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 allow users to determine their positions to within a few meters.
"The launch of the Proton-M carrier rocket with Glonass-M satellites on board has been scheduled for 13:43 Moscow time [10:43 GMT]," the Roscosmos spokesman said.
According to the Central Research Institute for Machine Building, the Glonass system currently consists of 19 satellites, of which 16 are operational, two are undergoing maintenance, and one is due to be withdrawn.
The Glonass system requires 18 satellites for continuous navigation services covering the entire territory of the Russian Federation, and 24 satellites to provide services worldwide.
A total of 9.9 billion rubles ($360 million at the current exchange rate) was allocated for Glonass from the federal budget in 2007, and 4.7 billion rubles ($170 million) in 2006.
Russian Prime Minister Vladimir Putin signed a directive on September 12 allocating an additional $2.6 billion to develop the system.
Roscosmos chief Anatoly Perminov said in September that the number of satellites in the Glonass network would be increased to 30 by 2011.
