Localization by RFID

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Localization by RFID

• ref
• LANDMARC Indoor Location Sensing Using Active
  RFID, PerCom03
• by L. Ni, Y. Liu, Y. C. Lau, and A. P. Patil

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Some Thought

• Solution 1 deploying many readers
• Solution 2 deploying many tags

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Goal of This Work

• goal
• few readers and many tags in the environment
• user only carries a tag
• to investigate whether the RFID technology is
  suitable for locating objects with accuracy and
  cost-effectiveness.
• LANDMARC by Active RFID Calibration
• for in-building use.
• utilizing the concept of reference tags.

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LANDMARC Architecture1. readers2. fixed
tags3. tracking tag (carried by user)
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LANDMARC Approach (I)

• In the sensing field
• n readers
• m fixed tags
• u tracking tags (attached to a moving object)
• Readers are configured with continuous mode.
  Detection range 1 8.
• Signal Strength Vector of a tracking tag
• S(S1, S2, , Sn)
• Signal Strength Vector of a fixed tag i
• Fi(?1, ?2, , ?n)

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LANDMARC Approach (II)

• Euclidian distance between a tracking tag and the
  i-th fixed tag
• Location of the tracking tag
• pick the k fixed tags with the smallest
  Euclidean distances
• weighted location

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ExperimentEnvironment
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Environmental Factors Daytime vs. Night

• Do not see much difference in the overall
  accuracy.

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Effect of n (Number of Readers)

• With more RF readers, a better decision can be
  made.

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Related Work

• Several types of location-sensing systems
• Infrared
• Active Badge
• use diffuse infrared technology
• Limitations line-of-sight requirement,
  short-range signal transmission
• IEEE 802.11
• RADAR
• measure signal strengths at multiple BS
• Adv. easy to set up, requires few BSs
• Disadv. the accuracy is not as optimal as
  desired
• Ultrasonic
• Cricket Location Support System Active Bat
  location system
• Use an ultrasound time-of-flight measurement
  technique
• Adv. accurate
• Disadv. require a great deal of infrastructure,
  cost
• RFID
• SpotON use an aggregation algorithm for 3D
  location sensing based on radio signal strength
  analysis, design and build hardware, but has not
  been made available yet