GPS is a satellite-based navigation system that provides location and time information to users worldwide. It uses a constellation of 24 satellites and trilateration techniques to determine the user's position by calculating distances to four or more satellites. Sources of error include atmospheric conditions and satellite clock errors, but differential GPS and systems like WAAS can achieve accuracy of 3 meters or better for civilian users.

1. GPS Overview Edit this ex :paras wadher

8. Three SV ranges known 20,000 Km radius 22,000 Km radius 21,000 Km radius Located at one of these 2 points. However, one point can easily be eliminated because it is either not on earth or moving at impossible rate of speed.

19. GPS Accuracy Comparison Some common GPS devices used by FWS: Accuracy given in meters Sub-meter 1-3 ~3 ~ 10 Trimble - GeoXT NA 3 NA ~ 8 - 15 Rockwell – PLGR Federal Users Only 1 - 3 3 ~3 ~ 10 - 15 Garmin GPSMap 76s Post-process DGPS Real-time DGPS WAAS DGPS Autonomous GPS Device

23. ArcPad Software Bring GIS data into the field! Custom forms for data collection Integrate GPS with GIS