... DETERMINATION2839.2 LADGPS, WADGPS, AND WAAS9.2.1 Description of Local-Area DGPS (LADGPS)LADGPS is a form of DGPS in which the user's GPS receiver receives real-timepseudorange and, possibly, ... s2HTHÀ1:284DIFFERENTIAL GPS 9Differential GPS 9.1 INTRODUCTIONDifferential GPS (DGPS) is a technique for reducing the error in GPS- derivedpositions by using additional data from a reference GPS receiver ... system-level testing, WAAS operational testing, and long-term supportfor WAAS. GPS satellitesUser’s WAASreceiverGEO subsystem Wide-areamaster stationWide-areareference station-nWide-areareference...