Location determinnation for mobile decives

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Location Determinnation for Mobile Decives

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Location determinnation for mobile decives

  1. 1. Location Determination for Mobile Devices Wencong Yuan Apr 27 2012 yuanwencong@gmail.com
  2. 2. Keynotes Cell tower ip GPS Wi-Fi RSS Three-axis gyroscope
  3. 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. 4. IP Geolocation City level accuracy For example : http://ip.taobao.com
  5. 5. http://ip.taobao.com
  6. 6. GPS or Assisted-GPS Location Best Available accuracy Power cost and unavailable indoors For example : experiment in yanchang’s grass ground
  7. 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. 8. Wi-Fi Location Bad MAC address assignment : Ad-hoc , tethering mode , duplicated addresses Mobile APs
  9. 9. Wi-Fi Location Accuracy case study San Francisco
  10. 10. Wi-Fi Location
  11. 11. Wi-Fi Location
  12. 12. Wi-Fi LocationGoogle Street ViewMaxradBMMG24005SSIDMAC
  13. 13. Wi-Fi Location
  14. 14. Wi-Fi Location
  15. 15. Wi-Fi Location Google Location Database Geolocation API For example : http://www.ip2location.com/html5geolocationapi.aspx
  16. 16. Wi-Fi Location
  17. 17. Wi-Fi Location
  18. 18. RSS Radio Signal Strength
  19. 19. Three-axis gyroscope & MEMS Accelerometer
  20. 20. Q&A More information: http://www.ip2location.com/html5geolocationapi.aspx http://www.cnbeta.com/articles/110000.htm http://www.xieyidian.com/3240 http://ucdchina.com/snap/9797 http://en.wikipedia.org/wiki/W3C_Geolocation_API
  21. 21. Q&A http://static.googleusercontent.com/external_content/untrus ted_dlcp/www.google.com/zh-CN/us/intl/zh- CN/events/facultysummit/2010/files/mobile_location.pdf https://developers.google.com/maps/documentation/places/ http://www.zhihu.com/question/19809431 http://developer.android.com/guide/topics/location/obtainin g-user-location.html
  22. 22. Q&A http://www.microsoft.com/windowsphone/en- us/howto/wp7/web/location-and-my-privacy.aspx http://support.apple.com/kb/HT4995?viewlocale=en_US

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