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Terje Midtbø - Test of an indoor navigation system

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Terje Midtbø - Test of an indoor navigation system

  1. 1. Are indoor positioning systems mature for cartographic tasks? Evaluating the performance of a commercial indoor positioning system Terje Midtbø Norwegian University of Science and Technology
  2. 2. View of the world?
  3. 3. When we move indoor....
  4. 4. Overview • Indoor maps • Indoor navigation • Testing the WiFi positioning system at NTNU • Measurements • Results • Discussions and conclusions
  5. 5. Do we need indoor navigation? • Localization of persons and equipment at for example hospitals • Find your way in large complex and unknown buildings • Find products in large shopping areas • Most efficient shopping based on shopping list • Tourists at a museum • Alternative emergency exits • Localization of firefighter • …….
  6. 6. Indoor maps
  7. 7. Indoor visualization
  8. 8. Indoor maps
  9. 9. Floor plans
  10. 10. Map made by Jaan Tarmak
  11. 11. Floor plans
  12. 12. Indoor tube
  13. 13. Indoor navigation
  14. 14. GPS-”repeaters”
  15. 15. RFID-system - Present?
  16. 16. Systems based on ultrasound - Need free line of sight
  17. 17. Infrared signals - Present?
  18. 18. Bluetooth
  19. 19. Location by phone signals
  20. 20. WiFi positioning systems
  21. 21. WiFi positioning systems • Time for signal one way • Time for signal both ways • Time for signal in combination with angle to the access points • Phase measurements • Signal strength
  22. 22. Indoor navigation
  23. 23. Cisco positioning system at Norwegian University of Science and Technology (NTNU)
  24. 24. Investigation of the Ciscosystem at NTNU
  25. 25. Network of control points
  26. 26. Measurements • Accurate measurement of control points by surveying equipment and methods • New measured coordinates for the access points • Coordinates measured in UTM, Zone 32N • Transformed into local system used by the Cisco system. Units in feet.
  27. 27. New coordinates for the access points • Average 2D differences: 11.7 feet • Min: 3.7 feet • Max: 19.2 feet
  28. 28. Measurement of positions by using WiFi
  29. 29. Measurement application • Web-based interface • Measured data stored in SQLite database • Both UTM and local coordinate systems
  30. 30. Equipment for the measurement • Laptop with external antenna • Fixed height over the floor • Easy to move to next position
  31. 31. Measurements based on 4 configurations • Old coordinates for access points – no fingerprinting • Old coordinates for access points with fingerprinting • New coordinates for access points – no fingerprinting • New coordinates for access points with fingerprinting
  32. 32. Measurements based on 4 configurations • 10 points were measured in the 1st floor of Lerkendalsbygget • 5 measurements for each point in each configuration
  33. 33. Results
  34. 34. Differences from true values
  35. 35. Measured point and access points
  36. 36. Correlation coefficients X-components, 1- 4 Y-components, 1- 4
  37. 37. Variances
  38. 38. Differences from true values
  39. 39. Discussion and conclusions
  40. 40. • More accurate coordinates for access points gave no significant improvement for measured position • Fingerprinting as it is used today shows no significant improvement in the measured position. Lower variance is still observed. • Correlation between different types of measurements in the same control points indicate that geometry and obstacles are the dominating sources of error • Further research: include obstacles in the model
  41. 41. • More accurate coordinates for access points gave no significant improvement for measured position • Fingerprinting as it is used today shows no significant improvement in the measured position. Lower variance is still observed. • Correlation between different types of measurements in the same control points indicate that geometry and obstacles are the dominating sources of error • Further research: include obstacles in the model • Still too poor precision and accuracy for turn-by-turn navigation • Acceptable for localize equipment • Acceptable for overview of peoples position in social applications

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