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Overview of Localisation Technologies
ASK-IT for Technical Providers
13th October 2005 - Stuttgart
Richard [email protected]
School of Civil Engineering & GeosciencesPGR Centre, Cassie Building,
University of Newcastle upon Tyne,NE1 7RU, England
With RFID/Smartdust and Galileo
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 OutlineTechnology in contextSatellite technologies
RFIDSmartdust
Mobile phone based technologiesWireless network based technologies
SummaryConclusion
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
PDA in-car
Full in-car solution
• Transport user– Integration– Power– Display– Private / Public
Contents
ASK-IT OutlineTechnology in contextSatellite technologies
RFIDSmartdust
Mobile phone based technologiesWireless network based technologies
SummaryConclusion
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
Image: ESA, J. Huart
Galileo constellation
Galileo Launch Schedule• 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
surveyedImage: ESA
Galileo Constellation Population
• Launch by Ariane 5• Europe’s heavy
launcher• Up to 10 tonnes
payload mass• Capable of holding 8
Galileo satellites
Payload of 8 Galileo satellitesImage: Astrium
Galileo Services
• OS two free civil signals
• CS provides added value
• PRS for security agencies
• SoL gives integrity warnings
• SAR for fast rescue operations
• Open Service (OS)• Commercial Service
(CS)• Public Regulated
Service (PRS)• Safety of Life (SoL)• Search & Rescue
(SAR)
Galileo Services
• Free open access service for civilian users.
• Provides position, timing and velocity information
• Two frequencies, support for single frequency users
• Open Service (OS)• Commercial Service
(CS)• Public Regulated
Service (PRS)• Safety of Life (SoL)• Search & Rescue
(SAR)
Galileo Services
• 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
• Open Service (OS)• Commercial Service
(CS)• Public Regulated
Service (PRS)• Safety of Life (SoL)• Search & Rescue
(SAR)
Galileo Services
• Devoted to security agencies
• Anti-spoofing and anti-jamming
• Open Service (OS)• Commercial Service
(CS)• Public Regulated
Service (PRS)• Safety of Life (SoL)• Search & Rescue
(SAR)
Galileo Services
• Provides integrity warnings to OS users
• 12 m horizontal• 20 m vertical• 6 seconds time to
alarm• Free service, though
charge for equipment (tbc)
• Open Service (OS)• Commercial Service
(CS)• Public Regulated
Service (PRS)• Safety of Life (SoL)• Search & Rescue
(SAR)
Galileo Services
• Provides added functionality on top of current SARSAT / COSPAS
• Uses data carrier for acknowledgements
• Accurate position at time of alert
• Open Service (OS)• Commercial Service
(CS)• Public Regulated
Service (PRS)• Safety of Life (SoL)• Search & Rescue
(SAR)
Galileo PerformanceOpen Service
Carriers Single Frequency Dual-FrequencyComputesIntegrity
No
Type of ReceiverIonosphericcorrection
Based on simplemodel
Based on dual-frequencymeasurements
Coverage GlobalAccuracy (95%) H: 15 m
V: 35 mH: 4 mV: 8m
Alarm LimitTime-To-Alarm
Integrity
Integrity riskNot Applicable
Continuity Risk 8x10-6/15 sTiming Accuracy wrt UTC/TAI Not defined 50 nsecCertification/Liability No NoAvailability 99 % - 99.9 %
Service Performance for Open Service with the Satellite Navigation Signalsonly 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)
28 m Vertical accuracy
15 mHorizontal accuracy
95% Confidence
4 mVertical accuracy
2 m Horizontal accuracy
95% Confidence
Ref: users.erols.com
Average GPS accuracy
Average GPS accuracy with differential correction
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 OutlineTechnology in contextSatellite technologies
RFIDSmartdust
Mobile phone based technologiesWireless network based technologies
SummaryConclusion
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
The back (underside) of a typical simple RFID tag
Image: GAO
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
Proximity smartcard and reader
RFID reader in stock room (www.philips.com)
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
• 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)
A 0.25mm2 RFID tagImage: smartcode
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
SmartSignNCLU/0008
www.smartsign.co.uk
Contents
ASK-IT OutlineTechnology in contextSatellite technologies
RFIDSmartdust
Cellular phone based technologiesWireless network technologies
SummaryConclusion
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 OutlineTechnology in contextSatellite technologies
RFIDSmartdust
Mobile phone based technologiesWireless network based technologies
SummaryConclusion
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. Metrocentrethough 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 signal3. Compatibility with existing equipment4. Unit cost5. 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.intel-research.net
• Xbow www.xbow.com• Evans, J. 2005, Central
London Congestion Charging Scheme, presentation, October 7th