Multi-GNSS Future: GPS, GLONASS, Galileo, BeiDou,

Transcription

1 Sogei Workshop GNSS Technology Advances in a Multi-Constellation Framework Rome, April 22-23, 2013 Multi-GNSS Future: GPS, GLONASS, Galileo, BeiDou, Pratap Misra Source: International Committee on GNSS (ICG)

2 GNSS Global Satellite Navigation System Originally defined by the International Civil Aviation Organization (ICAO) as: a worldwide position and time determination system that includes one or more satellite constellations, aircraft receivers and system integrity monitoring, augmented as necessary to support the required navigation performance for the intended operation GNSS = a satellite navigation system All GNSSs follow the GPS model 2013 Pratap Misra 2

3 Multi-GNSS Future* Outline Why Do We Need So Many Systems? GNSSs Under Development: Global Systems: GPS III, GLONASS, Galileo, & BeiDou Regional Systems: Japan s QZSS, India s IRNSS Regional Augmentations: US WAAS, NDGPS; Europe s EGNOS; Japan s MSAS; Russia s SDCM; India s GAGAN Coexistence: Compatibility Cooperation: Interoperability Competition: Who will be Number 1? 2013 Pratap Misra * Opinions of the author alone 3

4 GNSS Status 75 working satellites in early 2013 GPS: 31 GLONASS: 24 Galileo: 4 BeiDou: Launches Scheduled in 2013: 2 GPS IIFs; 2 Galileo; 1 GLONASS-K Only GPS is operational and in > 1 billion mobile devices market expected to grow to 5 billion 4 operational systems with 120 satellites in 2020 Source: ICG-7 presentation by Dr. Lu Xiaochun 2013 Pratap Misra 4

5 It s Not Just About Navigation, It s About Economics & Politics Sovereignty National Pride Markets & International Trade Source: ICG Brand Building, Consumer Confidence Standards & Certification Intellectual Property & Patents Military Use & National Security 2013 Pratap Misra 5

6 GNSS Users Perspective Source: GPS SPS PS,

7 Accuracy Performance Metrics My System is Better than Yours Availability of Service Integrity (or Reliability) Can I count on my position estimate to be correct? Robustness Can the system withstand small disturbances? Security Challenge: Deliver service like a utility: water or power supply Rigorous, constant maintenance: No screw ups! 2013 Pratap Misra 7

8 GPS has Set High Standards Delivers a lot more than promised Near flawless performance over 20 years Made it Look Easy A Victim of its Own Success? Satellites last for ever, no screw-ups No urgency in Washington re budgets? Success Breeds Imitators Can GPS Remain #1? Remains to be seen: The race is GPS to lose Not sitting still 2013 Pratap Misra 8

9 GPS Modernization GPS III satellite Source: Lockheed Space Segment Cross links among satellites, flexible power, spot beam, integrity monitoring Additional, more capable military signals: M-code on L1 and L2 Additional, more capable civil signals: L2C, L5, L1C Control Segment Block II OCS OCX to fly new spacecraft Distributed architecture, security User Segment MGUE (Mil. GPS User Equip t): Enhanced A-J, A-S, A-T New security architecture: SAASM Pronav New paradigm: from form-fit military receivers to GPS chipsets 2013 Pratap Misra 9

10 GPS Signal Modernization Civil Signal (Starting 2010) MHz (L5) MHz (L1) C/A Code Civil Use Degraded (2 May 2000) MHz (L2) P(Y) Code Encrypted L1C (2014) P(Y) Code Encrypted M-Code (Starting 2005) L2C-Code (Starting 2005) M-Code (Starting 2005) Misra

11 Direct Sequence Spread Spectrum T 0 carrier T c spread spectrum waveform = T d data waveform modulated spread spectrum signal f 0 = 1/T 0 = carrier frequency (Hz) R c = 1/T c = chipping rate (chips/s) R d = 1/T d = data rate (bits/s) 11 Source: Dr. Chris Hegarty, MITRE

12 Binary Offset Carrier Modulation Carrier = F sq = 1/T sq = subcarrier frequency (Hz) T sq Spreading code Square wave Data BOC signal* *Shown at baseband (i.e., without carrier) Source: Dr. Chris Hegarty, MITRE 12

13 Evolution of GPS Signals P(Y) C/A P(Y) Block II / IIA / IIR M L2C M Block IIR-M Starting in 2005 Block IIF Starting in MHz L MHz MHz L2 L1 13

