WPI Precision Personnel Locator: Challenges and Progress

David Cyganski and Jim Duckworth Electrical and Computer Engineering Department

Worcester Polytechnic InstituteWorcester, Massachusetts

WPI PPL Workshop – August 4th 2008

System Overview

Personnel Unit

Reference units

Commander Display

Location and track of personnel locator units is continuously displayed on console

Location is computed with respect to reference antennas outside the building

Physiological data is shown on same display as location in response to stress or on demand

Prototype System Study Goals

Fundamental capabilities:3-D location of each user relative to a chosen reference pointGraphical display at the incident command centerGraphical path information on all users

Accuracy: ±1m Range: 20m Number of simultaneous users: 3Location updates every 2 seconds Physiological information telemetry

Heart Rate: ± 2.5 beats/minRespiration Rate: ± 2 breaths/minOxygen Saturation Level: ±2% (extra capability)Skin ±1°F, and Environment Temperature ±5°FPosture and Activity Level

Locator – Operational & Physical Specs

3 Radios in one unit!Transmitter – 550-700 MHz ranging signal Physiological wireless channels Command and Control

Worn in turn-out gearSupport 100 locatorsUpdates each secondLow power, long battery life, automatic on/offMonitor and report environmental status data

Temperature, movement, diagnostics, distress button

Small size, lightweight, low power

Locator Antenna System and Console

Operation of the WPI PPL system depends upon a set of antennas on two or more sides of the building.

Ultimately these antennas and the central processor will be integrated into response vehicles.

Prototype will be demoed by manual placement of antennas around building during set-up.

Command console is displayed on wireless laptop computer and can be viewed on several if desired

Locator unit is worn on turn-out gear and activated from the command console

2007 Demo: 3D Real-Time User Tracking

Walk/Crawl through 1st

and 2nd floors of the WPI Religious Center

WPI Locator

2007 Demo: Residential Building

16 by 14 m coverage Non-trivial multipath conditions due to wiring, plumbing, screen windows, appliances, wood, brick and glass panels

3D Location Performance

2nd floor error: 0.3m1st floor error: 0.72m

Locator motion track with Kalman filter

Real Time Tracking/Physiological Display

Locator height display

Locator position display with color ID

Environmental temp and heart rate

From 2007-2008: Ongoing R & D

Further enhancement of location algorithms to improve accuracy in 3DImproved wearable and receiver antenna designsEnhanced health/physiological stress monitoring and display with FMI vest and WPI SPO2 sensorDeveloping/testing automated antenna location system for hands-free ad hoc system deploymentLow cost MEMS inertial supplementation for improved tracking and drop-out resilienceInnovative building radio-penetration technologies

New Command Console Display

Laptop console integrates position and physiological display.

Physiological info can be requested by clicking on firefighter icon.

Firefighter icons show current position with visible trail of past positions

Colors indicate physiological stress

Separate display of building floor (click to id firefighter on map)

Rough building outlines can be drawn in by hand

Personnel on different levels can be displayed together or individually

Geometric Auto-Configuration (GAC)

Until the spring of 2008 the set-up of antenna/receivers outside a building required time-consuming set up

Relative positions of all antennas with respect to each other had to be manually measured

A practical, deployable system requires automatic antenna-location

Research has been underway since the summer of 2007Increasingly promising demonstrations in Winter/Summer 2008New hardware supporting GAC specific services coming on-line in Fall of 2008

Early result: auto-location of antennas

While results with easier residential structures were promising, industrial buildings proved this problem was no less difficult than the location problem.

Enhanced signals technology for GAC

•By applying new signal processing methods that are allowed by the more direct connectivity between receivers (than the mobile unit) we can solve a problem with more difficult geometry than posed by mobile locator position estimation.

Location Performance with GAC

RF-Inertial Location Fusion

Inside a complex structure, there severe multipath effects exacerbated by unavoidable signal losses and specular reflectionsRF location results suffer from path deviations and outlier location estimatesKalman filter can ameliorate short term losses and outliers

Hi-res RF-only track (blue) vs. true track (red)

Raw RF and Kalman Filtered• Kalman filtering can remove outlier artifacts and introduce simple motion physics

• Accuracy better than 1 ft achieved in residential structures

•Long duration drop-outs in industrial settings a huge challenge

Inertial and Combined Inertial/RF• Inertial sensors are free of radio propagation problems

• Drift of low cost inertial sensors causes solutions to rapidly veer away from truth

• Integration of RF and Inertial information can create a system robust to both inertial drift and RF dropouts

Track Comparison

By combining RF and Inertial technologies a truly robust positioning technology without user/movement restrictions can be constructed!Preliminary version of the fused RF/Inertial system will be used in Wednesday demonstration

Wednesday Test:A Harsh Indoor RF Environment!

Metal ceilingsMetal benches and cabinetsMesh WindowsMetal backed black/white boardsFire Doors20” Brick WallsMetal studded walls – 16 inch spacing!

WPI Precision Personnel Locator

AcknowledgmentsThe rest of the WPI team Worcester Fire DepartmentThe support of the National Institute of Justice of DOJThe support of DHS/FEMA – Fire Prevention and Safety Grant

Thank you!David Cyganski, cyganski@wpi.eduJames Duckworth, rjduck@wpi.edu

www.ece.wpi.edu/Research/PPL/