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GLONASS (, ; ) is a Russian
satellite navigation A satellite navigation or satnav system is a system that uses satellites to provide autonomous geopositioning. A satellite navigation system with global coverage is termed global navigation satellite system (GNSS). , four global systems are ope ...
system operating as part of a radionavigation-satellite service. It provides an alternative to
Global Positioning System The Global Positioning System (GPS) is a satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31. It is one of the global navigation satellite systems (GNSS) that provide ge ...
(GPS) and is the second navigational system in operation with global coverage and of comparable precision.
Satellite navigation device A satellite navigation (satnav) device or GPS device is a device that uses satellites of the Global Positioning System (GPS) or similar global navigation satellite systems (GNSS). A satnav device can determine the user's geographic coordinat ...
s supporting both GPS and GLONASS have more satellites available, meaning positions can be fixed more quickly and accurately, especially in built-up areas where buildings may obscure the view to some satellites. Owing to its higher
orbital inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth ...
, GLONASS supplementation of GPS systems also improves positioning in
high latitude The polar regions, also called the frigid zones or polar zones, of Earth are Earth's polar ice caps, the regions of the planet that surround its geographical poles (the North and South Poles), lying within the polar circles. These high latitud ...
s (near the poles). Development of GLONASS began in the Soviet Union in 1976. Beginning on 12 October 1982, numerous rocket launches added satellites to the system until the completion of the
constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...
in 1995. In 2001, after a decline in capacity during the late 1990s, the restoration of the system was made a government priority, and funding increased substantially. GLONASS is the most expensive program of
Roscosmos The State Corporation for Space Activities "Roscosmos", commonly known simply as Roscosmos (), is a State corporation (Russia), state corporation of the Russian Federation responsible for space science, space flights, List of space agencies, c ...
, consuming a third of its budget in 2010. By 2010, GLONASS had achieved full coverage of Russia's territory. In October 2011, the full orbital constellation of 24 satellites was restored, enabling full global coverage. The GLONASS satellites' designs have undergone several upgrades, with the latest version,
GLONASS-K2 GLONASS-K2 is the next-generation satellite design intended to support the Russian GLONASS radio-based satellite navigation system. Developed by ISS Reshetnev (Reshetnev Information Satellite Systems), the first satellite was successfully launch ...
, launched in 2023.


System description

GLONASS is a global navigation satellite system, providing real time position and velocity determination for military and civilian users. The satellites are located in middle circular orbit at altitude with a 64.8° inclination and an orbital period of 11 hours and 16 minutes (every 17 revolutions, done in 8 sidereal days, a satellite passes over the same location). GLONASS's orbit makes it especially suited for usage in high latitudes (north or south), where getting a
GPS The Global Positioning System (GPS) is a satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31. It is one of the global navigation satellite systems (GNSS) that provide geol ...
signal can be problematic. The constellation operates in three orbital planes, with eight evenly spaced satellites on each. A fully operational constellation with global coverage consists of 24 satellites, while 18 satellites are necessary for covering the territory of Russia. To get a position fix the receiver must be in the range of at least four satellites.


