What is WAAS?The Wide Area Augmentation System (WAAS) is anFAA-funded project to improve the overall integrityof the GPS signal and increase position accuracy forusers in North America.The system is made up of satellites and approximate-ly twenty-five ground reference stations positionedacross the United States that monitor GPS satellitedata. Two master stations, located on either coast, col-lect data from the reference stations and create a GPSdata correction message.According to the FAA’s Web site, testing in Septem-ber 2002 of WAAS confirmed an accuracy perfor-mance of 1–2 meters horizontal and 2–3 meters verti-cal throughout the majority of the continental UnitedStates and portions of Alaska.WAAS is just one service provider that adheres to theMOPS (Minimum Operational Performance Standard)for global Satellite Based Augmentation Systems(SBAS). Eventually, there will be several services ofworldwide geostationary communication satellites andground reference stations.All SBAS systems use the same receiver frequency;therefore, any operational SBAS system should becapable of providing your GPS unit with increased ac-curacy at any location in the world.Currently, enabling WAAS on your Garmin 76CSPlus in regions that are not supported by ground sta-tions may not improve accuracy, even when receivingsignals from an SBAS satellite. In fact it can degradethe accuracy to less than that provided by GPS satel-lites alone. For this reason, when you enable WAASon your Garmin GPS receiver, the receiver automati-cally uses the method that achieves the best accuracy.To enable WAAS, refer to page 6.For more information, go tohttp://gps.faa.gov/Programs/WAAS/waas.htm.76CS Plus Owner’s Manual 95APPENDIX > L EARNING ABOUT GPS190-00507-00_0A.indd 95 2/14/2005 3:33:58 PM
