RollCaller: User-Friendly Indoor Navigation SystemUsing Human-Item Spatial Relation

Yi Guo, Lei Yang, Bowen Li, Tianci Liu, Yunhao Liu

Hong Kong University of Science and Technology, Hong Kong

y School of Software and TNLIST, Tsinghua University, China

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Outline

• Motivation

• Our observation: Human-Item Spatial Relation

• System design: User-Friendly Indoor Navigation

• Implementation and Evaluation

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Motivation

• When we are searching something in libraries or supermarkets…

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Motivation

• Items are now tagged with RFID tags

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Motivation

• Items are now tagged with RFID tags

• Using existing RFID localization method is ok but wasteful

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Motivation

• Items are now tagged with RFID tags

• Using existing RFID localization method is ok but wasteful• Need to locate the user and desired item separately• Not accurate enough to be aware when the user is right

near the desired item• Noisy and volatile environment

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Motivation

• Items are now tagged with RFID tags

• Using existing RFID localization method is ok but wasteful• Need to locate the user and desired item separately• Not accurate enough to be aware when the user is right

near the desired item• Noisy and volatile environment

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Methodology

• Recall the difficulties using existing RFID localization:• Need to locate the user and desired item separately• Finding the spatial relation between the user and the

item instead of finding their global cords• Human-Item Spatial Relation

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Methodology

• Recall the difficulties using existing RFID localization:• Need to locate the user and desired item separately• Finding the spatial relation between the user and the

item instead of finding their global cords• Human-Item Spatial Relation• Not accurate enough to be aware when the user is right

near the desired item• Should be aware when the user is right near the desired

item

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Methodology

• Recall the difficulties using existing RFID localization:• Need to locate the user and desired item separately• Finding the spatial relation between the user and the

item instead of finding their global cords• Human-Item Spatial Relation• Not accurate enough to be aware when the user is right

near the desired item• Should be aware when the user is right near the desired

item • Noisy and volatile environment• The characteristics we utilize should be environment

insensitive

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Doppler Frequency Shift in RFID

• Definition:• The frequency change of the received reader carrier

signal due to relative motion between the transmitter (RFID tag or the attached object) and the receiver (reader antenna)

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Doppler Frequency Shift in RFID

• Definition:• The frequency change of the received reader carrier

signal due to relative motion between the transmitter (RFID tag or the attached object) and the receiver (reader antenna)

• How Impinj reader measures Doppler frequency shift

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Observation: human impact

• Noise

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Observation: human impact

• Noise

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Observation: human impact

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Observation: human impact

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Analysis

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Analysis

• Noise Stage

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Analysis

• Noise Stage• Peak Stage

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Human-Item Spatial Relation

• How to describe Human-Item Spatial Relation?

• Anchor Time Stamp

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System Design: RollCaller

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System Design: RollCaller

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System Design: RollCaller

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System Design: RollCaller

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Implementation

• Impinj Speedway Revolution RFID Reader loaded with software version Octane 4.8 • 4 directional reader antennas

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Evaluation: Human-Item Spatial Relation

• Accuracy of Anchor Time Stamp

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• Performance of Reader Antenna Relation Map Generation

Evaluation: User-Friendly Navigation System

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• Performance of User Navigation Service

Evaluation: User-Friendly Navigation System

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• Performance of User Navigation Service (cont.)

Evaluation: User-Friendly Navigation System

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Conclusion

• A novel approach is proposed to depict the spatial relation between user and item using Doppler frequency shift in RFID system.• A user-friendly indoor navigation system is designed

based on the human-item spatial relation• Further works • Multi-user scenario • Real-world deployment

THANK YOU!!

Questions?