Russian GLONASS
RussianGLONASS at the Stage of Active Implementation
The Russian Federation is well into a 10-year program of implementing a modernized GLONASS satellitenavigation system. Four new-generation GLONASS-M satellites are now on orbit, and deploymentof a 24-satellite constellation is under way. Engineering leaders a t t h e a g e n c y r e s p o n s i b l e for designing the system discuss current efforts and describe GLONASS- Modernized M improvements . GLONASS-M satellite
n December 25, 2005, from the satellites were launched earlier in 2003 Vladimir Bartenev,V ictor Kosenko, Baikonur Launch Site, there and 2004). and Victor Chebotarev were three launched three nav- Today, the orbital GLONASS con- FederalSt ateU nitaryEn terprise,NPO igation satellites belonging to stellation includes 16 satellites (12 PrikladnoiM ekhaniki“ M.F. Re shetnev” theO GLONASS system: one GLONASS GLONASS satellites and 4 GLONASS- satellite (the last of the first generation) M satellites). This article discusses the and two new GLONASS-M satellites (see planned modernization of the GLONASS the accompanying photo). satellite navigation system with particu- This launch ensured the possibility of lar emphasis on the improved design of completing the flight tests for the mod- GLONASS-M satellites. ernized GLONASS system and perform- ing the direct navigation determination A New Commitment using four GLONASS-M satellites simul- The first satellite of the Russian naviga- taneously (two of these GLONASS-M tion system GLONASS was launched on
40 InsideGNSS APRIL 2006 www.insidegnss.com GLONASS launch on Proton LV at Baikonur develop this navigation system. The Fed- • qualitative improvement of radio- Launch Site eral Target Program “Global navigation navigation signal (introduction of the system” is one of these documents. third frequency, increase in message This program has been developed rate, addition of new information October 12, 1982, and the system was to be completed for the decade (from into a navigation signal, etc), shift in introduced into operation in 1993, being 2002 to 2011). During this period cer- the frequency bands keeping the pos- deployed to the complete constellation tain research and development activi- sibility to work for the current exist- of 24 satellites in 1995. With 24 satel- ties shall be performed, including the ing users of the GLONASS system lites in orbit, the GLONASS system can ground experimental development for • improvement of the reliability and ensure the continuous global navigation the prospective navigation spacecraft as accuracy of the navigation support for military and civil users by employing well as flight and design tests; the ground provided two types of signal: a signal of standard control segment for the navigation sys- • increase of the satellite operation accuracy for civil users and a high-accu- tem shall be modernized; the orbital autonomy period and decrease of the racy signal for military users. constellation with the nominal number level of the Ground Control Segment When Russia faced new economical of satellites (24) shall be replenished. support needed to control the satel- conditions in the 1990s, the financing for lites the space industry was reduced leading GLONASS Modernization • reduction of maintenance costs for to the orbital GLONASS constellation The 10-year program of creation and satellite constellation as a result of reduction and decrease of its effective- operation of the modernized Russian increased satellite lifetime, reduced ness. Navigation System GLONASS space mass and resulted decrease of cost Bearing in mind that the Space segment covers two stages: the current per satellite in-orbit Navigation System GLONASS is a part GLONASS-M satellites – at the first • extension of the range of mission of the national patrimony of Russia, in stage, and the proposed GLONASS-K tasks to be performed. 2001 the president of Russian and the satellites – at the second stage. With the preceding conditions government of the Russian Federation The GLONASS system is being mod- implemented, there is kept the orbital ratified the policy directives setting out ernized based on the following main configuration established earlier (three the intent to conclusively preserve and conditions: planes, with eight satellites in each www.insidegnss.com APRIL 2006 InsideGNSS 41 Modernized glonass
plane), the orbital parameters (Н=19,400 km, i=64.8°, е=0) and the quantity of sat- ellites in the nominal constellation (24 satellites). This enables the GLONASS operators to maintain the principles and methods of ballistic support of the satellite constellation and to provide the high-accuracy ephemeris. New Generation Satellites A GLONASS-М satellite, which is being developed at the first stage of the GLONASS Space navigation system modernization, has the following specif- ic features as compared to a GLONASS satellite which is in use now: 1) upgraded navigation radio signal 2) implementation of intersatel- lite radiolinks to provide ranging measurements and data exchange between satellites located in the same Increasedpointing accuracy of solar arrays will help improve the GLONASS dynamic model. plane and in different planes 3) the stability of navigation