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Ground Robotics Research CenterUniversity of Michigan College of Engineering
SAFE LocatorYohan Baillot
Director – AR GroupITT Advanced Engineering & Sciences
[email protected](703) 964 7702
SAFE• “Situational Awareness for Fire Emergencies”
• System Concept
• SAFE Locator• GPS• Inertial Navigation• RF Localization
• Ad hoc Mesh Network
• SAFE User Interface• Augmented Reality• Mobile, Vehicle Based
PPL Workshop, Worchester, MA, August 3-4, 2009
SAFE Locator: Genesis
PPL Workshop, Worchester, MA, August 3-4, 2009
Military RadioJTRSMeshData
Ranging
Wearable Computer
Military Battery
INS
Velocimeter
• Project funding redirected
• Volatile TOA measurements
• INS• Calibration
• Step Size, • Offset, • Magnetic Field
• Motion Dynamics• Repeatability
• 10X Rule
Track Recorded Actual Error (m) Error (%)Walk 800 412.25 441.50 29.2 7%
Stair(U) 800 26.54 16.21 -10.3 -64%Stair(D) 800 34.84 16.21 -18.6 -115%
Sideways 800 40.00 26.40 -13.6 -52%Walk 833 451.48 441.50 -10.0 -2%Run 833 420.71 441.50 20.8 5%
Stair(U) 460 16.73 16.21 -0.5 -3%Stair(D) 460 16.21 16.21 0.0 0%Crawling 400 29.90 26.40 -3.5 -13%
Average Error 11.84 7.4%
SAFE Locator: an auspicious start
PPL Workshop, Worchester, MA, August 3-4, 2009
• Project funding redirected
• Conversion of Military Radio• Waveform changes• Cost
• INS• Calibration
• Step Size• Offset• Magnetic Field
• Motion Dynamics• Repeatability
Track Recorded Actual Error (m) Error (%)Walk 800 412.25 441.50 29.2 7%
Stair(U) 800 26.54 16.21 -10.3 -64%Stair(D) 800 34.84 16.21 -18.6 -115%
Sideways 800 40.00 26.40 -13.6 -52%Walk 833 451.48 441.50 -10.0 -2%Run 833 420.71 441.50 20.8 5%
Stair(U) 460 16.73 16.21 -0.5 -3%Stair(D) 460 16.21 16.21 0.0 0%Crawling 400 29.90 26.40 -3.5 -13%
Average Error 11.84 7.4%
SAFE Locator: an auspicious start…,
PPL Workshop, Worchester, MA, August 3-4, 2009
SAFE Locator: Plan B?
• Q2 2008: Replace radios• COTS 900MHz• MSSI UWB
PPL Workshop, Worchester, MA, August 3-4, 2009
SAFE Locator: Plan B?
• Q3 2008: Evaluate trilateration alternatives• Sparse anchor networks• Accuracy• Scalability• Dynamic anchor selection• Extensibility
PPL Workshop, Worchester, MA, August 3-4, 2009
SpaseLoc (sub-problem algorithm for sensor localization)
SAFE Locator: But what about the INS?
• Q2/2006: Publication of POS research paper
• Q3/2006: On-site system evaluation
• Q4/2006: Contract with UM to fund PDR research• System miniaturization• IMU placement alternatives• Algorithm enhancements
• Q4/2008: PDR Field Trials
• Q1/2009: PDR Integration
PPL Workshop, Worchester, MA, August 3-4, 2009
• Personal Odometry System (POS)
PPL Workshop, Worchester, MA, August 3-4, 2009
Personal Dead-reckoning (PDR) System Under development at the University of Michigan
• Principle of operation: Foot-mounted IMU
• Features• Eliminates effect of accelerometer drift with every step• Uses patent-pending Heuristic Drift Elimination (HDE) algorithm to
• eliminate effects of gyro drift, • eliminate errors due to MEMS gyros’ sensitivity to linear acceleration
• Performance• Average heading errors near zero in walks of unlimited duration!• Average position errors <1% of distance
traveled in walks > 30 min.• Average elevation (Z-axis) errors: < 1 m.
• Limitations• Above performance attained only in buildings.
On-boot version of the IMU mount
PPL Workshop, Worchester, MA, August 3-4, 2009
Personal Dead-reckoning (PDR) System Under development at the University of Michigan
• Additional Features• Does not require any user-specific calibration
whatsoever.• Indifferent to user changing step-length or gait • Indifferent to user walking backward or sideways• Two IMU mounting versions: in-heel and
external• Temperature control system assures stable IMU
temperature under all environmental conditions• Three modes for Z-axis estimates:
Mode Advantages Disadvantages
Quick Mode Average errors: <1.0 m. No need for floor height measurements.
Uses barometer – therefore not compatible with pressurization techniques
Precision Mode
Average errors < 0.2 m. Requires measurement of floor heights and uses differential barometer
Firefighter mode
Works without barometer. Average errors: <1.5 m.
Reliability decreases in high risers.Requires measurement of floor height.
In-heel IMU is entirely contained within the heel of a boot
PPL Workshop, Worchester, MA, August 3-4, 2009
Typical Experimental Results
PDR-based trajectory of a 1-hour/2.5-mile walk through seven buildings, overlaid over a satellite photo. Average heading error: ~0o. Final position error: 8 m (0.2% of distance traveled).
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-120 -100 -80 -60 -40 -20 0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300
CSEDOW
GGB
EECS
Autolab
Duderstadt
Pierpont
100 m
GGB
Pierpont
Start/End
SAFE Locator: Q2/2009 Status
• Personnel Locator• PDR Integration• SpaseLoc Integration• INS / TOA Fusion
• Ad hoc Network• Mesh Comms & TOA• Self initialize, Self locate• Centralized / Decentralized
PPL Workshop, Worchester, MA, August 3-4, 2009
1. Reference Nodes self localize• Network connected• GPS/UWB• Correct GPS errors
Reference Nodes
Start Position
2. Reference Nodes initialize INS• Start Position• Heading
3. TOA/INS fusion within Reference Node range
4. INS only when beyond Reference Node range
SAFE Locator: 2010 Goals
PPL Workshop, Worchester, MA, August 3-4, 2009
• Sensor Upgrades• Algorithm Enhancements• GPS Integration
INS
• Distributed Processing• Collaborative Localization• Longer Standoff Range
RF Localization
• Anchor Strategy Enhancements• Common Processor Platform• P&P Enhancements
Architecture
• Design/Packaging• SWAP Reduction• Operational Testing
Commercialization
