www.DLR.de • Chart 1

> IPIN 2013 > Patrick Robertson

Simultaneous Localization and Mapping for
Pedestrians using Distort...
www.DLR.de • Chart 2

> IPIN 2013 > Patrick Robertson

Magnetic Localization in Buildings?
- Listing
- Second Level
- Thir...
www.DLR.de • Chart 3

> IPIN 2013 > Patrick Robertson
www.DLR.de • Chart 4

> IPIN 2013 > Patrick Robertson

Human Step Measurement: Odometry

-Zero Velocity Updates
during sti...
www.DLR.de • Chart 5

> IPIN 2013 > Patrick Robertson

Unaided Human Odometry Exhibits Drift
www.DLR.de • Chart 6

> IPIN 2013 > Patrick Robertson

Magnetic Localisation in Buildings
- Goldenberg, Geomagnetic naviga...
www.DLR.de • Chart 7

> IPIN 2013 > Patrick Robertson

Simultaneous Localization and Mapping (SLAM)
- Simultaneously Local...
www.DLR.de • Chart 8

> IPIN 2013 > Patrick Robertson

Objectives for this Paper
- Magnetic SLAM for “free roaming” pedest...
www.DLR.de • Chart 9

> IPIN 2013 > Patrick Robertson

Basis for Derivation: Dynamic Bayesian Network
“MagSLAM”
- B: Magne...
www.DLR.de • Chart 10 > IPIN 2013 > Patrick Robertson

MagSLAM Implementation with a Sequential
Monte Carlo Filter
- FastS...
www.DLR.de • Chart 11 > IPIN 2013 > Patrick Robertson

Magnetic Field Strength at Ground Level: Finding
a Robust Map Repre...
www.DLR.de • Chart 12 > IPIN 2013 > Patrick Robertson

Hierarchical Magnetic Field Map
Composed of Regular Grids
www.DLR.de • Chart 13 > IPIN 2013 > Patrick Robertson

Mapping: Spatial Binning of Measurements
1: 65 mT
2: 63 mT
3: 94 mT...
www.DLR.de • Chart 14 > IPIN 2013 > Patrick Robertson

Localization: Conjugate Bayesian Analysis
- Assume the measurements...
www.DLR.de • Chart 15 > IPIN 2013 > Patrick Robertson

Prior PDF

Evolution of the Posterior Predictive
- No Measurements
www.DLR.de • Chart 16 > IPIN 2013 > Patrick Robertson

Histogram per bin

Posterior PDF

Evolution of the Posterior Predic...
www.DLR.de • Chart 17 > IPIN 2013 > Patrick Robertson

Histogram per bin

Posterior PDF

Evolution of the Posterior Predic...
www.DLR.de • Chart 18 > IPIN 2013 > Patrick Robertson

Results
www.DLR.de • Chart 19 > IPIN 2013 > Patrick Robertson

Video of Walking in Holodeck
www.DLR.de • Chart 20 > IPIN 2013 > Patrick Robertson

Comparison of MagSLAM Map with Ground Truth
Not visited by
the huma...
www.DLR.de • Chart 21 > IPIN 2013 > Patrick Robertson

Position Error Evolution

Average error over 4 similar datasets: ~1...
www.DLR.de • Chart 22 > IPIN 2013 > Patrick Robertson

MagSLAM Map of a Residential Flat
www.DLR.de • Chart 23 > IPIN 2013 > Patrick Robertson

Error at the Reference = Revisited Starting
Location

Error for Mag...
www.DLR.de • Chart 24 > IPIN 2013 > Patrick Robertson

meters

Example in Large Office Buildings - 1

meters
www.DLR.de • Chart 25 > IPIN 2013 > Patrick Robertson

meters

MagSLAM from IPIN Demo
www.DLR.de • Chart 26 > IPIN 2013 > Patrick Robertson

Example in Large Office Buildings - 2
Chart 27

> IPIN 2013 > Patrick Robertson

3D Video
www.DLR.de • Chart 28 > IPIN 2013 > Patrick Robertson

Thanks!
Questions?
Videos on our website

www.kn-s.dlr.de/indoornav...
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Simultaneous Localization and Mapping for Pedestrians using Distortions of the Local Magnetic Field Intensity in Large Indoor Environments

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Presentation at IPIN 2013; Simultaneous Localization and Mapping for Pedestrians using Distortions of the Local Magnetic Field Intensity in Large Indoor Environments

