Introduction to glonass, march 2009

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Kees de Jong'sintroductie over GLONASS en de stand van zaken

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Introduction to glonass, march 2009

  1. 1. Introduction to Glonass Kees de Jong, Fugro Intersite B.V., Leidschendam March 2009www.fugro.com
  2. 2. ContentsGlobal’naya Navigatsionnaya Sputnikovaya SistemaGlobal Navigation Satellite System • History • System • Signals • Augmentation • Performancewww.fugro.com
  3. 3. History • Development started by Soviet Union in 1960’s-1970’s • Successor of Tsikada • First launch 1982 • Full constellation (24 satellites) in 1996 Tsikada satellitewww.fugro.com
  4. 4. History United States • Development started by Soviet Union in 1960’s-1970’s • Successor to Tsikada Transit • First launch 1982 1978 • Full constellation (24 satellites) in 1996 1994 Transit Tsikada satellitewww.fugro.com
  5. 5. Glonass system components Ground control Orbit Launchers segment constellation Spacecraft Glonass Proton control Orbit Glonass-M Soyuz determination Time Glonass-K synchronizationwww.fugro.com
  6. 6. Ground control segment SCC System Control Center TT&C Telemetry, Tracking & Commanding station ULS Uplink Station MS Monitoring Station CC Central Clock SLR Satellite Laser Ranging stationwww.fugro.com
  7. 7. Satellites • Glonass (one operational satellite) • Glonass-M (19 operational satellites) • Glonass-K (from 2010 onwards)Status March 2009 www.fugro.com
  8. 8. Satellite launches • Recent – September 2008 – December 2008 • Near future – September 2009 – December 2009 Three satellites per launchwww.fugro.com
  9. 9. Constellation age 70 60 50 Age (months) 40 30 20 10 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Satellite Glonass Glonass-MStatus March 2009 www.fugro.com
  10. 10. Satellite constellation 120° 120° 135° 6 14 22 - Not available - Available 90° 7 15 23 45° 8 16 24 0° 1 9 17 315° 2 10 18 270° 3 11 19 225° 4 12 20 64.8° 64.8° 64.8° 180° 5 13 21 Latitude Plane I Plane II Plane IIIStatus March 2009 www.fugro.com
  11. 11. Orbital characteristics System Glonass GPS Number of satellites 24 30+ Number of orbital planes 3 6 Semi-major axis 25500 km 26550 km Eccentricity < 0.01 < 0.01 Inclination 64.8° 55° Period of revolution 11h16m 11h58m Repeat period 8 days 1 daywww.fugro.com
  12. 12. Satellite orbits (1) Glonass Glonass GPS GPS North North 0 0 30 30 60 60 West East West East 90 60 30 0 90 60 30 0 South South One satellite, eight consecutive dayswww.fugro.com
  13. 13. Satellite orbits (2) Glonass Glonass North 0 30 60 West East 90 60 30 0 South Two adjacent satellites, three consecutive dayswww.fugro.com
  14. 14. Signals – carriers • Nominal carrier frequencies – L1: 1602 MHz (GPS: 1575.42 MHz) – L2: 1246 MHz (GPS: 1227.60 MHz) • Satellite specific frequencies – L1k = L1 + k×0.5625 MHz k = -7…13 – L2k = L2 + k×0.4375 MHz Note: L1k/ L2k = 9/7 for all kwww.fugro.com
  15. 15. GNSS spectrum Glonass Galileo GPS (L3) L2 L1 E5a E5b E6 E1 L5 L2 L1Frequency (MHz) 16 15 12 12 11 12 12 02 75 78 46 76 27 07 .4 .7 .4 .6 .1 2 5 5 4www.fugro.com
  16. 16. Signals – codes Glonass GPS C/A code Frequency 0.511 MHz 1.023 MHz Chip length 587 m 293 m P-code Frequency 5.11 MHz 10.23 MHz Chip length 59 m 29 m Modulation scheme FDMA CDMAFDMA - Frequency Division Multiple Access (Glonass: same code for all satellites, different frequencies)CDMA - Code Division Multiple Access (GPS: different codes for all satellites, same frequencies) www.fugro.com
  17. 17. Signals – navigation message Glonass GPS Orbit Position, velocity, Keplerian elements acceleration at and corrections at reference time at reference time Clock Clock offset and Clock offset, drift drift at reference and drift rate at time reference time Update period 30 minutes Two hours Almanac Keplerian elements Keplerian elementswww.fugro.com
