Out of the many things that fascinate me, GPS will have its place in the top few!! I always keep on looking out for information on GPS on the net. Here's something that i found interesting. (taken from http://www8.garmin.com/aboutGPS/)
The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. GPS was originally intended for military applications, but in the 1980s, the government made the system available for civilian use. GPS works in any weather conditions, anywhere in the world, 24 hours a day. There are no subscription fees or setup charges to use GPS.