Position measuring systems
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Position measuring systems Presentation Transcript

  • 1. Typical DP system sensors DGPS COMPUTER CYSCAN SURFACE POSITION MEASURING SYSTEM TAUTWIRE POSITION MEASURING SYSTEM ACOUSTIC POSITION MEASURING SYSTEM ACOUSTIC WEIGHT BEACON
  • 2. Taut Wire
  • 3. Artemis
  • 4. Artemis ANTENNA LOCKED RANGEAZIMUTH BEARING
  • 5. Fixed Station - Calibration North North Visual reference point A Telescope, mounted on top of the fixed antenna, is used FIX
  • 6. Range and bearing measurements North Azimuth North MOB Azimuth DistanceFIX True bearing = Azimuth + 180°
  • 7. Heading presented on the EOP North Azimuth North Heading MOB Azimuth Distance Relative Mobile Antenna Bearing FIX Heading = Azimuth + 180° - Relative Mobile Antenna Bearing
  • 8. Artemis beacon ARTEMIS BEACON BASE POSITION ARTEMIS ARTEMIS BEACON MOBILE ANTENNA ARTEMIS MICROWAVE LINK THE BEACON IS SIMPLY A TRANSPONDER. NO BEARING DATA TRANSMITTEDOFFSHORE LOADING BEARING MEASURED SHUTTLE TANKER TERMINAL WITH AT MOBILE ANTENNA DURING APPROACHROTATING TURNTABLE TELEMETRY LINK ALLOWS TURNTABLE AZIMUTH TO BE TRANSMITTED TO THE VESSEL SUCH THAT BEACON OFFSET CAN BE COMPENSATED FOR, CORRECTING THE RANGE TO THE BASE LOCATION
  • 9. Range and bearingmeasurements - Beacon North Gyro MOB Distance Relative Mobile Antenna BearingBeacon True Bearing = Gyro + Relative Mobile Antenna Bearing
  • 10. Dip Zones AT SPECIFIC RANGES, THE DIRECT LINK WILL INTERFERE WITH THE SURFACE REFLECTED SIGNAL CAUSING LOSS OF SIGNALFIXED ANTENNA DIRECT MICROWAVE LINK REFLECTED LINK
  • 11. Dip ZonesPRODUCTH1 x H2 800H1 = 6000 10000 14000 18000 22000 26000 30000Mobile 700antennaheightH2 = 600Fixedantennaheight 500 DIP 400 ZONES 300 6000 10000 14000 18000 22000 26000 30000 DISTANCE (metres)
  • 12. Vertical beamwidth ARTEMIS FIXED STATION MOBILE ARTEMIS ANTENNAMOBILE AND FIXED ARTEMIS LOST DUE ARTEMIS ACQUIREDANTENNAE AT TO VERTICAL BEAMWIDTH NORMALLY AT AT CLOSE RANGE LONG RANGEDIFFERENT HEIGHTS
  • 13. Artemis alarms, warning and messages on the SDP: Artemis basic unit timeout Artemis system communication error Artemis system out of range Artemis system telegram error
  • 14. Accuracy and specification: Distance accuracy = 1m Azimuth accuracy = 0.02° Beacon accuracy = using gyro accuracy = approximately: 0.5°
  • 15. Artemis - advantages and disadvantages Advantages: • Long range system - compared with HPR, Fanbeam, LTW • High accuracy Disadvantages: • Affected by heavy rain and snow in same way as a radar • Line of sight problems • Interference from 3 cm radar • Requires personnel to set up the fix station
  • 16. More users at one siteSystem1:Pair “0” = Mobile 9200 - Fix 9230 orPair “2” = Mobile 9230 - Fix 9200System 2:Pair “1” = Mobile 9300 - Fix 9270 orPair “3” = Mobile 9270 - Fix 9300
  • 17. More users at one site
  • 18. GPS FundamentalsGPS & GLONASS Specifications GPS GLONASSNumber of Satellites 24 24Number of Orbital Planes 6 3Satellites Per Plane 4 8Orbital Inclination 55 deg. 64.8 deg.Orbital Radius 26.560 km 25.510 kmOrbital Period 11h 58m 11h 15mL1 Frequency 1575.42 MHz 1602+K*9/16 K=[-7,24] MHzL2 Frequency 1227.60 MHz 1246+K*7/16 K=[-7,24] MHzTime Reference UTC UTC (US Naval Observatory) (Sovjet Union)Geodetic Datum WGS 84 PZ-90The number of available GPS satellites varies around 27-29 due to longer lifetimethan expected. The GLONASS satellite service has not been able to provide acomplete constellation due to lack of satellite replacements and fundings.