14 > $1b award to LMC in 2008 > $1b award to Raytheon in

15 15

16 Global naya Navigatsionnaya Sputnikovaya Sistema GLONASS History Developed by Soviet Union, first launch: 1982 Declined under Russia, but now revived Have launched 81 satellites so far Constellation 24 satellites in 3 orbital planes, 64.8º inclination 19,100 km altitude, 11 ¼ hour period Signals 3 allocated bands: G1 (1602 MHz), G2: (1245 MHz), G3 (1202 MHz) C/A-like code: 511 chips, 1 ms code period, 50 bps data All SVs use same PRN with frequency division multiple access (FDMA) using 16 frequency channels, reused for antipodal SVs 2013 Pratap Misra GLONASS Constellation Source: ROSCOSMOS 16

17 Soviet-built GLONASS Aviation Receiver & Tool box (circa 1990) ASN-16 17

18 GLONASS Status & Plans GLONASS-K GLONASS-M 24 working satellites in 2013 New satellites GLONASS-K and GLONASS K2 under development CDMA signal planned No significant user base Source: ROSCOSMOS 2013 Pratap Misra 18

19 Galileo Jointly financed by EC and ESA Seen as a civil system, but military role may emerge 5 Services being considered Free: Open Service For a Fee : Commercial Service Safety-of-Life Service Public Regulated Service Search & Rescue Service Source: ESA 30 MEOs in 3 planes inclined at 56 First experimental satellite launched in

20 Galileo Status & Plans 4 in-orbit validation (IOV) satellites (launched in 2011 & 2012) Ground infrastructure (monitor stations & control centers) capable of generating navigation messages First 3-D positioning demonstrated at ESTEC (March 12, 2013) Plans First full-operational capability (FOC) satellites to be launched in FOCs in orbit in 2014 Budget of 7.9 billion for deployment & exploitation ( ) under discussion Source: ESA 2013 Pratap Misra 20

21 Etymology of BeiDou BeiDou ( 北斗 )* Bei: North/Northern Dou: a traditional Chinese container used for measuring grain by volume BeiDou: Big Dipper constellation Ladle Butcher s cleaver Drinking gourd Coffin & mourners Charles wain *Courtesy of Dr. Grace Gao, Stanford University 2013 Pratap Misra Source: Wikimedia 21

22 BeiDou/Compass Chinese Beidou -- 1 Regional system 3 GEOs orbited in Active system Beidou-- 2 or Compass Global system (under development) Plan: 5 GEOs, 27 MEOs, 5 IGSOs 2013 Pratap Misra 22

23 BeiDou Status & Plans Constellation: 5 GEOs, 5 IGSOs, 4 MEOs Regional (Asia/Pacific) system operational Launched 16 BeiDou-2 satellites since 2007, No launches in 2013 Released an ICD for B1 open service SIS in 2012 Plans: Final constellation: 5 GEOs, 3 IGSOs, 27 MEOs 40 more satellites to be launched Operational: Pratap Misra 23

24 Marketing a GNSS: You d Like Our System Better! Protecting Domestic Markets, Finding Foreign Markets Balance between open trade and Protectionism Regulation (A Little Arm Twisting) 2013 Pratap Misra Russia s plan to require GLONASS in civil aircraft operating in its airspace; import tariffs on GNSS receivers that don t include GLONASS China s plan to require transportation operators to use BeiDou Political Muscle Russia agreement with India to promote GLONASS adoption 24

25 Marketing GPS-1 25

26 Marketing GPS-2 26

27 Marketing GPS-3 Is This the Best of Madison Avenue? 27

28 Marketing Galileo 28

29 Marketing GLONASS 29

30 Marketing BeiDou 30

31 Case for QZSS-1 Source: A presentation by Japan at the ION GNSS 2008 in Savannah, Georgia, on 17 September

32 Case for QZSS-2 Source: A presentation by Japan at the ION GNSS 2008 in Savannah, Georgia, on 17 September

33 QZSS Status 3 satellites planned in highly elliptical 36,000-km altitude orbits First satellite launched in Pratap Misra Source: JAXA 33

34 IRNSS Indian Regional Navigation Satellite System 3 GEOs, 4 IGSOs First launch: any day Source: ISRO 2013 Pratap Misra 34

