A Portable Wideband System for Monitoring and Locating Firefighters and Other Emergency Personnel Ted Kochanski, PhD Sensors Signals Systems Lexington, MA 02421 And

PPM Associates, Inc. Reading, MA 01867

Outline • Motivation – Key issues

• Approach – System concept – Factors influencing design

• Implementation – Prime – Alternatives – Operational issues

Motivation for System • Save lives – Locate incapacitated personnel – Direct rescue teams

• Situational awareness – Monitor personnel status – Personnel deployment – Real-time sensor data

Key Issues • Required parameters – Spatial resolution/accuracy – Update rate – Number of transponder units

• Environmental factors – Absorption/scattering – Multipath – Interference and noise

Approach • • • • •

Multistatic Time Difference of Arrival Frequency Hopping Separate Transmit and Receive Frequencies Isolating Delay Window for Each ID Wide Band Modulation – Pseudo random phase modulation

• Separate data link and localization

System Concept • Command Elements – 1 Master Transmit / Receive Station – 2 or more Slave Receive Stations – Data link

• Portable Transponders – Locate the emergency personnel inside the building – Unique ID’s – Data links to command elements

System Concept Response (f1, t3+dt)

a at D

R

1+d (f1, t e s n espo

Transponder

t)

Sy

nc

(f0

,t

0)

(f2

,t

0)

Slave 2

)

, t0) er (f0

spo

(f0, t 0)

Re

SYNC

nse

(f1

, t2

+dt

T r ig g

D a ta (f 2 , t0 )

Master Slave1

Multi-Transponder System Concept

R

p es

Tr

on

igg

se

(f1

(f0 er

1 ,t

+d

t1

)

Transponder 1

f1, se ( pon s e R

Trigg

) , t0

t3+d

, t0) er (f0

t3) Transponder 3

Response (f1, t2+dt2)

Trigger (f0, t0)

Master

Transponder 2

TDOA Location Concept

TP3

Master Slave 1

text

text

TP1

TP2

text

Slave 2

Factors Influencing Design • Required Specifications • Choice of Frequencies • Choice of Addressing • Operational Considerations

Factors Influencing Choice of Freq • Higher

• Lower

– Bandwidth for range resolution

– Cost of components

– Bandwidth for hopping

– SiGe large scale integration

– Penetration of structures – Interference from other uses

– Complexity of design

Implementation • Prime – Modified “Slotted Aloha” – System timing – Block level design – System specs

• Alternatives – Poled wideband – Ultrawideband

Prime Implementation • Two Frequencies • Master Frequency – Pulse sequence for synchronization – Received by Slaves and Transponders

• Transponder Reply Frequency – Modified Slotted Aloha Timing

• Independent Command Data Link

Frequency and Timing Frequency Hopping Spectrum

Master Transmit Frequency Spectrum

Ranging Modulation

Transponder Transmit Frequency Spectrum

Tine of Arrival with delay (ID)

TP1 TOA TP2 TOA

TP3 TOA TP4 TOA

Transmit Window ID Specific Delay

Timing & Frequencies Master Station

Timing

T=0, Pulse =1

Transmit Output

T=0, Pulse =2 f(0,2)

f(0,1)

Transponder1

Receiver Output

f(0,1)

Transmit Trigger f(1,1)

Transmiter Output DT1 Transponder2

Receiver Output

f(0,1)

Transmit Trigger Transmiter Output

f(1,1)

DT2 Slave 1

Receiver Output (f1,0) TP 1

TP 2

Slave 2

Receiver Output (f1,0) TP 2

TP 1

Master

Receiver Output (f1,0) TP 1

TP 2

System Block Diagram

11 12 1 2 10 9 3 8 4 7 6 5

Display

Data Link

(ID's, Positions)

Data Link

Timing

11 12 1 2 10 9 3 8 4 7 6 5

Timing

Timing Manual Input

Database Transmitter f0

Master Station

Receiver f0

Receiver f1 Position, Sensor Data, ID

Receiver f1

Slave Station

Timing

11 12 1 2 10 9 3 8 4 7 6 5

Timing

Receiver f0

Transmitter f1

Manual Input

Transponder

Sensor Input

Position, Sensor Data, ID

Master Station Blocks Transmit Frequency Control

Command Trigger Master Scheduling

Code Generator

RF

Receive Frequency Control

transmit f0

Slave Delta T's Master Clock

Delta T Extractor

Position Determinator

External data Link

receive f1

ID Extractor Correlator Aux Data Extractor RF

Display Generator

Aux Database

Tracking Database

Display

Receive f0

Slave Station Blocks

RF

Receive Frequency Control Master Clock Master Scheduling External data Link

receive f1

Receive Frequency Control

Delta T Extractor

Correlator RF

Slave Delta T1(ID#1) Slave Delta T1(ID#2) Slave Delta T1(ID#N)

ID Extractor

Transponder Blocks Sensor2 Data Sensor1 Data

ID #

RF Correlator

Data MUX

DeltaT(ID#)

Receive Frequency Control

receive f0

Trigger Code Sample

Emergency Master Clock

Master Scheduling

Code Generator

transmit frequency control

RF

transmit f1

System Specifications Range Accuracy

1m

Maximum Range

1 km

Track Update Rate

1 /s

Operating Frequency

5 GHz

Max # of Active Transponders

100

System Application

up

Master Station Display Legend Shaft Structure

Window

Door False Wall

Normal

Warm

Normal

ALARM

Hot

Alternative Implementations • Wideband

– * Modified Slotted Aloha with extra delays – Poled 2 frequency code modulated

• Ultra Wideband – Master + Slaves + Transponders – Peer-to-Peer Network

Alternatives • Wideband – Poled Simplified addressing scheme Rep rate varies with number of transponders Possibly lower probability of detection on each pulse

• Ultrawideband Better penetration of complex structures possibly simpler deployment Short range Low data rate Undeveloped technology

Operational Issues • Availability of Building CAD Data • Reliability of System Under Extreme Conditions – Heat – Water – Shock

• Availability of Operating Frequencies