GPS stands for "The Global Positioning System", which is a satellite-based, precise-positioning navigation system. GPS is a worldwide radio-navigation network system formed from a constellation of 24 satellites and their ground stations. Developed by the U.S. Department of Defense in 1973, GPS was originally designed for military applications, such as locating soldiers and military vehicles, planes, and ships worldwide.

In 1983, President Ronald Reagan issued an order making the GPS available free for civilian use. Since then, GPS has become a useful tool for mapping, positioning, locating, commerce, and scientific uses. Today, the uses of GPS have extended to people's daily life. GPS is widely used as a navigation and positioning tool in automobiles, boats, airplanes, and outdoor activities such as hiking, fishing, and camping. Scientists use GPS for weather forecasting, global climate studies, geology surveying and earthquake studies.

The GPS signal can be used without a charge by any person who has a GPS receiver. The only requirement is an unobstructed view of the satellites.

GPS uses at least 24 Medium Earth Orbit satellites to transmit precise microwave signals to a GPS receiver to determine its location, speed, direction and time. GPS uses satellites as reference points to calculate positions as accurate as meters. It works in any weather conditions, anywhere world-wide, and around clock. Soon GPS will become as basic and popular as the cell phone.