Review & PResentation
Tagoram: Real-Time Tracking of Mobile RFID Tags to High-Precision Accuracy Using COTS Devices Lei Yang, Yekui Chen, Xiang-Yang Li, Chaowei Xiao, Mo Li, Yunhao Liu
Tsinghua University Illinois Institute of Technology, USA
Review & PResentation
Tagoram: Real-Time Tracking of Mobile RFID Tags to High-Precision Accuracy Using COTS Devices Lei Yang, Yekui Chen, Xiang-Yang Li, Chaowei Xiao, Mo Li, Yunhao Liu
Tsinghua University Illinois Institute of Technology, USA
outline TAGORAM
outline Background ~ Motivation ~ State of the Art Overview – How Tagoram Works Detailed Study ~ Movement with known track ~ Movement with unknown track Implementation & Evaluation Pilot Study Concluding Remarks
Imagine you can localize RFIDs to within 0.1cm to 1 cm!
Human-computer interface
Imagine you can localize RFIDs to within 0.1cm to 1 cm!
Baggage sortation in airport
Imagine you can localize RFIDs to within 0.1cm to 1 cm!
Goal-line technology
The Big Picture - This is what they have done in the Lab
small Demo
http://young.tagsys.org/tracking /tagoram/youtube
High-Precision RFID Tracking Using COTS Devices
40cm
30cm
TrackPoint Deployed at Airports Reader
Industrial computer
RFID Tracking & Localization State-of-the-art
LANDMARC
[1] Lionel M. Ni, Yunhao Liu, etal LANDMARC: Indoor Location Sensing Using Active RFID Wireless Networks
Lionel M. Ni
1120mm
2004
2010
2011
2013
2014
RFID Tracking & Localization State-of-the-art
LANDMARC
[1] Lionel M. Ni, Yunhao Liu, etal LANDMARC: Indoor Location Sensing Using Active RFID Wireless Networks
Lionel M. Ni
1120mm
Spatial based
[3] P.Nikitin, etal Phase based spatial identification of uhf rfid tags. IEEE RFID 2010.
P. Nikitin
Diff based
[2] C.Hekimian-Williams, elta Accurate localization of rfid tags using phase difference. IEEE RFID 2010.
680mm
C. H.Williams
280mm
2004
2010
2011
2013
2014
RFID Tracking & Localization State-of-the-art [4] Salah Azzouzi, etal New measurement results for the localization of uhf RFID transponders using an angle of arrival (aoa) approach IEEE RFID 2011.
AOA based
[1] Lionel M. Ni, Yunhao Liu, etal LANDMARC: Indoor Location Sensing Using Active RFID Wireless Networks
S. Azzouzi
Holographic
[5] R. Miesen etal. Holographic localization of passive uhf rfid transponders. IEEE RFID 2011.
R. Miesen
1120mm
Spatial based
[3] P.Nikitin, etal Phase based spatial identification of uhf rfid tags. IEEE RFID 2010.
P. Nikitin
Diff based
[2] C.Hekimian-Williams, elta Accurate localization of rfid tags using phase difference. IEEE RFID 2010.
680mm
C. H.Williams
280mm
300mm 210mm
2004
2010
2011
2013
2014
RFID Tracking & Localization State-of-the-art [1] Lionel M. Ni, Yunhao Liu, etal LANDMARC: Indoor Location Sensing Using Active RFID Wireless Networks
[4] Salah Azzouzi, etal New measurement results for the localization of uhf RFID transponders using an angle of arrival (aoa) approach IEEE RFID 2011.
AOA based S. Azzouzi
Holographic
[5] R. Miesen etal. Holographic localization of passive uhf rfid transponders. IEEE RFID 2011.
R. Miesen
1120mm
[3] P.Nikitin, etal Phase based spatial identification of uhf rfid tags. IEEE RFID 2010.
[2] C.Hekimian-Williams, elta Accurate localization of rfid tags using phase difference. IEEE RFID 2010.
