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Location Determination for Mobile Devices Wencong Yuan Apr 27 2012

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Presentation on theme: "Location Determination for Mobile Devices Wencong Yuan Apr 27 2012"— Presentation transcript:

1 Location Determination for Mobile Devices Wencong Yuan Apr

2 Keynotes Cell tower ip GPS Wi-Fi RSS Three-axis gyroscope

3 Cell Tower Triangulation Neighborhood or city level accuracy Two-step, crowd- sourcing approach: Estimate cellular tower location using crowd-sourcing data At serving time, depends on the content in the query, compute device location using : a :nearest tower b : neighbor towers and c : fingerprint

4 IP Geolocation City level accuracy For example

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6 GPS or Assisted-GPS Location Best Available accuracy Power cost and unavailable indoors For example experiment in yanchangs grass ground

7 Wi-Fi Location Similar to cellular,however Wi-Fi radium is much much smaller 30m to 200m vs 500m to 2000m Most Wi-Fi AP are consumer grade, the RF is usually low quality and the radiation patterns among different vendors are usually poor

8 Wi-Fi Location Bad MAC address assignment : Ad-hoc, tethering mode, duplicated addresses Mobile APs

9 Wi-Fi Location Accuracy case study San Francisco

10 Wi-Fi Location

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12 Google Street View Maxrad BMMG24005 SSID MAC

13 Wi-Fi Location

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15 Google Location Database Geolocation API For example :

16 Wi-Fi Location

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18 RSS Radio Signal Strength

19 Three-axis gyroscope & MEMS Accelerometer

20 Q & A More information:

21 Q & A sted_dlcp/www.google.com/zh-CN/us/intl/zh- CN/events/facultysummit/2010/files/mobile_location.pdf sted_dlcp/www.google.com/zh-CN/us/intl/zh- CN/events/facultysummit/2010/files/mobile_location.pdf https://developers.google.com/maps/documentation/places/ g-user-location.html g-user-location.html

22 Q & A us/howto/wp7/web/location-and-my-privacy.aspx us/howto/wp7/web/location-and-my-privacy.aspx


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