A TSB business Support Solution Delivered through the Technology Programme
1 Where to now with GNSS? A TSB business Support Solution Delivered through the Technology Programme
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 What’s up there now? A TSB business Support Solution Delivered through the Technology Programme
• 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 A TSB business Support Solution Delivered through the Technology Programme
http://en.wikipedia.org/wiki/File:ConstellationGPS.gif
4 What’s up there now? A TSB business Support Solution Delivered through the Technology Programme
• 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 Picture: NPO PM to secure frequencies, G2 launched 15 th Apr 2009 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 three- way ranging system. Remote terminal -> satellites -> ground station (calculate position) -> satellites -> remote terminal. so the number of users was limited to 150 simultaneously.
5 What’s up there now? A TSB business Support Solution Delivered through the Technology Programme
• 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 Giove-B . Credit:. ESA – DORIS – French system using Doppler ranging
I was not aware of DORIS until I started researching for this presentation: http://ids.cls.fr/
6 Signals A TSB business Support Solution Delivered through the Technology Programme
• GPS – L1 - (1575.42MHz) • C/A, P(Y), L1M – L2 - (1227.60MHz) • P(Y), L2C, L2M – L3 – (1381.05MHz) • Used by NUDET – L5 – (1176.45MHz) • New civilian (safety-of-life) signal
GPS currently transmits the Coarse/Acquisition signal on the L1 (1575.42MHz), The encrypted military (precision) signal ( P(Y) ) and on the latest 7 satellites, the new military signal (L1M). On the L2 frequency (1227.60MHz) 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 Signals A TSB business Support Solution Delivered through the Technology Programme
• GLONASS – L1 - (1602.2MHz) • FDMA Civilian & Military – L2 - (1246.00MHz) • FDMA Civilian & Military • Beidou – Satellite signal 2491.75MHz, ground station 1615.68MHz • Compass – Currently transmitting on E2 (1561.098MHz), E5b (1207.14MHz) & E6 (1268.52MHz)
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 2491.75MHz, ground station 1615.68MHz.
8 Signals A TSB business Support Solution Delivered through the Technology Programme
• 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 2491.75MHz, ground station 1615.68MHz.
9 Signals A TSB business Support Solution Delivered through the Technology Programme
European Space Agency
10 What’s going up A TSB business Support Solution Delivered through the Technology Programme
• 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 2012. Incl L2C + L5, 2 Rb + 1 Cs clocks – Block III launches start 2013. 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 What’s going up A TSB business Support Solution Delivered through the Technology Programme
• 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 21 + 3 spares by 2010
December 25, 2008, launch of three GLONASS-M satellites; Roscosmos photo by S. Sergeev (TSENKICOM)
12 What’s going up A TSB business Support Solution Delivered through the Technology Programme
• Galileo – 4 in-orbit-validation satellites in production now, launching 2010. – 30 medium earth orbit (27 + 3 spares). Full Operation Capability 2013. • Compass – 1 launched 15/04/09, 2 more planned to launch 2009, 7 more in 2010. – 5 Geo-stationary & 30 medium earth orbit, “complete by 2015” Photo: Xinhua News Agency
13 What’s going up A TSB business Support Solution Delivered through the Technology Programme
IRNSS Satellite Locations • Other satellites – IRNSS (1 st due for launch 2009/2010) – independent Indian system, 3 geo- Indian Space Research Organisation (ISRO) stationary + 4 geo- synchronous. India region.
– QZSS (1 st due for launch 2009) – Japanese. Local GPS enhancement & timing transfer. QZNSS satellite track
http://en.wikipedia.org/wiki/File:Qzss-45-0.09.jpg
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 New Signals A TSB business Support Solution Delivered through the Technology Programme
• 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 What can we do now? A TSB business Support Solution Delivered through the Technology Programme
Error Source Typical Range Error Magnitude (meters, 1 σσσ) Without SA Without SA plus 2 or more coded signals Selective Availability 0.0 0.0 Atmospheric Error Ionospheric 7.0 0.01 Tropospheric 0.2 0.2 Clock and Ephemeris Error 2.3 2.3 Receiver Noise 0.6 0.6 Multipath 1.5 1.5 Total User Equivalent Range Error (UERE) 7.5 2.8 Typical Horizontal DOP (HDOP) 1.5 1.5 Total Stand-Alone Horizontal Accuracy, 95% 22.5 8.5 Source: Shaw et. al., GNSS-2000.
