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R . F . I . D .Rescuing Firefighters in Distress

Team Ganz: Jonathan Bruso Michael Carney Daniel Fortin James Schafer

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Background and Motivation:

Firefighters have an enormous task and endanger their life when going into burning buildings• Most of the time they have never been in the building• Visibility skewed by smoke• There is nothing keeping track of where a firefighter is

• Trapped and needs help• Lost in building

A device that can track firefighters in a building could aid in directing as well as finding firefighters in a building

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Background and Motivation: Many firefighter have perished after becoming lost or unconscious

in a burning building. Worcester, MA 1999

• Six firefighters were killed after becoming lost in a six story building while trying to save homeless inhabitants.

Bronx, NY 2006• One firefighter killed and three seriously injured when roof of

building collapsed on them.• Took a significant amount of time to locate their distress

signals. Charleston, SC 2007

• Nine firefighters killed in a Sofa Store blaze.• They became trapped when part of the building collapsed and

they could not be located.

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Concept:

Lives would be saved if there is a way to track a firefighters location inside a building

Person in build with question mark over headPerson in build with question mark over head

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Current Technologies:

On Site Emergency Resource Tracking (OnSite ERT)• Firefighters drop boxes in and around building• Firefighter are equipped with a monitoring system.• PC accessible interface for commander.

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OnSite ERT Pros & Cons

Pros• Gives an GUI display of the incident and personal on hand• Can track firefighters location and vitals• Gives a well documented time-stamped information on what

occurred at the incident

Cons• Uses GPS and safelight databases (subscription fees) • Suitcase unit is expensive• Does not give a view of the incident inside the building

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System Requirements:

Has to be able to track firefighters in the building• Show firefighters path over time• Alert Incident Commander (IC) if firefighter has not moved for

fixed period of time• Warn IC if firefighter is moving out of the Tag range.

Store these locations in a database

Dynamically display firefighters position on a visual blueprint of the building

Critical System, must be able to detect and recover from error quickly

User Friendly

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Idea #1:

Digital Representation with Scanners

Cons Scanners have a high cost

~$700 Big Building = $$$ Must be used sparsely

Loss of Scanner means loss of precision

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Idea #2:

Digital Representation with Tags

Pros Tags have low cost

~$18 Decreased scalability

cost Increased precision Loss of a Tag does not entail

critical error Mobile scanner is less prone

to destruction

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System Block Diagram:

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The basic User Interface (UI) Design

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The basic User Interface (UI) Design:

Locations Displayed on pre-loaded blueprint

Traveled paths can be viewed

Incident Commander (IC) can relay positional information via radio

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UI With Path Selected

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How is location determined?

Trilateration is used to determine the position based on simultaneous length measurements from three known sites (Nodes A, B and C)

• The point where the three circles intersect is the desired coordinate

• More circles could be used to reduce error

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Signal Strength to Distance conversion Radio waves diminish logarithmically with distance Tag distance (d) may be calculated as a function of:

• Signal strength (sT)• Carrier frequency (fc)• Signal strength exponent (n)

• sT = 20*log(fc)+ 10*n*log(d) – 28• Equation from Retscher, Fu, www.http://www.mycoordinates.org/may08/trilateration.php

• ITU Indoor Location Model

Distance

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Location of tag from Trilateration

Algorithm• Signal strength gives distances• Distances give equations for three spheres• Spheres can be equated to find location of reader

Sources of error• Walls• Multiple floors• Wave interference

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Math behind Trilateration

Trilateration can be expressed as the problem of finding the intersection of three spheres.

Equation from Thomas, Ros, http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=01391018

Note that the solution depends on the chosen reference frame. Usually one of the nodes is placed at the origin to simplify the

calculations

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Dealing with error

Error solutions• Calibrate signal strength variation before entry into building• Calibrate variation for different building materials• Use ITU Indoor Calibration Model

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Additional Tag Applications

Distress Tags• Located in hot spots across building where those in distress

can obtain in order to be rescued• Pros:

• Can give a general location of person in distress• Finding a person in distress would be much faster and

more direct• Cons:

• The tags could be false alarms• Person holding tag could be moving

• Currently being researched

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Additional Tag Possibilities cont..

Point of Interest tags (PoI)• Carried by firefighters and can be thrown down to point out a

particular point of interest or a certain path• Pros

• Important points in a building can be highlighted• A trail could be left to help guide firefighters to safety

• Cons• Tags will need to be carried in a signal blocking pouch or

they will interfere with the scanners• Currently undergoing research

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Database Functionality

Stores incoming point data of each fireman within the building

Stores pre-existing data of stationary RFID tags

Stores blueprints/building information

Must be fast and reliable

Due to budget constraint a laptop will be used in place of a real server

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General Attribute Tables: These tables contain the pre-instantiated general attributes of the

Active tags and Scanners

Tag ID Gen. Loc X-cord Y-cord

0x0001 Hallway 100 245

0x0002 Kitchen 455 103

0x0003 Office 009 102 250

General Attribute Table MakeupGeneral Attribute Table Makeup

FF ID Name Signal Str

0x0001 Ortiz .86

0x0002 Lowell .56

Fireman Attribute TableFireman Attribute Table

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Collected Positioning Table A general layout of the positioning table below

This table lists all tags positions given with respect to time Updated frequently with new coordinates Various Queries can be used to get certain tags, paths, floors, ect…FF ID X-Cord Y-Cord Time

0x013 100 245 15:59:06

0x017 455 103 15:59:07

0x013 102 250 15:59:09

0x014 52 600 15:59:11

0x013 99 256 15:59:13

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Challenges

Trilateration Algorithm• Formula seems straight forward• Indoor scenario causes problems interference and RF

propagation• Errors accumulate fast.• Correlating the signal strength to distance• Position Calibration

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Challenges cont…

Incident Commander GUI• Must display in Real Time• On the fly path animation and image generation is

difficult.

Using Pre-Inputted Blueprint• Displaying firefighters “relative” tag position to absolute

blueprint position.• Must use GPS to provide this association

• Coordinating blueprint with error checking• Making sure firefighter does not “walk through walls”

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Proposed MDR Deliverables

Incident Commander GUI• Use mock data inside database to simulate GUI

• Able to see location of Firefighter on blueprint• Ability to show the total path traveled (with

timestamps)

RFID Reader and Tags• Purchase• Research SDK and Trilateration Algorithms• Begin experimentation with point location and error

correction

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Division of Labor

Jon Bruso• Interactive Incident Commander GUI, blueprint

generation software, on the fly image generation

Mike Carney• Trilateration Algorithm, On the fly path(animation)

generation

Dan Fortin• Purchase RFID equipment, GPS location integration, and

Trilateration Algorithm

James Schafer• Database creation and management, coordinating

relative RFID positions with blueprint

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Final Deliverables

Design documents and specifications Blueprint generation software Incident Commander GUI

• Path and Point Display• With timestamps

• Firefighter’s signal strength warning• Ability to track multiple Firefighters

Demonstrate tracking a RFID reader throughout a location on campus.