Signal


FDMA

GLONASS satellites transmit two types of signals: open standard-precision signal L1OF/L2OF, and
obfuscated Obfuscation is the obscuring of the intended meaning of communication by making the message difficult to understand, usually with confusing and ambiguous language. The obfuscation might be either unintentional or intentional (although intent u ...
high-precision signal L1SF/L2SF. The signals use similar DSSS encoding and
binary phase-shift keying Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency carrier wave. The modulation is accomplished by varying the sine and cosine inputs at a precise time. It is w ...
(BPSK) modulation as in GPS signals. All GLONASS satellites transmit the same code as their standard-precision signal; however each transmits on a different frequency using a 15-channel
frequency-division multiple access Frequency-division multiple access (FDMA) is a channel access method used in some multiple-access protocols. FDMA allows multiple users to send data through a single communication channel, such as a coaxial cable or microwave beam, by dividing ...
(FDMA) technique spanning either side from 1602.0
MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base u ...
, known as the L1 band. The center frequency is 1602 MHz + ''n'' × 0.5625 MHz, where ''n'' is a satellite's frequency channel number (''n''=−6,...,0,...,6, previously ''n''=0,...,13). Signals are transmitted in a 38° cone, using right-hand
circular polarization In electrodynamics, circular polarization of an electromagnetic wave is a polarization state in which, at each point, the electromagnetic field of the wave has a constant magnitude and is rotating at a constant rate in a plane perpendicular to ...
, at an
EIRP Effective radiated power (ERP), synonymous with equivalent radiated power, is an IEEE standardized definition of directional radio frequency (RF) power, such as that emitted by a radio transmitter. It is the total power in watts that would ha ...
between 25 and 27
dBW The decibel watt (dBW or dBW) is a unit for the measurement of the strength of a signal expressed in decibels relative to one watt. It is used because of its capability to express both very large and very small values of power in a short range of ...
(316 to 500 watts). Note that the 24-satellite constellation is accommodated with only 15 channels by using identical frequency channels to support
antipodal Antipode or Antipodes may refer to: Mathematics * Antipodal point, the diametrically opposite point on a circle or ''n''-sphere, also known as an antipode * Antipode, the convolution inverse of the identity on a Hopf algebra Geography * Antipodes ...
(opposite side of planet in orbit) satellite pairs, as these satellites are never both in view of an Earth-based user at the same time. The L2 band signals use the same FDMA as the L1 band signals, but transmit straddling 1246 MHz with the center frequency 1246 MHz + ''n'' × 0.4375 MHz, where ''n'' spans the same range as for L1.GLONASS transmitter specs In the original GLONASS design, only obfuscated high-precision signal was broadcast in the L2 band, but starting with GLONASS-M, an additional civil reference signal L2OF is broadcast with an identical standard-precision code to the L1OF signal. The open standard-precision signal is generated with modulo-2 addition (XOR) of 511 kbit/s pseudo-random ranging code, 50 bit/s navigation message, and an auxiliary 100 Hz
meander A meander is one of a series of regular sinuous curves in the Channel (geography), channel of a river or other watercourse. It is produced as a watercourse erosion, erodes the sediments of an outer, concave bank (cut bank, cut bank or river cl ...
sequence (
Manchester code In telecommunications and data storage, Manchester code (also known as phase encoding, or PE) is a line code in which the encoding of each data bit is either low then high, or high then low, for equal time. It is a self-clocking signal with no ...
), all generated using a single time/frequency oscillator. The pseudo-random code is generated with a 9-stage shift register operating with a period of 1
millisecond A millisecond (from '' milli-'' and second; symbol: ms) is a unit of time in the International System of Units equal to one thousandth (0.001 or 10−3 or 1/1000) of a second or 1000 microseconds. A millisecond is to one second, as one second i ...
s. The navigational message is modulated at 50 bits per second. The superframe of the open signal is 7500 bits long and consists of 5 frames of 30 seconds, taking 150 seconds (2.5 minutes) to transmit the continuous message. Each frame is 1500 bits long and consists of 15 strings of 100 bits (2 seconds for each string), with 85 bits (1.7 seconds) for data and check-sum bits, and 15 bits (0.3 seconds) for time mark. Strings 1-4 provide immediate data for the transmitting satellite, and are repeated every frame; the data include
ephemeris In astronomy and celestial navigation, an ephemeris (; ; , ) is a book with tables that gives the trajectory of naturally occurring astronomical objects and artificial satellites in the sky, i.e., the position (and possibly velocity) over tim ...
, clock and frequency offsets, and satellite status. Strings 5-15 provide non-immediate data (i.e.
almanac An almanac (also spelled almanack and almanach) is a regularly published listing of a set of current information about one or multiple subjects. It includes information like weather forecasting, weather forecasts, farmers' sowing, planting dates ...
) for each satellite in the constellation, with frames I-IV each describing five satellites, and frame V describing remaining four satellites. The ephemerides are updated every 30 minutes using data from the Ground Control segment; they use Earth Centred Earth Fixed (ECEF) Cartesian coordinates in position and velocity, and include lunisolar acceleration parameters. The almanac uses modified
orbital elements Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same o ...
(Keplerian elements) and is updated daily. The more accurate high-precision signal is available for authorized users, such as the Russian military, yet unlike the United States P(Y) code, which is modulated by an encrypting W code, the GLONASS restricted-use codes are broadcast in the clear using only ''
security through obscurity In security engineering, security through obscurity is the practice of concealing the details or mechanisms of a system to enhance its security. This approach relies on the principle of hiding something in plain sight, akin to a magician's slei ...
''. The details of the high-precision signal have not been disclosed. The modulation (and therefore the tracking strategy) of the data bits on the L2SF code has recently changed from unmodulated to 250 bit/s burst at random intervals. The L1SF code is modulated by the navigation data at 50 bit/s without a Manchester meander code. The high-precision signal is broadcast in phase quadrature with the standard-precision signal, effectively sharing the same carrier wave, but with a ten-times-higher bandwidth than the open signal. The message format of the high-precision signal remains unpublished, although attempts at reverse-engineering indicate that the superframe is composed of 72 frames, each containing 5 strings of 100 bits and taking 10 seconds to transmit, with total length of 36 000 bits or 720 seconds (12 minutes) for the whole navigational message. The additional data are seemingly allocated to critical
Lunisolar A lunisolar calendar is a calendar in many cultures, that combines monthly lunar cycles with the solar year. As with all calendars which divide the year into months, there is an additional requirement that the year have a whole number of months ...
acceleration parameters and clock correction terms.