[6] Jue Wang, etal Dude, where's my card?: RFID positioning that works with multipath and non-line of sight ACM SIGCOMM 2013
PinIt
Jue Wang
RF-Compass
[7] Jue Wang, etal RF-compass: robot object manipulation using RFIDs ACM MobiCom 2013
680mm
Jue Wang
280mm
300mm 210mm
110mm 12.8mm
2004
2010
2011
2013
2014
RFID Tracking & Localization State-of-the-art [1] Lionel M. Ni, Yunhao Liu, etal LANDMARC: Indoor Location Sensing Using Active RFID Wireless Networks
1120mm
[4] Salah Azzouzi, etal New measurement results for the localization of uhf RFID transponders using an angle of arrival (aoa) approach IEEE RFID 2011.
BackPos
[8] Tianci Liu, etal, Anchor-free Backscatter Positioning for RFID Tags with High Accuracy IEEE INFOCOM 2014
[5] R. Miesen etal. Holographic localization of passive uhf rfid transponders. IEEE RFID 2011.
[3] P.Nikitin, etal Phase based spatial identification of uhf rfid tags. IEEE RFID 2010.
[2] C.Hekimian-Williams, elta Accurate localization of rfid tags using phase difference. IEEE RFID 2010.
Tianci Liu
RF-IDRaw
[9] Jue Wang, etal, RF-Idaw: Virtual Touch Screen in the Air Using RF Signals IEEE INFOCOM 2014
[6] Jue Wang, etal Dude, where's my card?: RFID positioning that works with multipath and non-line of sight ACM SIGCOMM 2013
PinIt
Jue Wang
Jue Wang
RF-Compass
[7] Jue Wang, etal RF-compass: robot object manipulation using RFIDs ACM MobiCom 2013
680mm
Jue Wang
280mm
300mm 210mm
128mm 110mm
37mm 27.6mm
2004
2010
2011
2013
2014
RFID Tracking & Localization State-of-the-art [1] Lionel M. Ni, Yunhao Liu, etal LANDMARC: Indoor Location Sensing Using Active RFID Wireless Networks
1120mm
[4] Salah Azzouzi, etal New measurement results for the localization of uhf RFID transponders using an angle of arrival (aoa) approach IEEE RFID 2011.
BackPos
[8] Tianci Liu, etal, Anchor-free Backscatter Positioning for RFID Tags with High Accuracy IEEE INFOCOM 2014
[5] R. Miesen etal. Holographic localization of passive uhf rfid transponders. IEEE RFID 2011.
[3] P.Nikitin, etal Phase based spatial identification of uhf rfid tags. IEEE RFID 2010.
[2] C.Hekimian-Williams, elta Accurate localization of rfid tags using phase difference. IEEE RFID 2010.
Tianci Liu
RF-IDRaw
[9] Jue Wang, etal, RF-Idaw: Virtual Touch Screen in the Air Using RF Signals IEEE INFOCOM 2014
[6] Jue Wang, etal Dude, where's my card?: RFID positioning that works with multipath and non-line of sight ACM SIGCOMM 2013
Jue Wang
[7] Jue Wang, etal RF-compass: robot object manipulation using RFIDs ACM MobiCom 2013
680mm
280mm
300mm 210mm
128mm 110mm
37mm 27.6mm 7mm
WE ARE HERE
2004
2010
2011
2013
2014
State-of-the-art TECHNIQUES 1
RSS based Methods
Orientation
VS
RSS
RSS is not a reliable location indicator especially for UHF tags
State-of-the-art TECHNIQUES 2
Phase based Methods
PinIt (SIGCOMM 2013)
RF-Compass (MobiCom 2013)
Needs to deploy dense reference tags
Summary of Challenges
Need mm-level localization accuracy achieved • especially for mobile tags.
Small overhead, COTS devices
• infeasible for using many references for a tracking system spanning a long pipeline.
Fast-changing environment
• multipath reflection of RF signals • varied orientation of tags • Doppler effect
outline Background ~ Motivation ~ State of the Art Overview – How Tagoram Works Detailed Study ~ Movement with known track ~ Movement with unknown track Implementation & Evaluation Pilot Study Concluding Remarks
Backscatter Communication Continuous wave
Device diversity
Double distance
COTS RFID READER
0.0015 radians (4096 bits)
accuracy
Problem Definition
Surveillance region Reader antenna
Utilizing antennas’ locations, sampled phase values and timestamps to find out the tag’s trajectory ?
