35 ways to find your location
DESCRIPTION
Presentation at O'Reilly Emerging Technology 2004.TRANSCRIPT
- 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?
- 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?
- [email_address]
- 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)