Presentation on theme: "Personalized Services Using Location Based Services (LBS) Wei-Meng Lee (firstname.lastname@example.org) Technologist & Co-Founder Active Developer http://www.activedevelop.com/"— Presentation transcript:
1 Personalized Services Using Location Based Services (LBS) Wei-Meng Lee Technologist & Co-Founder Active Developer O’Reilly Emerging Technology Conference February 9-12, 2004
2 Agenda Motivation for LBS – E911 Location-Based Services – the fundamentalsLocation-Based Services – the techniquesTelcos adopting LBS in the USLBS Applications ModelSome Case Studies in SingaporeIssues of LBS
3 * Singapore Location: About 140 kilometres north of the equator It is 42 kilometers long and 23 kilometers across at its widest pointTotal area: sq km (slightly more than 3.5 times the size of Washington, DC )Population 4,608,595 (July 2003 est.)*
4 Motivation for LBS – E911The wireless Enhanced 911 (E911) rules seek to improve the effectiveness and reliability of wireless 911 service by providing 911 dispatchers with additional information on wireless 911 calls.Phase I requires carriers, upon appropriate 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 100 meters in most cases.
5 Triangulation – Locating the caller Triangulate from two angles – at least two reference pointsTriangulate from two points – at least three reference pointsThree-dimensional triangulation – at least four reference points
6 Triangulate from two angles Two lines intersect at one point
7 Triangulate from two points Two circles intersect at two points; a third circle is needed to remove the second point.
10 Cell of OriginThe tower transmitting the call is deemed to be the cell of origin.Good for densely populated area where towers are close together.
11 Useful for sparely populated area; less likelihood of interference. Angle of Arrival (AOA)Measures the angle at which a cell phone’s signal arrives at two or more towersUseful for sparely populated area; less likelihood of interference.
12 Time Difference of Arrival (TDOA) Measures the time at which a cell phone’s signal reaches at three or more towersVendors using TDOA:Cell-Loc (TruePosition (
13 Enhanced Observed Time Difference (E-OTD) Measures the time at which signals from towers reaches the handset (requires changes to handsets and requires GSM).Vendor supporting E-OTD:Cambridge Positioning Systems (CPS)(
14 Global Positioning Systems Uses 27 satellites (3 for backup) orbiting around the earth twice each day, emitting low-power radio waves in the frequency range of 1500MHz.Very costly to maintain – using GPS for LBS costs about $12 billion to build, staff, maintain and monitor. Lifespan: 7-15 years.
16 Selective Availability GPS was originally developed in the 1980s by the U.S. Department of Defense for military use.The U.S. Department of Defense introduced Selective Availability (SA) to degrade the signal accuracy so that civilian usage could be restricted.In May 2000, President Clinton announced that the U.S. would no longer degrade the accuracy of GPS. With SA turned off, the accuracy of the GPS data could be within 5 meters.In the second Gulf war against Iraq in 2003, the United States reportedly degraded the GPS system so that Iraq could not make use of GPS against U.S. forces.While this is good news for the military, it certainly affected all those who rely on GPS for their daily activities. So, if you arrived at the wrong destination using a GPS navigational system, now you know why!
17 Assisted-GPS (A-GPS) Handset broadcast request to towers Location server tells handset which satellite to listen toHandset listens to GPS satellitePositional information combined with ranging information are sent back to the Location serverLocation server calculates the actual position and returns the coordinates to the handset, or application serverAssisted-GPS (A-GPS)
19 Comparing the different Location Determination Technologies Cell-IDEOTDTDOAGPSAGPSConsistencyPoorAverageVery goodAccuracy100m – 20km2D Positioning100m-500mGood5m-100m3D PositioningExcellent5m-50mTTFF1sVery Good5s30s-15min5-10sNeed to modify handset?NoYesNetwork EfficiencyOverall CostLowHighModerateSummary* Source: SnapTrack (
20 Telcos adopting the various technologies AT&T is adding GSM to its network as part of its migration to the third generation (3G), and implement E-OTD in its GSM network. VoiceStream, the largest GSM operator in the U.S., is also supporting EOTD.Sprint PCS, Alltel, U.S. Cellular, and Nextel Communications, have opted for a handset-based E-911 system using the satellite-based global positioning system (GPS).Verizon and Western Wireless plan to use a network-based system, using a combination of TDOA and AOA.
26 Geo-Gaming“Our game technology enables producers to place virtual representations of products in specific geo-graphic areas. For example, a teen playing one of our games near a popular fast-food chain could find virtual “burgers” that could be consumed to provide extra energy or power to their game avatar.”
28 Some Potential LBS applications Enhanced Shopping ExperienceSending promotional information to your cell phoneInforming you on the discounts you are entitled toMapping ApplicationsTraffic MonitoringSingapore has the Electronic Road Pricing (ERP)WarehousingEmergency servicesTracking