= Accuracy

= At peak efficiency, the standard-precision signal offers horizontal positioning accuracy within 5–10 metres, vertical positioning within , a velocity vector measuring within , and timing within 200
nanosecond A nanosecond (ns) is a unit of time in the International System of Units (SI) equal to one billionth of a second, that is, of a second, or seconds. The term combines the SI prefix ''nano-'' indicating a 1 billionth submultiple of an SI unit (e ...
s, all based on measurements from four first-generation satellites simultaneously;"A Review of GLONASS" Miller, 2000 newer satellites such as GLONASS-M improve on this. GLONASS uses a coordinate
datum Data ( , ) are a collection of discrete or continuous value (semiotics), values that convey information, describing the quantity, qualitative property, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols t ...
named "
PZ-90 PZ-90 (short for ''Parametry Zemli 1990 goda'', in ) is a geodetic datum defined for use in the GLONASS GLONASS (, ; ) is a Russian satellite navigation system operating as part of a radionavigation-satellite service. It provides an alterna ...
" (Earth Parameters 1990 – Parametry Zemli 1990), in which the precise location of the
North Pole The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where the Earth's rotation, Earth's axis of rotation meets its surface. It is called the True North Pole to distingu ...
is given as an average of its position from 1990 to 1995. This is in contrast to the GPS's coordinate datum,
WGS 84 The World Geodetic System (WGS) is a standard used in cartography, geodesy, and satellite navigation including GPS. The current version, WGS 84, defines an Earth-centered, Earth-fixed coordinate system and a geodetic datum, and also descri ...
, which uses the location of the North Pole in 1984. As of 17 September 2007, the PZ-90 datum has been updated to version PZ-90.02 which differ from WGS 84 by less than in any given direction. Since 31 December 2013, version PZ-90.11 is being broadcast, which is aligned to the International Terrestrial Reference System and Frame 2008 at epoch 2011.0 at the centimetre level, but ideally a conversion to ITRF2008 should be done.National Reference Systems of the Russian Federation used in GLONASS.
V. Vdovin and M. Vinogradova (TSNIImash), 8th ICG meeting, Dubai, November 2013


