Fundamental Differences Between Location, Tracking, and ...Fundamental Differences Between Location,...
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Fundamental Differences Between Location, Tracking, and Navigation Systems Wayne C. Haase, Ph.D. Summit Safety, Inc. www.SummitSafetyInc.com
Fundamental Differences Between Location, Tracking, and ...Fundamental Differences Between Location, Tracking, and Navigation Systems Wayne C. Haase, Ph.D. Summit Safety, Inc. A structural
A structural fire presents significant dangers to firefighters. Those operating inside the building face the hostile environment’s lethal smoke and high temperatures, and risk injury from operating under zero-visibility conditions and from falling debris and structural collapse. Even those operating outside the building risk injury from falling debris and structural collapse. Knowing exactly where a firefighter is located and being able to find him quickly becomes critical in the event of an emergency. This presentation will focus on the different types of geo-location systems and technologies that can be used in specific situations occurring in structural firefighting. How, when, and under what conditions first responders will use these systems will be discussed.
Geo-location—both inside and outside buildings—involves at least three major types of firefighting situations for first responders: tactical, firefighter rescue by a rapid intervention team or crew, and self-rescue. There are three major types of systems which would fall under the general category of geo-location. These can be classified as location systems, tracking systems, and navigation or homing systems. As we will see shortly, the capabilities of the three types differ considerably. There are different technologies that can be used to implement the different types of systems. Technologies include RF (radio-frequency), acoustic, inertial, optical, magnetic compass and pressure (for altitude).
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Who needs the information?
Who uses the tool?
What information is needed?
Why is information needed?
Accuracy and Range?
Situations
Summit Safety, Inc
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Presentation Notes
Focusing first on firefighting situations—which include tactical, rescue, and self rescue—each one involves certain information. Who needs that information, what information is needed, and why depend on the particular situation.
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Who: Incident commander
What: Firefighter locations
Why: Accountability
Resource management
Situational awareness
Accuracy/Range: 3-10 ft / 100-1000 ft
Tactical Situations
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For example, for tactical situations, the incident commander needs to know the location—both inside and outside the building—of every firefighter. He is responsible for the accountability of all the firefighters, and he needs to know that the available resources are used as efficiently as possible to get the specific firefighting tasks accomplished. In terms of accuracy, the incident commander would need to know the position of the firefighters to about 3-10 feet over a range of about 100-1000 feet, which would cover most fire scenes.
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Who: Rapid intervention team/crew
What: Shortest path to firefighter
Why: Lost member
Firefighter down
Mayday
Accuracy/Range: 6 in / 20-150 ft
RIT-Rescue Situations
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For rescue situations, the rapid intervention team (RIT) or crew (RIC) needs to know the shortest path to a specific firefighter or group of firefighters. If a firefighter is down or a mayday is called, the RIT/RIC needs to find the shortest and quickest path to the victim. In terms of accuracy, a RIT/RIC would need to know the location of a downed firefighter to about 6 inches to be certain on what side of a wall the firefighter was located. The system would need to operate over a distance of typically 50-150 feet, representing the approximate distance from the exit that a firefighter might have traveled into a building.
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Who: Firefighter
What: Shortest path to exit
Why: Disorientation, excessive heat,
low air, potential collapse,
evacuate order
Accuracy/Range: 2-3 ft / 20-150 ft
Self-Rescue Situations
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In the case of self-rescue situations, the firefighter inside a building needs to know the shortest and quickest path to the exit. He could be disoriented, there may be excessive heat, he may be low on air, there may be the danger of a potential collapse, or there may be an evacuation order. In terms of accuracy, a system would need to be accurate to about 2-3 feet, representing the size of a door or window. The system would need to operate over a distance of typically 50-150 feet, representing the approximate distance from the exit that a firefighter might have traveled into a building.
Location System
Current Position in Building
7Summit Safety, Inc
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Turning now to the different types of geo-location systems, recall that there are three types: location, tracking, and navigation. An ideal location system provides information about the position in or around a building. The focus is on the present; that is, on his current position. A tracking system provides essentially a “bird’s eye view” of where a firefighter would be located by showing that location on a grid or map.
