1. Presenter Ho-lin Chang

2. Introduction Design Implementation Evaluation Conclusion and future Work 2

3. Indoor location-based service 3 Healthcare Security Warehouse

4. Existed indoor localization technique – UWB – Ultrasound – WiFi 4 UWB WiFi Ultrasound

5. UWB (Ubisense) – Accuracy: 10 ~ 20 cm – Time difference of arrival – Expensive specialized hardware (10,000 USD) 5

6. Ultrasonic (Cricket) – Accuracy: 10 ~ 20 cm – Short range – Non-line of sight problem 6

7. WiFi (Ekahau, RADAR) – RSS fingerprinting – Accuracy: 3 ~ 5m – Low cost – Offline training 7

8. TechnologiesAccuracyProperties UWB15 cm Specialized hardware Ultrasound15 cm Short range Non-line of sight problem WiFi300~500 cm Offline training ?cm range Low cost Radio No offline training 8

9. Develop a novel localization system – Spinning beacon (RF) – Indoor environment – Sub-meter accuracy 50% < 39 cm 90% < 70 cm – Low cost Low cost motes (100 USD) Rotation motor 9

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11. S SS X R Doppler Angulation 2 nd Doppler Angulation 3 rd Doppler Angulation LocalizationLocalization X 11 The location of X Doppler Angulation

12. X S v f v project 12

13. X Δf = 0 Hz Δf = 30 Hz Δf = - 30 Hz time frequency Δf (t) = ? 30Hz 0Hz - 30Hz v S 13

14. v(t) S X α x y d r S : (r cosθ, r sinθ) v(t) = (-ωr sinθ, ωr cosθ) θ(t) = ωt+φ X : (d cosα, d sinα) 14

15. S v(t) X α x y R β 15

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17. centroid S SS X R Frequency observation observation Frequency observation observation Time delay estimation estimation Time delay estimation estimation Doppler Angulation 2 nd Doppler Angulation 3 rd Doppler Angulation LocalizationLocalization X 17 The location of X

18. 18 500 Hz A 900 MHz 900 MHz + 500 Hz B centroid centroid Frequency observation observation Frequency observation observation Time delay estimation estimation Time delay estimation estimation Doppler Angulation 2 nd Doppler Angulation 3 rd Doppler Angulation LocalizationLocalization The location of X Typical RF frequency is too high. Radio Interferometry “Radio Interferometric Geolocation” [sensys ‘05] Typical RF frequency is too high. Radio Interferometry “Radio Interferometric Geolocation” [sensys ‘05]

19. 19 centroid centroid Frequency observation observation Frequency observation observation Time delay estimation estimation Time delay estimation estimation Doppler Angulation 2 nd Doppler Angulation 3 rd Doppler Angulation LocalizationLocalization The location of X Delay-and-compare method

20. Hardware – Crossbow MICA2 – Rotational motor Software – TinyOS 1.x – C/C++ 20

21. Testbed – 國發所地下室停車場 – Three spinning beacons – 30 sample points (2m grid) 10 position samples (300 samples) 3 angles (900 angles) Evaluation metrics – Positional error – Angular error Parameter Tuning 21

22. 50% < 3 degrees 90% < 10 degrees 50% < 3 degrees 90% < 10 degrees 22

23. 50% < 3 degrees 90% < 10 degrees 50% < 39 cm 90% < 70 cm 23

24. Data collection time Rotational velocity Interference frequency Angulation filtering threshold – Minimum distance as a quality indicator 24

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27. Lower frequency estimation precision 27

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29. Track fast moving targets Rotational device 29

30. Develop a novel localization system – Spinning beacon – Indoor environment – Low cost – Sub-meter accuracy 39cm / 70cm 30

31. Reduce the localization latency – Reduce the routing time Distributed version Data compression Track the fast moving targets 31

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35. r/d 0.1 0.3 0.5 0 35

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37. 37 k

38. AB X v fAfA fBfB |f A -f B | |f A + Δf X - f B |

39. R S A S S 39

40. 40 Time Signal strength

41. Each infrastructure perceives different Doppler shift. Localize the target by different Doppler shifts X v 41 I I I II I

42.  Maximum Doppler shift f : 900 MHz ω : 2.5 round/sec r : 30 cm ~ 50 cm 42

43. Data collection Routing Localization Data collection Routing Data collection Routing 0.3 ~ 1.5 sec 8 ~ 10 sec 1 st Doppler angulation 2 nd Doppler angulation 3 rd Doppler angulation Localization 43

44. v(t) S X α x y d r S : (r cosθ, r sinθ, 0) v(t) = (-ωr sinθ, ωr cosθ, 0) θ(t) = ωt+φ X : (d cosα, d sinα, h) 44