What is GPS? (Global Positioning System) - as used by Sat Nav, (Satellite Navigation)
US Satellite Navigation (currently used across the world)
Satellite Navigation uses GPS, (Global Positioning System), was developed by the department of defence in the United States. It was designed to be a high quality system for navigating accurately. The GPS system works by using a network of 24 NAVSTAR satellites orbiting the earth. NAVSTAR stands for Navigation System using Timing and Ranging. Functioning 24/7, at a height of 10,900 - 12,625 miles above the earths surface. The satellites with an impressive 2 tons, are 18.5 feet long, transmit on two frequencies: 1575.42Mhz for civilians and 1227.60 for military services. NAVSTAR orbit the earth in just 12 hours.
These satellites are designed to be resistant to interference and jamming, thus they make incredibly good positioning beacons when used in conjunction with one and another to give accurate positioning. The Global Positioning System gives every square metre of the earth's surface, therefore every square metre of the earth is unique to each of the 24 satellites.
European Satellite Navigation - Coming Soon
The
European Union in conjunction with
the European Space Agency decided in March, 2002 that the EU needed its own
alternative to Global Positioning System. It was decided to call this system
Galileo. The Galileo project is expected to cost about $2,500,000,000.00,
($2.5billion dollars). The satellites will or have been
launched between 2006 and 2008, with the Galileo system expected to go live in
2008. The first satellite was launched in December,
2005. Next generation Sat Nav, (Satellite Navigation), is expected to be live
and fully operational by 2012 when it will be totally under civilian control.
The receivers on the Galileo program will be able to work with the NAVSTAR
satellites which should greatly increase the accuracy.