CDMA

Since 2008, new
CDMA Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communicatio ...
signals are being researched for use with GLONASS.GLONASS Status and Progress
, S.G.Revnivykh, 47th CGSIC Meeting, 2007. "L1CR and L5R CDMA interoperable with GPS and Galileo"
GLONASS Status and Development
, G.Stupak, 5th ICG Meeting
Russia's First GLONASS-K In Orbit, CDMA Signals Coming
''
Inside GNSS ''Inside GNSS'' (IG) is an international Magazine#Controlled circulation, controlled circulation trade magazine and website owned by Gibbons Media and Research LLC. It covers space-based National Executive Committee for Space-Based Positioning, N ...
'' (2011-02-26) Retrieved on 6 October 2011
GLONASS Status and Modernization
Ekaterina Oleynik, Sergey Revnivykh, 51st CGSIG Meeting, September 2011
GLONASS Status and Modernization
Sergey Revnivykh, 6th ICG Meeting, September 2011
GLONASS Status and Modernization
, Sergey Revnivykh, 7th ICG Meeting, November 2012
GLONASS Government Policy, Status and Modernization Plans
, Tatiana Mirgorodskaya, IGNSS-2013, 16 July 2013
The interface control documents for GLONASS CDMA signals was published in August 2016.Russian Space Systems JSC - GLONASS Interface Control Documents
(in Russian)
According to GLONASS developers, there will be three open and two restricted CDMA signals. The open signal L3OC is centered at 1202.025 MHz and uses BPSK(10) modulation for both data and pilot channels; the ranging code transmits at 10.23 million
chips ''CHiPs'' is an American crime drama television series created by Rick Rosner and originally aired on NBC from September 15, 1977, to May 1, 1983. After the final first-run telecast on NBC in May 1983, the series went into reruns on Sundays fr ...
per second, modulated onto the carrier frequency using QPSK with in-phase data and quadrature pilot. The data is error-coded with 5-bit
Barker code In telecommunication technology, a Barker code or Barker sequence is a finite sequence of digital values with the ideal autocorrelation property. It is used as a synchronising pattern between the sender and receiver of a stream of bits. Explanat ...
and the pilot with 10-bit Neuman-Hoffman code. Open L1OC and restricted L1SC signals are centered at 1600.995 MHz, and open L2OC and restricted L2SC signals are centered at 1248.06 MHz, overlapping with GLONASS FDMA signals. Open signals L1OC and L2OC use time-division multiplexing to transmit pilot and data signals, with BPSK(1) modulation for data and BOC(1,1) modulation for pilot; wide-band restricted signals L1SC and L2SC use BOC (5, 2.5) modulation for both data and pilot, transmitted in quadrature phase to the open signals; this places peak signal strength away from the center frequency of narrow-band open signals.GLONASS Modernization
, Yuri Urlichich, Valery Subbotin, Grigory Stupak, Vyacheslav Dvorkin, Alexander Povalyaev, Sergey Karutin, and Rudolf Bakitko, Russian Space Systems, GPS World, November 2011
Binary phase-shift keying Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency carrier wave. The modulation is accomplished by varying the sine and cosine inputs at a precise time. It is w ...
(BPSK) is used by standard GPS and GLONASS signals.
Binary offset carrier Binary offset carrier modulation (BOC modulation) was developed by John Betz in order to allow interoperability of satellite navigation systems. It is currently used in the US GPS system, Indian IRNSS system and in Galileo and is a square sub-carr ...
(BOC) is the modulation used by
Galileo Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei ( , , ) or mononymously as Galileo, was an Italian astronomer, physicist and engineer, sometimes described as a poly ...
, modernized GPS, and BeiDou-2. The navigational message of CDMA signals is transmitted as a sequence of text strings. The message has variable size - each pseudo-frame usually includes six strings and contains
ephemerides In astronomy and celestial navigation, an ephemeris (; ; , ) is a book with tables that gives the trajectory of naturally occurring astronomical objects and artificial satellites in the sky, i.e., the position (and possibly velocity) over time. ...
for the current satellite (string types 10, 11, and 12 in a sequence) and part of the almanac for three satellites (three strings of type 20). To transmit the full almanac for all current 24 satellites, a superframe of 8 pseudo-frames is required. In the future, the superframe will be expanded to 10 pseudo-frames of data to cover full 30 satellites. The message can also contain
Earth's rotation Earth's rotation or Earth's spin is the rotation of planet Earth around its own Rotation around a fixed axis, axis, as well as changes in the orientation (geometry), orientation of the rotation axis in space. Earth rotates eastward, in progra ...
parameters,
ionosphere The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays ...
models, long-term orbit parameters for GLONASS satellites, and
COSPAS-SARSAT The International Cospas-Sarsat Programme is a satellite-aided search and rescue (SAR) initiative. It is organized as a treaty-based, nonprofit, intergovernmental, humanitarian cooperative of 45 nations and agencies (see infobox). It is dedica ...
messages. The system time marker is transmitted with each string; UTC leap second correction is achieved by shortening or lengthening (zero-padding) the final string of the day by one second, with abnormal strings being discarded by the receiver.GLONASS: Developing Strategies for the Future
, Yuri Urlichich, Valeriy Subbotin, Grigory Stupak, Vyacheslav Dvorkin, Alexander Povalyaev, and Sergey Karutin. GPS World, November 2011
The strings have a version tag to facilitate
forward compatibility Forward compatibility or upward compatibility is a design characteristic that allows a system to accept input intended for a later version of itself. The concept can be applied to entire systems, electrical interfaces, telecommunication signal ...
: future upgrades to the message format will not break older equipment, which will continue to work by ignoring new data (as long as the constellation still transmits old string types), but up-to-date equipment will be able to use additional information from newer satellites.New Structure for GLONASS Nav Message
, Alexander Povalyaev, GPS World, 2 November 2013
The navigational message of the L3OC signal is transmitted at 100 bit/s, with each string of symbols taking 3 seconds (300 bits). A pseudo-frame of 6 strings takes 18 seconds (1800 bits) to transmit. A superframe of 8 pseudo-frames is 14,400 bits long and takes 144 seconds (2 minutes 24 seconds) to transmit the full almanac. The navigational message of the L1OC signal is transmitted at 100 bit/s. The string is 250 bits long and takes 2.5 seconds to transmit. A pseudo-frame is 1500 bits (15 seconds) long, and a superframe is 12,000 bits or 120 seconds (2 minutes). L2OC signal does not transmit any navigational message, only the pseudo-range codes:
Glonass-K1 test satellite launched in 2011 introduced L3OC signal. Glonass-M satellites produced since 2014 (s/n 755+) will also transmit L3OC signal for testing purposes. Enhanced Glonass-K1 and
Glonass-K2 GLONASS-K2 is the next-generation satellite design intended to support the Russian GLONASS radio-based satellite navigation system. Developed by ISS Reshetnev (Reshetnev Information Satellite Systems), the first satellite was successfully launch ...
satellites, to be launched from 2023, will feature a full suite of modernized CDMA signals in the existing L1 and L2 bands, which includes L1SC, L1OC, L2SC, and L2OC, as well as the L3OC signal. Glonass-K2 series should gradually replace existing satellites starting from 2023, when Glonass-M launches will cease.GLONASS Program Update
, Ivan Revnivykh, Roscosmos, 11th ICG Meeting, November 2016
Glonass-KM satellites will be launched by 2025. Additional open signals are being studied for these satellites, based on frequencies and formats used by existing GPS, Galileo, and Beidou/COMPASS signals: * open signal L1OCM using BOC(1,1) modulation centered at 1575.42 MHz, similar to modernized GPS signal L1C, Galileo signal E1, and Beidou/COMPASS signal B1C; * open signal L5OCM using BPSK(10) modulation centered at 1176.45 MHz, similar to the GPS "Safety of Life" (L5), Galileo signal E5a, and Beidou/COMPASS signal B2a; * open signal L3OCM using BPSK(10) modulation centered at 1207.14 MHz, similar to Galileo signal E5b and Beidou/COMPASS signal B2b. Such an arrangement will allow easier and cheaper implementation of multi-standard
GNSS A satellite navigation or satnav system is a system that uses satellites to provide autonomous geopositioning. A satellite navigation system with global coverage is termed global navigation satellite system (GNSS). , four global systems are op ...
receivers. With the introduction of CDMA signals, the constellation will be expanded to 30 active satellites by 2025; this may require eventual deprecation of FDMA signals. The new satellites will be deployed into three additional planes, bringing the total to six planes from the current three—aided by System for Differential Correction and Monitoring ( SDCM), which is a GNSS augmentation system based on a network of ground-based control stations and communication satellites
Luch 5A Luch 5A ( meaning ''ray'' and sometimes Romanisation of Russian, transliterated as Loutch-5A) is a Russian Luch (satellite), Luch relay satellite which transmits data from the Russian Orbital Segment of the International Space Station, and from o ...
and
Luch 5B Luch 5B ( meaning ''ray'' and sometimes transliterated as Loutch-5B) is a Russian Luch relay satellite which transmits data from the Russian Orbital Segment of the International Space Station, and from other satellites in low Earth orbit. It is ...
.SDCM status and plans
, Grigory Stupak, 7th ICG Meeting, November 2012
GLONASS-KM satellites will also use new L3SVI open signal to broadcast Precise Point Positioning (PPP) to deliver GLONASS High Accuracy Services. Six additional Glonass-V satellites, using
Tundra orbit A Tundra orbit () is a highly elliptical geosynchronous orbit with a high inclination (approximately 63.4°), an orbital period of one sidereal day, and a typical eccentricity between 0.2 and 0.3. A satellite placed in this orbit spends most of ...
in three orbital planes, will be launched starting in 2025; this regional high-orbit segment will offer increased regional availability and 25% improvement in precision over
Eastern Hemisphere The Eastern Hemisphere is the half of the planet Earth which is east of the prime meridian (which crosses Greenwich, London, United Kingdom) and west of the antimeridian (which crosses the Pacific Ocean and relatively little land from pole to p ...
, similar to Japanese QZSS system and Beidou-1. The new satellites will form two ground traces with inclination of 64.8°, eccentricity of 0.072, period of 23.9 hours, and ascending node longitude of 60° and 120°. Glonass-V vehicles are based on Glonass-K platform and will broadcast new CDMA signals only. Previously
Molniya orbit A Molniya orbit ( rus, Молния, p=ˈmolnʲɪjə, a=Ru-молния.ogg, "Lightning") is a type of satellite orbit designed to provide communications and remote sensing coverage over high latitudes. It is a highly elliptical orbit with ...
,
geosynchronous orbit A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital ...
, or
inclined orbit A satellite is said to occupy an inclined orbit around Earth if the orbit exhibits an angle other than 0° to the equatorial plane. This angle is called the orbit's inclination. A planet is said to have an inclined orbit around the Sun if it has a ...
were also under consideration for the regional segment. Roscosmos also plans to launch up to 240 small size satellites on the
low Earth orbit A low Earth orbit (LEO) is an geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial object ...
(LEO) to improve signal availability and interfecence; LEO satellites will have a limited lifespan of 5 years to allow a faster pace of replenishment.