signals increased up to 1·10-13 as a result of Spacecraft Design Sun-satellite-Earth plane with accuracy providing precision thermal stabili- A GLONASS-М satellite design (Figure of ~0.5°, solar array axes are oriented zation of on board cesium frequency 1) is based on a pressurized container towards the Sun with the accuracy of standards inside which comfortable temperature 2°. The orientation is provided by elec- 4) an improved dynamic model will conditions are maintained, ensuring the trical wheels, periodically unloaded by decrease the level of unaccounted temperature range from 0 to 40°С, and electromagnets. active forces impacting the satellite, local areas of temperature stabilization The propulsion subsystem being a mainly as result of increased accu- (near atom frequency standards) with single component thruster subsystem racy of solar arrays pointing towards ±1°С accuracy based on the the Sun level. The tem- catalytic thermal 5) increased operational life of a satel- perature range is An improved dynamic model hydrazine sepa- lite — up to seven years. maintained by an will decrease the level of ration method A GLONASS-М satellite can be active gas loop, unaccounted active forces provides the pos- injected into orbit by a cluster launch shutter subsys- impacting the satellite. sibility to form (three satellites by a single launch vehicle tem with electri- control torques — see photo on page 41) from the Baik- cal drivers and a within the initial our Launch Site (using Proton LV and set of controlled heaters. All dissipating orientation modes of the satellite, and Breeze-M Booster) or by a single satellite mission equipment units are located to generate pulses for orbit correction. launch from Plesetsk Launch Site using outside the pressurized container on the The orbit correction is performed after Soyuz-2 LV and Fregat Booster. antenna module in the areas not illumi- the satellite has been injected into orbit, nated by the Sun. while drifting to the designated orbital Due to the fact that on board a slot. High accuracy of the initial correc- GLONASS-M satellite there is a great tion of orbital parameters allows keeping amount of mission equipment units the satellite within the specified station operating in the open space environ- limits (±5° latitude argument) without ment, the satellite design represents need for further corrections during the the intermediate stage between pres- remaining lifetime. surized and non-pressurized design. In An electric power subsystem based the nominal mode, the satellite longitu- on nickel-hydrogen batteries and silicon dinal axis is continuously maintained solar arrays (30m2 area) provides electric pointed to the Earth, with accuracy of power supply for onboard equipment of FIGURE 1 GLONASS-M 0.5°, the satellite lateral axis is kept in the continuous stable voltage of 27+1-2 V and
42 InsideGNSS APRIL 2006 www.insidegnss.com the power of up to 1400W, continuously versity. Professor Bartenev is a recipient of the Viktor E. Chebotarev is chief engineer and in eclipse and illuminated orbit arcs. The USSR Council of Ministry and Russian Federation designer at FSUE“Scientific and Production Com- onboard control subsystem based on an state prizes and has been awarded both USSR and pany of Applied Mechanics named after Acade- onboard digital computer provides data Russian Federation orders. Professor Bartenev mician M. F. Reshetnev.” He participated in many Russian and international exchange between the equipment via holdsa doctor of philosophy space projects, such as MOLNIYA, EXPRESS, and degree and is an associated MIL-STD-1553-B buses and performs SESAT communications satellites, the project of professor. Dr. Chebotarev the functions of control, diagnostic, thesecond-generation Russian Global Navigation has received both USSR and intersatellite ranging data processing, Systembased on both GLONASS and GLONASS- M Russian Federation orders. calculation and generation of ephemeris satellites, GALILEO, etc. His list of publications He participated in projects time data. includes more than 100 items. of the first-generation Viktor E. Kosenko is head of the Design Depart- Russian satellite naviga- Authors ment at FSUE“Scientific and Production Compa- tion system based on TSIKADA satellites and the ny of Applied Mechanics Russian global navigation system based on both VladimirA. Bartenev is deputy designer general named after Academician GLONASS and GLONASS-M satellites. at the Federal State Unitary Enterprise (FSUE) Sci- M. F. Reshetnev.” He has entificand Production Com - been awarded both USSR pany of Applied Mechanics and Russian Federation “M. F. Reshetnev” (NPO orders. Kosenko has par- Prikladnoi Mekhaniki” ticipated in projects of named after Academician the space-based geodetic M. F. Reshetnev, Zhelezno- system based on the GEO- gorsk, Russia). He holds a IK satellite, the first-generation Russian satellite doctor of sciences degree navigation system based on TSIKADA satellites, in engineering and is a the Russian Global Navigation System based on professor and head of the mechanics and control both GLONASS and GLONASS-M satellites, and processes department at Krasnoyarsk State Uni- GALILEO.
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