35 Multi-GNSS Future* Outline Why Do We Need So Many Systems? GNSSs Under Development: Global Systems: GPS III, GLONASS, Galileo, & BeiDou Regional Systems: Japan s QZSS, India s IRNSS Regional Augmentations: US WAAS, NDGPS; Europe s EGNOS; Japan s MSAS; Russia s SDCM; India s GAGAN Coexistence: Compatibility Cooperation: Interoperability Competition: Who will be Number 1? 2013 Pratap Misra * Opinions of the author alone 35

36 Coexistence & Cooperation among GNSSs Coexistence: Compatibility Living peacefully with others despite fundamental disagreements Cooperation: Interoperability Working together for a common purpose 2013 Pratap Misra 36

37 Coexistence: RF Compatibility Spectrum Allocations Radio Spectrum LF MF HF VHF UHF SHF 30 khz 300 khz 3 MHz 30 MHz 300 MHz GPS 3 GHz L2 L1 GPS GLONSS ~ GPS 1587 MHz L-Band: 1 GHz 2 GHz 37

38 Coexistence: RF Compatibility Spectrum Allocations Radio Spectrum LF MF HF VHF UHF SHF 30 khz 300 khz 3 MHz 30 MHz 300 MHz GNSS 3 GHz L5, E5A Galileo GPS E5B L2 G2 E6 E2 L1 E1 Galileo GPS GLONASS Galileo ~ Galileo GPS G1 GLONASS 1587 MHz L-Band: 1 GHz 2 GHz 38

39 Coexistence: RF Compatibility GPS, GLONASS, & Galileo Fill Upper L-Band Source:? 39

40 L5 GNSS Signal Plans L2 L1 GPS (US) GLONASS (Russia) Future CDMA signal Galileo (Europe) COMPASS (China) IRNSS (India) QZSS (Japan) SBAS (US Europe India Japan) Frequency (MHz) Compass & IRNSS In S-band 40 Source: Dr. John Betz, MITRE

41 Coexistence: Political Compatibility Galileo s erstwhile plans to broadcast over the M-code frequencies BeiDou s current plans to broadcast over Galileo s PRS code 2013 Pratap Misra 41

42 Cooperation: Interoperability The More Systems, The Better Common time standard: UTC Each GNSS uses its national time standard Transmit biases among national standards Common coordinate frame: ITRF Each GNSS uses its reference coordinate frame Establish transformations among coordinate frames 2013 Pratap Misra 42

43 GPS + GLONASS + Galileo in 2013 Source: Curran-Petovello-Lachapelle, GPS World, April

44 U.N. is on the Job 44

45 45

46 Next generation satellites First launch anticipated ~2014 GPS III Potential Block III features (to be phased in incrementally): New L1 civil (L1C) signal Increased levels of accuracy, availability, reliability, and integrity High-speed uplink/downlinks/cross-links Spot beam for military M-code signal Longer pseudorandom codes for open signals Improves cross-correlation performance Data-less (pilot) components Portion of signal energy devoted to component with no navigation data modulation Enables more robust tracking Advanced modulation schemes Binary offset carrier and variants Robust forward error correction Convolution encoding, low-density parity check 2013 Pratap Misra More precise navigation data Hegarty 46

47 Spectrum Sharing Considerations All systems recognize the need for Radio Frequency Compatibility Technical details for assessment and acceptance still being worked Increasing recognition of National Security Compatibility for military or authorized signals Pioneered by GPS for M code signal Mimicked by Galileo for PRS Accepted by IRNSS Still being discussed with GLONASS and COMPASS Interoperability of civil signals with GPS civil signals viewed as benefitting everyone New systems become useful even with only a few satellites launched GPS remains the world standard as others mimic it Users obtain better geometry and availability from more satellites 2013 Pratap Misra 47

48 QZSS Status 3 satellites planned in highly elliptical 36,000-km altitude orbits First satellite launched in Pratap Misra Source: JAXA 48

49 IRNSS Indian Regional Navigation Satellite System 3 GEOs, 4 IGSOs First launch: any day Source: ISRO 2013 Pratap Misra 49

50 GPS III Source: Lockheed-Martin. 50

51 51

52 GPS Modernization First announced in 1998 by Vice President Gore Additional civil signals More and More Capable Signals Civil signals: from 1 to 4 Military signals: from 2 to 4 Classic GPS Modernized GPS GPS III 2005 was the Year of Transition First GPS Block IIR-M satellite launched An additional civil signal: L2C Additional military signals on L1 and L2: M-codes GPS III to be completed ~ Pratap Misra 52

