35 ways to find your location Chris Heathcote Product experience manager Orange SA

1. 35 ways to find your locationChris HeathcoteProduct experience managerOrange SA O’Reilly Emerging Technology ConferenceFebruary 9-12, 2004

2. why am I here? • in 10 years' time, • there will be • no concept of lost • There will come an age in the far-off years When Ocean shall unloose the bonds of things, When the whole broad earth shall be revealed Seneca

3. where have we come from? • the stars, the sun • reading nature - birds, vegetation, wind direction, ocean swells (Polynesians) • follow a path or coast • the compass • the almanac • the astrolabe • the sextant • accurate clocks • the map • local knowledge (bushcraft)

4. no magic bullet • GPS is not the solution • don't just throw technology at the problem • appreciate the toolbox • match needs to methods for you and your users

5. measures • accuracy • availability • reliability / trust • output useful to humans • output useful to computers • requirements for conversion (extra enablers needed) • acquire or refine?

6. good enough • what is good enough for your users? • how much benefit will they get? • what will it cost them? - time, money, frustration • most current consumer applications - 20-50m

7. 0. assume: The Earth • EARTH PIC • accuracy: ~510 square Megametres • availability: until we conquer space • requirements: belief in a spherical Earth • best for: acquiring

8. the time • (light, dark, timezones) • mainly relative position of people • "It's 3 pm here” • "It's 7 am here” • easiest to use when moving long distances • (these days) • accuracy: 1000 miles (E-W) n/a (N-S) • availability: clocks • requirements: UTC • best for: seafaring, conf calls

9. 2-7. cultural clues • which cell phone operators available? • which wi-fi providers? • phonebox operators? • phone number syntax? • newspapers available? • language being spoken? • accuracy: 1000 - 100,000 miles • availability: civilisations • requirements: up-to-date list of providers/information • best for: acquiring

10. 8. ask someone • POLICEMAN PIC • accuracy: 10 metres ........ • availability: civilisations • requirements: someone who knows where they are, social interaction, a common language • best for: refining

11. 9. use a map • maps tell stories • have to have a map that tells your story • high cognitive load - getting orientation or locating on a map • accuracy: 10 metres - 1 mile • availability: from any good bookstore (good for civilisations) • requirements: geolocated mapping • best for: refining

12. mobile phone location • mainly available through network operators • methods often made invisible to the user and the requester • just different accuracy

13. 10. cell ID • network reports which cell you are using • not always connected to nearest cell • can appear to move as you roam from cell to cell • Timing Advance • http://sitefinder.radio.gov.uk • accuracy: 50 metres - 2 miles • availability: cell coverage • requirements: network hooks • best for: acquiring

14. 11. cell ID (local lookup) • extract cell ID from phone radio stack • can be used for context (home, work) • cell IDs reported may not correspond to available data • proprietary information needed for real geopositioning (or lots of collaborative mapping) • out-of-date / inaccurate data a problem • accuracy: 50 metres -5 miles • availability: wherever there's coverage • requirements: cell ID to lat/long data • best for: acquiring

15. 12. angle of arrival (AOA) • detects angle of phone to transmitter • network could then use more than one transmitter to position • resolution not always precise • - can be 45 degrees • accuracy: 50 metres - 200 metres • availability: coverage • requirements: AOA network • best for: acquiring

16. 13. time difference of arrival (TDOA) • times signal from handset to cell transmitters • http://www.trueposition.com • accuracy: 30 metres - 50 metres • availability: wherever there's coverage (and can find several transmitters) • requirements: network hooks, TDOA-enabled network • best for: acquiring

17. 14. observed time difference (OTD) • phone times differences • between receiving signals • phone passes data to • network for analysis • accuracy: 25 - 250 metres • availability: coverage • requirements: OTD handsets/network • best for: acquiring

18. 15. assisted GPS • assistance information produced by cell network • Simple GPS receiver built into phone handset • combines with information from one or more GPS satellites • needs AGPS enabled network • needs more hardware and software in phone • accuracy: 10 metres - 50 metres • availability: wherever there's coverage (and clear view of one GPS satellite) • requirements: network hooks, AGPS-enabled network, AGPS-enabled phone • best for: acquiring

19. geolocation technology

20. 16. GPS • pretty good accuracy - at a cost • Selective Availability • can appear to move as satellites appear and disappear • other systems - GLONASS, LORAN-C, Galileo

21. GPS contd. • needs more technology (though cost is coming down) • eats battery • needs clear line of sight to 3 or more satellites • - cannot be used in a building, let alone in your pocket • slow (for first fix) • accuracy: 10 metres - 75 metres • availability: clear view of three GPS satellites - four for elevation • requirements: a GPS receiver (and a few dozen satellites) • best for: acquiring

22. 17. WAAS and other GPS enhancements • improve accuracy using other satellites, or fixed radio stations (EGNOS in Europe) • reports any foreseen errors in GPS, and corrects • could be commercialised • accuracy: 2 metres - 25 metres • availability: clear view of three GPS satellites + other data sources (satellite, radio) • requirements: an enhanced GPS receiver (and a few dozen satellites) • best for: acquiring