Tracking System
Position History
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In the case of tracking, an ideal system provides the position history: that is, the location of the firefighter from some point in the past to the present. A tracking system also provides a “bird’s eye view” of the history of the firefighter’s location on a grid or map.
Navigation System
Shortest Path to Location
9Summit Safety, Inc
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An ideal navigation system provides the shortest path from the current location to a new location. In this case, the focus is on the future. Unlike the “bird’s eye view” provided by location and tracking systems, the navigation system’s information is essentially a “rat’s eye view” because it tells the person inside the maze how to navigate. Note that a tracking system may not provide the shortest or quickest path. For example, if the firefighter calls a mayday when he has 5 minutes of air left in a 30-minute bottle, can he get out in 5 minutes by simply reversing his path when it took him 25 minutes to get to where he is? Similarly, can a rescue crew get to him by following his previous path?
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?
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x
x
Location
Self-Rescue
RIT-Rescue
Tactical
Tracking Navigation
Preferred Combinations
10Summit Safety, Inc
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Presentation Notes
If we now consider the three types of systems—location, tracking, and navigation—how well do they perform in tactical, rescue, and self-rescue situations? Location systems provide exactly what is needed for tactical situations: the position of each firefighter inside and outside the building. However, location systems fall short for rescue and self-rescue because they tell you nothing about how to find a particular firefighter; they tell you nothing about the path to the firefighter. One would need to know the detailed layout of the building in order to determine the shortest path to the firefighter. Tracking systems also work well for tactical situations: they provide the current location of all the firefighters inside and outside the building. However, tracking systems may or may not work well for rescue and self-rescue. As we saw in the previous slide, the path taken by the firefighter may not be the shortest path. Navigation or homing systems only tell the path to a location and may provide little help for tactical situations. However, they excel in rescue and self-rescue situations where time is critical, because they provide the shortest and quickest path in a maze to a victim or an exit.
Location
Self-Rescue
RIT-RescueTactical
Tracking Navigation
System Types
Situations
Preferred Combinations
11Summit Safety, Inc
“I know where he is” “I can find him”
Presenter
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To summarize, we have identified three types of systems: location, tracking, and navigation; three types of situations: tactical, rescue, and self rescue; and four technologies: RF, inertial, acoustic, and optical. Of all the possible combinations, only a few are preferred, and these can be separated into two distinct groups. In the first group, location and tracking systems are preferred for tactical situations (accountability and resource management). As we will see, these are best implemented by either RF or inertial technologies. In the second group, navigation systems are preferred for rescue and self-rescue situations, and these are best implemented by acoustic technology. The fact that there are two distinct groups may seem counter-intuitive. A fairly common statement expressed by people is, “If I know where someone is, I can find him.” Unfortunately, inside a building, this statement may not be true. In the next few slides, we will look at examples of rescue inside a building that show that knowing a person’s exact location does not imply a quick rescue.
RIT-Rescue: Which Door?
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1 2 3
Search Time is CriticalSummit Safety, Inc
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For the first example in which the location is known, consider the following scenario. You are the rescuer shown as the green dot; the disabled firefighter is the red dot. You have a thermal camera and can see three doors; which one should you use for the quickest rescue?
RIT-Rescue: Which Door?
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1 2 3
Search Time is CriticalSummit Safety, Inc
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If this is the structure, then obviously door #2 is the correct choice.
RIT-Rescue: Which Door?
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1 2 3
Search Time is CriticalSummit Safety, Inc
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However, if this is the structure, then door #1 is correct.
RIT-Rescue: Which Door?
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1 2 3
Search Time is CriticalSummit Safety, Inc
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In this case, door #3 is actually the correct choice. Even though the disabled firefighter is to the rescuer’s left, the rescuer should go to the door on the right. If this is the building, a rescuer could easily lose valuable time going to door #2, and then door #1.
Technology: Which Door?