53 GPS Modernization Space Segment Cross links among satellites, flexible power, spot beam, integrity monitoring Additional, more capable military signals: M-code on L1 and L2 Additional, more capable civil signals: L2C, L5, L1C Control Segment Block II OCS OCX to fly new spacecraft Distributed architecture, security User Segment MGUE (Mil. GPS User Equip t): Enhanced A-J, A-S, A-T New security architecture: SAASM Pronav New paradigm: from form-fit military receivers to GPS chipsets 2013 Pratap Misra 53

54 The current Hand-Held Military Receiver Suffers in Comparison to Civil Counterpart DAGR Comm: voice, /text message Positioning: GPS, Wi-Fi, cell towers Camera: geo-tagged pictures Social networking: Where other iphones are Lost iphone 54

55 Hand-Held Military Receiver Suffers in Comparison to Civil Counterpart DAGR 55

56 Common GPS Module (CGM) Commercial Method (GPS engines enable multiple applications) Enablers Build Integrators Build Engines + Applications = Global GPS Use Proposed MGUE Approach (Emulate commercial, Build the engine!) Common GPS Module (CGM) GPSW Builds Enabling Engines Integrators Build + Applications = Global Military GPS Use

57 GPS Has Raised Expectations Instantaneous, meter-level position estimates EVERYWHERE Performance metrics: accuracy, continuity, integrity, availability Intense research focus on multi-sensor navigation 57

58 Current Navigation Challenges Multi-Sensor Navigation Open interface standards for plug-and-play sensors Software architectures to accommodate re-configuration of sensors Dynamic calibration/characterization of sensors of diverse quality Kalman-type filters to process asynchronous data from changing sensors of diverse quality New Technologies Better MEMs sensors, Atomic reference mass accelerometers & gyros ( cold atoms interferometry ) Chip-scale atomic clocks (CSACs) Inertia of elastic waves/self-calibration/3-d fabrication 2013 Pratap Misra Ohio State Univ. photo 58

59 59

60 BeiDou/Compass Chinese Active system 2-3 geostationary satellites orbited in I MEO launched in 2007 Mission: unclear (08/15/2011) four geostationary satellites, a medium earth orbiting spacecraft, and the four IGSO satellites now on orbit Pratap Misra 60

61 Implications of Foreign GNSSs for GPS Technical Compatibility and Interoperability Political Sovereignty, national pride, Who is #1? Economic Commercial activity, technical innovation Military Complicates Navwar issues: Protect U.S. military use Prevent hostile use, Preserve civil use (outside the area of military ops) 2013 Pratap Misra 61

62 Satellite Navigation Overview Outline Principles of Satellite Navigation GPS Overview: System, Signals and measurements, Performance Applications and Performance Metrics Potential Partners/Rivals: GLONASS, Galileo, BeiDou/Compass, 2013 Pratap Misra 62

63 Frequency Plans

64 Frequency Plans* *Adapted from T. Grelier et al., Inside GNSS, May/June 2007

65 Frequency Plans* *Adapted from T. Grelier et al., Inside GNSS, May/June

66 GLONASS History Developed by Soviet Union, first launch: 1982 Declined under Russia, but newly revived Similar to GPS: Passive, one-way ranging working satellites over the past 5 of years, currently 16 No significant user base Constellation 24 satellites in 3 orbital planes, 64.8º inclination 19,100 km altitude, 11 ¼ hour period Signals 3 allocated bands: G1 (1602 MHz), G2: (1245 MHz), G3 (?) C/A-like code: 511 chips, 1 ms code period, 50 bps data All SVs use same PRN with frequency division multiple access (FDMA) using 16 frequency channels, reused for antipodal SVs Plans: 18 SVs in 2008, full constellation in 2011 (?) 2013 Pratap Misra 66

67 GPS+GLONASS Satellite Visibility GLONASS-21 GPS+GLONASS (2x21) Probability (%) Satellites Visible Probability (%) HDOP VDOP Dilution of Precision (DOP) GLONASS-21 GPS+GLONASS (2x21) Misra/

68 68 GPS & GLONASS Position Estimates* 1-Minute Samples, 15 June 1996

69 69 GPS & GLONASS Position Estimates* 1-Minute Samples, 15 June 1996

70 BeiDou/Compass Chinese BeiDou: Regional System Active system 2-3 geostationary satellites orbited in Compass: GNSS 1 MEO launched in Pratap Misra 70

