Transcript Location Based Services

Location meets social networking
Larry Magid
co-director, ConnectSafely.org
founder, SafeKids.com
[email protected]
Location-Based Services
A service that depends on the network knowing your location
Examples include:
•Emergency 911
•Navigation
•Vehicle Assistance (OnStar)
•Child Finder
•Advertising
•Local Search
•Traffic applications
•Automotive Vehicle Location (Fleet tracking)
•Asset Tracking
•Personnel Tracking
•Social Mapping
•Self Guided Tours
•Finding elderly or individuals with Alzheimers
Estimated size of LBS market
• At least $750 Million in 2007 US & Canada
• Estimated to grow by at least 75 to 100% next
two years
Estimates include WiFi but not RFID
Source: David H. Williams; LBS Globe.com, E911 LBS Consulting
Why phones have location
capability
The Federal Communication Commission’s Enhanced
911 Rules
• Phase 1 requires carriers, upon valid request by a
local Public Safety Answering Point (PSAP), to
report the telephone number of a wireless 911
caller and the location of the antenna that
received the call.
• Phase II requires wireless carriers to provide far
more precise location information, within 50 to
300 meters in most cases.
Technologies used
GPS (Global Positioning System)
• 24 satellites in orbit. Typically 5 to 8 are visible
from any one place
– Device gets fix by triangulating position of satellites.
– Distance calculated by time it takes for signal to travel
from satellite to receiver. Calculating the time it takes
from 4 satellites provides an accurate fix.
Regular GPS vs. AGPS
Regular GPS is fine when you’re in the clear with a
strong battery, powerful receiver and a line-of-sight
view of the sky. But indoors and with less powerful
systems, you need an assist. Another problem is TTFF
(Time to First Fix).
AGPS (Assisted Global Position System)
– The receiver communicates with an “assistance server”
that helps calculate position using GPS coordinates and
possibly other data such as distance from cell phone
tower(s). Computations may take place on remote server.
Extra data from the networks
AGPS systems can also download map data,
points of interests and other data on demand
even to a device with limited storage capacity.
Telenav for example can plot gas stations
based on gas prices.
Triangulation
• Triangulation (also known as
trilateration) uses the known locations of
two or more reference points, and the
measured distance between the subject and
each reference point.
Positioning relative to cell towers
• Whenever any device is in contact with a cell
tower, it’s possible to determine which tower
and, therefore, the approximate location
within a general radius.
• When it can receive data from two towers, the
fix is more accurate but still approximate.
• Three or more towers provides a reasonably
accurate fix.
1 Point: Rough idea
2 Points: Aproximate
3 Points: Accurate fix
“Fancy Math Triangulation Off Cell Towers”*
U-TDOA (Uplink Time Difference of Arrival ) technology locates by
comparing the time it takes signal to reach several Location
Measurement Units installed at base stations. Accurate to
within 50 meters. (www.3g.co.uk)
Advanced Forward Link Trilateration (AFLT)
• Does not use satellites but phone takes time distance
measurements from nearby towers (ideally at least 3) to
determine location
• *Sam Altman, Founder Loopt
WPS: Wifi Positioning System
• Skyhook Wireless has been driving the country
mapping out WiFi hotspots in top 2,500 cities. Has
database of > 16.5 million access points, public
private & encrypted.
• A device can get a fix from a WiFi hotspot
• Increasing number of handheld devices including
“Skype Phones” can access WiFi systems
Wi-Fi works best in dense urban areas
Source: Skyhook Wireless
AIM applications
Geo Tagging
Self-Reporting
Users tell the system where they are and/or
what they are doing
Short distance technologies
• RFID – Now used to track assets. Could be
used in hospitals to track patient movement
within facility
– Ericsson’s Bluetooth Local Infotainment Point
(BLIP). Download coupons as you walk near a BLIP
device
Technology is neutral, uses aren’t
• Like many technologies, location-based
services have an enormous potential for good
but they can also be misused.
• The potential for misuse doesn’t invalidate the
technology, but it does mean that we must be
thoughtful about how we apply it, especially
during its developmental stages.
Please join us in the online safety
community’s forum for mobile &
fixed social networking.
[email protected]
[email protected]