  • 19. GPS Navigation Global Positioning System US DoD system 21 +3 satellites Satellite Altitude of 20,200 km Orbit Separation of 60 degrees 6 Orbit Planes 12 hour Satellite Orbit 2 frequencies – C/A code and P-code
  • 20. FOUR SIX SATELLITESORBITS PER ORBIT FOUR SATELLITES IN VIEW
  • 21. Signal division FDMA – Frequency Division Multiple Access TDMA – Time Division Multiple Access CDMA – Code Division Multiple Access FDMA-CDMA – Frequency + Code Division Multiple Access
  • 22. GPS Pseudo-Range Orbital Satellite clock Ionospheric TroposphericReceiver clock Multipath, receiver noise, antenna setup
  • 23. The Atomicclock from thesatellite iscomparedwith the clock Orbitalonboard or at Satellite clockthe referencestation, thisproduces the Ionosphericpseudo range Troposphericfrom which a Receiver clock Multipath, receiver noise, antenna setupposition iscalculated.
  • 24. GPS position computation
  • 25. Basic Principles of Positioning with GPS
  • 26. Basic Principles of Positioning with GPS
  • 27. GPS AccuraсyDepends on: Satellite Constellation Geometry Satellite Orbit Atmospheric Path Propagation Clock Stability Multipath Signals Selective Availability
  • 28. GPS Fundamentals Good DOP Good DOP is when the intersection between ranges from two (or several) satellites are perpendicular or particularly well defined.The intersection area Satellite(A-B-C-D) is the area B rangewhere it is mostpropable that theposition solution lies A Cwithin. UERE UERE D Satellite range footprint
  • 29. GPS Fundamentals Poor DOPPoor DOP is when theintersection between rangesfrom two (or several)satellites are notperpendicular orparticularly well defined. SatelliteThe intersection area (A-B- rangeC-D) is the area where it ismost propable that theposition solution lies within. B A C UERE Satellite range footprint UERE D
  • 30. GPS Fundamentals Good & Poor DOPBulls eye plot of satellites in the sky Elevation Mask (10 degrees) Good Dilution of Precision Poor Dilution of Precision
  • 31. GPS Fundamentals How Positions are ComputedPosition accuracy is a function of how accurate ranges to theindividual satellites can be determined and how well thesatellites are distributed on the sky. Position accuracy = UERE * DOP Satellite range UERE UERE
  • 32. GPS Fundamentals Computed Position Accuracy Estimated SPS C/A-Code Pseudorange Error Budget GPSSegment Source Error Source 1 sigma Error (m)Space Satellite clock stability 3,0 Satellite perturbations 1,0 Selective Availability - Other 0,5Control Ephemeris prediction error 4,2 Other 0,9User Ionospheric delay 5,0 Tropospheric delay 1,5 Receiver noise & resolution 1,5 Multipath 2,5 Other 0,5System UERE total (rss) 8,0Actual HDOP 1,0Position Accuracy (2-D, 67%) 8,0Position Accuracy (2-D, 95%) 16,0
  • 33. GPS Fundamentals Computed Position AccuracyA reported position with 16 m (95% CEP)accuracy number 16 m (95%CEP) means that there is a 95%probability that the nexthorizontal position will beinside a circle with radius 16meters.
  • 34. DOP - Dilution of Precision
  • 35. Acronym Type Position Component(s) GDOP Geometric 3D position & time PDOP Positional 3D position HDOP Horizontal 2D horizontal position VDOP Vertical 1D heightPoor Geometry (High DOP number) Good Geometry (Low DOP number)
  • 36. GPS Satellite
  • 37. Monitor Stations Colorado Springs Diego GarciaHawaii Kwajalein Ascension
  • 38. GPS Error Sources
  • 39. Selective Availability Deliberate Degradation of GPS Signals by DoD Affects SPS Service – Accuracy Reduced from 20m to 100m drms • Errors Due To – clock bias
  • 40. Reduction of GPS Position ErrorA period from 01/05/2000 till 02/05/2000
  • 41. Satellite NavigationSystem ”GLONASS”  24 satellites  3 Orbits  Orbit Height 19100 КМ  Inclination 64,8 °  Period: 11,26 hours
  • 42. GLONASS’s SatelliteMain GLONASS satellite characteristics: Weight – about 1300 kg; Diametre – 2,35; Length overall – 7,84m; Width overall (with sun batteries ) -7,23m; Data transfer speed on navigational channel – 50bit/sec; Received signal power - -156/-161 dBWt
  • 43. GLONASS System Current State according to Almanac data Number of GLONASS satellites/ coverage area №/ plane 01 02 03 04 05 06 07 08 I - + + + + - + + II - - - - - - - - III + + - - + + + +
  • 44. КНС ГЛОНАСС на 16.10.2007| Пл-ть 1/точка | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 || Номер частоты | 07 | -- | -- | 06 | -- | 01 | 05 | 06 ||---------------- |----|----|----|----|----|----|----|----|| Пл-ть 2/точка | 09 | 10 | 11 | 12 | 13 | 14 | 15 | 16 || Номер частоты | -- | 04 | -- | -- | -- | 04 | 00 | -- ||---------------- |----|----|----|----|----|----|----|----|| Пл-ть 3/точка | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 || Номер частоты | -- | -- | -- | -- | 08 | -- | -- | -- |
