Uragan-M spacecraft are the second generation of GLONASS satellites
with an increased lifetime of 7 years following up the first generation Uragan spacecraft.
GLONASS (Globalnaya Navigationnaya Sputnikovaya Sistema, Global Orbiting Navigation Satellite System) is a Russian space-based navigation system
comparable to the American GPS system, which consists of Uragan spacecraft. The
operational system contains 21 satellites in 3 orbital planes, with 3 on-orbit spares.
GLONASS provides 100 meters accuracy with its C/A (deliberately degraded) signals and
10-20 meter accuracy with its P (military) signals.
The Uragan-M spacecraft are 3-axis stabilized, nadir pointing with dual solar arrays.
The payload consists of L-Band navigation signals in 25 channels separated by 0.5625 MHz
intervals in 2 frequency bands: 1602.5625 - 1615.5 MHz and 1240 - 1260 MHz. EIRP 25 to 27 dBW.
Right hand circular polarized. On-board cesium clocks provide time accuracy to 1000
nanoseconds. A civil reference signal on L2 frequency was added after the
completion of flight testing of Glonass-M in 2004 to substantially increase the accuracy
of navigation relaying on civil signals.
The spacecraft can be launched in triplets using Proton-K Blok-DM-2, Proton-K Briz-M, Proton-M Blok-DM-2 or Proton-M Blok-DM-03 boosters. Single launches on Soyuz-2-1b Fregat boosters are also planned. At some time within a collaboration on the GLONASS system signed with India 2013, at least one single launch using an Indian GSLV Mk.2C was also planned, but never conducted.
The Urgan-M satellites are being replaced by the smaller Uragan-K and Uragan-K2 satellites.
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