Russia is planning to add four Glonass navigation satellites to its orbital grouping in November.
Three Glonass-M satellites will be launched on November 4 aboard a Proton-M carrier rocket from the Baikonur space center in Kazakhstan, while the fourth Glonass-M will be delivered to orbit by a Soyuz 2.1b launch vehicle at the end of November from the Plesetsk space center.
The fourth satellite was delivered to Plesetsk on Monday to undergo the necessary pre-launch procedures.
Glonass is Russia's answer to the U.S. Global Positioning System, or GPS, and is designed for both military and civilian uses. Both systems allow users to determine their positions to within a few meters.
Russia currently has a total of 28 Glonass satellites in orbit, although only 20 of them are operational.
According to the Russian Federal Space Agency, five Glonass satellites are under maintenance, one is on a standby, and two recently launched satellites are being integrated into the grouping.
The complete Glonass grouping needs 24 functioning and 2-3 reserve satellites to operate with global coverage.