GLONASS stands for Global Navigation Satellite System and is a Russian satellite-based navigation system that works alongside the Global Positioning System (GPS) . It was developed by the Soviet Union in 1976 as an experimental military communications system and became fully operational in 1995. GLONASS comprises a constellation of 24 satellites, in three orbital planes, with eight satellites per plane, and operates at an altitude of 19,130 km. The system provides an alternative to GPS and is the second navigational system in operation with global coverage and of comparable precision. GLONASS satellites transmit the same code at different frequencies, a technique known as FDMA (frequency division multiple access) . GLONASS signals have the same polarization as GPS signals and have comparable signal strength. Satellite navigation devices supporting both GPS and GLONASS have more satellites available, meaning positions can be fixed more quickly and accurately, especially in built-up areas where buildings may obscure the view to some satellites. GLONASS supplementation of GPS systems also improves positioning in high latitudes (north or south) .