Lessons Learned Building TeamTrak: An UrbanOutdoor Mobile Testbed - PowerPoint PPT Presentation
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Title:
Lessons Learned Building TeamTrak: An UrbanOutdoor Mobile Testbed
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Garmin GPS-18 or HP iPAQ Navigation. PNI V2Xe digital 2-axis compass. Watchport/V2 digital camera ... GPS needs assistance when deployed in urban environments ... – PowerPoint PPT presentation
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Title: Lessons Learned Building TeamTrak: An UrbanOutdoor Mobile Testbed
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Lessons Learned Building TeamTrak An
Urban/Outdoor Mobile Testbed
Jeffrey Hemmes, Douglas Thain, Christian
Poellabauer, Chris Moretti, Phil Snowberger, and
Brendan McNutt University of Notre Dame
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Overview
- System Components
- Experience with Sensor Measurements
- Experience with Field Tests
- Lessons Learned and Future Work
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System Components
- Hardware
- 32 Lenovo X41 Thinkpad tablet computers
- 8 HP iPAQ hx2795b PDA
- Garmin GPS-18 or HP iPAQ Navigation
- PNI V2Xe digital 2-axis compass
- Watchport/V2 digital camera
- SparkFun SerAccel v5 digital accelerometer
- Network
- Wireless Ethernet (802.11b) in ad hoc mode
- Standard Windows IP configuration
- Routing Protocol
- Simple distance-vector routing à la RIP or DSDV
- Sensor data included in routing packets
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System Components
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System Components
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Experience With Sensors
- GPS position subject to drift errors
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Experience With Sensors
- Effect of compass roll on heading
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Experience With Field Tests
- Conducted field tests with undergraduate class
- Purpose
- Gain practical experience with the system
- Uncover implementation and design issues
- Suggest areas for future research
- Objectives
- Find a designated node hidden somewhere on campus
- Communicate its location to others via routing
protocol - Construct longest unbroken chain of links possible
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Experience With Field Tests
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Lessons Learned and Future Work
- GPS needs assistance when deployed in urban
environments at human scale - Obtaining a fix in many locations practically
impossible - Partial obstructions of the horizon can delay
obtaining a GPS fix by as much as 5 to 10 minutes - Extreme cases of position drift can render GPS
information useless for many applications - Need new ways of estimating location based on the
reported position and location quality of other
nodes
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Lessons Learned and Future Work
- Sensors can compensate for poor network
connectivity - Ad hoc network connections haphazard at best
- Displaying last known position of other nodes
proved quite helpful for locating a particular
node - Even very transient connections with few packets
exchanged allowed users to identify other nodes
positions fairly quickly - How long do we maintain stale data?
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Lessons Learned and Future Work
- Human operators play an important role
- Users generally tend to prefer maintaining
connectivity, and will adjust their position
accordingly - Such behavior can be exploited to augment network
protocols in mobile applications - Much work in this area remains to be done
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For More Information
- General
- http//www.nd.edu/teamtrak
- Downloads
- http//www.nd.edu/teamtrak/start
- Contact
- Jeffrey Hemmes
- jhemmes_at_cse.nd.edu
- www.nd.edu/jhemmes
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