A TSB business Support Solution Delivered through the Technology Programme

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2 Where to now with GNSS? Peter Lancaster Technology Translator Location & Timing KTN What is the Location & Timing KTN? Knowledge Transfer Networks are funded by the UK government, through the Technology Strategy Board. Our role is to stimulate innovation through knowledge transfer. Between industry, universities, researchers etc. Primarily within the UK, but also increasingly with Europe and worldwide. Our specific focus is on technologies and applications that identify or use location, and timing. 2

3 What s up there now? GPS 31 operational, plus 1 launched last month. 7 x Block IIR-M have L2C & L1M, L2M Lockheed Martin Global Positioning Satellite IIRM Artist Impression Lockheed Martin Global Positioning Satellite IIRM 3

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5 What s up there now? GLONASS 20 operational, incl 3 launched on Christmas Day 2008, 6 have a predicted life of less than 1 year. FDMA signals. Beidou-1 Geo-stationary, 2-way communication method so limited users & accuracy. 3 operational, (2 needed to cover SE Asia). Compass-M1 launched Apr 07 to secure frequencies, G2 launched 15 th Apr 2009 Picture: NPO PM Glonass-M (Uragan-M) Glonass is the Russian system. Currently undergoing an programme to replace and update the constellation. Currently 20 satellites operational, but several have a short predicted life span (2 are due to go out of service about now). They need 21 for minimum global coverage, 24 including spares. Beidou is the older Chinese system that uses geo-stationary satellites and a threeway ranging system. Remote terminal -> satellites -> ground station (calculate position) -> satellites -> remote terminal. so the number of users was limited to 150 simultaneously. 5

6 What s up there now? Galileo GIOVE-A & GIOVE-B. A launched 28/12//05 primarily to secure the frequencies. B launched 27/04/08 re-secure frequencies, test transmission codes and hydrogen-maser clock. Other satellites DORIS French system using Doppler ranging Giove-B. Credit:. ESA I was not aware of DORIS until I started researching for this presentation: 6

7 Signals GPS L1 - ( MHz) C/A, P(Y), L1M L2 - ( MHz) P(Y), L2C, L2M L3 ( MHz) Used by NUDET L5 ( MHz) New civilian (safety-of-life) signal GPS currently transmits the Coarse/Acquisition signal on the L1 ( MHz), The encrypted military (precision) signal ( P(Y) ) and on the latest 7 satellites, the new military signal (L1M). On the L2 frequency ( MHz) they transmit the encrypted military signal and on the latest 7 satellites the new military signal (L2M) and the new civilian signal (L2C). L3 is used to transmit data for the Nuclear Detonation Detection System NUDET L5 will carry the new safety-of-life signal, high integrity signal for transport, eg. air traffic control etc. Latest satellite is broadcasting test signals. 7

8 Signals GLONASS L1 - (1602.2MHz) FDMA Civilian & Military L2 - ( MHz) Beidou FDMA Civilian & Military Satellite signal MHz, ground station MHz Compass Currently transmitting on E2 ( MHz), E5b ( MHz) & E6 ( MHz) Glonass currently transmits (FDMA) signals on L1 (1602.2) and L2 (1246MHz). Both frequencies carry a civilian signal and a military signal. The L2 civilian signal is not on the older satellites (3) Beidou - Satellite signal MHz, ground station MHz. 8

9 Signals Galileo L1, E5, E6 European Space Agency Glonass currently transmits (FDMA) signals on L1 (1602.2) and L2 (1246MHz). Both frequencies carry a civilian signal and a military signals.the L2 civilian signal not on the older satellites (3) Satellite signal MHz, ground station MHz. 9

10 Signals European Space Agency 10

11 What s going up GPS 1 launched last month, 1 more Block IIR-M to be launched in August with 2 nd civilian frequency (L2C). New military signals (M-code) on L1 & L2 frequencies. New safety-of-life frequency (L5) test. 12 x Block IIF to be launched Oct/2009 to Incl L2C + L5, 2 Rb + 1 Cs clocks Block III launches start New civilian signal L1C, spot power for M-code. SIS-URE 0.25m Photo by Pat Corkery, United Launch Alliance A lot of the basic accuracy of the system is down to the clocks fitted. Rubidium (Rb) are lighter and slightly more accurate but use more power than Caesium (Ca). Block II-F have digitally controlled clocks instead of analogue Various new clock technologies being tested at present for GPS Block III. Eg. Caesium beam, hydrogen maser. 11

12 What s going up GLONASS GLONASS-K will begin launching next year and include a CDMA (code division multiple access) signal on L3, similar to the other GNSS systems. Total spares by 2010 December 25, 2008, launch of three GLONASS-M satellites; Roscosmos photo by S. Sergeev (TSENKICOM) 12

13 What s going up Galileo 4 in-orbit-validation satellites in production now, launching medium earth orbit ( spares). Full Operation Capability Compass 1 launched 15/04/09, 2 more planned to launch 2009, 7 more in Geo-stationary & 30 medium earth orbit, complete by 2015 Photo: Xinhua News Agency 13