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, 2009. 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 What can we do now? A TSB business Support Solution Delivered through the Technology Programme
Error source Description Potential magnitude of positional error (m)
Orbit errors Our inexact knowledge of where the satellites are in their 2.5 orbit. Satellite clocks The small inaccuracy in the satellite clocks means the 1.5 distance measurement is not precise.
Ionosphere The atmospheric layer from 50 to 500 km disturbs the GPS 5.0 signal, leading to inexact range measurements.
Troposphere The atmospheric layer which includes the Earth’s weather 0.5 disturbs the GPS signal, leading to inexact range measurements.
Receiver noise Internal receiver errors. 0.1
Multipath The effect of indirect GPS signals arriving at the GPS 0.6 antenna.
Source: Ordnance Survey
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 10-20 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, 2009. William J. Hughes Technical Center NSTB/WAAS T&E Team
17 What will we be able to do? A TSB business Support Solution Delivered through the Technology Programme
• 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 What Enhancements are there? A TSB business Support Solution Delivered through the Technology Programme
• 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 2007. 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 What Enhancements are there? A TSB business Support Solution Delivered through the Technology Programme
Coverage of Satellite Based Augmentation Systems for aircraft use, as of 2009. EGNOS should be certified 2009.
20 Planned A TSB business Support Solution Delivered through the Technology Programme
• 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 2011. • MASS – Multi-Constellation Augmentation Service System (MASS) in China
21 What Enhancements are there? A TSB business Support Solution Delivered through the Technology Programme
• 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 2006. SBAS systems will not cover Australia PPP – this uses clock & ephemeris data from fixed reference stations to post- process RTK, a version of Differential that uses a fixed reference and a 2 frequency receiver Network RTK, as RTK but uses CORS
22 What can we do? A TSB business Support Solution Delivered through the Technology Programme
• 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 What Enhancements are there? A TSB business Support Solution Delivered through the Technology Programme
• 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 What else can be done? A TSB business Support Solution Delivered through the Technology Programme
• 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 Innovations A TSB business Support Solution Delivered through the Technology Programme
Galileo Masters: • Sci-Tech POB – Person-Overboard location system • My Visit Sci-Tech Systems Ltd. 2008 – Indoor navigation using GNSS pseudolites and WiFi • ubigrate – Ultrasonic truck volume measurement, combined with location
Galileo Masters is an international, annual competition for best innovations using GNSS. Entries for 2009 open end of April.
26 Innovations A TSB business Support Solution Delivered through the Technology Programme
Galileo Masters:
• Cardiomobile – A Remote Monitoring System for Alive Technologies Pty Ltd Cardiac Rehabilitation • Carbon Hero – Carbon footprint monitor
The British Standards Institution 2007
27 Research A TSB business Support Solution Delivered through the Technology Programme
• CVIS – Cooperative Vehicle Infrastructure Systems
http://www.cvisproject.org/ Lots of research going on about reducing congestion, traffic flow, road safety etc. This is just one example.
28 Research A TSB business Support Solution Delivered through the Technology Programme
• Atmospheric moisture measurement
Royal Netherlands Meteorological Institute
Live monitoring of atmospheric moisture by measuring the changes in time delays of GNSS signals.
29 Research A TSB business Support Solution Delivered through the Technology Programme
• 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., http://www.altimetry.info, 2009
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 Thank You A TSB business Support Solution Delivered through the Technology Programme www.locationktn.com [email protected]
31 Underwater GPS A TSB business Support Solution Delivered through the Technology Programme
A.C.S.A. - 9 EUROPARC - 13590 MEYREUIL FRANCE - Tel.: +33 (0) 442 58 54 52 - Fax: +33 (0) 442 58 65 46 - [email protected]
I searched the internet for “Underwater GPS” came up with two very different solutions. This is a commercial product.
32 Underwater GPS A TSB business Support Solution Delivered through the Technology Programme
http://www.divester.com/2005/12/14/underwater-gps/
The DIY approach
33 A TSB business Support Solution Delivered through the Technology Programme
34