pdf - ASK-IT
Transcription
pdf - ASK-IT
ASK-IT for Technical Providers Overview of Localisation Technologies With RFID/Smartdust and Galileo 13th October 2005 - Stuttgart Richard Fairchild [email protected] School of Civil Engineering & Geosciences PGR Centre, Cassie Building, University of Newcastle upon Tyne, NE1 7RU, England Contents • • • • • • • • • ASK-IT Outline Technology in context Satellite technologies RFID Smartdust Mobile phone based technologies Wireless network based technologies Summary Conclusion ASK-IT Outline • …to provide personalised, configurable, intuitive and context-related applications and services. These will be derived from a number of sources and will be made available via a web-based system serving a variety of fixed and mobile devices.’ (ASK-IT Outline) Contents ASK-IT Outline Technology in context Satellite technologies RFID Smartdust Mobile phone based technologies Wireless network based technologies Summary Conclusion Technology in context • Need to match localisation technology with user location and profile • Must appreciate limitations of technologies • Redundancy • Why? – GPS in a multi level indoor shopping centre – Wireless networking in large open areas Context: User location • Outdoors – Dense urban – cities – Low density urban – suburbs – Open areas – recreation grounds, tourist areas Context: User location • Indoors – Shopping centres – Sports centres – Transport interchanges – Hotel / Restaurant / Bar / Other leisure Context: User profile • Pedestrian – – – – – Weight Power Portability Discreteness Compatibility Smartphone PDA Context: User profile • Transport user – – – – Integration Power Display Private / Public Full in-car solution PDA in-car Contents ASK-IT Outline Technology in context Satellite technologies RFID Smartdust Mobile phone based technologies Wireless network based technologies Summary Conclusion Satellite Technologies • Galileo • GPS • Differential Corrections • EGNOS • SISNeT GPS Satellite Galileo – basic facts • • • • • • European GPS 30 satellites 27 active + 3 spare 10 SVs in 3 orbits Altitude of 23 222 km Operational: 2010 Galileo constellation Image: ESA, J. Huart Galileo Launch Schedule Image: ESA • Currently lab testing • Galileo test bed satellite launch end 2005 • Test campaign for 2.5 years • Secure Galileo frequencies • Atomic clock characterisation • Test signals broadcast • Operating environment surveyed Galileo Constellation Population • Launch by Ariane 5 • Europe’s heavy launcher • Up to 10 tonnes payload mass • Capable of holding 8 Galileo satellites Image: Astrium Payload of 8 Galileo satellites Galileo Services • Open Service (OS) • Commercial Service (CS) • Public Regulated Service (PRS) • Safety of Life (SoL) • Search & Rescue (SAR) • OS two free civil signals • CS provides added value • PRS for security agencies • SoL gives integrity warnings • SAR for fast rescue operations Galileo Services • Open Service (OS) • Commercial Service (CS) • Public Regulated Service (PRS) • Safety of Life (SoL) • Search & Rescue (SAR) • Free open access service for civilian users. • Provides position, timing and velocity information • Two frequencies, support for single frequency users Galileo Services • Open Service (OS) • Commercial Service (CS) • Public Regulated Service (PRS) • Safety of Life (SoL) • Search & Rescue (SAR) • Provides added value • External agencies able to buy bandwidth • Built on top of OS • Two further frequencies • Data carrier available for transmission of data such as maps/charts, databases & correction data Galileo Services • Open Service (OS) • Commercial Service (CS) • Public Regulated Service (PRS) • Safety of Life (SoL) • Search & Rescue (SAR) • Devoted to security agencies • Anti-spoofing and anti-jamming Galileo Services • Open Service (OS) • Commercial Service (CS) • Public Regulated Service (PRS) • Safety of Life (SoL) • Search & Rescue (SAR) • Provides integrity warnings to OS users • 12 m horizontal • 20 m vertical • 6 seconds time to alarm • Free service, though charge for equipment (tbc) Galileo Services • Open Service (OS) • Commercial Service (CS) • Public Regulated Service (PRS) • Safety of Life (SoL) • Search & Rescue (SAR) • Provides added functionality on top of current SARSAT / COSPAS • Uses data carrier for acknowledgements • Accurate position at time of alert Galileo Performance Open Service Type of Receiver Carriers Computes Integrity Ionospheric correction Coverage Accuracy (95%) Single Frequency No Based on simple model Based on dualfrequency measurements Global H: 4 m V: 8m H: 15 m V: 35 m Alarm Limit Time-To-Alarm Integrity risk Continuity Risk Timing Accuracy wrt UTC/TAI Certification/Liability Availability Dual-Frequency Integrity Not Applicable 8x10-6 /15 s Not defined No 50 nsec No 99 % - 99.9 % Service Performance for Open Service with the Satellite Navigation Signals only and without any other augmentations. From Forrest, W., 2002 GPS • GPS and Galileo very similar • Differences – Galileo two civil frequencies from start – GPS one civil frequency, one more in future – SoL life service not available with GPS (currently) 95% Confidence Horizontal accuracy 15 m Vertical accuracy 28 m Average GPS accuracy 95% Confidence Horizontal accuracy 2m Vertical accuracy 4m Average GPS accuracy with differential correction Ref: users.erols.com GNSS Multipath Effects (Evans, J., 2005) (Evans, J., 2005) (Evans, J., 2005) Differential Corrections • DGPS, WAAS etc. • Basic theory: • Two receivers, stationary known position and roving receiver • Stationary receiver works out timing signals from GNSS coordinates and its known position • Stationary receiver compares real with receivers • Difference is correction factor • Transmitted in local area Augmentation technologies • EGNOS • European Geostationary Navigation Overlay Service • Three satellites • Contains information about accuracy and reliability plus correctional data • Allows users to determine position to about 5 meters • Operational early 2006 • SISNeT • Signal in Space over internet • Gives access to wide area differential corrections including EGNOS integrity messages • Gets over problems that satellites have in urban areas including EGNOS EGNOS Demonstration • Used in German round of World Rally Championships in August • Simultaneous recording of GPS and EGNOS data • Comparison of positing by displaying GPS and EGNOS position of the car relative to highly accurately surveyed track EGNOS Demonstration Satellite Technology for Localisation • • • • • • Points to consider: Outdoor Large error – block size Urban canyons Indoor? Signals through (wireless) internet • Compactness of current devices • Low cost – mature technology Contents ASK-IT Outline Technology in context Satellite technologies RFID Smartdust Mobile phone based technologies Wireless network based technologies Summary Conclusion RFID System • Radio Frequency IDentification • A complete RFID system has three key components and maybe extended Image: GAO RFID System - Tags • Quite mature technology • Friend of Foe -1939 • Comprises of antenna (wire coil), microchip and is most often stuck to the underside of a label • Uses: – Security (stock) – Inventory systems – Freight handling Image: GAO The back (underside) of a typical simple RFID tag RFID Image: kennedy group RFID Tag Classification • By power: • Passive – Not powered • Active – Has internal battery or connected to an external power source – Hence greater cost • By radio frequency transmission ability: • Passive RF – Can only transmit data by reflecting incoming electromagnetic waves • Active RF – Can transmit data by using internal power source to power aerial and microchip RFID Tag Classification • By tag type: • Type I – Read-only • Type II – Read/write • Type II+ – As type II but with enhanced external features • Type II++ – As type II but with serial connection • Type III – Read/write plus LCD display • Type IV – Read/write as smartcard RFID Sytem - Reader • RF passive, non-powered tags: • Reader initiates conversation • Reader emits RF energy that cause a current flow in the antenna and powers the chip • Reader extracts data from the chip via the antenna and powers off RFID reader in stock room (www.philips.com) Proximity smartcard and reader RFID System - Reader • Powered, RF active tags: • Reader or tag may initiate conversation • Tag uses power source to power microchip and send data via antenna • Range is larger than RF passive tags • Read write tags may have new data written e.g. road user charging Image: www.cs.hku.hk/~clwang / Image: www.derwinbell.com State Road-91 Express Lanes (SR91) in Orange County, CA the first totally automated electronic toll collection system in the U.S RFID Performance Characteristics 10 – 100 tags / s 100 – 1000 tags / s RFID Tags – Size and Costs • Size: any size, from in car units – smart cards – stock labels – millimetre dimensions A 0.25mm2 RFID tag Image: smartcode • Cost: average price for passive type I tags around €0,15 - 0,40 • Ultra small in large quantities ˜ €0,05 • More complex tags with long transmission range ˜ €17 ($20) RFID Standards • EPCglobal Class 1 Generation 2 RFID Specification • Establishes a single UHF specification over several previous ones • Sets minimum read and write speeds to 500 / 30 tags/sec RFID for Localisation • RFID tags in doorways, lifts, shop fronts, breadcrumb trail • Map database integrated into reader • Considerations: • Power • Range • Low cost simple tags Newcastle Smart Sign Project SmartSign NCLU/0008 www.smartsign.co.uk Contents ASK-IT Outline Technology in context Satellite technologies RFID Smartdust Cellular phone based technologies Wireless network technologies Summary Conclusion Smartdust (motes) • Motes > smartdust • Similar to Class IV RFID tags • RF active • Powered • Tiny OS • Sensor stack Images: intel, xbow Ad Hoc Networks Smartdust @ Newcastle • ASTRA project • Smartdust corridor • Network reporting of bus position • Demonstration of use for localisation • Various MSc projects Newcastle Smartdust Corridor Smartdust for Localisation • Similar characteristics to RFID • IEEE802.11.x standards widely used • Hence better compatibility with existing equipment • Costs: • Current devices are not cheap • ˜ €140 for MICA2 mote • Smartdust costs will be signifcantly lower Contents ASK-IT Outline Technology in context Satellite technologies RFID Smartdust Mobile phone based technologies Wireless network based technologies Summary Conclusion Mobile phone based technologies • Cellular mobile phone based • GSM (TDMA) – Triangulation method gives horizontal accuracy of 50 – 200 meters • 3G (CDMA) – Smaller sized cells with greater overlapping accuracy more than that of TDMA networks – 4G phones will have GPS chips inside to allow the phone to calculate it’s position Mobile phone based technologies • Mobile Phone Features • Good in urban areas where cells overlap • Can be used indoors with additional network access points e.g. Metrocentre though leaky coaxial not suitable • Tend to have good network strength around major road networks • Limited signal in remote areas Wireless Networks • Wireless networks • Infrastructure based – e.g. university network, device can detect range to nearest access points and calculate position • Mobile ad-hoc – Allows information from devices with knowledge to pass to other devices and so on e.g. traffic jams • Bluetooth • Smartdust Key Issues 1. Technology must be compatible with the users mode of travel and application area 2. Accuracy of localisation signal 3. Compatibility with existing equipment 4. Unit cost 5. Combination & redundancy of technologies References and links • Kennedy Group www.kennedygrp.com • European Space Agency www.esa.int • SmartCode Corp. www.smartcodecorp.com • United States Government Accountability Office www.gao.gov • EPCglobal Inc. www.epcglobalinc.org • Intel www.intelresearch.net • Xbow www.xbow.com • Evans, J. 2005, Central London Congestion Charging Scheme, presentation, October 7th