What is it ?

The Global Positioning System (GPS) is a constellation of satellites that orbit the earth transmitting precise time and position (latitude, longitude and altitude) information. With a GPS receiver, users can determine their location anywhere on the Earth. Position and navigation information is vital to a broad range of professional and personal activities, including vehicle tracking, hiking, hunting, camping, boating, surveying, aviation, national defense, navigation and more.

How many satellites are there ?

The complete system consists of 24 satellites orbiting about 12,000 miles above the Earth, and five primary ground stations to monitor and manage the satellite constellation. These satellites provide 24-hour-a-day/ 7 days-a-week coverage for both two and three dimensional positioning anywhere on Earth.

Who developed it ?

Development of the $10 billion GPS satellite navigation system was begun in the 1970s by the US Department of Defense, which continues to manage the system, to provide continuous, worldwide positioning and navigation data to US military forces around the globe. However, GPS has an even broader civilian, commercial application. To meet these needs, GPS offers two levels of service: one for civilian access and the second encrypted for exclusive military use. The GPS signals are available to an unlimited number of users simultaneously, and there is no charge for using the GPS Satellites.

How exactly does it work ?

The basis of GPS technology is precise time and position information. Using atomic clocks and location data, each satellite continuously broadcasts the time and its position. A GPS receiver receives these signals, listening to three or more satellites at once, to determine the user's position on earth. By measuring the time interval between the transmission and the reception of a satellite signal, the GPS receiver calculates the user and each satellite. Using the distance measurements of at least three satellites in an algorithm computation, the GPS receiver arrives at an accurate position fix. Information must be received from three satellites in order to obtain two-dimensional fixes (latitude and longitude), and four satellites are required for three-dimensional positioning (latitude, longitude and altitude).

Who is utilizing this technology ?

Vehicle tracking is one of the fastest-growing GPS applications. GPS-equipped fleet vehicles, public transportation systems, delivery trucks, and courier services use receivers to monitor their locations at all times. Not only can vehicle tracking help improve efficiencies and productivity in mobile businesses, but they can also help overcome common problems such as getting lost and vehicle theft.