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|Title={{PAGENAME}}
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The [[GLONASS General Introduction|GLONASS]] Ground Segment (also referred to as Control Segment or Operational Control System) is the responsible for the proper operation of the GLONASS system. Like in GPS, the 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.<ref name="GNSS-Book ">J. Sanz Subirana, JM. Juan Zornoza and M. Hernández-Pajares, ''Global Navigation Satellite Systems: Volume I: Fundamentals and Algorithms''</ref>


The [[:Category:GLONASS|GLONASS]] Ground Segment (also referred to as Control Segment or Operational Control System) is the responsible for the proper operation of the GLONASS system.
==Introduction==
The [[:Category:GLONASS|GLONASS]] Control Segment is composed by a network of Monitor Stations (MS), a Master Control Station (MCS), a backup of the MCS and the Ground Antennas (GA).
[[File:GLONASS_GroundSegment.JPG‎|GLONASS Ground Segment|350px|right|thumb]]
In order to ensure operation and coordination of the entire system, the GLONASS ground segment determines satellite orbits as well as time and frequency parameters regularly. In addition, the health of all satellites is monitored continuously.These corrections and the navigation message are uploaded to the satellites through the Ground Antennas,''' which are co-located in four of the Monitor stations (Ascension Island, Cape Canaveral, Diego Garcia, and Kwajalein)'''.
[[File:SLR_Shelkovo.jpg|SLR Station in Shelkovo (near Moscow)|thumb|right|350px]]
The GLONASS ground segment consists of:<ref>[http://www.oosa.unvienna.org/pdf/publications/icg_ebook.pdf  Current and planned global and regional navigation satellite systems and satellite-based augmentation systems]</ref>
* A '''System Control Centre''' located at Krasnoznamensk.


==Introduction==
*A network of five '''Telemetry, Tracking and Command''' centers (TT&C):
The ground segment consists of the System Control Center and the Central Synchronizer situated in Moscow. Seven additional ground stations are maintained in the territory of the former Soviet Union, serving for orbit determination and satellite monitoring. These stations are equipped with radar, laser distance meters and/or telemetry. They are situated near the following towns:<ref name="rossbach-udo">[http://ub.unibw-muenchen.de/dissertationen/ediss/rossbach-udo/inhalt.pdf Positioning and Navigation Using the Russian Satellite System GLONASS, Udo Roßbac]</ref>
**Schelkovo
* St. Petersburg TT&C
**Komsomoisk
* Ternopol TT&C, laser ranging, monitoring
**St-Peteburg
* Jenisejsk TT&C
**Ussuriysk
* Komsomol’sk-na-Amure TT&C, laser ranging, monitoring
**Yenisseisk
* Balchas Laser ranging
* Jevpatoria Laser ranging
* Kitab Laser ranging


==System Control Centre (SCC)==
*The '''Central Clock''' situated in Schelkovo (near Moscow).
The System Control Center (SCC) is responsible for satellite constellation control and management of [[:Category:GLONASS|GLONASS]] satellites. It provides the telemetry, telecommand and control function for the whole [[:Category:GLONASS|GLONASS]] satellite constellation.
The SCC coordinates all functions and operations at the system level. It processes the information from the Command and Tracking stations to determine satellite clock and orbit states, and updates the navigation message for each satellite.


==Command and Tracking Stations==
* Three Upload Stations:
The CTSs track the [[:Category:GLONASS|GLONASS]] satellites in view and accumulate ranging data and telemetry from the satellites signals. The information from CTSs is processed at the SCC to determine satellite clock and orbit states and to update the navigation message of each satellite. This updated information is transmitted to the satellites via the CTSs, which also used for transmitting of control information.
**Yenisseisk
**Komsomoisk
**Schelkovo


The Command and Tracking Stations are composed by a main network of four
* Two '''Laser Ranging Stations''' (SLR):
Telemetry, Tracking and Control (TT&C) stations distributed throughout the Russian territory (in St. Petersburg, Ternopol, Eniseisk and Komsomolsk-na- Amure).
**Schelkovo
**Komsomoisk


