Transcript 35 ways to find your location - anti-mega

35 ways to find your location
Chris Heathcote
Product experience manager
Orange SA
O’Reilly Emerging Technology Conference
February 9-12, 2004
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
Chris Heathcote
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)
Chris Heathcote
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
Chris Heathcote
measures
accuracy
availability
reliability / trust
output useful to humans
output useful to computers
requirements for conversion (extra enablers needed)
acquire or refine?
Chris Heathcote
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
Chris Heathcote
0. assume: The Earth
EARTH PIC
accuracy: ~510 square Megametres
availability: until we conquer space
requirements: belief in a spherical Earth
best for: acquiring
Chris Heathcote
1. 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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
mobile phone location
mainly available through network operators
methods often made invisible to the user and the
requester
just different accuracy
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
geolocation technology
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
street furniture
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
emerging technology
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
31. broadcast TV/radio triangulation
needs broadcast reception from three different locations
not likely in many areas (planning regulations)
accuracy: 50m
availability: ok
Chris Heathcote
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
Chris Heathcote
location advertising
Chris Heathcote
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
Chris Heathcote
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.
Chris Heathcote
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.
Chris Heathcote
a social future
Chris Heathcote
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
Chris Heathcote
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
Chris Heathcote
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?
Chris Heathcote
questions?
[email protected]
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)
Chris Heathcote