Satellite Navigation Systems are an extremely useful development that allows a small electronic device to determine its exact location via satellite. Once it knows your position, the navigation device can obtain or calculate navigation information such as directions, terrain, roads, etc, etc.

Satellite navigation devices are used by the military, motor vehicle drivers, boaters, nature lovers and many others. Many vehicles now come with pre-installed satellite navigation systems.

The only satellite navigation system that is fully functional at the time of this writing is the Global Navigation System or GPS. GPS is the United States satellite navigation system and contains between 24 and 27 satellites in orbit.

Russia also has a satellite navigation system in the works. The Russian system is called GLONASS, which is derived from the GLObal NAvegation Satellite System. The first satellites for GLONASS were launched in 1982, but the system was not fully operational until 1995. Due to economic difficulties, the GLONASS system has deteriorated to only 12 satellites, which does not reach full coverage. Russia has signed an agreement with India to work together on the system, with the intention of having GLONASS return to full functionality by 2010.

The European Union is currently working on two satellite navigation systems. EGNOS, which is expected to become operational sometime in 2006, will consist of 3 satellites, which are designed to complement GPS and GLONASS.

The EU and the European Space Agency are also working on an advanced satellite navigation system, called Galileo, which should be operational in 2010. This system will include 30 satellites and will be compatible with GPS, which means ground units can combine data of GPS and Galileo to obtain highly accurate positions.

Several other countries also have satellite navigation systems under construction. China’s system is called Beidou and France’s is called Doris. Nor are they of the caliber of GPS, GLONASS or Galileo.