INF245 Mobile applications Location Based Services

1
INF245 Mobile applications Location Based
Services

• H 2007
• Ola Bø

2
Location based services Introduction

• Uses information about the users position to
  deliver a service
• Valuable for the mobile user
• Possible services
• Emergency services
• Finding the route
• Advertise local events and services
• Driving force
• USA FCC requires an improved 911-service
• Europe E-112
• Europe and Asia m-commerce
• What if the service will be used somewhere else
  than current position

• 1. generation The user registers position
  information himself postal code or city/street
• Position-dependent content driving directions,
  restaurants, shops, weather
• 2. generation Can find position with no user
  assistance. low accuracy
• Similar to 1. generation
• 3. generation Accurate positioning with no user
  assistance
• Starting services, updated information from
  nearby shops and detailed maps, fleet mgmt.

3
The E911-service

• 911 is the US emergency number
• FCC requires positioning of emergency calls
• Position as important as type of emergency
• Phase 1 done
• What tower received the call and callers number
• Phase 2 to be completed by 1.10.2001difficult
• Positioning accuracy 124 m in 67 of the cases
• should be 95 finished by 2005
• Consequences
• Accurate positioning of mobile phones available
  in the US
• Many possible applications will they become
  reality Cost, Privacy legislation
• Similar initiative in Europe E112

4
Applications using positioning information

• Emergency services
• Traffic information
• Navigation
• Service personnel management
• Fleet management

• Tracking
• Packages
• Cars
• Wireless advertising
• Finding services
• Map services
• Weather information

5
Mobile positioning techniques

• Accuracy vs. cost
• Network based solutions
• Cost effective, but inaccurate 1000 m
• Works for all handsets
• Handset based solutions
• More expensive and more accurate 10 m
• Mixed solutions

6
Network based positioningCell identity

• The cell is identified
• But where is the user in the cell?
• Accuracy 1 km
• Dependent upon cell size
• Unusable for many purposes
• Can be improved
• Cell divided into sectors
• Distance from tower measured in Timing Advance
• Combined method Cell global Identity-Timing
  Advance (CGI-TA) Accuracy 100m
• Applications get information from MPC (Mobile
  Positioning Center)
• Higher accuracy in cities than in the countryside
  Why?

7
Network based positioningTime of Arrival

• Uses information from three or more base stations
• Time for arrival of signal from phone to base
  stations is measured
• Base stations with accurate and synchronous
  clocks (expensive)
• Distance from phone to base stations is measured
• With three or more base stations position can be
  accurately determined
• No handset modification necessary
• Accuracy 50 m30m/300 000 000m/s0,000 000 1 s
  maximum deviation between base station clocks

8
Hand set based positioningEnhanced Observed Time
Difference (E-OTD)

• Same solution as for Time of Arrival, but on the
  handset
• The base station sends accurate and synchronized
  clock signals
• Time difference is measured
• Position is calculated in handset or by network
• Requires special handsets

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More possibilities for network/handset- based
positioning

• Signal strength
• Relative time difference supported by a database
  for the area

10
Handset based positioning GPS

• Global positioning system
• 24 satellites in orbit
• Limitations
• requires free sight to at least 3 satellites
• trees and buildings block
• No GPS inside buildings
• But up to the building entrance
• Heavy calculations
• Takes time to find first position (20-40s)

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Handset based positioning GPS

• GPS as a separate unit
• Now starting to be embedded
• Falling prices, augmenting use
• One Way communication from satellite
• Built upon triangulation
• Accurate 10 m improved using D-GPS
• Can be combined with other positioning services
• Assisted GPS (A-GPS)
• Calculations performed on server
• Satellite information already collected quicker
  positioning
• Differential GPS solutions can improve accuracy
  to 10 cm