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1 2 3
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RF
Acoustic
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Consider the choice of technology. A radio-based navigation system would provide no hint as to which door to pick. You could easily waste precious time going through the wrong doors. On the other hand, if the system is based on acoustics (audible sound or ultrasound), then the sound will be emanating only from door #3, the correct door. Thus an acoustic-based system will tell you which door to pick.
Technology: Office Complex
17Search Time is CriticalSummit Safety, Inc
RFAcoustic
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Here is a slightly more complicated structure. As before, you are the green dot and the disabled firefighter is the red dot. A right-hand search would take a very long time, and a left-hand search would miss the firefighter entirely. If the navigation system’s technology is radio-based, the rescuer will be encouraged to enter the door to his right, and then go through to the second office only to find that he is on the wrong side of a wall. If he chooses not to breach the wall, he must return to the hallway. When he gets to the conference room door, he will go into the room, and again discover a wall. If he returns to the hall, he may even go into the second door to the conference room. As he goes down the hall, he will go into the next office, only to again find a wall. Finally he will get to the correct room. He will have wasted a considerable amount of time searching the wrong rooms. If the navigation system is based on acoustic technology, the sound will travel out of the office and down the hall to the rescuer. The rescuer only needs to follow the strongest signal to go directly to the correct room. As in the previous example, an acoustic-based navigation system will identify the correct path to the victim, and the rescuer will not waste valuable time searching in the wrong rooms or trying to breach a wall.
Location
Self-Rescue
RIT-RescueTactical
Tracking Navigation
System Types
Situations
Preferred Combinations
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Presentation Notes
We now return to our summary slide, showing systems and situations.
Location
Self-Rescue
RIT-RescueTactical
Tracking Navigation
RF
InertialAcoustic
System Types
Situations
Technologies
Preferred Combinations
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Multiple Technologies
Sensor Fusion
Inertial + RF• Inertial + GPS/Trilateration• Inertial + RFID
Acoustic + Optical• Pathfinder + thermal camera
Acoustic: Audible + Ultrasound• PASS + Pathfinder
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Several systems have been reported combining two or more technologies. Such combinations provide the opportunity for the strengths of one technology to enhance or compensate for the limitations of another technology. Several combinations of RF and inertial technologies have been proposed for a location or tracking system. One of the earliest was the combination of an inertial system to supplement the GPS system in so-called “GPS-denied” environments, such as in buildings and tunnels. The combination has also been proposed for the “urban canyon,” that is, in cities with tall buildings that block a clear view of the GPS satellites and produce multipath echoes. To date, low-cost inertial systems do not have sufficient accuracy over the desired operating time. A combination of RF and inertial technologies in which the use of pre-positioned RFID tags attempts to compensate for the drift of the inertial system has been proposed. NIST has done extensive tests on this combination of technologies. Whether such a system can be developed that would be practical in a fire environment is being investigated. Another pair of technologies that is already available is the ultrasound-based Pathfinder system with a thermal imaging camera (TIC). The TIC enables a rescue team to move more quickly under zero-visibility conditions, but does not indicate if the rescuer is heading in the correct direction to find a disabled firefighter. By adding the Pathfinder’s ultrasonic component, the rescuer can quickly determine the direction of the shortest path to the victim. The combination of audible and ultrasonic technologies should also be noted. Because the sound from a PASS device is at a lower frequency (2-4 KHz) than the Pathfinder (35-40 KHz), the PASS device sound will propagate a much farther distance. The PASS device can be used to reach the approximate location of a disabled firefighter. However, as a rescue team gets close (within 50-100 feet), locating the firefighter becomes difficult. Since the Pathfinder system operates with a maximum distance of 120+ feet, as the PASS device becomes hard to find, the rescuer can switch to the Pathfinder system to rapidly locate the firefighter.
