History of the Global Positioning System

The global positioning system (GPS) is a space-based satellite network originally created and realised by the US Department of Defence for use as a military and intelligence application in the 1960s during the Cold War. It came out of developments in technology after World War II and was additionally inspired by the first man-made satellite Sputnik launched by the Soviet Union in 1957. GPS is a constellation of satellites that orbit the earth at fixed points far above the planet and beam down signals to anyone using a GPS device. The GPS system provides accurate and reliable location and time information anywhere on or near the Earth.

In 1960 Transit was the first satellite to be launched by the USA and successfully tested by the US Navy. Transit used a system of five satellites in orbit around the earth and could provide a navigational fix for ships anywhere on the seas to set their positioning once per hour. By 1967 the new Timation satellite was developed with highly precise atomic clocks that could be operated in space, a vital technology for GPS devices. From that point GPS made quick progress and between 1978 and 1985 a further 11 ‘Block’ satellites were launched.

But it wasn’t until 1983 when the Korean Air Lines Flight 007 was shot down by the USSR carrying 269 people after straying into prohibited airspace that the Reagan led US administration was motivated to make GPS freely available for civilian use. This meant that shipping, aircraft and other GPS navigation systems all over the world could fix their positions to avoid inadvertently wandering into restricted foreign territory.

The disaster of the NASA space shuttle SS Challenger in 1986 slowed the progress and development of GPS until 1989 when the first Block II satellites were launched. Navstar was the 24th satellite and made the modern system complete, it was launched by the US in the summer of 1993. At any one time 21 of the satellites were in use and the remaining three were spares. This constellation of 24 satellites is now commonly known as the Global Positioning System. GPS was announced as fully operational in 1995 and today has a network of 30 active satellites in orbit.

GPS has a dual-use technology, which means it serves both military and civilian purposes. GPS software has become widely used as a tool for commerce, science, and surveillance and for a large number of everyday activities. Handheld GPS systems and car GPS systems are commonly used and Geotracking is an important tool in vehicle, person and pet tracking. GPS is used in climate studies and earthquake research but its uses now also extend to recreational activities, such as Geocaching - an outdoor treasure hunt game.