Aug 7, 2007 - User representatives. Swedish Rescue Services Agency ... Development of improved tactical behavior require
Precision Indoor Personnel Location and Tracking for Emergency Responders Technology Workshop, August 6-7 2007 Worcester Polytechnic Institute, Worcester, MA
Positioning of incident responders - scenarios, user requirements and enablers Jouni Rantakokko Swedish Defence Research Agency This work was funded by the − Swedish Governmental Agency for Innovation Systems − Swedish Emergency Management Agency − Swedish Defence Materiel Administration
Participating organizations Technical experts Swedish Defence Research Agency, FOI Royal Institute of Technology, KTH Luleå University of Technology, LTU SAAB Aerotech SAAB Bofors Dynamics AB Swedish Defence Materiel Administration, FMV
User representatives Swedish Rescue Services Agency Rescue Service in Linköping National Criminal Police Army Combat School
Scenarios, user needs and requirements
Scenarios Military personnel, peace-keeping or peace-enforcement Search through building for sniper Navigation through mine field
Police Hostage situation in large building Under-cover surveillance of suspects entering building (e.g. shopping mall or night club) Search for fugitives in rural areas
Firefighter Fire in multi-story apartment building Fire in complex building (shopping mall, night club, office buildings)
User needs and requirements User needs and requirements were mainly discussed from the stand-point of current tactical behavior Likely that a personnel positioning system enable improved tactical behavior, which in turn will yield new requirements Development of improved tactical behavior requires extensive experimentation and training with positioning systems Tactical behavior different in US and Sweden – does this affect the identified requirements?
User needs and requirements Similar needs and requirements for police, military and firefighters More dependant on the scenario environment
Benefits with a personnel positioning system increases as the building size/complexity increases Easier to obtain situational awareness in smaller buildings Example - firefighters stated limited need for positioning system in typical apartment fires focus was on large buildings and unpredicted events where typical tactical behavior insufficient US events (9/11 and Charleston) shows importance of tracking firefighters under collapsed buildings?
Examples of identified user needs Efficient local command and control
M, P, F
Rescue of injured personnel
M, P, F
Navigation through complex buildings
M, P, F
Safe exit (e.g. from collapsing building)
F
Friendly-fire / Blue-force-tracking
M, (P)
Distance and heading to targets/threats
M, P
Health status and automatic alarm functionality
M, P, F
Know what rooms have been ”cleared” (searched)
M, P, (F)
After-action review (de-briefing) and training analysis
M, F, (P)
Safe navigation through e.g. mine fields
M
Fugitive movement pattern analysis (positions of dogs)
P
Free the radio resource for command and control
M, P, F
y
Examples of user requirements What needs to be estimated? Position (x,y) Height Position error (and integrity monitoring) Heading for weapon and/or body Distance and direction to targets and threats
Who needs the estimated positions? Local command Other units in group
x
x
y
z z
Examples of user requirements Preliminary requirements list Accuracy (x-y): < 1 meter in all environments (what room?) Accuracy (z): < 2 meter (what floor?) 100 % availability Accuracy in estimated heading? Weigth < 1 kg Battery – minimum 8 hours, several days desired Robustness more important than stealth Encrypted data transfer Combine positioning information with health status
Examples of user requirements No dependence of pre-installed infrastructure Integrated positioning and communication system Covert positioning system Modular system Avoid large antennas, integrate antenna/cables into uniform
Different users - different systems ”Safety-of-Life” critical systems Special forces, local/state/federal ”SWAT-teams”, firefighters Accuracy and availability before cost
Increased safety Soldiers, police, correction officers, security guards Availability, accuracy and cost important
Demanding consumers/applications (and ”first adopters”) Alarm functionality (hospitals - social workers - immigration), interactive services, gaming, surveillance of visitors in companies, … Availability and cost important, errors accepted
Regular consumers (mass market) Positioning of emergency calls, games, interactive services, … Cost most important (e.g. when integrating pos/nav in all mobile phones)
Possible trade-offs - performance vs cost Potential users
Predicted needs
Maximum cost
Special forces, local/state/federal ”SWAT-teams”, firefighters
100 % availability and sub-meter accuracy, robust against interference/jamming, integrity monitoring and position error estimates
US$ 1.000 - 10.000
Soldiers, police, correction officers, security guards (at sensitive objects)
100 % availability, lower accuracy and robustness demands, integrity monitoring
US$ 100 - 1.000
Demanding applications/consumers
Good accuracy during normal conditions, high availability desired but position errors accepted occasionally, integrity monitoring
US$ 10 - 100
Mass market
Good accuracy during normal conditions, acceptans for large errors and loss of service in certain conditions (e.g. indoors, tunnels)
US$ 1 – 10
Enablers
”Draft” report available in the report data base at www.ee.kth.se “Positioning of emergency personnel in rescue operations possibilities and vulnerabilities with existing techniques and identification of needs for future R&D”, Technical report TRITAEE 2007:037, Royal Institute of Technology, Stockholm, Sweden
Part of the command and control system The positioning system must include Estimation of positions, heading, health status Transfer of information (local command, other units) Presentation of information Decision support (navigation, safe exit, etc)
NICE
DARPA
WPI: Precision Personnel Locator (PPL) System
Summary of existing positioning techniques GNSS Exiting future with GPS, Galileo, GLONASS and Beidou/COMPASS(?), new receiver algorithms with increased sensitivity (assisted-receivers, high-sensitivity receivers), EGNOS, pseudolites Substantially improved availability expected indoors, poor accuracy still
Insufficient performance indoors due to signal attenuation and multipath propagation, sensitive against interference and jamming Performance with future combined receivers (GPS+GALILEO => 50 satellites)?