Navigational message


L1OC


L3OC


Common properties of open CDMA signals


Satellites

The main contractor of the GLONASS program is Joint Stock Company
Information Satellite Systems Reshetnev JSC Information Satellite Systems Reshetnev () is a Russian satellite manufacturing company. It is based in the closed city of Krasnoyarsk-26 (today called Zheleznogorsk), Krasnoyarsk Krai near the city of Krasnoyarsk. The company was formerly ca ...
(ISS Reshetnev, formerly called NPO-PM). The company, located in Zheleznogorsk, is the designer of all GLONASS satellites, in cooperation with the Institute for Space Device Engineering ( :ru:РНИИ КП) and the Russian Institute of Radio Navigation and Time. Serial production of the satellites is accomplished by the company
Production Corporation Polyot Production Association Polyot () is a Russian aerospace engineering state corporation best known for being the manufacturer of GLONASS satellites and the Kosmos-3M space launch vehicle. The company is based in Omsk, in the Russian Federation. In 2 ...
in
Omsk Omsk (; , ) is the administrative center and largest types of inhabited localities in Russia, city of Omsk Oblast, Russia. It is situated in southwestern Siberia and has a population of over one million. Omsk is the third List of cities and tow ...
. Over the three decades of development, the satellite designs have gone through numerous improvements, and can be divided into three generations: the original GLONASS (since 1982), GLONASS-M (since 2003) and GLONASS-K (since 2011). Each GLONASS satellite has a
GRAU The Main Missile and Artillery Directorate of the Ministry of Defense of the Russian Federation (), commonly referred to by its transliterated acronym GRAU (), is a department of the Russian Ministry of Defense. It is subordinate to the Chief of ...
designation 11F654, and each of them also has the military "Cosmos-NNNN" designation.


First generation

The true first generation of GLONASS (also called Uragan) satellites were all three-axis stabilized vehicles, generally weighing and were equipped with a modest propulsion system to permit relocation within the constellation. Over time they were upgraded to Block IIa, IIb, and IIv vehicles, with each block containing evolutionary improvements. Six Block IIa satellites were launched in 1985–1986 with improved time and frequency standards over the prototypes, and increased frequency stability. These spacecraft also demonstrated a 16-month average operational lifetime. Block IIb spacecraft, with a two-year design lifetimes, appeared in 1987, of which a total of 12 were launched, but half were lost in launch vehicle accidents. The six spacecraft that made it to orbit worked well, operating for an average of nearly 22 months. Block IIv was the most prolific of the first generation. Used exclusively from 1988 to 2000, and continued to be included in launches through 2005, a total of 56 satellites were launched. The design life was three years, however numerous spacecraft exceeded this, with one late model lasting 68 months, nearly double. Block II satellites were typically launched three at a time from the
Baikonur Cosmodrome The Baikonur Cosmodrome is a spaceport operated by Russia within Kazakhstan. Located in the Kazakh city of Baikonur, it is the largest operational space launch facility in terms of area. All Russian Human spaceflight, crewed spaceflights are l ...
using
Proton-K The Proton-K, also designated Proton 8K82K after its GRAU index or SL-12 after its model number, was a Russian, previously Soviet, carrier rocket derived from the earlier Proton. It was built by Khrunichev, and launched from sites 81/23, 8 ...
Blok-DM2 or Proton-K
Briz-M The Briz-K, Briz-KM and Briz-M ( meaning ''Breeze-K, KM and M'') are Russian liquid-propellant rocket orbit insertion upper stages manufactured by Khrunichev State Research and Production Space Center and used on the Proton-M and Angara A5. T ...
boosters. The only exception was when, on two launches, an Etalon geodetic reflector satellite was substituted for a GLONASS satellite.