  18. 18. Differential corrections and integrity • SDCM – System of Differential Correction and Monitoring • Similar to – WAAS (USA) – EGNOS (Europe) – MSAS (Japan) – GAGAN (India)www.fugro.com
  19. 19. SDCM – principle of operationwww.fugro.com
  20. 20. SDCM – characteristics • Service area – Russian Federation • Real-time differential positioning – Code • Horizontal positioning accuracy 1-1.5 m • Vertical positioning accuracy 2-3 m – Carrier • Horizontal positioning accuracy 0.01-0.02 m • Vertical positioning accuracy 0.04-0.06 m • GNSS monitoring – Real-time integrity monitoring – A posteriori system performance evaluation • Two geostationary satelliteswww.fugro.com
  21. 21. SDCM – reference stationswww.fugro.com
  22. 22. Modernization • New (Glonass-K) satellites (from 2010 onwards) • More satellites (30, probably not before 2015) • Improved accuracy • Modernized ground control segment • New signals: – L3 (1201-1212 MHz, to be defined (Galileo E5b 1207.14 MHz)) – CDMA (on first Glonass-K demonstration satellite in 2010) • Interoperability with GPS and Galileo Glonass-K satellitewww.fugro.com
  23. 23. Availability of signalsL1OF – L1 Open FDMAL2OF – L2 Open FDMA www.fugro.com
  24. 24. Recent accomplishments • New geodetic datum – Change from PZ90 to PZ90.02 in September 2007 – PZ90.02, differences with ITRS less than 0.5 m • User range accuracy – ICD 3.7 m – Actual 1.8 • Clock stability – 10-13 s/sICD – Interface Control Document www.fugro.com
  25. 25. Example of current geometry PDOPwww.fugro.com
  26. 26. GPS/Glonass reference stations Fugro’s G2 network, 40+ GPS/Glonass reference stationswww.fugro.com
  27. 27. Fugro G2 GPS/Glonass positioning service • Real-time GPS/Glonass orbit and clock corrections – Accuracy better than 0.15 m • Precise Point Positioning (PPP) – Global accuracy 0.1 – 0.2 m • Combined GPS/Glonass solution – Improved reliability – Increased availabilitywww.fugro.com
  28. 28. www.fugro.com Number of satellites 0 5 10 15 20 25 0:00:00.0 1:00:00.0 2:00:00.0 3:00:00.0 4:00:00.0 5:00:00.0 6:00:00.0 7:00:00.0 8:00:00.0 9:00:00.0 10:00:00.0 11:00:00.0 GPS 12:00:00.0 13:00:00.0 14:00:00.0 Glonass 15:00:00.0 16:00:00.0 17:00:00.0 18:00:00.0 19:00:00.0 Delft, Netherlands, March 2009 20:00:00.0 21:00:00.0 22:00:00.0 23:00:00.0 Increased availability
  29. 29. Error (m) -5 -4 -3 -2 -1 0 1 2 3 4 10:30:00.0 5 10:45:00.0 Z Y X 11:00:00.0www.fugro.com 11:15:00.0 Clock 11:30:00.0 Satellite 2 11:45:00.0 12:00:00.0 -0.3 4.9 0.1 -2.4 12:15:00.0 12:30:00.0 Mean (m) Clock 12:45:00.0 X 13:00:00.0 13:15:00.0 Y 5.8 1.4 3.6 3.0 13:30:00.0 Z 13:45:00.0 RMS (m) 14:00:00.0 14:15:00.0 14:30:00.0 Error (m) 14:45:00.0 -15 -12 -9 -6 -3 0 3 6 9 12 15 15:00:00.0 10:30:00.0 15:15:00.0 10:45:00.0 11:00:00.0 11:15:00.0 11:30:00.0 Z Y X 11:45:00.0 12:00:00.0 Clock 12:15:00.0 12:30:00.0 Clock 12:45:00.0 -3.1 0.9 -2.6 1.5 X 13:00:00.0 13:15:00.0 Mean (m) Y 13:30:00.0 Z 13:45:00.0 14:00:00.0 1.6 0.7 0.7 0.5 14:15:00.0 RMS (m) 14:30:00.0 14:45:00.0 15:00:00.0 Broadcast clock and orbit errors Satellite 24 15:15:00.0
  30. 30. G2 PPP GPS onlywww.fugro.com
  31. 31. G2 PPP GPS and Glonasswww.fugro.com
  32. 32. G2 PPP Glonass onlywww.fugro.com
  33. 33. Resources • Russian Space Agency, status and ICD – http://www.glonass-ianc.rsa.ru • Trimble GPS/Glonass almanacs – ftp://ftp.trimble.com/pub/eph/almanac.alm • University of New Brunswick, constellation – http://gge.unb.ca/Resources/GLONASSConstellationStatus.txt • Wikipedia, general information – http://en.wikipedia.org/wiki/Glonasswww.fugro.com

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