71 Summary: Take-Away Points Satellite navigation systems exploit basic properties of radio waves: Transit exploited the Doppler effect, GPS exploits the known speed of propagation GPS is based on the old idea of trilateration, but implemented with the technology of the second-half of the 20 th century: space-based radio transmitters, ultra-stable clocks, and spread spectrum signals A GPS receiver measures pseudoranges to the satellites by measuring pseudo-transit times of radio signals. It takes 4 satellites (i.e., 4 pseudoranges) in order to estimate position (x, y, z) and time t With a clear view of the sky, it s easy to get positioning accuracy of several meters with a $100 GPS receiver, or relative positioning accuracy of millimeters with a pair of $1000 receivers. GPS satellites are 20-watt transmitters 20,000 km away, so the signals reaching the earth are very weak and, therefore susceptible to interference. The success and breadth of GPS applications is attributable largely to the chip. The VLSI revolution was well-timed for GPS 2013 Pratap Misra 71

72 GPS Modernization First announced in 1998 by Vice President Gore Additional civil signals More and More Capable Signals Civil signals: from 1 to 4 Military signals: from 2 to 4 Classic GPS Modernized GPS GPS III 2005 was the Year of Transition First GPS Block IIR-M satellite launched An additional civil signal: L2C Additional military signals on L1 and L2: M-codes GPS III to be completed ~ Pratap Misra 72

73 GPS Signal Modernization Civil Signal (Starting 2010) MHz (L5) MHz (L1) C/A Code Civil Use Degraded (2 May 2000) MHz (L2) P(Y) Code Encrypted L1C (2014) P(Y) Code Encrypted M-Code (Starting 2005) L2C-Code (Starting 2005) M-Code (Starting 2005) Misra

74 L5, E5A Galileo GPS E5B L2 G2 E6 E2 L1 E1 Galileo GPS GLONASS Galileo Galileo GPS G1 GLONASS 2013 Pratap Misra ~

75 2013 Pratap Misra GLONASS History Developed by Soviet Union, first launch: 1982 Declined under Russia, but now revived Similar to GPS: Passive, one-way ranging 22 working satellites in March 2011 No significant user base Constellation 24 satellites in 3 orbital planes, 64.8º inclination 19,100 km altitude, 11 ¼ hour period Signals 3 allocated bands: G1 (1602 MHz), G2: (1245 MHz), G3 (1202 MHz) C/A-like code: 511 chips, 1 ms code period, 50 bps data All SVs use same PRN with frequency division multiple access (FDMA) using 16 frequency channels, reused for antipodal SVs Plans: full constellation in 2011, evolving capability as CDMA signals are added < 75

76 Soviet-built GLONASS Aviation Receiver & Tool box (circa 1990) ASN-16 76

77 2013 Pratap Misra Summary: Take-Away Points GPS is based on the old idea of trilateration, but implemented with the technology of the second-half of the 20 th century: space-based radio transmitters, ultra-stable clocks, and spread spectrum signals. The success and breadth of GPS applications is attributable largely to the chip. The VLSI revolution was well-timed for GPS. A GPS receiver measures pseudoranges to the satellites by measuring pseudo-transit times of radio signals. It takes 4 satellites in view (i.e., 4 pseudoranges) in order to estimate position (x, y, z) and time t With a clear view of the sky, it s easy to get positioning accuracy of several meters with a $100 GPS receiver, or relative positioning accuracy of millimeters with a pair of $1000 receivers. GPS satellites are 30-watt transmitters 20,000 km away, so the signals reaching the earth are very weak and, therefore susceptible to interference. 77

78 78

79 GNSS = A Satellite Navigation System 79

80 Compatibility & Interoperability of Radionavigation Systems Compatibility Radio Frequency Compatibility: no harmful interference among signals National Security Compatibility: spectral separation between GPS civil signals and other systems signals, and M code Interoperability Two systems are better than one Requires attention to signal designs, system performance, and coordinate frames and time references 2013 Pratap Misra Source: Unknown 80

81 81

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84 84

85 85 Source: A presentation by Japan at the UN International Committee on GNSS Expert Meeting in Montreal on 15 July 2008

86 86 Source: A presentation by Japan at the ION GNSS 2008 in Savannah, Georgia, on 17 September 2008

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