The CTSs ranging data is periodically calibrated using a laser ranging devices at the Quantum Optical Tracking Stations which are within GCS. Each [[:Category:GLONASS|GLONASS]]satellite specially carries laser reflectors for this purpose.
* A network of four '''Monitoring and Measuring Stations''':
This network is complemented by other additional measurement stations (LS) in former Soviet Union territory (Balkhash in Kazakhstan, Evpatoria in Ukraine, Kitab in Uzbekistan), equipped with laser ranging and other monitoring facilities.
**Schelkovo
**Krasnoznamensk
**Yenisseisk
**Komsomolsk
*  Six '''additional Monitoring and Measuring Stations''' are to start operating on the territory of the Russian Federation  and the Commonwealth of Independent States in the near future:
**Yakutsk
**Ulan-Ude
**Nurek
**Vorkuta
**Murmansk
**Zelenchuk


==Central Synchroniser==
==System Control Centre (SCC)==
The synchronization of all the processes in the [[:Category:GLONASS|GLONASS]] system is very important for its proper operability. There is the Central Synchronizer within GCS to meet this requirement. The Central Synchronizer is high-precise hydrogen atomic clock which forms the [[:Category:GLONASS|GLONASS]] system time scale. The onboard time scales (on a basis of satellite cesium atomic clocks) of all the GLONASS satellites are synchronized with the State Etalon UTC (CIS) in Mendeleevo, Moscow region, through the [[:Category:GLONASS|GLONASS]] System Time scale.
The System Control Center (SCC) is responsible for satellite constellation control and management of [[GLONASS General Introduction|GLONASS]] satellites. It provides the telemetry, telecommand and control function for the whole [[GLONASS General Introduction|GLONASS]] satellite constellation.
The SCC coordinates all functions and operations at the system level. It processes the information from the Command and Tracking stations to determine satellite clock and orbit states, and updates the navigation message for each satellite.


==System of Differential Correction and Monitoring (SDCM)==
==Command and Tracking Stations==
Russia is advancing its plan to implement a GLONASS System of Differential Correction and Monitoring (SDCM) covering the Russian Federation. The SDCM would perform integrity monitoring of both GPS and GLONASS satellites as well as provide differential corrections and a posteriori analyses of GLONASS system performance.<ref>[http://www.insidegnss.com/node/1631 Russia Building Out GLONASS Monitoring Network, Augmentation System, InsideGNSS]</ref>
The Command and Tracking Stations are composed by a main network of five Telemetry, Tracking and Control (TT&C) stations distributed throughout the Russian territory. The CTSs track the [[GLONASS General Introduction|GLONASS]] satellites in view and accumulate ranging data and telemetry from the satellites signals. The information from CTSs is processed at the SCC to determine satellite clock and orbit states and to update the navigation message of each satellite. This updated information is transmitted to the satellites via the Upload Stations, which are also used for the transmission of control information.


The SDCM orbit constellation will consist of three geostationary satellites from the multifunctional space relay system Luch (which means “ray” or “beam” in Russian). Luch 5A, to be launched in 2011 and positioned at 16°W longitude and Luch 5B, to be launched in 2012 and positioned at 95°E longitude, will transmit signals on an L1 frequency. Luch 4, to be launched in 2013 and positioned at 167°E longitude, will transmit on two frequencies. The three satellites will provide almost global coverage.<ref>[http://www.gpsworld.com/gnss-system/glonass/innovation-glonass-11405?page_id=4 GLONASS Augmentation Development, GPS World]</ref>
==Laser Ranging Stations==
The high precision of laser ranging allows use of SLR as a single source of calibration data for GLONASS ephemeris determination, providing solution of following problems:<ref>[http://cddis.gsfc.nasa.gov/lw15/docs/papers/Russian%20Laser%20Tracking%20Network.pdf Russian Laser Tracking Network]</ref>
*Estimation of accuracy, and calibration of radio-frequency means for GLONASS orbit measurements.
*Providing SLR stations with geodetic-class RF navigation receivers connected to hydrogen maser frequency standards allows monitoring of on-board clocks and use of the data for operational control of GLONASS time and ephemeris data.
* SLR station coordinates are used as geodetic base for the GLONASS reference frame.
* SLR data are used to provide declared values of ephemeris precision.