Second generation

The second generation of satellites, known as Glonass-M, were developed beginning in 1990 and first launched in 2003. These satellites possess a substantially increased lifetime of seven years and weigh slightly more at . They are approximately in diameter and high, with a solar array span of for an electrical power generation capability of 1600 watts at launch. The aft payload structure houses 12 primary antennas for L-band transmissions. Laser corner-cube reflectors are also carried to aid in precise orbit determination and geodetic research. On-board cesium clocks provide the local clock source. 52 Glonass-M have been produced and launched. A total of 41 second generation satellites were launched through the end of 2013. As with the previous generation, the second generation spacecraft were launched three at a time using
Proton-K The Proton-K, also designated Proton 8K82K after its GRAU index or SL-12 after its model number, was a Russian, previously Soviet, carrier rocket derived from the earlier Proton. It was built by Khrunichev, and launched from sites 81/23, 8 ...
Blok-DM2 or Proton-K Briz-M boosters. Some were launched alone with Soyuz-2-1b/
Fregat Fregat () is an upper stage developed by NPO Lavochkin for universal compatibility with a wide range of medium- and heavy-lift launch vehicles. Fregat has been used primarily with Soyuz and Zenit rockets, and entered operational service in ...
. In July 2015, ISS Reshetnev announced that it had completed the last GLONASS-M (No. 61) spacecraft and it was putting it in storage waiting for launch, along with eight previously built satellites. As on 22 September 2017, GLONASS-M No.52 satellite went into operation and the orbital grouping has again increased to 24 space vehicles.


Third generation

GLONASS-K is a substantial improvement of the previous generation: it is the first unpressurised GLONASS satellite with a much reduced mass of versus the of GLONASS-M. It has an operational lifetime of 10 years, compared to the 7-year lifetime of the second generation GLONASS-M. It will transmit more navigation signals to improve the system's accuracy — including new CDMA signals in the L3 and L5 bands, which will use modulation similar to modernized GPS, Galileo, and BeiDou. Glonass-K consist of 26 satellites having satellite index 65-98 and widely used in Russian Military space. The new satellite's advanced equipment—made solely from Russian components — will allow the doubling of GLONASS' accuracy. As with the previous satellites, these are 3-axis stabilized,
nadir The nadir is the direction pointing directly ''below'' a particular location; that is, it is one of two vertical directions at a specified location, orthogonal to a horizontal flat surface. The direction opposite of the nadir is the zenith. Et ...
pointing with dual solar arrays. The first GLONASS-K satellite was successfully launched on 26 February 2011. Due to their weight reduction, GLONASS-K spacecraft can be launched in pairs from the
Plesetsk Cosmodrome Plesetsk Cosmodrome () is a Russian spaceport located in Mirny, Arkhangelsk Oblast, near the town of Plesetsk, from which it takes its name. Until 2025 and the commissioning of the Andøya Space, Andøya base in Norway, it was the only operati ...
launch site using the substantially lower cost
Soyuz-2.1b Soyuz2 (; GRAU index: 14A14) is a Russian expendable medium-lift launch vehicle and the seventh major iteration of the Soyuz rocket family. Compared to its predecessors, Soyuz-2 features significant upgrades, including improved engines and ...
boosters or in six-at-once from the
Baikonur Cosmodrome The Baikonur Cosmodrome is a spaceport operated by Russia within Kazakhstan. Located in the Kazakh city of Baikonur, it is the largest operational space launch facility in terms of area. All Russian Human spaceflight, crewed spaceflights are l ...
using Proton-K Briz-M launch vehicles.


Ground control

The ground control segment of GLONASS is almost entirely located within former Soviet Union territory, except for several in Brazil and one in Nicaragua. The GLONASS ground segment consists of: * a system control centre; * five Telemetry, Tracking and Command centers; * two Laser Ranging Stations; and * ten Monitoring and Measuring Stations.


