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INF245 Mobile applications Location Based Services

INF245 Mobile applications Location Based Services. H 2007 Ola Bø. 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

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INF245 Mobile applications Location Based Services

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  1. INF245 Mobile applicationsLocation Based Services H 2007 Ola Bø Molde University College INF 245 Fall 2007 OBø

  2. 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. Location based services Introduction Molde University College INF 245 Fall 2007 OBø

  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 caller’s number • Phase 2: to be completed by 1.10.2001:difficult • 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 Molde University College INF 245 Fall 2007 OBø

  4. Emergency services Traffic information Navigation Service personnel management Fleet management Tracking Packages Cars Wireless advertising Finding services Map services Weather information Applications using positioning information Molde University College INF 245 Fall 2007 OBø

  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 Molde University College INF 245 Fall 2007 OBø

  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? Molde University College INF 245 Fall 2007 OBø

  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/s=0,000 000 1 s maximum deviation between base station clocks Molde University College INF 245 Fall 2007 OBø

  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 Molde University College INF 245 Fall 2007 OBø

  9. More possibilities for network/handset- based positioning • Signal strength • Relative time difference supported by a database for the area Molde University College INF 245 Fall 2007 OBø

  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) Molde University College INF 245 Fall 2007 OBø

  11. 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 Molde University College INF 245 Fall 2007 OBø

  12. 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,00706.6064,E,1,04,3.2,92.9,M,42.7,M,0.0,0000*45 $GPGSA,A,3,05,09,30,04,,,,,,,,,4.6,3.2,3.3*3A $GPRMC,121431.839,A,6244.1788,N,00706.6064,E,0.14,136.60,041104,,*05 $GPGGA,121432.839,6244.1791,N,00706.6061,E,1,04,3.2,92.4,M,42.7,M,0.0,0000*46 $GPGSA,A,3,05,09,30,04,,,,,,,,,4.6,3.2,3.3*3A $GPRMC,121432.839,A,6244.1791,N,00706.6061,E,0.11,144.76,041104,,*0C $GPGGA,121433.839,6244.1788,N,00706.6059,E,1,04,3.2,92.9,M,42.7,M,0.0,0000*49 $GPGSA,A,3,05,09,30,04,,,,,,,,,4.6,3.2,3.3*3A $GPRMC,121433.839,A,6244.1788,N,00706.6059,E,0.15,143.11,041104,,*0C $GPGGA,121434.839,6244.1786,N,00706.6055,E,1,04,3.2,93.6,M,42.7,M,0.0,0000*42 $GPGSA,A,3,05,09,30,04,,,,,,,,,4.6,3.2,3.3*3A $GPRMC,121434.839,A,6244.1786,N,00706.6055,E,0.18,149.46,041104,,*0C $GPGGA,121435.839,6244.1788,N,00706.6056,E,1,04,3.2,93.5,M,42.7,M,0.0,0000*4D $GPGSA,A,3,05,09,30,04,,,,,,,,,4.6,3.2,3.3*3A $GPGSV,3,1,10,05,71,213,41,09,47,144,36,14,44,281,00,30,40,242,40*7B $GPGSV,3,2,10,07,22,048,00,04,19,086,28,01,13,330,00,20,09,010,00*73 $GPGSV,3,3,10,31,08,040,00,24,05,117,00*72 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 (0=invalid, 1=GPS fix, 2=DGPS 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 Molde University College INF 245 Fall 2007 OBø

  13. 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. Molde University College INF 245 Fall 2007 OBø

  14. 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) Molde University College INF 245 Fall 2007 OBø

  15. Telenor’s positioning product Molde University College INF 245 Fall 2007 OBø

  16. 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 it’s own right! Molde University College INF 245 Fall 2007 OBø

  17. Geographic information systems Demonstration and Discussion • Demonstration • Norgesglasset http://ngis2.statkart.no/norgesglasset/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? Molde University College INF 245 Fall 2007 OBø

  18. 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 Molde University College INF 245 Fall 2007 OBø

  19. Other solutions • http://www.mapsolutions.no/mapengine.html • http://www.opengeospatial.org • Ugland IT • Statkart Molde University College INF 245 Fall 2007 OBø

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