tagoram

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