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Feasibility Study of Mobile Phone WiFi Detection in Aerial Search and Rescue Operations
Wei Wang, Raj Joshi, Aditya Kulkarni, Wai Kay Leong, and Ben Leong National University of Singapore
Feasibility Study of Mobile Phone WiFi Detection in Aerial Search - - PowerPoint PPT Presentation
Feasibility Study of Mobile Phone WiFi Detection in Aerial Search - - PowerPoint PPT Presentation
Feasibility Study of Mobile Phone WiFi Detection in Aerial Search and Rescue Operations Wei Wang, Raj Joshi, Aditya Kulkarni, Wai Kay Leong, and Ben Leong National University of Singapore Search and Rescue Highest incidents - Hiking Current
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Highest incidents - Hiking
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Current Methods
Limitations
- Terrain
- Manpower
Ground Based
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Aerial Based
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Hobbyist UAV
Affordable Easy to fly
- iPad or Android
- Autopilot
Easy to deploy
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Current Aerial Approach
- P. Rudol and P. Doherty. Human body detection and geolocalization for UAV search and
rescue missions using color and thermal imagery.
Cameras Real Time Image Processing
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Drawbacks
Requires Line-of-Sight Requires daylight Heavy payload
Optics On-board CPU
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Key Idea
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Is it Feasible?
Signals from a phone? Battery life? Range of detection?
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WiFi Scan/Probe
Probe Request Frame
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WiFi Scan
Time WiFi Scan
…
802.11 Channel
…
Scan interval
Different Scenarios Different Devices Different Intervals
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Different Scenarios
Settings Screen High Home Screen Moderate Display Off Low
Scan Frequency
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Different Devices
HTC Desire
Every 6 s Settings Screen Every 15 s Home Screen Does not scan Display Off
iPhone 5
{8.7, 10.7, 10.7, 10.7, 10.7} repeat Settings Screen {31, 31, 62, 62} repeat Home Screen 3, 7, 12, 17, 62, 62, 62, … Display Off
More results in the paper (Table 1)
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Battery Life
Settings Screen
High Short
Display Off
Low Long
Scan Frequency Battery Life
- Android WiFiManager API
- Increase scan frequency with display off
Custom Android App
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Monsoon Power Monitor
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Sample Result of Battery Life
Motorola Electrify Default Scanning Freq 11 X Default WiFi Setting Screen Our Custom App 11 hours 51 hours 21 hours
More results in the paper (Table 2)
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Passive Detection
4 to 5 Probe Request Frames
WiFi Scan
…
Probe Request Frame
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Active Probing
Request To Send Clear To Send
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Is it Feasible?
Signals from a phone? Battery life? Range of detection?
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DIY Quadrotor
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Detection Range
Distance 250 m
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Effective Range
≈200 m range
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Effect of Phone Orientation
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Conclusion
Phone WiFi signal Battery life: 2 days Range: 200 to 230 m
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Backup Slides
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RSSI Threshold
Good signal strength
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Effect of Altitude
90 m 150 m 210 m
30 m
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Effect of Altitude
No improvement