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Personal Dead-reckoning (PDR)

System for Firefighters

Presented by

Johann Borenstein Research Professor at the University of Michigan

29 years experience in GPS-free position estimation for mobile robots and pedestrians

Mobile Robotics Lab

Precision Indoor Personnel Location and Tracking for Emergency Responders, Worcester, MA, August 6-7, 2012

If you like the GLANSER form factor

you’re gonna love ours


4.1

3”

(10

5 m

m)

2.64” (67 mm)

Multi-function

button

Battery test button

RadioLED

Batterytest

LEDs

AntennaIMU &

chargerport

4.1

3”

(10

5 m

m)

2.64” (67 mm)

Multi-function

button

Battery test button

RadioLED

Batterytest

LEDs

AntennaIMU &

chargerport

PDR Packaging

IMU is fully embedded in heel of firefighter boot.

IMU is easily transferable among boots of different firefighters.

Computer & battery kept in pouch on shaft of firefighter boot – no need to run IMU-to-computer cable up the firefighter’s leg.

Battery life: >3.5 hours.

Built-in connectivity:

• Bluetooth

• WiFi

• USB, RS-232

• 900 MHz consumer-grade radio


PDR Features

Eliminates effect of accelerometer drift with every step (ZUPT).

Uses our patent-pending Heuristic Drift Elimination (HDE)

algorithm to eliminate effects of gyro drift and other gyro errors in

buildings.

Does not require any user-specific calibration whatsoever.

Does not require setup of any infrastructure whatsoever on location.

Initialization at start of mission takes less than 8 seconds.

Demo/test at undisclosed military

test site in June 2012. Walk

included walking backward,

sideways, zig-zag, up and down

stairs, intentional walking in

arbitrary directions.

Return Position Error: ~3 m.


PDR Performance

Average heading errors: <1o in missions of unlimited duration!

Average position errors: <1% of distance traveled in walks >30 min.

Average elevation (Z-axis) errors: <1.5 m in walks of unlimited duration.

Works with running Errors ~2 x walking errors

Works with crawling on hands and knees, even up and down stairs Errors ~2-4 x walking errors

Works with users changing step-length or gait.

Works with users walking/crawling backward or sideways.

Battery life: >3.5 hours.

CCAT demo in January 2012

Included one lap each of:

Walking, running, crawling,

even hopping on one leg

Start End


What’s New since 2011 WPI PPL Workshop

Support for running

Improved accuracy during crawling

New Flexgain feature

Initialization time is now < 8 seconds (was 25 s)

New Adaptive Footfall Detection

Much greater accuracy

Much greater robustness

Latest News:

• Customer in Singapore purchased two PDR systems for testing with firefighters.

• PDR systems were delivered to customer on July 24, 2012, after three days of

acceptance testing by customer’s representative at our lab.


Live Demo

“A picture is worth a thousand words” (unnamed wise man)

“A video is worth a thousand pictures” (Steven Spielberg)

“A live demo is worth a thousand videos” (Johann)

Initialization:

Stand still for 7+ seconds

Walk 8 steps in parallel to one of the walls of the building

Start Stop

Trajectory of live demo

walk/crawl performed during

this presentation.

Lap 1: walking

Lap 2: crawling

Return position error: ~1.2 m


Summary

U of Michigan personal dead-reckoning (PDR) system

Two key features:

1. Removes drift from IMU’s accelerometers

2. Removes drift from IMU’s gyros

3. Work will every conceivable kind of legged motion, including crawling

Results:

Average position errors: <1% of distance traveled in walks >30 minutes

Average heading errors: <1o in walks of unlimited duration (at steady state, indoors, in >99.5% of buildings)

Two modes of elevation estimation (average Z-axis error: < 1.5 m)

The PDR system is ready for field testing and for integration

with other first responder systems.

We are seeking industry licensees for our technology


Backup Slides The following slides are not part

of the oral presentation but may be

useful in the Q&A session


Live Demo of Walk and Crawl at 2011 PPL Workshop

Presenter performed a live demo of a short walk and crawl

Trajectory of live walk (~50 m long).

RPE < 0.4 m (<1% of distance traveled) Trajectory of live crawl in continuation of the

walk. Total travel, ~85 m long. RPE <3 m (3.5%

of distance traveled)

Crawl

Walk

End of

walk, start

of crawl

Podium


Most Recent Results (July 24, 2012)

Running



Crawling on

hands and knees



Crawling up

staircase


Dominant Directions in HDE Algorithm

The HDE algorithm is based on the concept

of Dominant Directions(DDs)

Two sub-sets: primary and secondary DDs

“Primary DDs” are those that one notices

immediately when looking at the floor plans of

most buildings, and they are usually the same

as the directions of the outside walls of the building.

Most corridors in buildings are parallel to primary DDs (see floor

plan to the right).

In rare cases corridors intersect with primary DDs at

angles of 45o. Those are called “secondary DDs.”

Typically, a walk with the PDR system must be

confined to just one building. That is because

the DDs must be the same throughout a walk.

If adjacent buildings have the same DDs, then a

single walk may stretch across all of these buildings. Floor plan of the conference center of an unnamed hotel. The general direction of the corridors is highlighted by thick red lines. The four primary dominant directions (0o, 90o, 180o, and 270o) are typically those that are parallel to the walls and main corridors of the building. Secondary dominant directions (45o, 135o, 215o, and 315o) intersect primary ones at angles of 45o.

0o

45o

90o

135o

180o

215o

270o

315o


What’s New Since 2010 PPL Workshop, cont’d

Floorplan Mode

Allows incident commander to define regions that are not rectilinear

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