Garmin GPSMAP 292 Owner's Manual

Also see for GPSMAP 292 - Marine GPS Receiver: Install guide Quick reference guide Declaration of conformity

Contents

Garmin GPSMAP 292 Owner's Manual Manual pdf 102 page image

96 GPSMAP 292/298 Owner’s ManualAPPENDIX > WHAT IS WAAS/EGNOS?What is WAAS/EGNOS?The Wide Area Augmentation System (WAAS) is an FAA fundedservice to improve the overall integrity of the GPS signal for usersin North America. In Europe, WAAS is referred to as EGNOS.The system is made up of satellites and approximately 25 groundreference stations positioned across the United States that monitorGPS satellite data. Two master stations, located on either coast,collect data from the reference stations and create a GPS datacorrection message.According to the FAA’s Web site, testing of WAAS in September2002 confirmed an accuracy performance of 1-2 meters horizontaland 2-3 meters vertical throughout the majority of the continentalUnited States and portions of Alaska.WAAS is just one service provider that adheres to the MOPS(Minimum Operational Performance Standard) for global SatelliteBased Augmentation Systems (SBAS). Eventually there willbe several services of worldwide geostationary communicationsatellites that broadcast integrity information and differentialcorrection data as transmitted by ground reference stations.All SBAS systems use the same receiver frequency; therefore anyoperational SBAS system should be capable of providing your GPSunit with increased accuracy at any location in the world.Currently, enabling WAAS on your GPSMAP 292/298 in regionsthat are not supported by ground stations, may not improveaccuracy, even when receiving signals from an SBAS satellite. Infact it can degrade the accuracy to less than that provided by GPSsatellites alone. For this reason, when you enable WAAS on yourGarmin GPS receiver, the receiver automatically uses the methodthat achieves the best accuracy.For more information, go to http://gps.faa.gov.