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