The Global Positioning System (GPS), developed by the United States Department of Defense, uses a constellation of between 24 and 32 Medium Earth Orbit satellites, transmiting precise microwave signals, that enable GPS receivers to critically determine their geographic location. With a GPS Golf Range Finder we are able to superimpose this information onto a detailed map of your golf course (downloadable) and you have an immediate, accurate (+/- 1 metre) guage of the distance to the next pin. Club selection immediately becomes a lot easier.