Managers of Russia’s Glonass satellite navigation constellation will reach their goal of having a full set of 24 functioning satellites in orbit by the end of this year, fulfilling a decade-long ambition to return Glonass to fully operational status alongside the U.S. GPS system, according to Grigory Stupak, deputy general designer of the Russian Institute of Space Device Engineering.

Glonass, which suffered a near-death experience in the late 1990s when the program was denied the resources needed to replace aging satellites, has been a priority of the Russian government for the past several years.

With six Glonass-M satellites successfully placed into orbit by Proton-K rockets in December 2009 and on March 2, the Glonass constellation features 20 operational satellites plus three new spacecraft to be integrated into the constellation by late March, Stupak said.

The December launch had been delayed from October for last-minute work “to improve the reliability of the satellites,” Stupak said. That work apparently was completed with success.

Two more Proton-K launches, each carrying three Glonass-M spacecraft, are scheduled for August and November.

Glonass is designed as a 24-satellite constellation operating at about 19,100 kilometers in altitude.

The Glonass-M satellites have a service life of seven years and a more-precise attitude-control system than their predecessors. The next-generation Glonass model, Glonass-K, will introduce CDMA, or code-division multiple access, signals, a modification that will permit better interoperability with GPS and with the future Galileo and Compass/Beidou systems planned, respectively, by Europe and China.

With its core Glonass network now on track for full deployment, Russia is focusing on an augmentation system using satellites in higher geostationary orbit to validate Glonass signal accuracy for users. Similar systems are in operation in the United States, Europe and Japan.

Stupak said Russia’s Geo Luch 5A satellite, with an L1 navigation signal transponder, will be launched into geostationary orbit at 16 degrees west longitude in 2011. A Geo Luch 5B, to operate at 95 degrees east, is set for launch in 2012, with a Luch 4 now planned for launch in 2013. With these satellites in orbit, Glonass managers will have near-global coverage in geostationary orbit with what they call the System for Differential Control and Monitoring.