Garmin Administrator Guide Administrator's Manual

Garmin Administrator Guide Administrator's Manual Manual pdf 28 page image

24 c320 Owner’s ManualAPPENDIXWhat is GPS?The Global Positioning System (GPS) is a satellite-based navigationsystem made up of a network of 24 satellites placed into orbit by theU.S. Department of Defense. GPS was originally intended for militaryapplications, but the government made the system available for civilianuse in the 1980s. GPS works in any weather condition, anywhere in theworld, 24 hours a day. There are no subscription fees or setup charges touse GPS.A GPS receiver must be locked on to the signal of at least three GPSsatellites to calculate a 2D position (latitude and longitude) and trackmovement. With four or more satellites in view, the receiver candetermine your 3D position (latitude, longitude, and altitude). Once yourposition has been determined, the receiver can display it on the c320’sMap page and calculate other information, such as speed and bearing.What is WAAS?The Wide Area Augmentation System (WAAS) is an FAA-funded projectto improve the overall integrity of the GPS signal and increase positionaccuracy for users in North America. The system is made up of satellitesand approximately 25 ground reference stations positioned across theUnited States that monitor GPS satellite data. Two master stations,located on either coast, collect data from the reference stations and createa GPS data correction message.According to the FAA’s Web site, testing in September 2002 of WAASconfirmed an accuracy performance of 1–2 meters horizontal and 2–3meters vertical throughout the majority of the continental United Statesand portions of Alaska. For more information, go to http://gps.faa.gov/Programs/WAAS/waas.htm.WAAS is just one service provider that adheres to the MOPS(Minimum Operational Performance Standard) for global SatelliteBased Augmentation Systems (SBAS). Eventually, there will be severalservices of worldwide geostationary communication satellites and groundreference stations.Currently, enabling WAAS on your c320 in regions that are not supportedcan degrade accuracy. For this reason, when you enable WAAS on yourc320, the receiver automatically uses the method that achieves the bestaccuracy. To enable WAAS, refer to page 20.