Post on 24-Dec-2015
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RFID and Positioning
Outline
• RFID Introduction• Indoor Localization• RFID positioning Algorithm– LANDMARC– RFID-Based 3-D Positioning Schemes
• RFID application
Outline
• RFID Introduction• Indoor Localization• RFID positioning Algorithm– LANDMARC– RFID-Based 3-D Positioning Schemes
• RFID application
RFID
• Automatic identification technology• Transponder, interigator, antennaReaderRF
Characteristics
• No line-of-sight required• Multiple simultaneous reads• Long read range(active tag)• Long life span• Very low cost• No (so) orientation sensitive
RFID Localization
• An important application of RFID – Localization (warehouse, shipping container, ……)
Outline
• RFID Introduction• Indoor Localization• RFID positioning Algorithm– LANDMARC– RFID-Based 3-D Positioning Schemes
• RFID application
Indoor Localization
• Infrared– Active Badge– IR emitter communicate with a network of sensors in
the building– Line-of-sight required, transmission range is short
• IEEE 802.11– RADAR– Combine empirical measurement and signal strength
modeling to determine location– NIC needed, not practical for small device
Indoor Localization
• Ultrasonic– Cricket Location Support System & Active Bat
Location System– Use time-of-arrival to measure distances– High accuracy, expensive
• RFID– LANDARC– Use RFID tags as reference tags– Coarse accuracy, 2-D
Outline
• RFID Introduction• Indoor Localization• RFID positioning Algorithm– LANDMARC– RFID-Based 3-D Positioning Schemes
• RFID application
LANDMARC
本圖取自” LANDMARC: Indoor Location Sensing Using Active RFID”, Wireless Networks, Vol. 10, 701-710, 2004.
LANDMARC
Define : Signal Strength Vector of
tracking tags Signal Strength Vector of
reference tags
• Methodology Suppose : n RF readers m reference tags u tracking tags
),...,,( 21 unuuu SSSS ),1( uu
),...,,( 21 mnmmm ),1( mm
LANDMARC
Define : Euclidean distance in signal strength between a
tracking tag and a reference tag j
When there are m reference tags, a tracking tag has its E vector as
n
i uijiuj SE1
2)( ),1( mj
),...,,( 21 umuuu EEEE
LANDMARC
• To determine the weights assigned to different neighbors
• Tracking tag location:
k
i iii yxwyx1
),(),(
k
ii
ij
E
Ew
1 2
2
1
1
Outline
• RFID Introduction• Indoor Localization• RFID positioning Algorithm– LANDMARC– RFID-Based 3-D Positioning Schemes
• RFID application
Active Scheme Setup
本圖修改自“ RFID-Based 3-D Positioning Schemes”, Infocom 2007.
Effective Reference Tag Set
Effective Reference Tag Set
Coordinate Calculation
Compensate Degree of Irregularity
• Problem– Diff. antenna gains and
path loss in different directions
– Imperfect circle
• Solution– Low cost antenna array
with multiple radiation elements
– Superpose responses
本圖取改自“ RFID-Based 3-D Positioning Schemes”, Infocom 2007.
Passive SchemeDetails
Outline
• RFID Introduction• Indoor Localization• RFID positioning Algorithm– LANDMARC– RFID-Based 3-D Positioning Schemes
• Conclusion
Conclusion
LANDMARC Advantage:– No need for a large number of expensive RFID
reader.– Environmental dynamic can easily be
accommodated.– Location information is more accurate and
reliable.
Conclusion
• Although active RFID is not designed for accurate indoor location sensing, LANDMARC approach does show that active RFID is a viable cost-effective candidate for indoor location sensing.
• Three problem :– SSI & Power level– Long latency– Variation of the behavior of tags
Conclusion
• Proposed two 3-D positioning schemes– Both schemes are based on nonlinear
optimization methods
本圖取改自“ RFID-Based 3-D Positioning Schemes”, Infocom 2007.
Reference
• [1] LIONEL M. NI, YUNHAO LIU, YIU CHO LAU, ABHISHEK P. PATIL, “LANDMARC: indoor location sensing using active RFID ”, in PerCom 2003
• [2] Chong Wang, Hongyi Wu, and Nian-Feng Tzeng, “RFID-Based 3-D Positioning Schemes”, in INFOCOM 2007