GPS Video 1 - GPS Basics

This video has should help you understand some of the basic concepts of GPS, which will be useful when trying to understand more advanced concepts like RTK. This is the Wikipedia article on GPS: http://en.wikipedia.org/wiki/Global_Positioning_System This screen shows where all of the GPS satellites are, and which ones are being used in the WAAS solution: http://www.nstb.tc.faa.gov/RT_WaasSatelliteStatus.htm