The Global Positioning System (GPS) is a system of 24 satellites orbiting the Earth in six orbital planes. This orbital configuration provides 24-hour coverage of the Earth for uses in positioning, timing, and navigation.
The system works by having the satellites send precisely timed signals to the earth. GPS receivers use these signals to determine the ranges (distance) to the satellites. Since the positions of the satellites are known at any given time, the position of a GPS receiver can be determined by intersecting the ranges from four different satellites. Understanding this process involves knowledge in the areas of geodesy, statistics, algebra, and linear regression.
Mapping large tracts of land, performing resource surveys, collecting evidence for boundary surveys, guiding heavy construction equipment, and establishing points with precise coordinates are a few of the GPS applications used by surveyors.