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Global Navigation Satellite Systems GNSS

Global Navigation Satellite Systems GNSS . About Glonass, GPS Modernization and Galileo. AE4-E08 Satellite Navigation, 14 November 2005. Hans van der Marel Delft University of Technology Faculty of Aerospace Engineering The Netherlands. Global Navigation Satellite Systems. GPS. GLONASS.

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Global Navigation Satellite Systems GNSS

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  1. Global Navigation Satellite SystemsGNSS About Glonass, GPS Modernization and Galileo AE4-E08 Satellite Navigation, 14 November 2005 • Hans van der Marel • Delft University of Technology • Faculty of Aerospace Engineering • The Netherlands

  2. Global Navigation Satellite Systems GPS GLONASS GALILEO

  3. GLO bal’nayaNA igatsionnayaS putnikovaS istema

  4. GLONASS Russian satellite navigation system positioning by measuring distances to satellites with known positions Not operational (anymore) first launch in 1982 (GPS in 1978) complete constellation in 1996 (GPS in 1993) present constellation (14) satellites (GPS 28 satellites) Modernization plan: Modernized Glonass-M and new Glonass-K next launch: 25 December 2005 (3 Satellites) 18 operational satellites in 2007 Introduction to Glonass

  5. GLONASS satellite constellation

  6. GLONASS+GPS = 44 navigation satellites >= 8 satellites @ 15+ degrees elevation (GPS >= 4 satellites) GLONASS-GPS integration (1) Situation in 1998 • Advantages • improved precision • improved reliability and integrity • more flexibility w.r.t obstructions • (positioning in cities)

  7. Visibility of satellites Delft 06/11/1998 0 deg. cut off GLONASS-GPS Integration (2)

  8. better precision for single point positioning lower update rate for DGLONASS corrections GLONASS-GPS Integration (3) No S/A with GLONASS S/A will be removed from GPS latest 2006 GPS S/A 2 may 2000 disabled No A-S with GLONASS Everybody can use GLONASS P(recise)-code

  9. Single point positioning 1000 epochs GPS 10 SVs GLONASS 7 SVs GLONASS-GPS Integration (4) S/A is still enabled for GPS

  10. Different definition of time GLONASS and GPS system time do not match GLONASS-GPS integration (problems) consequence estimate both GPS and GLONASS clock errors Different definition of reference system GLONASS and GPS reference systems do not match consequence position GLONASS system - position GPS system = deviation up to 15 m

  11. GLONASS GPS 24 satellites 24 3 orbit planes 6 64,8° inclination 55° 11h16m orbit period 11h58m GLONASS Space Segment (1) 1998

  12. GLONASS Space Segment (2) skyplot - 8 days ground tracks - 8 days GPS PRN 1 GLONASS slot 1

  13. Main task predict satellite orbits and clock behavior Components System Control Center planning and coordination of activities Phase Control System monitor satellite clocks by comparing satellite signals with system time Telemetry, Tracking and Command Stations computation of satellite orbits by radar distance measurement, communication, control segment for the satellites, monitoring of satellite signals GLONASS Control Segment (1)

  14. Telemetry, Tracking and Command stations Because of the geographic location of TT&C stations it is system integrity is difficult to maintain St. Petersburg Golitsino RUSLAND Jeniseysk Komsomolsk GLONASS Control Segment (2)

  15. GLONASS Control Segment (3) Navigation message anomaly 17-18/11/98 21:45-6:15 slot 9 TT&C St. Petersburg

  16. development of user segment GLONASS in 1993 released for international civil use “all-in-view” single frequency receivers available since 1996 “all-in-view” dual frequency receivers available since 1998 receiver manufacturers Ashtech, JPS/TPS, 3S Navigation (single & dual freq.) Novatel, MAN Technologie, Zeiss, Dasa (single freq.) GLONASS User Segment

  17. Components of GLONASS and GPS signals carrier two carriers (L1- and L2-frequency band) PRN-code bi-phase modulation two PRN-code modulations (C/A- and P-code) data modulation two types of data: satellite orbit en clock & system almanac GLONASS signal structure (1)

  18. Difference GLONASS and GPS signals carrier + PRN-code modulation also: GPS PRN-codes are transmitted with a higher chip-rate than GLONASS PRN-codes GLONASS signal structure (2) GLONASS: satellites transmit the same PRN-code on different carrier frequencies GPS: satellites transmit different PRN-codes on the same carrier frequency

  19. carrier frequencies k : channel number 1998 : k= 1 …24 >2005 : k= -7…4 (some) anti-podale satellites use the same channel GLONASS signal structure (3)

  20. using different carrier frequencies results in hardware delays that do not cancel out phase ambiguities cannot be determined directly important for relative positioning lower chip-rate for the PRN-code results in lower precision (higher standard.dev.) for the observations But, GLONASS has no S/A or A-S! GLONASS functional/stochastical model (1)