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Data stream from a GPS
GPRMC,121430.839,A,6244.1787,N,00706.6071,E,0.12,
67.71,041104,,3C GPGGA,121431.839,6244.1788,N,00
706.6064,E,1,04,3.2,92.9,M,42.7,M,0.0,000045 GPG
SA,A,3,05,09,30,04,,,,,,,,,4.6,3.2,3.33A GPRMC,1
21431.839,A,6244.1788,N,00706.6064,E,0.14,136.60,0
41104,,05 GPGGA,121432.839,6244.1791,N,00706.606
1,E,1,04,3.2,92.4,M,42.7,M,0.0,000046 GPGSA,A,3,
05,09,30,04,,,,,,,,,4.6,3.2,3.33A GPRMC,121432.8
39,A,6244.1791,N,00706.6061,E,0.11,144.76,041104,,
0C GPGGA,121433.839,6244.1788,N,00706.6059,E,1,0
4,3.2,92.9,M,42.7,M,0.0,000049 GPGSA,A,3,05,09,3
0,04,,,,,,,,,4.6,3.2,3.33A GPRMC,121433.839,A,62
44.1788,N,00706.6059,E,0.15,143.11,041104,,0C GP
GGA,121434.839,6244.1786,N,00706.6055,E,1,04,3.2,9
3.6,M,42.7,M,0.0,000042 GPGSA,A,3,05,09,30,04,,,
,,,,,,4.6,3.2,3.33A GPRMC,121434.839,A,6244.1786
,N,00706.6055,E,0.18,149.46,041104,,0C GPGGA,121
435.839,6244.1788,N,00706.6056,E,1,04,3.2,93.5,M,4
2.7,M,0.0,00004D GPGSA,A,3,05,09,30,04,,,,,,,,,4
.6,3.2,3.33A GPGSV,3,1,10,05,71,213,41,09,47,144
,36,14,44,281,00,30,40,242,407B GPGSV,3,2,10,07,
22,048,00,04,19,086,28,01,13,330,00,20,09,010,007
3 GPGSV,3,3,10,31,08,040,00,24,05,117,0072
Sentence GGA Function Global Positioning Fix
Data Example GPGGA,120757,5152.985,N,00205.733,W
,1,06,2.5,121.9,M,49.4,M,,52 Synopsis time of
fix (hhmmss), latitude, N/S, longitude, E/W, Fix
quality (0invalid, 1GPS fix, 2DGPS fix),
number of satellites being tracked, horizontal
dilution of position, altitude above sea level, M
(meters), height of geoid (mean sea level) above
WGS84 ellipsoid, time in seconds since last DGPS
update, DGPS station ID number, checksum fra
http//www.scnt01426.pwp.blueyonder.co.uk/Articles
/GPS/NMEA.htm
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EGNOS European Geostationary Navigation Overlay
Service

• Satellite based augmentation system
• Supplements the GPS and Galileo positioning
  system reporting their errors to improve accuracy
• Started July 2005 2m accuracy, 99 availability
• Certified for life critical applications from
  2008
• Galileo is an European parallel to the GPS
  system to be completed by 2011.

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Proximity based positioning

• If you are connected you are there!
• Built upon short range technology
• RFID
• BT
• WLAN (proprietary solutions to identify the base
  station being used)

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Telenors positioning product
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Geographic Information Systems GIS

• Coordinates is not enough
• GIS gives position information a context
• GIS can contain a wealth of information
• What is where
• Patterns
• Applications
• What is near by m-commerce
• Driving directions
• Emergency messages
• In Norway GAB (Grunneiendommer, Adresser og
  Bygningsmasse) is a developed GIS
• GIS a study in its own right!

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Geographic information systems Demonstration and
Discussion

• Demonstration
• Norgesglasset http//ngis2.statkart.no/norgesglass
  et/default.html
• Visveg http//www.visveg.no/
• Gule sider www.gulesider.no
• Finn http//www.finn.no/finn/map
• Mappoint http//www.mappoint.com
• Drøfting
• What generation of LBS do the presented services
  represent
• How can the services exploit position information
• Can the services be interesting in a mobile
  context as well
• What must be changed to permit mobile use of the
  services?

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Development of location based services

• A Market in development
• A Complex situation
• Proprietary API for access
• Network based API
• Mobile Positioning Center MPC
• Hand set based API
• Standardization
• Location Interoperability Forum under OMA
• Open Gis Consortium
• ISO/TC211

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Other solutions

• http//www.mapsolutions.no/mapengine.html
• http//www.opengeospatial.org
• Ugland IT
• Statkart