The Russian GNSS operational constellation now includes 23 spacecraft, including two spares in orbital plane III, slots 22 and 23, as well as GLONASS space vehicle 716, which remains in maintenance status with a malfunctioning signal generator.

"We decided to have two back-up satellites in GLONASS, similar to GPS," Yury Urlichich, director-general of the Russian Space Device Engineering company, told a press conference during the InfoSpace forum in Moscow on March 26.

Six more satellites are scheduled for launch this year, including the first GLONASS-K spacecraft, with a full operational constellation of 24 satellites expected to be in place by the end of this year, according to Grigoriy Stupak, deputy chief designer for GLONASS.

Currently, the Joint Stock Company "Information Satellite Systems - Reshetnev Company" (JSC "ISS-Reshtetnev") is conducting tests on the first GLONASS-K demonstration satellite. The test sequence includes evaluation of the onboard computer and telemetry, command, and ranging systems as well as measuring the antenna RF parameters and electromagnetic compatibility testing, according to a March 25 JSC "ISS" Reshtenev press release published on the Russian Federal Space Agency (Roscosmos) website.

Two full-size Glonass-K engineering qualification models (EQMs) for further thermal vacuum tests (TVTs) tests are being manufactured by the company. TVTs represent a crucial step for the GLONASS-Ks, which unlike previous generations of GLONASS satellites will not be pressurized space vehicles that must operate in the vacuum of outer space.

Dynamic tests of the prototype EQMs will begin in May to verify the spacecraft stability at vibration and acoustic loads, as well as the conditions that occur during transportation and launch sequence.

JSC "ISS-Reshetnev",which builds the GLONASS satellites, was established on March, 3, 2008, by reforming the FSUE "Academician M.F. Reshetnev Nauchno-Proizvodstvennoe Obiedinenie Prikladnoi Mekhaniki" (FSUE "NPO PM").

 

Speaking last week (March 10) at the Munich Satellite Navigation Summit in Germany, Stupak reaffirmed that the first code division multiple access signal would be implemented on the next-generation GLONASS-K satellite scheduled for launch this year and broadcast on the GLONASS L3 frequency. In that band, the open signal is centered at 1201.743 MHz and the secure (encrypted) signal, at 1208.088 MHz. 

Eventually, additional CDMA signals would be introduced at new GLONASS frequencies, L1, L2, and at L5.

Stupak emphasized at the baseline frequency division multiple access (FDMA) signals used since the beginning of GLONASS would continue to be broadcast.

Meanwhile, he said that three GLONASS-M spacecraft launched on March 2 are expected to come on-line before the end of this month. Russia has 20 "healthy" satellite on orbit, Stupak said, although GLONASS #726 has been in "maintenance" status since last August 31 due to a problem with its signal generator. The 20 space vehicles include two ¡°duplicate slots¡± in Plane 3 where redundant satellites are in place.

If all goes well with two additional launches of triple-satellite missions this year, Russia should be able to declare full operational capability for GLONASS by the end of this year. Stupak predicted that GLONASS performance would be comparable to that of GPS by the end of 2011.

Stupak also said that Luch geostationary communications satellites would be in orbit by 2013 to provide complete ground coverage of Russia as part of the GLONASS System of Differential Correction and Monitoring (SDCM).

[Editor's note: An earlier version of this article identified the GLONASS center frequencies and signal structures, including a BOC 2,2 signal at 1575.42 MHz, based on a slide of the Russian, U.S., and European GNSS spectrum from a 2008 presentation. Prof. Stupak did not include those details in his Munich presentation, and Russian officials have indicated to Inside GNSS that some of those frequency/signal plan elements are yet to be decided.]