Location
Self-Rescue
RIT-RescueTactical
Tracking Navigation
RF
Inertial
Acoustic
System Types
Situations
Technologies
Preferred Combinations w/Fusion
Inertial + RFAcoustic +
Optical21Summit Safety, Inc
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Presentation Notes
If we return to the summary chart, the combinations of technologies can be added. Thus there are three types of systems, three types of situations, and four technologies. The preferred combinations are in two groups. In the first group, location and tracking systems are preferred for tactical situations (accountability and resource management) and RF, inertial, and a combination of RF and inertial are the best technologies. In the second group, navigation systems are preferred for rescue and self rescue, and either acoustic alone or a combination of acoustic and optical are the preferred technologies. It is important to note that each type of system works well in certain situations, but no system works well in all situations. Similarly, each technology works well for certain systems, but no technology works well for all systems. In the next few slides we will focus on navigation systems for rescue and self-rescue and discuss the Pathfinder system and the combination of the Pathfinder system with a thermal imaging camera.
The Pathfinder navigation system consists of an omnidirectional transmitter called the Beacon and a directional receiver called a Tracker. The system uses ultrasound as the primary technology. For typical situations, the range is about 120 feet or more; in completely unobstructed, open situations, the range is on the order of 150 feet or more. Search times in hundreds of tests are typically on the order of 2-5 minutes. That is, once the Beacon’s ultrasound signal is detected by the Tracker, the rescuers can typically reach the victim in 2-5 minutes in situations where rescue times for blind searches require 20-35 minutes and where rescue times for PASS-aided searches require 10-20 minutes.
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Why Ultrasound?• Not Affected by Fire Environment• Reflected Waves: Locate Behind
Obstacles, Around Corners• Penetrates Small Openings: Locate
Behind Doors, Under Debris• No Blind Alleys• Indicates Path
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The technology for the Pathfinder system is ultrasound, which is not affected by the fire environment. Because virtually all solid materials reflect sound waves, the Pathfinder can locate a firefighter behind obstacles and around corners. And because ultrasound will penetrate through small openings, the Pathfinder system can locate a firefighter behind doors and under debris. Because unlike radio waves, sound will not go through walls, a rescuer is not led down a blind alley only to find that he is on the wrong side of an impenetrable wall. Probably the most important reason for using ultrasound for the Pathfinder system is that it indicates the path to the downed firefighter. As we saw before, the path is precisely the information needed by the rescuer.
Pathfinder Firefighter Beacons
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Stand-Alone Beacon
Survivair/Sperian Panther SCBA
ISI Viking SCBA
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On the Survivair Panther SCBA, there are two firefighter Beacons: one on the front of the firefighter, next to the PASS device, and the second on the back of the firefighter next to the air tank; both Beacons turn on when the PASS device is in alarm mode. The system is fully integrated into the SCBA system. Only the components inside the circles are for the Pathfinder system. For the Avon-ISI Viking 2007-compliant SCBA, there is a single firefighter Beacon with two transducers, one on the left and one on the right. The Beacon mounts under the neck of the air tank. In the near future, a stand-alone firefighter Beacon will be available. It too has two ultrasonic transducers.
25Survivair/Sperian Warrior
Pathfinder Firefighter Beacon
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For the new Survivair/Sperian 2007 compliant Warrior, there are three firefighter Beacons, one on the front and two on the back. The Pathfinder Beacons are shown with the arrows.
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Pathfinder Aux & Exit Beacon
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There are Auxiliary Beacons (on the left) and Exit Beacons (on the right). The Exit Beacons are left at the exit by the entering firefighters. The Auxiliary Beacons are used to tag points inside the building, such as way points, a spare air tank, a civilian victim, or the end of a fire hose; their use depends on the SOP of the particular fire department. Exit Beacons are not used in the interior of the building and are reserved for exits only.
To summarize, tactical situations—accountability and resource management—are best served by location and tracking systems, built from RF or inertial technologies. In contrast, rescue and self-rescue situations are best served by navigation systems, built from either acoustic technology or a combination of acoustic and optical technologies. Each type of system works well in certain situations, but no system works well in all situations. Similarly, each technology works well for certain systems, but no technology works well for all systems.
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Every Toolhas its
LimitationsSummit Safety, Inc
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It is also important to know the limitations of each system.