14 What s going up Other satellites IRNSS (1 st due for launch 2009/2010) independent Indian system, 3 geostationary + 4 geosynchronous. India region. Indian Space Research Organisation (ISRO) IRNSS Satellite Locations QZSS (1 st due for launch 2009) Japanese. Local GPS enhancement & timing transfer. QZNSS satellite track QZSS Quasi-Zenith Satellite System The system will be a three-satellite constellation, with at least one satellite observable at high-elevation angle at all times over central Japan. Helps GNSS performance in Urban Canyons eg Tokyo 14

15 New Signals GPS L2C New NAV message, Long code & moderate length code L1M & L2M, L5 Galileo E1 (L1) ( 4 signals), E5 (5 signals) L6 Search and Rescue uplink GLONASS L1 CDMA L3 civilian signal for safety-of-life apps Search and Rescue Compass E1 (1589 MHz), E2 (1561 MHz), E5b (1207 MHz) & E6 (1268 MHz) I ve covered these a bit already. Generally the systems are designed to be interoperable to an extent and do not interfere. The current debate is about the overlap between the Compass E2 And the Galileo E2 PRS signal. The problem is that if the Europeans wanted to jam the Chinese, we would jam ourselves as well. A similar problem with the US was overcome by negotiation. 15

16 Error Source What can we do now? Typical Range Error Magnitude (meters, 1σ) Without SA Selective Availability Atmospheric Error Ionospheric Tropospheric Without SA plus 2 or more coded signals Clock and Ephemeris Error Receiver Noise Multipath Total User Equivalent Range Error (UERE) Typical Horizontal DOP (HDOP) Total Stand-Alone Horizontal Accuracy, 95% Source: Shaw et. al., GNSS There is a lot of variation in accuracy specifications, how they are defined and what they are using as a reference. GPS currently gives a Signal in Space - User Range Error of 0.9 m. (this is the error of the transmitted signal) GPS-SPS Performance Analysis Report January 31, William J. Hughes Technical Center NSTB/WAAS T&E Team Glonass gives about 1.8 m SIS-URE error. Selective Availability has been off since 2000, and GPS Block III will not have the feature installed. If they need to, the US military will just jam the civilian signals and use the military signals only. As the ionosphere delays different frequencies by different amounts, 2 frequency operation allows this error to be mathematically reduced and so remove a significant proportion of the ionospheric error; also reduces a small amount of the multi-path error. 16

17 What can we do now? Error source Description Potential magnitude of positional error (m) Orbit errors Satellite clocks Ionosphere Our inexact knowledge of where the satellites are in their orbit. The small inaccuracy in the satellite clocks means the distance measurement is not precise. The atmospheric layer from 50 to 500 km disturbs the GPS signal, leading to inexact range measurements Troposphere The atmospheric layer which includes the Earth s weather disturbs the GPS signal, leading to inexact range measurements. 0.5 Receiver noise Internal receiver errors. 0.1 Multipath Source: Ordnance Survey The effect of indirect GPS signals arriving at the GPS antenna. 0.6 For GPS, a basic indication is that if there is a good view of the sky, then a good consumer GPS unit will give position to within 5-10 m horizontally and m vertically. Typical errors are 2 m horizontal, 3 m vertical. Better clocks in newer satellites has reduced the clock error term. Some augmentation systems make available measured ephemeris and clock data, allowing these errors to be significantly cancelled. GPS-SPS Performance Analysis Report January 31, William J. Hughes Technical Center NSTB/WAAS T&E Team 17

18 What will we be able to do? New constellations give: More satellites Fewer geometric errors (PDOP) More possibilities for RAIM (Receiver Autonomous Integrity Monitoring Better coverage at high latitudes Better reception in urban canyons Higher powers More accurate clocks Augmentation data transmitted as part of GNSS signal More frequencies Reduce atmospheric errors Reduce multi-path New codes Resistance to jamming Ability to jam others Galileo & Glonass will have reflectors to enable laser ranging from the ground for independent ephemeris tracking. Should bring typical consumer accuracies down to 1 m and more satellites will mean better chance of seeing enough in a good geometry to reduce PDOP (Position Dilution of Precision ). If the satellites in view are spaced far apart then we get better geometric precision. But in urban environments, if the satellites are far apart, then they are more likely to be obscured by buildings etc. Also, satellites low on the horizon are more easily obscured and the signal has more atmosphere to travel through, thus increasing errors. However still won t work indoors! 18