The SDCM will make use of 12 monitor stations <ref>[http://www.navcen.uscg.gov/pdf/cgsicMeetings/50/%5B3%5DCGSIC_GLONASS_Revnivykh_20_09_2010.pdf Status and Progress,
==Central Synchronizer==
Sergey Revnivyk]</ref> currently in operation in Russia and one in Antarctica at Russia’s Bellingshausen research station. Eight more monitor stations will be added in Russia and five more outside Russia ( Cuba, Brazil, Vietnam, Australia, and Antarctica).
The Central Synchronizer implements the [[GLONASS General Introduction|GLONASS]] system time scale by means of a high-precise hydrogen atomic clock. The State Etalon UTC (CIS), in Mendeleevo, allows the synchronisation of GLONASS Cesium atomic clocks on-board satellites.
SDCM will also provide service through the Internet. A system website (www.sdcm.ru) already gives users information about real-time and a posteriori GLONASS and GPS monitoring


==Notes==
==Notes==
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<references/>
<references/>


[[Category:GLONASS|GLONASS Arquitecture]]
[[Category:GLONASS|GLONASS Architecture]]

Latest revision as of 17:16, 18 September 2014


GLONASSGLONASS
Title GLONASS Ground Segment
Edited by GMV
Level Basic
Year of Publication 2011
Logo GMV.png

The GLONASS Ground Segment (also referred to as Control Segment or Operational Control System) is the responsible for the proper operation of the GLONASS system. Like in GPS, the 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.[1]

Introduction

GLONASS Ground Segment
SLR Station in Shelkovo (near Moscow)

The GLONASS ground segment consists of:[2]

  • A System Control Centre located at Krasnoznamensk.
  • A network of five Telemetry, Tracking and Command centers (TT&C):
    • Schelkovo
    • Komsomoisk
    • St-Peteburg
    • Ussuriysk
    • Yenisseisk
  • The Central Clock situated in Schelkovo (near Moscow).
  • Three Upload Stations:
    • Yenisseisk
    • Komsomoisk
    • Schelkovo
  • Two Laser Ranging Stations (SLR):
    • Schelkovo
    • Komsomoisk
  • A network of four Monitoring and Measuring Stations:
    • Schelkovo
    • Krasnoznamensk
    • Yenisseisk
    • Komsomolsk
  • Six additional Monitoring and Measuring Stations are to start operating on the territory of the Russian Federation and the Commonwealth of Independent States in the near future:
    • Yakutsk
    • Ulan-Ude
    • Nurek
    • Vorkuta
    • Murmansk
    • Zelenchuk

System Control Centre (SCC)

The System Control Center (SCC) is responsible for satellite constellation control and management of GLONASS satellites. It provides the telemetry, telecommand and control function for the whole GLONASS satellite constellation. The SCC coordinates all functions and operations at the system level. It processes the information from the Command and Tracking stations to determine satellite clock and orbit states, and updates the navigation message for each satellite.

Command and Tracking Stations

The Command and Tracking Stations are composed by a main network of five Telemetry, Tracking and Control (TT&C) stations distributed throughout the Russian territory. The CTSs track the GLONASS satellites in view and accumulate ranging data and telemetry from the satellites signals. The information from CTSs is processed at the SCC to determine satellite clock and orbit states and to update the navigation message of each satellite. This updated information is transmitted to the satellites via the Upload Stations, which are also used for the transmission of control information.

Laser Ranging Stations

The high precision of laser ranging allows use of SLR as a single source of calibration data for GLONASS ephemeris determination, providing solution of following problems:[3]

  • Estimation of accuracy, and calibration of radio-frequency means for GLONASS orbit measurements.
  • Providing SLR stations with geodetic-class RF navigation receivers connected to hydrogen maser frequency standards allows monitoring of on-board clocks and use of the data for operational control of GLONASS time and ephemeris data.
  • SLR station coordinates are used as geodetic base for the GLONASS reference frame.
  • SLR data are used to provide declared values of ephemeris precision.

Central Synchronizer

The Central Synchronizer implements the GLONASS system time scale by means of a high-precise hydrogen atomic clock. The State Etalon UTC (CIS), in Mendeleevo, allows the synchronisation of GLONASS Cesium atomic clocks on-board satellites.

Notes

References

  1. ^ J. Sanz Subirana, JM. Juan Zornoza and M. Hernández-Pajares, Global Navigation Satellite Systems: Volume I: Fundamentals and Algorithms
  2. ^ Current and planned global and regional navigation satellite systems and satellite-based augmentation systems
  3. ^ Russian Laser Tracking Network