Tagoram: Real-Time Tracking of Mobile RFID Tags to High-Precision Accuracy Using COTS Devices

Transcription

1 Tagoram: Real-Time Tracking of Mobile RFID Tags to High-Precision Accuracy Using COTS Devices Xiang-Yang Li Lei Yang, Yekui Chen Chaowei Xiao, Mo Li, Yunhao Liu

2 Tagoram: Real-Time Tracking of Mobile RFID Tags to High-Precision Accuracy Using COTS Devices Xiang-Yang Li Lei Yang, Yekui Chen Chaowei Xiao, Mo Li, Yunhao Liu

3 Outline 01. Motivation 02. State-of-the-art 03. Technique Overview 04. Known Track 05. Unknown Track 06. Implementation & Evaluation 07. Pilot Study 08. Other Research

4 Motivation

5 RFID Technology Real-time Tracking Portal Access control Payment devices Livestock Logistics Passport Automobile immobilizers

6 RFIDs Battery-free RF stickers with unique IDs Imagine you can localize RFIDs to billions of within RFIDs were 10 deployed to 15 cm! for inventory management and object tracking 5-cent stickers to tag any and every object Reader s range is ~15m

7 If we can locate RFID to within 10 to 15cm No more customer checkout lines

8 RFID Proximity as Indicator! RFIDs on Basket, goods

9 Imagine you can localize RFIDs to within 0.1cm to 1 cm! Automatic production

10 Imagine you can localize RFIDs to within 0.1cm to 1 cm! Goal-line technology

11 Imagine you can localize RFIDs to within 0.1cm to 1 cm! Human-computer interface

12 Imagine you can localize RFIDs to within 0.1cm to 1 cm! Baggage sortation in airport

13 Demonstration agoram/youtube

14 High-Precision RFID Tracking Using COTS Devices Drawing in the Air 40cm 30cm

15 TrackPoint Deployed at Airports Reader Industrial computer

16 State-of-the-art

17 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

18 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 P. Nikitin Diff based [2] C.Hekimian-Williams, elta Accurate localization of rfid tags using phase difference. IEEE RFID C. H.Williams 680mm 280mm

19 RFID Tracking & Localization State-of-the-art [1] Lionel M. Ni, Yunhao Liu, etal LANDMARC: Indoor Location Sensing Using Active RFID Wireless Networks 1120mm AOA based [4] Salah Azzouzi, etal New measurement results for the localization of uhf RFID transponders using an angle of arrival (aoa) approach IEEE RFID S. Azzouzi Spatial based [3] P.Nikitin, etal Phase based spatial identification of uhf rfid tags. IEEE RFID P. Nikitin Holographic [5] R. Miesen etal. Holographic localization of passive uhf rfid transponders. IEEE RFID R. Miesen Diff based [2] C.Hekimian-Williams, elta Accurate localization of rfid tags using phase difference. IEEE RFID C. H.Williams 680mm 280mm 300mm 210mm

20 RFID Tracking & Localization State-of-the-art [1] Lionel M. Ni, Yunhao Liu, etal LANDMARC: Indoor Location Sensing Using Active RFID Wireless Networks 1120mm [2] C.Hekimian-Williams, elta Accurate localization of rfid tags using phase difference. IEEE RFID AOA based [4] Salah Azzouzi, etal New measurement results for the localization of uhf RFID transponders using an angle of arrival (aoa) approach IEEE RFID S Azzouzi [3] P.Nikitin, etal Phase based spatial identification of uhf rfid tags. IEEE RFID mm Holographic [5] R. Miesen etal. Holographic localization of passive uhf rfid transponders. IEEE RFID R. Miesen PinIt [6] Jue Wang, etal Dude, where's my card?: RFID positioning that works with multipath and non-line of sight ACM SIGCOMM Jue 2013 Wang RF-Compass [7] Jue Wang, etal RF-compass: robot object manipulation using RFIDs ACM MobiCom 2013 Jue Wang 280mm 300mm 210mm 110mm 12.8mm

21 RFID Tracking & Localization State-of-the-art [1] Lionel M. Ni, Yunhao Liu, etal LANDMARC: Indoor Location Sensing Using Active RFID Wireless Networks 1120mm [2] C.Hekimian-Williams, elta Accurate localization of rfid tags using phase difference. IEEE RFID [4] Salah Azzouzi, etal New measurement results for the localization of uhf RFID transponders using an angle of arrival (aoa) approach IEEE RFID [3] P.Nikitin, etal Phase based spatial identification of uhf rfid tags. IEEE RFID mm [5] R. Miesen etal. Holographic localization of passive uhf rfid transponders. IEEE RFID PinIt [6] Jue Wang, etal Dude, where's my card?: RFID positioning that works with multipath and non-line of sight ACM SIGCOMM Jue 2013 Wang RF-Compass [7] Jue Wang, etal RF-compass: robot object manipulation using RFIDs ACM MobiCom 2013 Jue Wang BackPos [8] Tianci Liu, etal, Anchor-free Backscatter Positioning for RFID Tags with High Accuracy IEEE INFOCOM 2014 Tianci Liu RF-IDRaw [9] Jue Wang, etal, RF-Idaw: Virtual Touch Screen in the Air Using RF Signals IEEE INFOCOM 2014 Jue Wang 280mm 300mm 210mm 110mm 27.6mm 128mm 37mm

