Emergency Locator Transmitters - Essay Example

Emergency Locator Transmitters In an ever globalizing world, no spot on Earth is beyond man’s reach. The skies are steadily filling up with aircraft; the seas with ships; the land with cars and trains. Transportation has become swift, safe and global, such that for modern man, to circle the globe is no longer an impossible dream. Cities across continents, across oceans are minutes away. Travel time is no longer measured in years or even days, but by the number of songs on the IPod or number of movies. The world is getting smaller. People are traveling more. With the booming transportation industry, uncharted waters, skies and land have become more accessible to more people now. Technological advances in design of all these modes of transportation have made them far safer than they have ever been since their inception. Aircraft are some of the most technologically advanced systems today, with some having the capacity to travel at the speed of sound, others capable of transcontinental flight, still others practically built to be fortresses in the sky. Ships have become more massive, or more streamlined. They have become floating island cities. Trains nowadays are technological marvels of speed and safety, carrying people from one place to another at a fraction of the time they used to. However, despite all these technological leaps, there have still been instances that disasters strike, and none of these modes of transportation have been spared from the rare occurrences of disaster. Most accidents are external in nature – lightning strikes an aircraft, an iceberg rams a ship, a bridge collapses under the weight of a train. Because of the ease at which these transportation agents bring people to their destinations, there has been a bigger volume of commuters in the world today than ever before. Therefore, there are far more people who start passengers and end up as victims of an accident, and the sad reality is, they could potentially be casualties in the final calculation. Recent accidents like that of Air France 447 where the debris of the ill-fated aircraft, an ultra-modern Airbus A330 jet carrying 228 passengers, have yet to be found, remind us of the importance of having equipment that allows for quick location of an accident. Casualties usually mount as more time passes from the time of the accident to the time rescue teams arrive. There has to be a way to decrease this time because every second literally means lives. To solve this problem, the distress radio beacons or emergency beacons were developed. They are basically tracking transmitters that allow for faster and more rapid detection and location of ships, aircraft and people in compromising accidents and general distress. The main idea behind the emergency beacon system is to be able to locate people within the so-called “golden day” (the first 24 hours following a disaster) when a significant number of victims can still be saved. There are three types of distress radio beacons in use today. These are (1) EPIRBs (emergency position-indicating radio beacons) for use by ships, boats and other maritime crafts for sea distress; (2) ELTs (emergency locator transmitters) for use by aircrafts of any size or design for air distress; and (3) PLBs (personal locator beacons) for use by persons and groups of people, especially those who are away from normal rapid response emergency services such as 9-1-1. These systems are reliant on a system of non-geostationary satellites under the Cospas-Sarsat system that will be discussed further later in this article. The system was first created in the United States of America after the deaths of Congressmen Hale Boggs (D-LA) and Nick Begich (D-AK) in Alaska on October 16, 1972. The aircraft carrying them crashed somewhere in the frigid Alaskan wilderness. Despite a massive search and rescue effort mounted by the authorities and law enforcement agencies on all levels (local, state-wide and federal), the representatives of Congress were not found in time. By 1973, the resolution in the U.S. Congress to have all aircraft flying in the country fitted with emergency beacons or distress radio beacons had already passed in to law, carried by the impetus of the deaths of two members of Congress. In the United States, there are various agencies that respond to distress signals from the emergency beacons. For offshore beacons, the United States Coast Guard responds quickly to victims of maritime disasters. For on-shore beacons, the local area handles search and rescue. For land-based distress signals, the Air Force Rescue Coordination Center notifies the United States Air Force Auxiliary Civil Air Patrol that sends volunteer members to the scene. Seeing the value of expanding the capabilities of authorities to respond to distress signals even in international waters, Cospas-Sarsat, the international organization that responds to distress signals was formed in 1982. The original group was formed by Russia, the United States of America, Canada and France. This was despite the fact that at that time, Russia and the United States were engaged in the Cold War. Sarsat means Search And Rescue SATellite while COSPAS is a Russian acronym of the same meaning. Since then, 29 other countries joined the group, providing far reaching distress response capabilities in their areas of responsibility. Cospas-Sarsat, today, defines the standards for beacons, equipment on weather and communication satellites, ground stations and communication methods. The Emergency Locator Transmitters or ELTs are the emergency beacons used for aircraft. Currently, the subclassifcations for ELTs are: (1) A ELT, automatically ejected; (2) AD ELT, automatically deployed; (3) F ELT, fixed; (4) AF ELT, automatic fixed; (5) AP ELT, automatic portable; (6) W ELT, water activated; and (7) S, ELT, survival. The beacons, to be able to perform their function of sending distress signals to authorities with search and rescue capabilities, must withstand the stress that aircraft will potentially experience and the potential debris loss. Hence, ELTs are made brightly colored so that the beacons will be easier to find whether the aircraft lands on terrestrial or aquatic areas. This is especially useful because the beacon will be the central point on to which the search and rescue teams will rely on to find the victims on the aircraft. The transmitters also have to be waterproof in case the aircraft crashes at sea. The ELT will be useless if at one point, water just destroys the systems before search and rescue teams are able to locate the crash site. Usually, the size of a transmitter is that of a cube about 30 cm on every side and has an average weight range of two to five kilograms. The current lifespan of an ELT is around 10 years and because of the extreme conditions that the aircraft could encounter, current designs can operate from -40 oC to 40 oC. The transmission time is from 24 to 48 hours, which represents the amount of time where a plausible rescue operation can still happen. Current beacon systems are classified either as digital or analog, with the