Garmin 378 Manuale Proprietario

•  Using WAAS—WAAS capability is enabled and the unit is 

receiving WAAS corrections.

•  Check Beacon Wiring—the DGPS setting is enabled in the 

Interface sub tab on the Main Menu—Setup tab but no DGPS 

device is detected.

•  No Beacon Signal—DGPS receiver is attached, but not 

transmitting RTCM data to GPS.

•  Tuning Beacon—the receiver is tuning manually to a DGPS 

frequency.

•  Using Differential—the unit is receiving DGPS corrections.
•  Scanning for Beacon—the DGPS receiver is scanning for an 

available frequency.

The Wide Area Augmentation System (WAAS) is an FAA-funded 

service to improve the overall integrity of the GPS signal and 

increase position accuracy 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 in September 2002, WAAS 

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 and 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 Garmin GPSMAP 378/478 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. To enable WAAS, see page 

.

For more information, go to 

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