ALPS: A Bluetooth and Ultrasound Platform for Mapping and - - PowerPoint PPT Presentation

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ALPS: A Bluetooth and Ultrasound Platform for Mapping and - - PowerPoint PPT Presentation

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SenSys 2015 ALPS: A Bluetooth and Ultrasound Platform for Mapping and Localization Patrick Lazik, Niranjini Rajagopal, Oliver Shih, Bruno Sinopoli, Anthony Rowe Electrical and Computer Engineering Department Carnegie Mellon University

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SLIDE 1

SenSys 2015

ALPS: A Bluetooth and Ultrasound Platform for Mapping and Localization

Patrick Lazik, Niranjini Rajagopal, Oliver Shih, Bruno Sinopoli, Anthony Rowe

Electrical and Computer Engineering Department Carnegie Mellon University

http://wise.ece.cmu.edu

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SLIDE 2

SenSys 2015

Localization Approaches

Range-Based (Distance) Range-Free (Landmarks)

GPS LIDAR RADAR Ultrasonic Cellular Kinect WiFi IMU Magnetic Field Audio Bluetooth Low-Energy RFID VLC

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SenSys 2015

  • Uses near-ultrasound communication
  • Commodity mobile hardware
  • Provide accurate indoor localization

– Sub-meter, confined to rooms

  • Time Difference of Arrival (TDOA)

ALPS – Smartphone Acoustic

Localization Ultrasonic Ranging for Mobile Devices

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SLIDE 4

SenSys 2015

System Architecture

Speaker Phone

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SenSys 2015

Challenges

  • Transmitting omnidirectional ultrasonic signals is difficult

with standard speakers

  • Installation and setup
  • Obstructions (bodies) can block transmitters

– TDOA to TOF (RTAS 2015)

  • Multipath signals cause measurement errors

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SLIDE 6

SenSys 2015

Introducing ALPS

  • Easily Deployable Ultrasonic Localization
  • BLE, 802.15.4, Ultrasonic

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SenSys 2012

Come see our Demo!

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SenSys 2015

ALPS Enhancements

  • Embedded beacons

– Hardware – Ultrasonic Horn Design

  • Improved data transmission
  • Simplified system setup
  • Tracking with IMU data
  • Multipath Detection

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SenSys 2015

Original Hard-Wired Setup

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SenSys 2015

The ALPS Platform

Horn BLE Antenna 802.15.4 Antenna Piezo Bullet Driver Microphone Battery Pack

Back Front

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SenSys 2015

The ALPS Platform

TLV320 Audio Codec Atmega256RFR2 SoC RF Amplifier Microphone

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SenSys 2015

Omnidirectional Sound Dispersion

  • Ideally ALPS beacons should disperse

ultrasound in omnidirectional manner

  • Directivity pattern of speakers becomes more

narrow as frequency increases

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SenSys 2015

Omnidirectional Sound Dispersion

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SenSys 2015

Omnidirectional Horn Design

  • Horns increase the overall efficiency of driving elements
  • A rotated horn will disperse sound omnidirectionally

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SenSys 2015

Omnidirectional Sound Dispersion

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SenSys 2015

Omnidirectional Horn Performance

  • Evaluation criteria:

– Directional distortion: deviation from omnidirectionality – Frequency distortion: flatness of frequency response

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SenSys 2015

Omnidirectional Horn Performance

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SenSys 2015

ALPS Enhancements

  • Embedded beacons
  • Improved data transmission

– Integration with BLE

  • Simplified system setup
  • Tracking with IMU data
  • Multipath Detection

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SenSys 2015

Transmitter Identification

  • Originally modulated transmitter ID onto

ultrasound carrier

– Long packet length, limited robustness – Ultrasound is good for ranging – BLE is better for data

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SenSys 2015

System Architecture

BLE Data Beacon Phone

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SenSys 2015

The ALPS Platform

BLE Antenna 802.15.4 Antenna CC2460 SoC

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SenSys 2015

BLE TDMA Slot Synchronization

τtx0 τtx1 Slot 0 Slot 1 a) b) τtx2 . . . c) τtx3 τtx4 τrx0

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SenSys 2015

BLE Synchronization Performance

  • Typical TDMA slot length of 100ms

100ms advertisement interval 50ms advertisement interval 20ms advertisement interval

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SenSys 2015

ALPS Enhancements

  • Embedded beacons
  • Improved data transmission

– Integration with BLE

  • Simplified system setup
  • Tracking with IMU data
  • Multipath Detection

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SenSys 2015

User Assisted Mapping and Setup

  • Precise positioning of beacons, even in small

installations is difficult

  • Developed automated setup procedure for determining

beacon locations and floorplan

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SenSys 2015

User Assisted Mapping and Setup

Beacon

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SenSys 2015

Inter-beacon Ranging

Inter-Node Ranging Beacon

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SenSys 2015

Synchronize Receiver to Transmitters

Inter-Node Ranging Beacon

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SenSys 2015

Define Z Axis

Inter-Node Ranging Beacon Phone Beacon Ultrasound z

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SenSys 2015

Define X and Y Axis

Inter-Node Ranging Beacon Phone Beacon Ultrasound z x y

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SenSys 2015

Draw Floorplan

Inter-Node Ranging Beacon Phone Beacon Ultrasound z x y

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SLIDE 31

SenSys 2015

User-Assisted Mapping Performance

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SLIDE 32

SenSys 2015

ALPS Enhancements

  • Embedded beacons
  • Improved data transmission

– Integration with BLE

  • Simplified system setup
  • Tracking with IMU data
  • Multipath Detection

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SLIDE 33

SenSys 2015

Tracking Use Case – Insufficient Beacons

Beacons blocked

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SenSys 2015

ALPS Localization Performance

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x (m)

  • 6
  • 4
  • 2

2 4 6 8 10 y (m) 2 4 6 8 10 12

Localization

True path Localization

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SLIDE 35

SenSys 2015

ALPS and PDR Performance

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x (m)

  • 6
  • 4
  • 2

2 4 6 8 10 y (m) 2 4 6 8 10 12

Localization, PDR, both, with no obstacles

True path Dead Reckoning Localization Localization + Tracking

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SenSys 2015

ALPS with Obstacles Performance

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x (m)

  • 6
  • 4
  • 2

2 4 6 8 10 y (m) 2 4 6 8 10 12

Localization

True path Localization

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SenSys 2015

ALPS with Obstacles and PDR Performance

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x (m)

  • 6
  • 4
  • 2

2 4 6 8 10 y (m) 2 4 6 8 10 12

Localization and Loc+PDR

True path Localization Localization + Tracking

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SLIDE 38

SenSys 2015

ALPS and PDR Performance

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SenSys 2015

ALPS Enhancements

  • Embedded beacons
  • Improved data transmission

– Integration with BLE

  • Simplified system setup
  • Tracking with IMU data
  • Multipath detection

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SenSys 2015

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Multipath range

BLE

True range

Ultrasonic

  • Signal propagation different
  • Attenuation characteristics different

Multipath Detection

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SenSys 2015

SVM Classifier Features and Accuracy

Ratio of received ultrasound RSSI to TOF distance Ratio of received BLE RSSI to BLE distance RMS delay spread of received ultrasound signal

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SenSys 2015

Impact of Training Samples of FiB and Fus Performance

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SenSys 2015

Conclusion

  • Indoor localization systems need to be: Precise,

cheap and simple to install

– ALPS has cheap hardware and supports a user- assisted setup procedure

  • Range based localization systems suffer from

multipath ranging error

– ALPS incorporates a machine learning based LOS/ NLOS filtering approach

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SenSys 2015

Questions

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