  21. (simplified) observation equations GLONASS functional/stochastical model (2) (meters) range: phase: (cycles) (meters) The term marked in red depend on the carrier frequency (channel index q)

  22. Double Difference pseudo range 3500 C/A code pseudo ranges measured on a zero baseline Double Difference : differences between receivers and satellites elimination of clock errors Zero baseline : two receivers connected to the same antenna elimination of geometry GLONASS functional/stochastical model (3)

  23. Double Difference phase 3500 phase measurements on a zero baseline mean for phase in cycles correction clock errors with clock estimates in double diff. standard deviation for phase in meters elimination clock errors in double differences GLONASS functional/stochastical model (4)

  24. International GLONASS-GPS network IGEX-98 / IGLOS (1) status June 1999 objectives precise GLONASS orbits Validation of GLONASS-GPS processing software Comparison of GLONASS-GPS receivers GLONASS-GPS coordinate transformation Monitoring of GLONASS-GPS system time differences single frequency dual frequency IGEX-98 started 19 October 1998; continued under IGS banner as IGLOS

  25. IGEX-98 / IGLOS (2) GPS/GLONASS reference station in Delft • Single frequency GPS/GLONASS receiver (Augustus 1998) • Participation in International Glonass Experiment (IGEX-98) (Sept. 1998) • Dual-frequency GPS/GLONASS receiver (since February 1999)

  26. IGEX-98 / IGLOS (3) • Integrity monitoring of IGEX-98 data • objective • gain insight in status GLONASS • comparison of GPS/GLONASS receivers • method • application of MGP’s integrity monitoring software • output:cycle slip, outlier en epoch counts & • standard deviation multipath combinations • processed data of 6 IGEX-98 stations • 3 Ashtech Z18 and 3 JPS Legacy receivers

  27. Zimmerwald Zimmerwald Onsala MacDonalds Kiruna Delft IGEX-98 / IGLOS (4) average number of L1 slips per day (1/10/98 - 18/8/99)

  28. IGEX-98 / IGLOS (5) Performance of JPS Legacy receiver function of firmware MP1=M1

  29. Global Positioning System (GPS) Modernization No Selective Availability (SA) Third frequency (L5 1176.45 MHz) Two new civil signals (C/A code on L2, L5) New military signals S/A switched off 2 may 2000

  30. GPS signal upgrade Military M-code C/A code on L2 New civil signal on L5 More signal power Backward compatibility Keep the GPS constellation healthy Ensure the right strategy to design and field the best GPS System for the user’s needs in the long term New M-Code on L1/L2 1215 1227 1239 1563 1575 Frequency (MHz) 1587 New Civil Code on L5 1176.45 MHz GPS Modernization Goals

  31. L5 L2 L1 C/A P(Y) P(Y) Present Signal C/A C/A P(Y) P(Y) New Civil General Utility Signal C/A C/A Civil Safety of Life Applications and New Military Signals M M P(Y) P(Y) 1176 MHz 1227 MHz 1575 MHz Modernized Signal Evolution

  32. GPS satellites Block I Launch: 1978-1985 In use unil: 1995 Expected life: 5 years Weight: 759 kg Block II/IIA/IIR/IIR-M Launch: 1989-2003 2007 In use until: 2014 2017 Expected life: 7.5/7.5/10 years Weight: 1660/1816/2032 kg Block IIF Launch: starting 2005 2008 In use until: ? Expected life: 15 years Weight: ?

  33. Launch schedule for GPS satellites slip in original schedule

  34. Availability of new GPS signals Three alternatives 1. Fixed launch schedule: replace working satellites 2. Double constellation (maximal 40 satellites) 3. ‘Upgrade’ Block IIR satellites with C/A code on L2 and new military codes on L1 and L2 Option 3 was chosen: First retro-fitted Block IIR (including C/A code op L2) was launched Autumn 2005 (was planned for 2003). First block IIF will be launched in 2008?

  35. Block IIR- Modified Satellites • L1 Enhancements • Increased P(Y)code power • Increased C/Acode power • New ME code at higher power than the upgraded P(Y)code • L2 Enhancements • Increased P(Y)code power • New C/A code with increased power over the current C/Acode power levels • New ME code at higher power than the upgraded P(Y)code L1 L2

  36. Block IIF Satellites • L2 Enhancements • New ME code added • C/A code added • Complete definition of all new capabilities pending detailed design decisions • L1 Enhancements • New ME code added • Complete definition of all new capabilities pending detailed design decisions L2 L1 L5 • L5 Signal • New robust Civil Signal • Two new military signals (Mearth) L1 and L2 • Two new civil signals (C/A on L2 starting with • Block IIR - Modified and new civil code on L5) • Could increase power on some of these signals

