35 ways to find your location

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


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


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)


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


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")


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


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


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%)


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)