Summary of existing positioning techniques Local radio-based indoor positioning Pre-installed: RFID, UWB, ZigBee (IEEE802.15.4), WLAN, Bluetooth, ... Ranging-based systems utilizing bring-your-own infrastructure E.g. TDOA/TOA systems, vast power advantage compared to GNSS
Mobile ad-hoc networks with node-ranging and distributed positioning For very harsh environments, mobility and geometry restricts performance
Signals-of-opportunity (SOP) Expect insufficient indoor performance in large buildings due to multipath propagation, frequency regulations limits possibilities Indoor performance of proposed ”Governmental” UWB and likelihood for acceptance from FCC? What performance can be achieved with radiobased systems (”pseudolites”) at lower frequencies (200-500 MHz) with limited bandwidths (100 MHz)? What can SOP give us?
Summary of existing positioning techniques Inertial navigation sensors and systems Robust positioning Development of MEMS-sensors allows for very small, light-weight, lowpowered, and inexpensive(?) sensors - suitable for first responders Error increases with time, heavily dependant on how object moves What performance, and robustness against movement patterns, can be achieved with foot-mounted sensors?
Sensor fusion is needed Example: decentralized sensor fusion
BAROMETER Atm press
Vertical acc. GNSS height
Height Height error
HeightFilter
Map height
IMU
Map
GNSS Position
GNSS
Position
IMU Right foot
GNSS/DR Filter Pedometer
Position error
DR
IMU Left foot
3 acc Compass misalignment
3 gyro 3 magn
AHRS Filter
Heading/Attitude Heading/Attitude error
Example: integration issues
Helmet
- GNSS antenna - Radio antenna - Compass
Arm/Body/Weapon/Helmet ? - Display - Controller
Body / torso ? - GNSS receiver - Radio - Compass / AHRS - Pedometer - Barometer - Battery - ”Computer” Boots - IMU / AHRS (attitude and heading reference system)
Summary Affordable, robust and accurate personnel positioning system key technology to improve safety of military, police, firefighters Efficient Efficient local local command command and and control control
Todays technology insufficient – crucial user requirements cannot be fulfilled (simultaneously) 3D 3D positioning positioning accuracy accuracy and and availability availability indoors indoors Integrity Integrity monitoring, monitoring, estimate estimate of of position position errors errors Price, Price, size, size, weight, weight, battery battery Tactical Tactical behavior behavior
Sensor fusion approach needed to meet user requirements What What sensors sensors should should be be used? used? How How should should the the sensor sensor data data be be combined? combined?
Initial results from TDOA-based positioning measurements
Example: TDOA positioning TDOA/TOA-based systems, portable infrastructure Example Simple wideband radio transmitters placed on soldiers >3 wideband digital receivers positioned around building Receivers estimate their own positions and (possibly) perform time synchronization Received sampled data transmitted to central unit (e.g. C2 vehicle) Differences in traveled time to receivers are estimated (correlation) Differences in travel distance calculated from TDOA-estimates Transmitter positions - intersection between hyperbolic curves All estimated unit positions distributed through radio to all units inside building
Example: TDOA positioning Estimation of TDOA in receiver through correlation CRLB - Cramer-Raó Lower Bound Lowest possible variance for an unbiased estimator in AWGN
Can we achieve the CRLB? Synchronization errors (time and frequency) Multipath Interference
3 1 + 2 SNR CRLB ( ∆ t ) = 16π 2 TW 3 SNR 2
T – observation interval W – bandwidth SNR – signal-to-noise-ratio
Example: TDOA positioning Factors that will affect performance Transmitters Bandwidth, transmit power, waveform
Receivers Number of receivers, geometry, time and frequency synch.
Building Multipath, signal attenuation
Example: TDOA positioning Measurement set-up Three wideband receivers (8.5 MHz) placed outside 1st floor concrete/stone – 2nd floor wood – metal roof Transmitter inside building (178, 306 and 1125 MHz) Time synchronization error up to 20 ns 20 ms data collection 140
Pejl 1
120 100
y-koordinat
80 60 40 20
Pejl 2 HUS
0 -20 -40 -60
Pejl 3 -150
-100
-50
x-koordinat
0
50
178 MHz 306 MHz 1125 MHz
Example: TDOA positioning Position 1
1st floor
140 120 100 80 60 40 20 0 -20 -40 -60
-150
-100
-50
0
50
178 MHz 306 MHz 1125 MHz
Example: TDOA positioning Position 2
1st floor
140 120 100 80 60 40 20 0 -20 -40 -60
-150
-100
-50
0
50
178 MHz 306 MHz 1125 MHz
Example: TDOA positioning Position 3
1st floor
140 120 100 80 60 40 20 0 -20 -40 -60
-150
-100
-50
0
50
178 MHz 306 MHz 1125 MHz
Example: TDOA positioning Position 4
2nd floor
140 120 100 80 60 40 20 0 -20 -40 -60
-150
-100
-50
0
50
178 MHz 306 MHz 1125 MHz
Example: TDOA positioning Position 5
2nd floor
140 120 100 80 60 40 20 0 -20 -40 -60
-150
-100
-50
0
50
Example: TDOA positioning Initial results Position Position estimates estimates obtained obtained with with P Ptxtx
