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Professor Jonathan Raper LBS Research @ City

Future of Location Technologies Session 1: Positioning How positioning technologies are revolutionising the scope of location-sensitive applications. Professor Jonathan Raper LBS Research @ City. Jonathan Raper -bio.

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Professor Jonathan Raper LBS Research @ City

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  1. Future of Location TechnologiesSession 1: PositioningHow positioning technologies are revolutionising the scope of location-sensitive applications Professor Jonathan Raper LBS Research @ City

  2. Jonathan Raper -bio Professor of Geographic Information Science, Director of the giCentre and LBS @ City Member of the Location and Timing Knowledge Transfer Network, Editor of the Journal of Location Based Services Managing Director of Placr Ltd, LBS startup

  3. 10.15 – 11.30 Session 1: Positioning positioning technologies are revolutionising the scope of location-sensitive applications History of location technologies Cellular positioning technologies & applications GNSS infrastructures, services and devices Wireless positioning technologies & applications Indoor positioning

  4. History of location technologies GIS Ubiquitous computing CyberGuide NeoGeography Guide 1990 1995 2000 2005 2010 2015 GNSS Web Hypergeo Mobile data Lol@ GMM Mobile positioning Plazes

  5. Positioning 101 Positioning technologies all use: Signals in the electromagnetic spectrum Signal time transit from known points converted to distance Distances/ directions to known points are solved for the unknown position

  6. Cellular positioning- Cell-ID

  7. Cellular positioning- Cell-ID with TA

  8. Cellular positioning- EOTD Your location is in the zone at the intersection of 3 cell circular bands

  9. Cellular positioning performance Maps of the area served by individual cell towers are complex GSM signal reception Attenuated by barriers Change with call volume Cells size varies 100m- 30Km Resultant positioning is inconsistent and unreliable Sufficient for some applications

  10. Access to cellular positioning Cell tower IDs are broadcast by each mobile provider as part of the phone service Cellular signal strength is measured by the phone Locations of cell towers are registered in the OfCom SiteFinder database (in theory!) Cell-ID positioning is designed to be used by operators BUT can be used by anyone with cell locations & IDs Cell tower locations have been controversial in UK in a dispute over public access rights to the OfCom database Google has captured cell tower locations and IDs for its Mobile Maps service by crowd sourcing/ war driving

  11. Applications of Cell-ID positioning Operator location calling plans Operator local search Cell broadcast emergency service Google Latitude Positium Barometer m-polling Has held back LBS for 5 years Cell-ID is still the only universal mobile positioning Alternatives required investment- only done in JP

  12. Global Navigation Satellite Systems Satellite systems which depend upon hardware in orbit around the earth (space segment) Other components include: a system of ground stations (control segment) handheld receivers (user segment)

  13. Implemented GNSS GPS The Global Positioning System, created and maintained by US Dept of Defense (1990 ->) Synonymous with GNSS and positioning systems, the most widely used system Free at the point of use GLONASS Russian equivalent, built around the same time Lack of investment – system fell out of use, but now almost restored 18/24 satellites operational Used in high end surveying to augment GPS Free at the point of use

  14. Future systems EU concerned about reliance on a single foreign system developed 20 years ago EU is developing a modern EU civilian service Galileo in development phase, operational 2013(?) Will be interoperable with GPS China and India developing their own systems to be operational by c. 2015

  15. Galileo Services Open service: cf GPS system, free at point of use Commercial service: improved accuracy service guarantee, charged for service Safety of Life service: high quality positioning for safety-critical apps, charged for service Search and rescue service: can transmit Public regulated service: encrypted service resilient to jamming, intended for public bodies such as law enforcement

  16. GPS Positioning GPS receivers now fit on a chip costing $1: up to 20% of mobile phones in the UK now have GPS GPS require line of sight to at least 3 satellites, widely spaced in the sky, to receive signals Timing codes transmitted from each satellite are compared with codes generated on the GPS The codes differ depending on time taken to get from the satellites, this is converted to distance Three such distances allow position calculation from known satellite orbits

