pdf - ASK-IT

ASK-IT for Technical Providers
Overview of Localisation
Technologies
With RFID/Smartdust and Galileo
13th October 2005 - Stuttgart
Richard Fairchild
r.g.fairchild@ncl.ac.uk
School of Civil Engineering & Geosciences
PGR Centre, Cassie Building,
University of Newcastle upon Tyne,
NE1 7RU, England
Contents
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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
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•
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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
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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