35 ways to find your location
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Presentation at O'Reilly Emerging Technology 2004.
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- 1. 35 ways to find your location Chris Heathcote Product
experience manager Orange SA OReilly Emerging Technology Conference
February 9-12, 2004
- 2. why am I here?
- 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?
- reading nature - birds, vegetation, wind direction, ocean
swells (Polynesians)
- local knowledge (bushcraft)
- 4. no magic bullet
- don't just throw technology at the problem
- match needs to methods for you and your users
- 5. measures
- output useful to computers
- requirements for conversion (extra enablers needed)
- 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
- accuracy: ~510 square Megametres
- availability: until we conquer space
- requirements: belief in a spherical Earth
- 8.
- mainly relative position of people
- easiest to use when moving long distances
- accuracy: 1000 miles (E-W) n/a (N-S)
- best for: seafaring, conf calls
- 9. 2-7. cultural clues
- which cell phone operators available?
- accuracy: 1000 - 100,000 miles
- availability: civilisations
- requirements: up-to-date list of providers/information
- 10. 8. ask someone
- accuracy: 10 metres ........
- availability: civilisations
- requirements: someone who knows where they are, social
interaction, a common language
- 11. 9. use a map
- 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
- 12. mobile phone location
- mainly available through network operators
- methods often made invisible to the user and the requester
- 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
- http://sitefinder.radio.gov.uk
- accuracy: 50 metres - 2 miles
- availability: cell coverage
- requirements: network hooks
- 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
- 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
- accuracy: 50 metres - 200 metres
- requirements: AOA network
- 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
- 17. 14. observed time difference (OTD)
- between receiving signals
- accuracy: 25 - 250 metres
- requirements: OTD handsets/network
- 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
- 19. geolocation technology
- 20. 16. GPS
- pretty good accuracy - at a cost
- 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)
- needs clear line of sight to 3 or more satellites
- - cannot be used in a building, let alone in your pocket
- accuracy: 10 metres - 75 metres
- availability: clear view of three GPS satellites - four for
elevation
- requirements: a GPS receiver (and a few dozen satellites)
- 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
- 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)
- 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
- availability: clear view of three GPS satellites at two
locations (and communications between)
- requirements: DGPS receivers
- 24. street furniture
- 25. 19. post codes / zipcodes
- lookup list from codes to locations
- can be very accurate for positioning
- only available when at a computer/phone book
- accuracy: 10 metres to ... miles
- availability: not when mobile
- requirements: postcode database
- 26. 20. street names
- not all countries have street names
- hard to enter when mobile (picking is best)
- availability: pretty good
- requirements: street address lookup
- best for: acquiring or refining
- 27. 20a. street corners / intersections
- high accuracy in built-up areas
- 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
- 28. 21. street numbers
- great - if they're available
- availability: pretty good
- requirements: street number and address lookup
- 29. 22. business names
- hard to enter when mobile
- availability: good in urban locations
- requirements: business address lookup
- 30. 23. landmarks and littlemarks
- user picks what they can see
- orientation from large landmarks
- maybe from street frontage photos
- accuracy: < 1 mile - as far as the eye can see
- availability: ok in urban locations, depends on
- requirements: landmark database and lookup
- 31. 24-26. phone boxes / public transport stops / utility
markings
- bus stops, fire hydrants,
- street lamps, traffic lights
- proprietary data - but open for
- often localised - to council or area,
- availability: ok in urban locations
- requirements: access to database
- 32. 27. location street signs
- dedicated street signs for geolocation
- installed in London by a taxi firm (proprietary)
- http://www.location-net.co.uk/taxipoint/
- requirements: installation of street furniture
- 33. 28. geowarchalking
- spray paint/sticker barcodes
- requirements: crazy pirate geo-graffiti gangs
- 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
- requirements: accelerometer and decoding
- 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
- http://activecampus2.ucsd.edu/oreilly/
- 37. 31. broadcast TV/radio triangulation
- needs broadcast reception from three different locations
- not likely in many areas (planning regulations)
- 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
- 41. 34. local servers / Rendezvous
- fixed machines advertise their location through wi-fi
- 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
- 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
- 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?
- presentation available from:
- http://undergroundlondon.com/etech_35ways.ppt
- hope you had a good ETCon!
- (thanks to Rael and all at O'Reilly)