  17. GPS signals GPS operates 24/7 and is unaffected by cloud, rain, dark BUT Signals are weak– limited signals indoors, under trees, in bags! Getting position fix means seeing >3 satellites in part of sky you can see As you move visible satellites change Signals reflect off buildings leading to ‘multipath’ error Accuracy under ideal conditions with consumer devices= 5-10m Satnav snaps positions to roads Outer circle= horizon, squares are satellites. Red=blocked, Blue= fixing, black= fixed. Values are DOP quality of fix.

  18. A-GPS GPS needs to get data from satellites to calibrate the position-fixing codes, can take a minute to get @startup This data can be supplied over mobile web cutting time to first fix to a few seconds: this is called assisted GPS The more recent the assistance data, the quicker the fix

  19. Location Determination Architectures

  20. Access to GPS GPS usually connected to a serial port on device- any program can listen to this GPS positions and quality information are output in a NMEA ASCII ‘message’ repeating once per second Position is latitude/ longitude, WGS84 datum Needs some processing to overlay on OS maps GPS have high power needs for continuous use A-GPS services being implemented by operators now GPS driving the majority of applications for location

  21. Applications of GPS GPS are available as Standalone bluetooth devices Dedicated GPS receivers with embedded maps Chips embedded in phones, cameras, cars etc. GPS positioning is suitable for In-car navigation (with road snapping) Personal navigation (with A-GPS) Outdoor LBS- geotagging, mobile guides GPS is used but not ideal for Person tracking Urban LBS- find my nearest, social networking

  22. Comparing cellular and GPS positioning

  23. Wireless positioning WiFi access points (hotspots) broadcast signals up to 100m WiFi chips in devices detect the name of the access point, signal strength, and (sometimes) angle of arrival

  24. Wireless positioning techniques Wireless positioning works either by: survey the hotspots in the area, then ‘fingerprint’ signal strength of hotspots everywhere in area Converting signal strength of three hotspots to distance, trilaterate to find location Wireless signals are affected by signal attenuation, multipath, but accurate 3-5m

  25. Access to wireless positioning Skyhook supply the iPhone wireless positioning solution (XPS) based on fusion of GPS, WiFi & cellular Ekahau offer a commercial solution using fingerprinting mainly for internal building positioning

  26. Applications of wireless positioning Tracking & ‘service following’ within buildings Usage analysis in and around hotspots

  27. Other indoor positioning options Bluetooth positioning Used to send local messages about location/ services RFID chips embedded in the environment RFID scanners can check location/ services available UWB High precision industrial positioning of tags on items TMSI Temporary ID of GSM phones can be tracked for short period within small areas e.g. shopping centres IP positioning Using structure of Internet to situate IP address geographically

  28. Radio-navigation Synchronised signals are broadcast from coastal stations over large geographic areas Difference in the time of reception of the signals is constant along hyperbolic curves Position calculated by intersecting curves from 2 sets of stations Seen as an ideal backup for GPS in case of jamming/ outages Modern eLoran is accurate to 10-20m

  29. Future for positioning There is no universally suitable positioning technology, each has specific domain of usability Services need design for positioning to be used What is the positioning use case for accuracy/ latency Can service survive sudden positioning degradation Positioning fusion is available from Skyhook/ Spotigo/ Navizon but the service is a black box EU funded MetaPos project is working on a positioning quality service- a grey box solution

  30. MetaPos measured Other augmentation Quality classifiers Developers must currently write their own logic to test the accuracy of each positional stream. MetaPos will estimate the positional quality for all streams and send out a message that developers can use Position archive Enhanced multi-position message

  31. Crowdsourced positioning? Navizon buys GPS positions 15 points for cellular tower, 3 points for wifi point: 10,000 points is worth $20.

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