WAAS corrected 

signal to user in the service area.
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 and EGNOS are just two service providers 

that adhere to the MOPS (Minimum Operational 

Performance Standard) for global satellite based 

augmentation systems (SBAS.) Eventually there 

are to be several more 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 60Cx 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    

 

 

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