  • 45. GPS System Current State according to Almanac data Number of GPS satellites/ coverage area№ / plane I II III IV V VI 1 + + + + + + 2 + + + + + + 3 + + + + + + 4 + + + + + + 5 + + + + + +
  • 46. > 4 SV are visibleVisibility of SV 1-24
  • 47. Coverage areafor GLONASSwith not less than4 SV visible
  • 48. Availabilityof GLONASS
  • 49. Federal State Program fordevelopment of globalnavigation system
  • 50. GLONASS system structure
  • 51. Plan of satellite replenishmentfor GLONASS
  • 52. Growth of GLONASS users
  • 53. Galileo 30 Satellites at an Altitude of 23000 Kilometres Accurate Survey References for Roads & Bridges Available by 2010 Will Supply Real Time Data
  • 54. How it works It will be a civil system GPS accuracy is about 30 metres Galileo accuracy within 1 metre No correction signal is required Interoperable with GPS and Glonass
  • 55. 28.12.2005 GALILEO, Europe’s global satellite navigation system is now a concrete reality. Today, the 600-Kilogram GIOVE-A satellite, manufactured by the British company Surrey Satellite Technology Limited, was placed in a 23,222 kilometres orbit by a Soyuz rocket from the Baikonur cosmodrome in Kazakhstan. The GIOVE mission (Galileo In-Orbit Validation Element) comprises 2 satellites (GIOVE-A and B). GIOVE tests critical new technologies (such as the on-board atomic clocks, signal generator and user receivers) and validates the new features of the Galileo signal design, characterises the radiation environment of the Medium Earth Orbits (MEOs) planned for the Galileo satellites and secures access to the Galileo frequencies allocated by the International Telecommunications Union.
  • 56. 27.04.2008 A further step towards the deployment of Europes Galileo global navigation satellite system was taken tonight, with the successful launch of ESAs second Galileo In-Orbit Validation Element (GIOVE-B) satellite, carrying the most accurate atomic clock ever flown into space. The GIOVE-B satellite was lofted into a medium altitude orbit around the earth by a Soyuz/Fregat rocket departing from the Baikonur cosmodrome in Kazakhstan by launch operator Starsem. Lift-off occurred at 04:16 local time on 27 April (00:16 Central European Summer Time).
  • 57.  This 500 kg satellite was built by a European industrial team led by Astrium GmbH, with Thales Alenia Space performing integration and testing in Rome. Two years after the highly successful GIOVE-A mission, this latest satellite will continue the demonstration of critical technologies for the navigation payload of future operational Galileo satellites. Like its predecessor, GIOVE-B carries two redundant small-size rubidium atomic clocks, each with a stability of 10 nanoseconds per day. But it also features an even more accurate payload: the Passive Hydrogen Maser (PHM), with stability better than 1 nanosecond per day. The first of its kind ever to be launched into space, this is now the most stable clock operating in earth orbit.
  • 58. GALILEO
  • 59. The Modernized L2 Civil SignalAfter years of preparation, modernization called for: implementing military (M) code on the L1 and L2 frequencies for the Department of Defense (DoD) providing a new L5 frequency in an aeronautical radio navigation service (ARNS) band with a signal structure designed to enhance aviation applications adding the C/A code to L2.Implementation was underway when the System Program Director for the GPS Joint Program Office (JPO) asked whether it was wise simply to replicate the 20th-century C/A code in a 21st-century “modernized” GPS. Responding to this challenge, a truly modern L2 civil (L2C) signal was designed in a remarkably short time to meet a much wider range of applications. The first launch of a Block IIR-M satellite in 2003 will carry the new signal, as will all subsequent GPS satellites. As a result, civil GPS product designers eventually will have at least three rather different types of GPS signals to choose from. It also would be desirable for GPS III to add a modern civil signal to L1, further increasing the number of design choices. Depending on the application, designers will be able to select signals based on power, center frequency, code clock rate, signal bandwidth, code length, correlation properties, threshold performance, interference protection, and so on.