19 What Enhancements are there? Space Based Augmentation Systems Primarily for air traffic control applications. Target is <7.6m for "Category 1" landings (i.e. very close to the runway but not zero visibility). Tests show better than 2m horizontal & 4m vertical. WAAS - Wide Area Augmentation System N America. 38 ground stations, 2 Geo-stationary satellites (Commercial communications satellites). EGNOS - Wide Area Augmentation System Europe. 34 Ranging and Integrity Monitoring Stations (RIMS). EGNOS signal is transmitted by 3 geostationary satellites: 2 Inmarsat-3 satellites, eastern Atlantic & Indian Ocean, and the ESA Artemis satellite above Africa. MSAS - Multi-functional Satellite Augmentation System Japan. 2 geo-stationary satellites, 6 ground stations. StarFire & OmniSTAR Commercial systems (John Deere & Furgo) using commercial satellites & 60 to 100 ground reference stations GPS-C Canadian system with ground stations & uses MSAT-1 & MSAT-2 to transmit corrections WAAS has been in operation since 2003 in USA and over 35,000 aircraft are fitted with systems. MSAS certified for aviation use in 2007, EGNOS expected to be certified in 2009 been under test since In 2008 there had been 1100 Low Visibility Landings using WAAS in the US. As well as more reliable and accurate positioning, importantly WAAS etc. also provide warning of errors or faults. 19

20 What Enhancements are there? Coverage of Satellite Based Augmentation Systems for aircraft use, as of EGNOS should be certified

21 Planned GAGAN Indian; 1 geo-stationary satellite (GSAT-4, launch summer 2009), 8 reference stations, 1 control station. SDCM System for Differential Correction and Monitoring (SDCM) - Russian, planned for MASS Multi-Constellation Augmentation Service System (MASS) in China 21

22 What Enhancements are there? Land Based GBAS Ground Based Augmentation Systems LAAS Local Area Augmentation System JPALS -Joint Precision Approach and Landing System GRAS Australian system DGPS/GNSS Differential GPS/GNSS CORS Continuously Operating Reference Stations OS-Net, IGS etc. PPP - Precise Point Positioning RTK Real Time Kinematics Network RTK LAAS airfield approach system, civilian JPALS The Joint Precision Approach and Landing System will support aircraft landings on aircraft carriers and military air fields. GRAS - Ground-Based Regional Augmentation System been in operation by Qantas since SBAS systems will not cover Australia PPP this uses clock & ephemeris data from fixed reference stations to postprocess RTK, a version of Differential that uses a fixed reference and a 2 frequency receiver Network RTK, as RTK but uses CORS 22

23 What can we do? Network RTK can typically give <20mm horizontal and <30mm vertical TSA & Newcastle University Surveying Dynamic positioning Machine control Precision Agriculture Open-cast mining Differential RTK and Network RTK are extensively used for surveying Network RTK can typically give <20mm horizontal and <30mm vertical TSA & Newcastle University 23

24 What Enhancements are there? Pseudolites INS - Inertial Navigation Systems WiFi SSID mapping Signal strength RFID tags Cell-ID Cell tower triangulation Loran, e-loran Radar Ultrasonic/sonar Optical/laser Magnetic Gravitational SLAM Simultaneous Localisation and Mapping Visual Assisted GPS/GNSS (A-GPS/A-GNSS) Uses network (phone or internet) to supply ephemeris and clock data - gives faster first-time-to-fix (TTFF) Sometimes also uses WiFi cell ID or phone network Cell ID to give a position 24

25 What else can be done? Low cost, hand-held < 1m dynamic positioning indoors & outside Combining GNSS with non-satellite technologies Pedestrian navigation Enhanced Vehicle positioning lane identification A goal of ubiquitous positioning is to enable position accuracy of < 1m while moving, without 100% satellite coverage. Currently possible by combining GNSS with other technologies and expensive Favourites for consumer level: Inertial WiFi/Cell power Pseudolites or additional transmitters, eg. Inside a shopping centre 25

26 Innovations Galileo Masters: Sci-Tech POB Person-Overboard location system My Visit Indoor navigation using GNSS pseudolites and WiFi ubigrate Ultrasonic truck volume measurement, combined with location Sci-Tech Systems Ltd Galileo Masters is an international, annual competition for best innovations using GNSS. Entries for 2009 open end of April. 26

27 Innovations Galileo Masters: Cardiomobile A Remote Monitoring System for Cardiac Rehabilitation Alive Technologies Pty Ltd Carbon Hero Carbon footprint monitor The British Standards Institution

28 Research CVIS Cooperative Vehicle Infrastructure Systems Lots of research going on about reducing congestion, traffic flow, road safety etc. This is just one example. 28

29 Research Atmospheric moisture measurement Royal Netherlands Meteorological Institute Live monitoring of atmospheric moisture by measuring the changes in time delays of GNSS signals. 29

30 Research Sea surface height & state Using reflections of GNSS signals Rosmorduc, V., J. Benveniste, O. Lauret, C. Maheu, M. Milagro, N. Picot, Radar Altimetry Tutorial, J. Benveniste and N. Picot Ed., Can be used to accurately monitor ocean heights eg sea-level rise due to global warming. Also sea roughness/ wave size & frequency. Uses a low orbit satellite to receive reflections 30

31 Thank You 31

32 Underwater GPS A.C.S.A. - 9 EUROPARC MEYREUIL FRANCE - Tel.: +33 (0) Fax: +33 (0) info@underwater-gps.com I searched the internet for Underwater GPS came up with two very different solutions. This is a commercial product. 32

33 Underwater GPS The DIY approach 33

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