Lt. Col. Alexei Zolotukhin, a spokesman for Russian Space Forces, said the rocket was launched at 4:53 Moscow time (0:53 GMT).
Glonass - the Global Navigation Satellite System - is the Russian equivalent of the U.S. Global Positioning System, or GPS, and is designed for both military and civilian use. Both systems enable users to determine their positions to within a few meters.
Russia currently has a total of 22 Glonass satellites in orbit, but only 16 of them are functional. The system requires 18 operational satellites for continuous navigation services covering the entire territory of Russia and at least 24 satellites to provide navigation services worldwide.
RIA Novosti
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