Receivers

Companies producing GNSS receivers making use of GLONASS: * Furuno * JAVAD GNSS, Inc *
Septentrio Septentrio N.V. is a designer and manufacturer of high-end multi-frequency GNSS receivers. Its main target is to provide GNSS receiver boards and modules for further system integration by original equipment manufacturers (OEMs). Septentrio's co ...
*
Topcon is a Japanese manufacturer of optical equipment for ophthalmology and surveying. History 1930s TOPCON was established in September 1932 based the merger of the surveying instruments division of K. Hattori & Co., Ltd. (now known as Seiko ...
* C-Nav *
Magellan Navigation Magellan Navigation, Inc. is an American producer of consumer and professional grade global positioning system receivers, named after Ferdinand Magellan, the first explorer to circumnavigate the globe. Headquartered in San Dimas, California, wit ...
* Novatel * ComNav technology Ltd. *
Leica Geosystems Leica Geosystems (formerly known as Wild Heerbrugg or just Wild) based in eastern Switzerland produces products and systems for surveying and geographical measurement ( geomatics). Its products employ a variety of technologies including GPS ...
* Hemisphere GNSS *
Trimble Inc Trimble Inc. is an American software, hardware, and services technology company. Trimble also does hardware development of global navigation satellite system (GNSS) receivers, scanners, total stations, laser rangefinders, unmanned aerial vehicl ...
*
u-blox u-blox is a Swiss company that creates wireless semiconductors and modules for consumer, automotive and industrial markets. They operate as a fabless IC and design house. The company is listed at the Swiss Stock Exchange (SIX:UBXN) and has offi ...
NPO Progress describes a receiver called ''GALS-A1'', which combines GPS and GLONASS reception.
SkyWave Mobile Communications SkyWave Mobile Communications is a global provider of satellite and satellite-cellular devices in the Machine-to-Machine (M2M) market. Skywave products help customers track, monitor and control industrial vehicles, vessels and industrial equipme ...
manufactures an
Inmarsat Inmarsat is a British communications satellite, satellite telecommunications company, offering global mobile services. It provides telephone and data services to users worldwide, via portable or mobile terminals which communicate with groun ...
-based satellite communications terminal that uses both GLONASS and GPS. , some of the latest receivers in the
Garmin Garmin Ltd. is an American multinational technology company based in Olathe, Kansas. The company designs, develops, manufactures, markets, and distributes GPS-enabled products and other navigation, communication, sensor-based, and information ...
eTrex line also support GLONASS (along with GPS). Garmin also produce a standalone
Bluetooth Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is li ...
receiver, the GLO for Aviation, which combines GPS,
WAAS The Wide Area Augmentation System (WAAS) is an air navigation aid developed by the Federal Aviation Administration to augment the Global Positioning System (GPS), with the goal of improving its accuracy, integrity, and availability. Essenti ...
and GLONASS. Various
smartphone A smartphone is a mobile phone with advanced computing capabilities. It typically has a touchscreen interface, allowing users to access a wide range of applications and services, such as web browsing, email, and social media, as well as multi ...
s from 2011 onwards have integrated GLONASS capability in addition to their pre-existing
GPS The Global Positioning System (GPS) is a satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31. It is one of the global navigation satellite systems (GNSS) that provide geol ...
receivers, with the intention of reducing signal acquisition periods by allowing the device to pick up more satellites than with a single-network receiver, including devices from: *
Xiaomi Xiaomi (; ) is a Chinese multinational corporation and technology company headquartered in Beijing, China. It is best known for consumer electronics software electric vehicles. It is the second-largest manufacturer of smartphones in the worl ...
*
Sony Ericsson Sony Mobile Communications Inc., originally Sony Ericsson Mobile Communications AB, was a Multinational corporation, multinational consumer electronics and telecommunications company, best known for its Mobile phones, mobile phone products. The ...
*
ZTE ZTE Corporation is a Chinese partially state-owned technology company that specializes in telecommunication. Founded in 1985, ZTE is listed on both the Hong Kong and Shenzhen Stock Exchanges. ZTE's core business is wireless, exchange, opti ...
*
Huawei Huawei Technologies Co., Ltd. ("Huawei" sometimes stylized as "HUAWEI"; ; zh, c=华为, p= ) is a Chinese multinational corporationtechnology company in Longgang, Shenzhen, Longgang, Shenzhen, Guangdong. Its main product lines include teleco ...
*
Samsung Samsung Group (; stylised as SΛMSUNG) is a South Korean Multinational corporation, multinational manufacturing Conglomerate (company), conglomerate headquartered in the Samsung Town office complex in Seoul. The group consists of numerous a ...
*
Apple An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...
(since
iPhone 4S The is a smartphone that was developed and marketed by Apple Inc. It is the List of iPhone models, fifth generation of the iPhone, succeeding the iPhone 4 and preceding the iPhone 5. It was announced on October 4, 2011, at Apple's Cupertino ...
, concurrently with GPS) *
HTC HTC Corporation ( zh, t=宏達國際電子股份有限公司, p=Hóngdá Guójì Diànzǐ Gǔfèn Yǒuxiàn Gōngsī, first=t), or High Tech Computer Corporation (abbreviated and trading as HTC), is a Taiwanese consumer electronics corporatio ...
* LG *
Motorola Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois. It was founded by brothers Paul and Joseph Galvin in 1928 and had been named Motorola since 1947. Many of Motorola's products had been ...
*
Nokia Nokia Corporation is a Finnish multinational corporation, multinational telecommunications industry, telecommunications, technology company, information technology, and consumer electronics corporation, originally established as a pulp mill in 1 ...


Status


Availability

, the GLONASS constellation status is: The system requires 18 satellites for continuous navigation services covering all of Russia, and 24 satellites to provide services worldwide. The GLONASS system covers 100% of worldwide territory. On 2 April 2014, the system experienced a technical failure that resulted in practical unavailability of the navigation signal for around 12 hours. On 14–15 April 2014, nine GLONASS satellites experienced a technical failure due to software problems. On 19 February 2016, three GLONASS satellites experienced a technical failure: the batteries of GLONASS-738 exploded, the batteries of GLONASS-737 were depleted, and GLONASS-736 experienced a stationkeeping failure due to human error during maneuvering. GLONASS-737 and GLONASS-736 were expected to be operational again after maintenance, and one new satellite (GLONASS-751) to replace GLONASS-738 was expected to complete commissioning in early March 2016. The full capacity of the satellite group was expected to be restored in the middle of March 2016. After the launching of two new satellites and maintenance of two others, the full capacity of the satellite group was restored.