  • 60. The Modernized L2 Civil Signal
  • 61. DGPS system Configuration WGS 84 REF POSITION CO RR SIG ECTIO NA N L REFERENCE STATION WGS 84 REF POSITION
  • 62. Relative DGPS, DARPS- Differential and Relative Positioning Dif fe o n r e nt ne i ctio al n UHF LINKS SHUTTLE TANKER FPSO
  • 63. Sky Fix System Overview
  • 64. Why DGPS for DP Vessels Globally available 24 hours/day Not limited by geographic location Not effected by weather, e.g. Radio Nav Performance independent of water depth Acoustics Not effected by dynamic motion e.g. Taut Wire Weights Acoustic Interference – Thruster Wash
  • 65. What is DGPS• Basic Concept• Observe all satellites at fixed reference station• Reference station position is known very accurately• Reference station measures PR to all satellites• Satellites broadcast their positions in message• Reference station compares observed and calculated PR• Assumes all errors are range errors• Computes and transmits DGPS correction signals
  • 66. DGPS NetworksDefined by: Single Reference Station Solutions Multi-Reference Station Solutions Multi-Reference Station Network Solutions – also termed VBS (Virtual Base Station) Correction Message Data Link: • MF • HF • UHF/VHF • Inmarsat A/B/M • Eutelsat/Spot
  • 67. DGPS Configurations Direct Injection Solution COMMUNICATION DGPS DGPS ON-LINE RECEIVER DEMODULATOR RECEIVER NAVIGATOR
  • 68. DGPS Configurations Multi-Ref DGPS Solution COMMUNICATION DGPS DGPS ON-LINE RECEIVER DEMODULATOR MULTI-REF NAVIGATOR PROCESSOR DGPS RECEIVER
  • 69. 6 World-Wide Coverage
  • 70. DGPS North Sea
  • 71. DGPS Gulf of Mexico
  • 72. FANBEAMRANGE BEARING
  • 73. FANBEAM
  • 74. Fun beam screen
  • 75. AC IMPUT 28V POWER SUPPLY POWER CABLE DECK CABLE CURRENT LOOPFANBEAM CONVERTOR OR UCU TO DP CONSOLE OR SEISMIC SOFTWARE
  • 76. CyScan Positioning System BASELINE
  • 77. CyScan2nd Generation Marine Navigation Sensor Position Measurement • Autonomous Vehicles • Laser Scanners • Sensor and Control Systems • Electronic Tagging
  • 78. CyScan System Overview New MkII released 2001 Overview • High Precision and Repeatability Company Powerful Rotating Pulsed Ranging Laser • Single Target Operation Operation Position and Heading from 2+ Targets • Automatic Wave Motion Compensation Applications • Automatic Elevation Tracking Special Sophisticated Robust Target Tracking Features • Practical Tips • New HMI
  • 79. CyScan Who is Who ? Overview Design & Manufacture • Company • Guidance Control Systems Ltd Operation • Applications • Sales & Marketing Special Features • Practical Tips • New HMI
  • 80. CyScan How does it work (1) ? Continuously Rotating Fanned Laser Head Measures Overview Target Bearing, Range, Width etc... • Company • Operation • Applications • Special Features • Practical Tips • New HMI
  • 81. CyScan How does it work (2) ? Overview Laser Beam Fanned in Two Axes • Company Impact Resistant Glass Fibre • Body Operation • Applications RS485 Data Links • Special Features Stabilized Levelling Platform for Wave Motion Compensation • and Elevation Tracking Practical Tips • Flat, Cylinder or Prism Reflectors New HMI
  • 82. CyScanSimple Installation Overview • Company • Operation • Applications • Special Features • Practical Tips • New HMI
  • 83. CyScan Possible Application Areas Overview Flotels & Support Vessels • Company • Shuttle Tankers Operation • Supply Vessels Applications • Special Cable Laying Features • Practical Tips Diving Vessels • New HMI Power Conversion/CYSCAN ™/PE 106
  • 84. CyScan Special Competitive Features (1) Single Target Mode Position Feedback Overview • 2+ Targets Position & Heating Feedback Company • Operation • Applications • Special Features • Practical Tips • Power Conversion/CYSCAN ™/PE New HMI
  • 85. CyScan Special Competitive Features (2) Dynamic wave motion compensation/built-in VRU Overview Elevation tracking for draft change compensation • Company Low cost and maintenance/cheap passive targets • Interfaces easily to modern DP systems Operation High immunity to ambient or bright lights • Survives temporary obstruction of one or more targets Applications • Ignores spurious or erroneous reflections Special Features High accuracy and repeatability • High modularity for easy servicing and swap out of replacements Practical Tips • New HMI 108
  • 86. CyScan How does it work in practice ? Irregular Target Spacing Overview • Blind Zone (Software Configurable) Company •  Operation •  Applications • Special Features • Practical Tips • New HMI 109
  • 87. CyScan Overview • Company • Operation • Applications • Special Features • Practical Tips • New HMI
  • 88. CyScan2nd Generation Marine Navigation System Position Measurement • Autonomous Vehicles • Laser Scanners • Sensor and Control Systems • Electronic Tagging