22 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 [3] P.Nikitin, etal Phase based spatial identification of uhf rfid tags. IEEE RFID [5] R. Miesen etal. Holographic localization of passive uhf rfid transponders. IEEE RFID [6] Jue Wang, etal Dude, where's my card?: RFID positioning that works with multipath and non-line of sight ACM SIGCOMM 2013 BackPos [8] Tianci Liu, etal, Anchor-free Backscatter Positioning for RFID Tags with High Accuracy IEEE INFOCOM 2014 Tianci Liu RF-IDRaw [9] Jue Wang, etal, RF-Idaw: Virtual Touch Screen in the Air Using RF Signals ACM SigComm 2014 Jue Wang [2] C.Hekimian-Williams, elta Accurate localization of rfid tags using phase difference. IEEE RFID mm [7] Jue Wang, etal RF-compass: robot object manipulation using RFIDs ACM MobiCom mm 300mm 210mm 110mm 27.6mm 128mm 37mm 7mm WE ARE HERE

23 State-of-the-art Techniques 1 RSS based Methods Orientation VS RSS RSS is not a reliable location indicator especially for UHF tags

24 State-of-the-art Techniques 2 Phase based Methods PinIt (SIGCOMM 2013) RF-Compass (MobiCom 2013) Needs to deploy dense reference tags

25 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

26 How Tagoram works? Overview the basic idea

27 Backscatter Communication

28 COTS RFID Reader radians (4096 bits)

29 Problem definition Surveillance region Reader antenna

30 Bird s Eye View of Tagoram Surveillance region Reader antenna

31 Tagoram Case 1. Controllable Case Case 2. Uncontrollable Case

32 Movement with Known Track Controllable case

33 Track Track vs. Trajectory A function of geometric relationships VS Trajectory A function of time space relationships

34 Virtual Antenna Array Inverse Synthetic Aperture Radar Conveyor Initial position

35 RF Hologram

36 The key is How to define the likelihood?

37 RF Hologram Naïve Hologram Augmented Hologram Thermal noise Device diversity Differential Augmented Hologram

38 Naïve Hologram The real signal The theoretical signal A virtual interfered signal

39 Naïve Hologram Sum of all signals Virtual interfered signal

40 Naïve Hologram Imaginary axis Real axis

41 Naïve Hologram Imaginary axis Real axis

42 Naïve Hologram High PSNR

43 Influence from Thermal Noise Experiment Modeling Observations CDF

44 How to deal with thermal noise? Augmented Hologram

45 Augmented Hologram A probabilistic weight

46 Augmented Hologram Shift Ground truth Result scattered

47 What is missing again? Tags are different! Tag diversity

48 Influence from Tag Diversity Tag diversity Modeling Experiment Observations Random test At same position Pass KS-test to be verified over a uniform distribution with 0.5 significant level.

49 How to eliminate tag diversity? Differential Augmented Hologram

50 Differential Augmented Hologram Using difference of difference of phase values

51 Differential Augmented Hologram Ground truth Result

52 How to achieve the real-time? Incremental computations

53 Saving Computations in Spatial Domain Observation: The computations on blue pixel (low level PSNR) are totally wasted

54 Movement with Unknown Track Uncontrollable case

55 Overview 1 2 Estimating Speeds, Fitting tag s trajectory Selecting the optimal trajectory

56 Observations

57 Fitting tag s trajectory More complicate cases are discussed in our paper.

58 Fitting Tag s Trajectory Fitting the speed using NLS

59 Fitting Tag s Trajectory Speed Chain Trajectory

60 Selecting the Optimal Trajectory Unknown!

61 Implementation & Evaluation Purely based on COTS devices

62 Hardware & Software Introduction Reader ImpinJ R420 reader. Tag Alien 2 2 Inlay Software EPCglobal LLRP 4 directional antennas Alien Squiggle Inlay Java

63 Linear Track 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.

64 Tracking Accuracy in Linear Track DAH

65 Impacts of frequency and orientation Impact of frequency Impact of orientation Both frequency and orientation take limited impacts on tracking accuracy.

66 Real-time evaluation 100 reads (~ 3.3s) Read-time Accuracy vs. Real-time

67 Impact of distance No obvious pattern between distance and accuracy

68 Controllable Case with Nonlinear Track The track s internal diameter is 540mm

69 Nonlinear track DAH

70 Under Uncontrollable Case A median of 12.3cm accuracy with a standard deviation of 5cm ---- better method proposed later, with about 1cm accuracy

71 Pilot Study In two airports

72 TagAssist: RFID assisted baggage sortation Automatic Track & Check Service Collaborated with Hainan Airline

73 Where baggage lost? Main factors to baggage loss Relevant to baggage tracking

74 Current workflow Manual sortation It is error-prone step to find the baggage from the carousel in manual sortation. Sortation carousel Sorting baggage

75 How to assist sorter quickly find and sort baggage?

76 Step 1: Upgrade Printer We upgraded the tag printer by embedding a module of RFID reader in printer and an inlay inside each baggage tag.

77 Step 2: TrackPoint Reader Industrial computer

78 Step 3: Visualization

79 Pilot site Beijing Capital International Airport Sanya Phoenix International Airport

80 Setup Each airport contains 5 TrackPoints, 4 visualization screens, and 22 RFID Printers. The two-year pilot study totally spent more than $600,000

81 Setup Consumed 110,000 RFID tags. Involved 53 destination airports, 93 air lines, and 1,094 flights.