Patrick Robertson 1, Martin Frassl 1, Michael Angermann 1, Marek Doniec 2, Brian J. Julian 2, Maria Garcia Puyol 1, Mohammed Khider 1, Michael Lichtenstern 1, and Luigi Bruno 1

1 Institute of Communications and Navigation, German Aerospace Center (DLR)
2 Computer Science and Artificial Intelligence Laboratory, MIT

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Simultaneous Localization and Mapping for Pedestrians using Distortions of the Local Magnetic Field Intensity in Large Indoor Environments

  1. 1. www.DLR.de • Chart 1 > IPIN 2013 > Patrick Robertson Simultaneous Localization and Mapping for Pedestrians using Distortions of the Local Magnetic Field Intensity in Large Indoor Environments Patrick Robertson1, Martin Frassl1, Michael Angermann1, Marek Doniec2, Brian J. Julian2, Maria Garcia Puyol1, Mohammed Khider1, Michael Lichtenstern1, and Luigi Bruno1 1 Institute of Communications and Navigation, German Aerospace Center (DLR) 2 Computer Science and Artificial Intelligence Laboratory, MIT Presented at IPIN 2013, October 2013, Montbeliard, France
  2. 2. www.DLR.de • Chart 2 > IPIN 2013 > Patrick Robertson Magnetic Localization in Buildings? - Listing - Second Level - Third Level - Fourth Level - Fifth Level Photo source: The Salt Lake Tribune “One person’s noise is another’s signal” – Brad Parkinson
  3. 3. www.DLR.de • Chart 3 > IPIN 2013 > Patrick Robertson
  4. 4. www.DLR.de • Chart 4 > IPIN 2013 > Patrick Robertson Human Step Measurement: Odometry -Zero Velocity Updates during still phase! -Pioneering work: Foxlin, 2005 -Proposition: Use a foot mounted IMU with colocated magnetometer. “Close to the ground  lots of signal”
  5. 5. www.DLR.de • Chart 5 > IPIN 2013 > Patrick Robertson Unaided Human Odometry Exhibits Drift
  6. 6. www.DLR.de • Chart 6 > IPIN 2013 > Patrick Robertson Magnetic Localisation in Buildings - Goldenberg, Geomagnetic navigation beyond the magnetic compass, 2006 - Haverinen, Kemppainen, A global self-localization technique utilizing local anomalies of the ambient magnetic field, 2009 - Zhang, Martin, Robotic mapping assisted by local magnetic field anomalies, 2011 - Gozick et al, Magnetic maps for indoor navigation, 2011 - Riehle et al., Indoor waypoint navigation via magnetic anomalies, 2011 - Kim et al., Indoor positioning system using geomagnetic anomalies for smartphones, 2012 - Le Grand, Thrun, 3-axis magnetic field mapping / fusion for indoor localization, 2012 - Angermann et al., Characterizing Magnetic Field in Buildings, 2012 - Frassl et al., Magnetic maps of indoor environments for precise localization of legged and non-legged locomotion, 2013
  7. 7. www.DLR.de • Chart 7 > IPIN 2013 > Patrick Robertson Simultaneous Localization and Mapping (SLAM) - Simultaneously Localizing and has been done in robotics since ~25 years - Smith, Self, Cheeseman (1990) - Leonard, Durrant-Whyte (1991) - SLAM requires exteroceptive sensor to “see” the world - FootSLAM (2009) – Learns and uses a building layout while walking around in it (odometry only) - PlaceSLAM (human labeling) (2010) - Robotic SLAM using the local magnetic field: Haverinen,Vallivaara et al. (2009-2010) - ActionSLAM, Hardegger et al. (IPIN 2012, IPIN 2013) - Wifi-SLAM (Ferris, 2007) and WiSLAM (Bruno 2011, IPIN 2013) - SignalSLAM (Mirowski et al., IPIN 2013)
  8. 8. www.DLR.de • Chart 8 > IPIN 2013 > Patrick Robertson Objectives for this Paper - Magnetic SLAM for “free roaming” pedestrians in large environments - Foot mounted IMU / co-located magnetometer - Bayesian Derivation - Manageable complexity (real-time capability) - Confirm it works in 3D - Verification with accurate ground-truth to confirm low-decimeter accuracy aspirations
