Global
Positioning System (GPS) has been integrated in mobile telephones for a long time;
Nokia was the first to experiment with integrating GPS and mobile phones. I
still have one of the first, it used and GPS cover which was sold separately. With
this phone you could get the location in latitude and longitude degrees and store it for later use,
pretty much as basic GPS devices, it was slow and needed open space to get a
reliable position. Since, the devices have become smarter, faster, and more
important global map coverage is standard. All phones have been using the US
GPS system, as it is available for free, accurate and reliable. The 24 GPS satellites
give 24 hours global coverage.
So what is
GLONASS? GLONASS is the Russian counterpart of GPS, and the Nokia Lumia 900
supports both systems. GLONASS has an additional 21 satellites with global
coverage, and by using both the amount of available satellites nearly doubles,
which greatly enhances positioning capability.
Theoretically
one can calculate a position using three satellites, but for better accuracy a
minimum of four is needed, high buildings, forest or other objects can blocks
satellite visibility, and that is why adding 21 GLONASS satellites is
important.
Europe is
building its own global navigation system, Galileo, but this is still under
construction, and will be operational somewhere around 2020, adding 30 satellites
to the present GPS and GLONASS platforms.