Global Navigation Satellite Systems (GNSS)

Global Navigation Satellite Systems (GNSS) is the standard generic term for satellite navigation systems that provide autonomous geo-spatial positioning with global coverage. GNSS allows small electronic receivers to determine their location (longitude, latitude, and altitude) to within a few metres using time signals transmitted along a line-of-sight by radio from satellites. Receivers on the ground with a fixed position can also be used to calculate the precise time as a reference for scientific experiments.
As of 2009, the United States NAVSTAR Global Positioning System (GPS) is the only fully operational GNSS. The Russian GLONASS is a GNSS in the process of being restored to full operation. China has indicated it will expand its regional Beidou navigation system into the global COMPASS navigation system by 2015. The European Union's Galileo positioning system is a GNSS in initial deployment phase, scheduled to be operational in 2013.

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Do you have idea about the main differences between a Navigation satellite and a Telecommunication satellite?

For example, the navigation satellite has to perform ranging measurement so figures as group delay, antenna phase center have to be under control.. in the TLC satellite they are not so important..

Do you have other points to consider?

Regards,

Lupin