Russian Space Agency Roscosmos plans to launch five Glonass-M satellites and one Glonass-K satellite in 2011, Roscosmos' deputy chief Anatoly Shilov said Wednesday.

The first launch of the Glonass-M satellite is scheduled for August and the second is slated for October, Shilov said at a navigation forum here.

The Glonass-K new generation navigation satellite is expected to be launched in December, he added.

"Besides, we are still hoping to carry out a group launch of three Glonass-M satellites atop a Proton-M carrier rocket from Baikonur by the end of the year," he was quoted by Interfax news agency as saying.

The date of the group launch has yet to be determined, he said.

Last December a Proton-M carrier rocket, which lifted off from the Baikonur Cosmodrome in Kazakhstan, failed to deliver three Glonass-M navigation satellites to the orbit. The satellites fell into the Pacific Ocean. Investigators later blamed ground crew who had pumped too much fuel into a booster rocket.

Glonass is the Russian equivalent of the U.S. Global Positioning System (GPS), which is designed for both military and civilian use. The system requires 24 operational and 2-3 reserve satellites in orbit to ensure global coverage.