  9. 9. www.DLR.de • Chart 9 > IPIN 2013 > Patrick Robertson Basis for Derivation: Dynamic Bayesian Network “MagSLAM” - B: Magnetic environment map - E: Error states of the odometry - ZU: Measured odometry Step - ZB: Measured Magnetic Field - U: Actual step taken (pose change vector) - P: Pose - Int, Vis: Human processing - M: Physical environment map “FootSLAM”
  10. 10. www.DLR.de • Chart 10 > IPIN 2013 > Patrick Robertson MagSLAM Implementation with a Sequential Monte Carlo Filter - FastSLAM factorization (Montemerlo et al. 2002) - Proposal Function: - propose odometry error process - particles are propagated by odometry and their individual odometry error - Likelihood Functions: - FootSLAM weighting (hexagonal edge crossing counters) - and MagSLAM predictive posterior - MagSLAM & FootSLAM per-particle mapping: Update each cell’s statistics
  11. 11. www.DLR.de • Chart 11 > IPIN 2013 > Patrick Robertson Magnetic Field Strength at Ground Level: Finding a Robust Map Representation Source: M. Frassl et al., “Magnetic maps of indoor environments for precise localization of legged and non-legged locomotion,” in Intelligent Robots and Systems (IROS), Tokyo, Japan, Nov. 2013.
  12. 12. www.DLR.de • Chart 12 > IPIN 2013 > Patrick Robertson Hierarchical Magnetic Field Map Composed of Regular Grids
  13. 13. www.DLR.de • Chart 13 > IPIN 2013 > Patrick Robertson Mapping: Spatial Binning of Measurements 1: 65 mT 2: 63 mT 3: 94 mT 4: 74 mT 5: 84 mT 6: 87 mT 7: 42 mT 1: 74 mT 2: 84 mT 3: 87 mT 1: 84 mT All we save are sample mean, variance and N
  14. 14. www.DLR.de • Chart 14 > IPIN 2013 > Patrick Robertson Localization: Conjugate Bayesian Analysis - Assume the measurements in each bin follow a normal distribution with constant but unknown mean m and precision l - Assume a prior distribution on m and l that jointly follow the conjugate prior of a normal distribution, i.e., a normal-gamma distribution: - NG(m, l | m0, k0, a0, b0) - Then: Given the sufficient statistics of independent magnetic field measurements taken within a bin, the posterior mean and precision also jointly follow a normal-gamma distribution - The resulting posterior predictive of a new measurement is a student Tdistribution:
  15. 15. www.DLR.de • Chart 15 > IPIN 2013 > Patrick Robertson Prior PDF Evolution of the Posterior Predictive - No Measurements
  16. 16. www.DLR.de • Chart 16 > IPIN 2013 > Patrick Robertson Histogram per bin Posterior PDF Evolution of the Posterior Predictive
  17. 17. www.DLR.de • Chart 17 > IPIN 2013 > Patrick Robertson Histogram per bin Posterior PDF Evolution of the Posterior Predictive
  18. 18. www.DLR.de • Chart 18 > IPIN 2013 > Patrick Robertson Results
  19. 19. www.DLR.de • Chart 19 > IPIN 2013 > Patrick Robertson Video of Walking in Holodeck
  20. 20. www.DLR.de • Chart 20 > IPIN 2013 > Patrick Robertson Comparison of MagSLAM Map with Ground Truth Not visited by the human
  21. 21. www.DLR.de • Chart 21 > IPIN 2013 > Patrick Robertson Position Error Evolution Average error over 4 similar datasets: ~15 cm
  22. 22. www.DLR.de • Chart 22 > IPIN 2013 > Patrick Robertson MagSLAM Map of a Residential Flat
  23. 23. www.DLR.de • Chart 23 > IPIN 2013 > Patrick Robertson Error at the Reference = Revisited Starting Location Error for MagSLAM alone: ~13 cm
  24. 24. www.DLR.de • Chart 24 > IPIN 2013 > Patrick Robertson meters Example in Large Office Buildings - 1 meters
  25. 25. www.DLR.de • Chart 25 > IPIN 2013 > Patrick Robertson meters MagSLAM from IPIN Demo
  26. 26. www.DLR.de • Chart 26 > IPIN 2013 > Patrick Robertson Example in Large Office Buildings - 2
  27. 27. Chart 27 > IPIN 2013 > Patrick Robertson 3D Video
  28. 28. www.DLR.de • Chart 28 > IPIN 2013 > Patrick Robertson Thanks! Questions? Videos on our website www.kn-s.dlr.de/indoornav/magnetic.html

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