The use of satellites for navigation is actually a derived application from constellations of satellites launched to provide Position, Navigation and Timing (PNT) services. Perhaps the most famous satellite based navigation system is the US Global Positioning System (GPS), originally launched as part of a military programme.
A more generic term for GPS is Global Navigation Satellite System (GNSS). Many GNS Systems exist; the Russian system is called GLONASS, the European system is called Galileo, and the Chinese system is called COMPASS. All of these systems work in much the same way: the satellites emit pulses which can be detected by receivers on the Earth. These pulses are then run through specially designed software that turns it into information: the most widely used application is the one in the ‘Sat Nav’ system in your car or the one you use on your smart phone to help you get from A to B.
GNSS is also used extensively for surveying and mapping, to aid in rapid response for disaster relief and in transportation systems, particularly maritime and aviation.
The European Commission recently launched the first of 30 satellites as part of a new initiative for a state-of-the-art global satellite navigation system. The system, called Galileo, will be inter-operable with GPS and GLONASS, providing a highly accurate, guaranteed global positioning service under civilian control. Discover more about Galileo
The timing services provided by satellites provides us with precise time on our phones, watches, and television. It also enables data networks to share information in perfect synchronisation around the world enabling global banking transactions. Power stations use the precise timing signals to deliver efficient transmission and distribution through the grid to avoid power blackouts.
Further applications for PNT could include: traffic management to optimise bus routes and reduce journey times, the planning of road building, and monitoring the movement of infrastructure such as bridges and buildings to enable preventative action to be taken should it be required.