Accuracy

According to Russian System of Differentional Correction and Monitoring's data, , precision of GLONASS navigation definitions (for p=0.95) for latitude and longitude were with mean number of navigation space vehicles (NSV) equals 7—8 (depending on station). In comparison, the same time precision of GPS
navigation Navigation is a field of study that focuses on the process of monitoring and controlling the motion, movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navig ...
definitions were with mean number of NSV equals 6—11 (depending on station). Some modern receivers are able to use both GLONASS and GPS satellites together, providing greatly improved coverage in urban canyons and giving a very fast time to fix due to over 50 satellites being available. In indoor, urban canyon or mountainous areas, accuracy can be greatly improved over using GPS alone. For using both navigation systems simultaneously, precision of GLONASS/GPS navigation definitions were with mean number of NSV equals 14—19 (depends on station). In May 2009,
Anatoly Perminov Anatoly Nikolayevich Perminov (; born 16 June 1945) is a Russians, Russian aerospace engineering, rocket scientist and Mechanical engineering, mechanical engineer. He served as the List of heads of Roscosmos, General Director of Roscosmos, Russian ...
, then director of the
Roscosmos The State Corporation for Space Activities "Roscosmos", commonly known simply as Roscosmos (), is a State corporation (Russia), state corporation of the Russian Federation responsible for space science, space flights, List of space agencies, c ...
, stated that actions were undertaken to expand GLONASS's constellation and to improve the
ground segment A ground segment consists of all the ground-based elements of a spaceflight, space system used by operators and support personnel, as opposed to the Satellite space segment, space segment and user segment. The ground segment enables management of ...
to increase the navigation definition of GLONASS to an accuracy of by 2011. In particular, the latest satellite design,
GLONASS-K GLONASS-K is the latest satellite design intended as a part of the Russian GLONASS radio-based satellite navigation system. Developed by ISS Reshetnev (Information Satellite Systems Reshetnev) and first launched on 26 February 2011, it is a su ...
has the ability to double the system's accuracy once introduced. The system's ground segment is also to undergo improvements. As of early 2012, sixteen positioning ground stations are under construction in
Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
and in the
Antarctic The Antarctic (, ; commonly ) is the polar regions of Earth, polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is antipodes, diametrically opposite of the Arctic region around the North Pole. The Antar ...
at the Bellingshausen and
Novolazarevskaya Novolazarevskaya Station () is a Russian, formerly Soviet, Antarctic research station. The station is located at Schirmacher Oasis, Queen Maud Land, from the Antarctic coast, from which it is separated by Lazarev Ice Shelf. It was opened on Jan ...
bases. New stations will be built around the southern hemisphere from
Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
to
Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...
. Together, these improvements are expected to bring GLONASS' accuracy to 0.6 m or better by 2020. The setup of a GLONASS receiving station in the
Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...
is also now under negotiation.


History


See also

* Aviaconversiya – a Russian satellite navigation firm *
BeiDou The BeiDou Navigation Satellite System (BDS; ) is a satellite-based radio navigation system owned and operated by the China National Space Administration. It provides geolocation and time information to a BDS receiver anywhere on or near the ...
– Chinese counterpart * Era-glonass – GLONASS-based system of emergency response *
Galileo Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei ( , , ) or mononymously as Galileo, was an Italian astronomer, physicist and engineer, sometimes described as a poly ...
– European Union's counterpart *
Global Positioning System The Global Positioning System (GPS) is a satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31. It is one of the global navigation satellite systems (GNSS) that provide ge ...
- American counterpart * List of GLONASS satellites *
Multilateration Trilateration is the use of distances (or "ranges") for determining the unknown position coordinates of a point of interest, often around Earth ( geopositioning). When more than three distances are involved, it may be called multilateration, f ...
– the mathematical technique used for positioning *
NAVIC Indian Regional Navigation Satellite System (IRNSS), with an operational name of NavIC (acronym for Navigation with Indian Constellation; also, 'sailor' or 'navigator' in Indian languages), is an autonomous regional satellite navigation syste ...
– Indian counterpart *
Tsikada Tsikada ( meaning ''cicada'') was a Soviet satellite navigation system including ten Low Earth Orbit (LEO) satellites. It transmitted the same two carrier frequencies as the U.S. Transit (satellite), TRANSIT satellite system. The first satellite w ...
– a Russian satellite navigation system


Notes


References


Standards

* * * * *


Bibliography


''GLONASS Interface Control Document'', Edition 5.1, 2008backup

''GLONASS Interface Control Document'', Version 4.0, 1998
* * * * * * * * * * * * * * * * * * * * * *


External links


Official GLONASS web page
{{Russian space program Navigation satellite constellations Space program of Russia Space program of the Soviet Union Soviet inventions Wireless locating Earth observation satellites of the Soviet Union Military equipment introduced in the 1980s