Virtual Antenna Matrix Inverse Synthetic Aperture Radar
Conveyor
Initial position
RF Hologram
Na誰ve Hologram
Augmented Hologram
Device diversity
Thermal noise
Differential Augmented Hologram
outline Background ~ Motivation ~ State of the Art Overview – How Tagoram Works Detailed Study ~ Movement with known track ~ Movement with unknown track Implementation & Evaluation Pilot Study Concluding Remarks
TAGORAM
Case 1. Controllable Case
Case 2. Uncontrollable Case
Virtual Antenna Matrix Inverse Synthetic Aperture Radar
Conveyor
Initial position
RF Hologram
Surveillance region grids
RF Hologram pixels
The KEY is
How to define the likelihood?
RF Hologram
Na誰ve Hologram
Augmented Hologram
Device diversity
Thermal noise
Differential Augmented Hologram
Na誰ve Hologram 1.5 1 0.5
The real signal Chart Title
0 -0.5 .5.5 1 0.5 -1 1-1
Chart Title
0 -0.5 -1 -1.5
The theoretical signal
2
Chart Title
0 -2
A virtual interfered signal
Na誰ve Hologram
Sum of all signals
Virtual interfered signal
Na誰ve Hologram Imaginary axis
Real axis
If is the initial location, the waves add up constructively.
Na誰ve Hologram Imaginary axis
Real axis
If is not the initial location, the waves canceled out.
Na誰ve Hologram - PLOT
High PSNR
Influence from Thermal Noise
Experiment
Observations
Modeling
CDF
varying with
How to deal with thermal noise?
Augmented Hologram
Augmented Hologram A probabilistic weight
Probability of
Augmented Hologram - Plot Shift
Ground truth
Result scattered
Influence from the Tag Diversity times At same position
Experiment
Observations
Modeling
Random test
Tag diversity
Pass KS-test to be verified over a uniform distribution with 0.5 significant level.
How to deal with TAG DIVERSITY
Differential Augmented Hologram
Differential Augmented Hologram
Using the difference of phase values
Differential Augmented Hologram
Ground truth
Result
Movement with Unknown Track Overview 1 Estimating Speeds, Fitting
tag’s trajectory
2 Selecting the optimal trajectory
outline Background ~ Motivation ~ State of the Art Overview – How Tagoram Works Detailed Study ~ Movement with known track ~ Movement with unknown track Implementation & Evaluation Pilot Study Concluding Remarks
Hardware & Software Overview Reader ImpinJ R420 reader.
4 directional antennas
Tag Alien 2 Ă— 2 Inlay
Alien Squiggle Inlay
Software EPCglobal LLRP
Java
Linear Track
• A mobile object is emulated via a toy train on which a tag is attached. • A camera is installed above the track to capture the ground truth. • The system triggers the camera to take a snapshot on the train when firstly read.
Tracking Accuracy in Linear Track Chart Title 15 10 5 0
DAH
Improve the accuracy by in comparison to RSS, OTrack, PinIt and BackPos.
Controllable Case in Non-Linear Track
• The track’s internal diameter is 540mm
• The distance varies from to
Non-Linear Track
Chart Title 15 10 5 0
DAH
Under Uncontrollable Case
Achieve a median of 12.3cm accuracy with a standard deviation of 5cm.
outline Background ~ Motivation ~ State of the Art Overview – How Tagoram Works Detailed Study ~ Movement with known track ~ Movement with unknown track Implementation & Evaluation Pilot Study Concluding Remarks
Current workflow – Manual sortation
It is error-prone step to find the baggage from the carousel in manual sortation.
Sortation carousel
Sorting baggage
TrackPoint System Reader
Industrial computer
Tracking Visualization
Pilot Sites
Beijing Capital International Airport
Sanya Phoenix International Airport
Setup
• Each airport contains 5 TrackPoints, 4 visualization screens, and 22 RFID Printers. • The two-year pilot study totally spent more than $600,000
Setup
• Consumed 110,000 RFID tags.
• Involved 53 destination airports, 93 air lines, and 1,094 flights.
Tracking Accuracy
Tagoram achieves a median accuracy of 6.35cm in practice.
Concluding remark • Provides real-time tracking of mobile tags with accuracy to mm-level. • Limits almost all negative impacts. – – – –
Multipath effect Doppler effect Thermal noise Device diversity
Not well-studied before
• Implemented purely based on COTS RFID products. • Systematically evaluated under indoor environment and at two airports.
Back uP sliDes TAGORAM