GPS stands for Global Positioning System. The system consists of 24 Navstar satellites that orbit Earth. The satellites are monitored and controlled by stations on Earth. The satellites send back an exact location to anyone who has a GPS receiver. GPS is the most accurate navigation system developed to date. It gives latitude, longitude, altitude and time to an unlimited number of people anywhere on Earth in all kinds of weather.
History
The GPS system was initially developed by the U.S. Department of Defense to help the military pinpoint targets and guide missiles to them. The military began testing the first satellite systems in 1959. In 1973, the U.S. Air Force was put in charge of consolidating the various satellite concepts into one comprehensive system. From 1974 through 1979, the GPS system was tested successfully. The last satellite--the 24th--was launched into orbit in 1993.
Function
The GPS system is used for navigational systems in cars, trucks, air traffic control systems and ships. It can be used to pinpoint people in search-and-rescue missions, to track changes in the environment, to survey and to map. It is still used by the military for security, navigation and other applications.
Significance
The signals from the United States' GPS were made available to civilian users all over the world in 1996. According to the National Park Service, GPS is a multibillion dollar industry and generates more than 100,000 jobs.
Features
GPS technology "was made possible by a combination of scientific and engineering advances, particularly the development of the world's most accurate timepieces: atomic clocks that are precise to within a billionth of a second," according to the National Park Service.
Future
According to the government's Global Positioning System website, the United States intends to modernize the system with new signals, which will improve the accuracy of the civil GPS system. The U.S. government in 2004 pledged to "provide reliable civil space-based positioning, navigation and timing services through GPS on a continuous, worldwide basis--freely available to all."
Tags: Earth satellites, Global Positioning, Global Positioning System, most accurate, National Park