23. 18. differential GPS • two receivers pretty close to each other (~200km) • signals have had same atmospheric errors • reference receiver is very accurately located • transmits errors in location to roving receiver • accuracy: 1-3 metres • availability: clear view of three GPS satellites at two locations (and communications between) • requirements: DGPS receivers • best for: acquiring

24. street furniture

25. 19. post codes / zipcodes • lookup list from codes to locations • can be very accurate for positioning • proprietary data • goes out of date • only available when at a computer/phone book • accuracy: 10 metres to ... miles • availability: not when mobile • requirements: postcode database • best for: acquiring

26. 20. street names • not all countries have street names • hard to enter when mobile (picking is best) • not unique • accuracy: 20 metres to • hundreds of miles • availability: pretty good • requirements: street address lookup • best for: acquiring or refining

27. 20a. street corners / intersections • high accuracy in built-up areas • great for motorways • even provides orientation in US cities (streets and avenues) • accuracy: 10 metres to 5-10 miles (motorways/"freeways") • availability: pretty good • requirements: street address lookup • best for: refining

28. 21. street numbers • great - if they're available • need street name as well • accuracy: 10-100 metres • availability: pretty good • requirements: street number and address lookup • best for: refining

29. 22. business names • databases go out of date • hard to enter when mobile • multiple locations • accuracy: 10 metres • availability: good in urban locations • requirements: business address lookup • best for: refining

30. 23. landmarks and littlemarks • user picks what they can see • orientation from large landmarks • (e.g. skyscrapers) • maybe from street frontage photos • accuracy: < 1 mile - as far as the eye can see • availability: ok in urban locations, depends on • rural geography • requirements: landmark database and lookup • best for: refining

31. 24-26. phone boxes / public transport stops / utility markings • bus stops, fire hydrants, • street lamps, traffic lights • proprietary data - but open for • collaborative mapping • often localised - to council or area, • let alone a city • accuracy: 10 metres • availability: ok in urban locations • requirements: access to database • best for: acquisition

32. 27. location street signs • dedicated street signs for geolocation • a nice idea in principle • installed in London by a taxi firm (proprietary) • http://www.location-net.co.uk/taxipoint/ • accuracy: 10 metres • availability: bad • requirements: installation of street furniture • best for: acquisition

33. 28. geowarchalking • postcode • street name • street numbers • lat/long graffiti • spray paint/sticker barcodes • accuracy: depends • availability: bad • requirements: crazy pirate geo-graffiti gangs • (Marc Smith's 2%) • best for: acquisition

34. emerging technology

35. 29. dead reckoning • accelerometers, electronic compasses • highly accurate reckoning of relative position • needs an accurate location (and time source) to start with • accuracy: as good as initial lock • availability: everywhere • requirements: accelerometer and decoding • best for: refining

36. 30. wi-fi triangulation • needs wi-fi nodes with a location server • needs accurate location of nodes • ubiquitous wi-fi is an American dream • used in art galleries and museums • At this conference - • http://activecampus2.ucsd.edu/oreilly/ • accuracy: 5-20m. • availability: bad • best for: refining

37. 31. broadcast TV/radio triangulation • needs broadcast reception from three different locations • not likely in many areas (planning regulations) • accuracy: 50m • availability: ok

38. 32. IP lookup • currently uninformative (normally the address of an ISP or reseller) • some work to make this more dynamic • accuracy: a country, a continent

39. location advertising

40. 33. encoding of location in access point name / location points • wi-fi node advertises location through SSID • need a standard to be useful in more than one network of hotspots • http://www.orangecone.com/archives/000088.html • accuracy: 100m

41. 34. local servers / Rendezvous • fixed machines advertise their location through wi-fi • need a standard • http://www.headmap.org/ • accuracy: 100-300m • 35. bluetooth • accuracy: 1-100m.

42. 36. RFID • RFID card scanned; scanner is geolocated • or in reverse - card senses if scanned (and potential lookup) • http://www.starhill.us/mappingsensornets.html • accuracy: dead - 50m.

43. a social future

44. 37. who you are near (inference) • people (and people's things) reveal context • if one of these is geolocated, this could be used by all • 38. objects you are near • your device asks others around for more-accurate locations • "phone reports 50m accuracy” • "wi-fi connected computer nearby reports 10m accuracy by connected GPS” • "bluetooth node reports 5m accuracy with WAAS” • either pick what appears to be the most accurate, or aggregate and average the locations

45. 39. the road most traveled • recording and aggregation of accurate flows • time, speed and quantity of movement • maps autogenerate themselves • better directions, even see which direction your friends have been or normally go • Amsterdam Real Time, http://www.waag.org

46. a few messages • location finding helps fulfill a basic human need - security • technology helps - but no one technology fulfills every need • what happens when technology fails? • electronic acquisition pays no attention to geography - or the way humans think about their location • choose your weapons carefully • expect and use more than one method • what if you want to be lost?

47. questions? • 35ways@anti-mega.com • http://anti-mega.com • presentation available from: • http://undergroundlondon.com/etech_35ways.ppt • http://locative.net • Geowanking mailing list • #geo on irc.oftc.net • hope you had a good ETCon! • (thanks to Rael and all at O'Reilly)