From the app drawer, select Setup > System > Satellite.

Satellite System

Allows you to set the satellite system to GPS, GPS + GLONASS (GPS and GLONASS), or Demo Mode (GPS off).

WAAS/EGNOS

Sets the satellite system to Wide Area Augmentation System/European Geostationary Navigation Overlay Service (WAAS/EGNOS). For more information about WAAS, go to www.garmin.com/aboutGPS/waas.html.