Post on 17-Aug-2015
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A Battery-free RFID-based indoor acoustic localization platformYI ZHAO (EVE), JOSHUA SMITH
SENSOR SYSTEMS LAB, UNIVERSITY OF WASHINGTON
2SENSOR SYSTEMS LAB,
UNIVERSITY OF WASHINGTON
Outlineo Introduction
• Application• Challenge• Motivation
o Acoustic RFID localization• System Architecture• Localization method• Performance• Future work
3SENSOR SYSTEMS LAB,
UNIVERSITY OF WASHINGTON
Motivation & In-door Application
Navigation Assistance Robot Auto-manipulation
Object Tracking & Inventory
Activity Awareness & Logging
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Small systemcompatible
Life-timeSize
Efficiency
SENSOR SYSTEMS LAB, UNIVERSITY OF WASHINGTON
Ideal System
Low cost
Low power
High performance Accuracy LatencyRange
5SENSOR SYSTEMS LAB,
UNIVERSITY OF WASHINGTON
Small & low cost System
Acoustic systemo Acoustic Time of Arrival
(ToA) or Acoustic Angle of Arrival (AoA)
o Triangulation
RFID systemo RF Received Signal
Strength Indication (RSSI)o Proximity
Cricket LANDMARC
6SENSOR SYSTEMS LAB,
UNIVERSITY OF WASHINGTON
Pros & Cons
Acoustic system V.S. RFID system Accurate (cm) Inexpensive× New infrastructure × life-time × Size× External Synchronization
Ultra-low power Low cost Size RFID infrastructure × RF multi-path× Low accuracy (m)× Multitude tags or readers
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3 ToA
Acoustic transmitter
SENSOR SYSTEMS LAB, UNIVERSITY OF WASHINGTON
Localization method
Acoustic system RFID system
TriangulationPosition
3 object –transmitter distance
distance
EPC Gen2 RFID system
8SENSOR SYSTEMS LAB,
UNIVERSITY OF WASHINGTON
Idea
Acoustic system RFID system
Low cost tagsEPC Gen2 RFID compatibleLife-time Size Accuracy
? Other Performance? Synchronization
9SENSOR SYSTEMS LAB,
UNIVERSITY OF WASHINGTON
Outlineo Introduction
• Application• Challenge• Motivation
o Acoustic RFID localization• System Architecture• Localization method• Performance• Future work
10SENSOR SYSTEMS LAB,
UNIVERSITY OF WASHINGTON
Acoustic RFID-based Localization
WISP Rx
Reader
• UHF Gen2 RFID tag• Programmable• Extendable for sensing
WISP Tx WISP tag Ultrasonic transmitters (Tx)
11SENSOR SYSTEMS LAB, UNIVERSITY OF
WASHINGTON
System Architecture
WISP Tx
WISP Rx
Reader
Active WISP Ultrasonic transmitters (Tx)
Passive WISP Tone detector (Rx)
Antenna UHF Gen2 Reader
SENSOR SYSTEMS LAB, UNIVERSITY OF WASHINGTON
12
Location method
Reader
WISP Tx
WISP Rx
RF Command & Power
Spy RF Command
25kHz Ultrasound
WISP Rx
SENSOR SYSTEMS LAB, UNIVERSITY OF WASHINGTON
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ToAs measurement
Ultra-sonic emotion
EPC
EPC
(ToAs)
DetectToAs
Reader
Reader
time
WISP Tx
WISP Tx
WISP Rx
WISP RxACK + RN16
16%
84%
Acoustic: 119 (µJ)RFID: 622 (µJ)
SENSOR SYSTEMS LAB, UNIVERSITY OF WASHINGTON
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Performance Energy
Cost
PrecisionLatency
Reader WISP Rx2.2m
Mean 0.7s
Max 1.5 cm
Max 731uJ/ sample
RF Multi-path
RFPower
WISP Tx
SENSOR SYSTEMS LAB, UNIVERSITY OF WASHINGTON
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Experiment and Performance
Reader WISP Tx
x (cm)
Color bar: Latency (s) Size: Precision
Ultrasound Transmission: 102dB SPLMin. detectable SPL for WISP Rx: 71.59dB SPL (x = 5m)
16%
84%
Acoustic: 119 (µJ)RFID: 622 (µJ)
SENSOR SYSTEMS LAB, UNIVERSITY OF WASHINGTON
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Conclusion Energy
Cost
PrecisionLatency
Reader WISP Rx2.2m
Mean 0.7s
Max 1.5 cm
Max 731uJ/ sample
RF Multi-path
RFPower
WISP Tx
17SENSOR SYSTEMS LAB,
UNIVERSITY OF WASHINGTON
Future Work Analog-backsatter
see “Hybrid Analog-Digital Backscatter: A New Approach for Battery-Free Sensing” Vamsi Talla and Joshua R. Smith)
PerformanceAntenna Data processing & localization
algorithm Size Activity recognition
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Questions ?
SENSOR SYSTEMS LAB, UNIVERSITY OF WASHINGTON
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Thank you !
SENSOR SYSTEMS LAB, UNIVERSITY OF WASHINGTON