  37. Monitor Station Ground Antenna Master Control Station (Schriever AFB) GPS Operational Control Segment • Master Control Station (MCS): satellite control, system operations • Alternate Master Control Station (AMCS, Vandenberg AFB, FY04) • Monitor Station (MS): Collect range data, monitor navigation signal • NIMA Tracking Station (TS): Collect range data, monitor nav signal • Ground Antenna (GA): Transmit data/commands, collect telemetry

  38. L2 Enhancements • New ME code added • M Code Spot Beam Enhancement • 20db (-158 to -138) more power in new M-code L2 L1 L5 • L5 Signal • New Robust Civil Signal • L1 Enhancements • New ME code added COLORADO SPRINGS VANDEN- BERG CAPE CANAVERAL HAWAII KWAJALEIN ASCENSION DIEGO GARCIA GPS III Program • Involves looking at • the wholesystem • Space • Control • User Equipment

  39. www.galileo-pgm.org

  40. The 4 GALILEO arguments - European independence and sovereignty - Industrial politics Political Technological Social - Better and new services for the citizens - Improved safety of transport systems - Environmental benefits - Technological lead to European industry - Explore synergy of a number of technologies Economic - Global market shares - Global competitiveness of all segments of the Value Chain - Employment - Efficiency of transport industry

  41. GALILEO for the benefits of the Citizens Better public services Emergency Response time to be reduced by 50% 14% increased chance of survival - “911” service integrated in mobile phones - On-line Public Traffic information - Improved traffic capacity (air, train, etc) - Improved Search & Rescue Transportation time to be reduced by 35% New integrated services (mass market) - Advanced In-Car navigation systems, incl. Interactive traffic and journey planners - Seamless road tolling systems - Personal tracking systems (children, disabled, VIP’s) Direct fuel consumption to be reduces by 25% CO2 emission by a similar rate New professional services - Fleet management services (trucks, taxis, ambulance, etc) - Aviation free routing systems Reduce travel time by 5-10% (each 1% worth €500)

  42. Service Definition Study Early conclusions MARKET SIZES • Transport Networks and Safety of Life Applications. These markets look promising and should attract support. • Fleet Management (including aviation). This market looks promising, especially in remote areas, across borders for hazardous goods tracking. • Survey / Professional. A well established and tough market – individual niches are small and very price sensitive. • Personal / Road. A tough market because integration with GSM/UMTS could give enhanced performance in urban areas. In such a big market even a small share (such as rural road or personal emergency systems) may be interesting.

  43. Service Definition from Application Performance ·Position, Velocity and Time service (PVT) – Free of charge, is aimed at the mass market applications. ·Accuracy and Integrity service (AI) – High accuracy and availability for less demanding safety of life users and professional markets. The service is intended for subscribed users only. ·Ranging and Timing service (RT) – This service provides very precise ranging, positioning and timing signals for the knowledgeable professional. Again this service is intended for subscribed users only. ·High Integrity service (HI) – This service provides the highest integrity, availability, continuity and resistance to signal interference. This service is suitable for demanding safety of life markets, restricted to trusted subscribers.

  44. GALILEO Services Navigation Services Open Access Service (OS) Consumer market, e.g. car navigation systems Commercial Service (CS) Commercial and Professional applications (geodesy) Improved accuracy (3 frequencies) and integrity Public Regulated Service (PRS) “Safety of life” services (SAS) Govermental services (PRS) Free Not Free! Financed by government and industry - Public Private Partnership (PPP)

  45. Under control of civilian authorities Technological improvements New technology (improved signals) More frequencies and signals More ground stations for tracking and orbit determination Better choice of satellite orbits Integrity service for “safety of life” applications Integration (“interoperable”) with GPS combined GPS and Galileo receivers twice the number of satellites  this is the probably the single most important contribution to accuracy and reliability Galileo added value

  46. Galileo status GIOVE-A • Official go-ahead on 26 March 2002 • Galileo System Test Bed (GSTB-V1) delivered in 2004 • Implementation Galileo ground segment using GPS satellites • 10x better than GPS • First experimental satellite in 2005 (GSTB-V2) Launch 28 Dec 2005 • First four “operational” satellites in 2006-2007 (IOV) • Operational in 2009-2010 (officially 2008) • EGNOS (GPS/GLONASS Integrity Service) on geostationairy satellites • EGNOS operational in 2005 (slight delay; wind-up, operational 2006) • EGNOS integrated with GALILEO starting 2008 (GEO service available until 2015)

  47. GNSS frequency allocations From G.W. Hein et al., The GALILEO Frequency Structure and Signal Design

  48. GPS Signals

  49. GALILEO Signals

  50. Linear combinations (GPS) Ionosphere free Ionosphere

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