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Technical University of Košice
Faculty of Electrical Engineering and Informatics
Global Navigation
Satellite System (GLONASS)
Student:
School year:
Róbert Adam
2012/2013
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1 Introduction
(IRNSS) is an acronym for Globalnaya Navigatsionnaya Sputnikovaya Sistema (Global
Navigation Satellite System in English) is a radio-based satellite navigation system of MEO
type operated for the Russian government by the Russian Space Forces. Development began
in the Soviet Union in 1976. Beginning on 12 October 1982 GLONASS flight tests were
started with the launch of Kosmos-1413, Kosmos-1414 and Kosmos-1415 and at 1995 was
brought to optimal status of 24 operational satellites. Since May 2007 GLONASS is providing
free service for customers. By 2010 GLONASS has achieved 100% coverage of Russia’s
territory and in in October 2011 was enabled full global coverage.
There are two services provided by GLONASS system:
 Standard Precision Service (SP) – Equivalent for the Standard Positioning Service.
Originally SP was transmitted only on L1 band but after modernization a second civil
signal on L2 is transmitted allowing user to cancel out the ionospheric refraction.
Currently with first GLONASS-K sent to orbit the third band L3 is available for
civilian users. The PR ranging code is transmitted at 511 kbps, navigation message at
50 bps and 100 Hz auxiliary meander sequence. Given sequences are used for
modulation of carriers in L1 and L2 sub-bands when generating standard accuracy
signals.
 High Precision Service (HP) – Equivalent for the Precise Positioning Service. HP is
broadcast in phase quadrate with the SP signal, effectively sharing the same carrier
wave as the SP signal, but with a ten times bigger bandwidth than the SP signal. The
GLONASS P-code was never published by system operators, but it was made known
to scientific community which made it fully available. However, along with P-code
was not published by the system operators it neither was officially released for outside
the Russian Armed Forces. Instead they reserve the right to alter the code in the future.
This keeps a number of potential users and receiver manufacturer from actually
implementing the GLONASS P-code
 Military Signal Access to India – India is first country that has been given access to
GLONASS military signal. In 2008 Indian Territory was covered with 18 satellites
and by 2010 was fully operational with all 24 satellites. On December 2010 agreement
was sign by Dimitry Medvedev to share high precision signals from the GLONASS
2 GLONASS Space Segment
The GLONASS space segment consists of 24 operational satellites distributed over three
orbital planes. The longitude of ascending node differs by 120 degrees from plane to plane
and there are eight satellites equally spaced in each plane with argument of latitude of 45
degrees. GLONASS satellites operate in circular orbits at altitude of 19 100 km, an inclination
of 64.8 degree and each satellite completes the orbit in approximately 11 hours and 15
minutes which for stationary observer means that the same satellite is visible at same point at
the sky every eight sidereal days. Satellites carry atomic clocks and the payload needed for
handling navigation data.
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Fig. 1 GLONASS satellite constellation
GLONASS satellites are divided into blocks depending on the time interval when they were
launched. Bellow there is brief description of different blocks:




Prototypes – First prototypes was sent into orbit in October 1982. Designed to
lifetime of 1 year
First generation – First true GLONASS satellites launched between 1985 and 1990.
They are divided into different block vehicles. Lifetime ranges between 2 years to 3
years with many spacecraft exceeding this to up to 4.5 years.
Second generation, GLONASS-M – They were developed from 1990 with the first
one sent to orbit in 2003 and total 20 satellites were launched up to Match 2010. Their
size is 2.4 m in diameter and 3.7m in high with dual solar arrays of 7.2 m. A
remarkable feature is addition of second civil signal on L2 band.
Third generation. GLONASS-K
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Tab. 1 Characteristics of GLONASS satellites
3 IRNSS Ground Segment
The GLONASS Ground Segment is the responsible for the proper operation of the
GLONASS system. GLONASS Control Segment monitors the status of satellites, Determines
the ephemerides and satellite clock offsets and, twice a day, uploads the navigation data to the
satellites. The GLONASS control segment consists of:
•
•
•
•
•
•
•
System Control Centre in Krasnoznamensk
Five Telemetry, Tracking and Command centers in Schelkovo, Komsomoisk. St.
Petersburg, Ussuriysk, Yanisseisk
Central Clock in Schelkovo
Three Upload Stations in Yenisseisk, Komsomoisk, Schelkovo
Two Laser Ranging Stations in Schelkovo and Komsomoisk
Four Monitoring and Measuring Stations in Schelkovo, Krasnoznamensk,
Yenisseisk and Komsomolsk
Six Additional Monitoring and Measuring Stations in Yakutsk, Ulan-Ude, Nurek,
Vorkuta, Murmansk, Zelenchuk
4 The IRNSS User segment
The GLONASS User Segment consists of L-band radio receiver/processors and
antennas which receive GLONASS signals, determine pseudo ranges (and other observables),
and solve the navigation equations in order to obtain their coordinates and provide a very
accurate time. A GLONASS Receiver is a device capable of determining the user position,
velocity and precise time (PVT) by processing the signal broadcasted by satellites. Any
navigation solution provided by a GNSS Receiver is based on the computation of its distance
to a set of satellites, by means of extracting the propagation time of the incoming signals
traveling through space at the speed of light, according to the satellite and receiver local
clocks.
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5 IRNSS Signal Plan
GLONASS uses FDMA in both the L1 and L2 sub-bands. The details on the technical
characteristics
of
the
GLONASS
L1
signals
are
presented
next:
The details on the technical characteristic of the GLONASS L2 signals are presented in this
table:
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6 Used Literature:
[1] http://en.wikipedia.org/wiki/GLONASS
[2] http://navipedia.net/index.php/Category:GLONASS
[3] http://navipedia.net/index.php/GLONASS_General_Introduction
[4] http://navipedia.net/index.php/GLONASS_Space_Segment
[5] http://navipedia.net/index.php/GLONASS_Ground_Segment
[6] http://navipedia.net/index.php/GLONASS_User_Segment
[7] http://navipedia.net/index.php/GLONASS_Signal_Plan