latter representing the older versions still in use today. The digital ELTs usually use the frequency of 406 MHz and send out short bursts of digital distress signals to satellites. After the distress signals are sent, a small integrated analog homing beacon using the 121.5 MHz frequency continues to send a signal to allow for triangulation and accurate location of the transmitter and hopefully, the victims as well. Newer versions of the emergency locator transmitters allow transmissions of precise Global Position System (GPS) locations through the distress information itself. This allows the shortening of the process from actually searching for where the signal is coming from to just getting there and rescuing the victims. However, it is important to note that most crashes and disasters are at locations that are very difficult to reach. The information itself may contain very unique and specific parts such as the country, the identification code usually encrypted as a unique 15-degit hexadecimal code, the aircraft’s encoded registration and as said earlier, possibly the GPS position. GEOSAR and LEOSAR satellites monitor these messages. For analog beacons which were developed for the first ELT systems, only a simple analogue siren tone is sent out without end until the battery finally gives out. Prior to February 1, 2009, three frequencies are compatible with the Cospas-Sarsat – 243.0 MHz, 121.5 MHz and 406 MHz for the digital beacon. Comparing the analog and digital beacons, it is easy to see why the digital beacons are far superior than their analog ancestors. In terms of delay time for response of search and rescue, analog beacons expect a delay from 4 to 12 hours. The digital beacons can expect swift response, at most 10 minutes after beacon activation through GEOSAR satellites. On alerts, 98% of analog beacon signals are false while for digital 97.1% are false. However, 7 out of 10 alarms can easily be resolved via phone so not a lot of resources are wasted. The ELTs were actually the first emergency beacons developed and today, almost all civil aircraft operating in the United States of America are mandated to install and use them. Initially, the preferred frequency was at 121.5 MHz, not just for distress signal sending but also to alert nearby aircraft that the airplane carrying the beacon is there. The airplane must also be capable of responding in case the other aircraft sends a distress signal. The problem is the range that the signal reaches is very limited. This was solved when Cospas-Sarsat was initiated and developed. The problem with the old system is that there is a 97% false alarm rate and activation rate of 12% only in crashes. It did provide some help but not enough. This was solved by the introduction of the digital 406 MHz ELTs. The effectiveness of the emergency locator transmitters is not simply reliant on the device itself but the infrastructure behind it allowing for the objective of rescue to be achieved. The current Cospas-Sarsat system servicing over 30 countries includes a ground segment and a space segment. The ground segment includes, of course, the distress radio beacon itself, the satellite downlink receiving and signal processing stations known as local user terminals (LUT), the mission control centers that allocates and sends out the distress alert data generated and processed by the LUTs and the join rescue coordination centers or rescue coordination centers that provide coordination support for search and rescue response teams that rush to the scene of the distress. The space segment includes search and rescue signal processors (SARP) placed on four geosynchronous satellites (GEOSARs) and five low-earth polar orbit satellites (LEOSARs). SARP is simply a secondary payload on satellites that have different purposes – from communication to weather. Currently, the Cospas-Sarsat system is being improved to include a new capability known as MEOSAR or medium earth orbit search and rescue satellites. In the new system, SARPs will be fitted on current GPS satellite and Gallileo positioning system constellations. This will provide the Cospas-Sarsat system with near-instantaneous detection, identification, receipt of position and determination of Doppler triangulated position of the beacons. The cycle begins with a distress signal sent by the crashed aircraft, a sinking ship or a person lost in uncharted territory. The signal is received within 24 to 48 hours (the ordinary transmission time for ELTs) by GEOSAR, LEOSAR or currently MEOSAR satellites. The signal is forwarded to the local user terminal nearest to the site which analyzes the data. For older beacons, the signal has to be triangulated and the exact location identified. For newer beacons, the exact location is determined almost immediately. The information is sent to the mission control center for the country-member of Cospas-Sarsat. The mission control center will send it to an appropriate rescue coordination center that will send rescue teams to the site. This whole process has to be done within the first 24 hours or “golden day” to be able to significantly save more lives. When transmitters send digital signals, it contains hexadecimal codes that prompt search and rescue agencies to check tabbed information on phone numbers to call, description of aircraft, home port of the aircraft and all the other information obtained during registration of the ELT. This information allows the search and rescue agency to respond more quickly and effectively. There are safeguard protocols that allow for verification of a disaster. For example, if an aircraft communication device registered with the agency is unreachable, then there is greater likelihood that the real disaster has occurred. This is only true for 406 MHz since 121.5 and 243.0 MHz transmitters only produce a siren tone with no distinct information. The location triangulation requires more time and resources and thus, on February 1, 2009, Cospas-Sarsat has stopped servicing the other radio beacons. To prove the value of the Cospas-Sarsat, since 1982, the system has been able to assist 22,000 people in around 6,000 distress situations. Hence, the United States requires all its civil aircraft to be fitted with the ELTs. It is devices and systems such as these that allow the global transportation systems to continue to speed up globalization, and allow us to travel quickly, and safely across the world. In a world where every spot is accessible, there has to be an equally powerful system that can make sure potential disasters are averted. References: Industry Canada. February 2007 “Spectrum Management and Telecommunications.” Issue 1. Retrieved June 4, 2009 from http://www.ic.gc.ca/eic/site/smt- gst.nsf/vwapj/rss287e.pdf/$FILE/rss287e.pdf. Cospas-Sarsat. 2007. “System Concept.” Retrieved June 4, 2009 from http://www.cospas-sarsat.org/Description/concept.htm National Business Aviation Association. “Emergency Locator Transmitter (ELT) Requirements” Retrieved June 4, 2009 from www.nbaa.org/member/ops/cns/elt/ National Environmental Satellite, Data, and Information Service. “Search and Rescue Satellite-aided Tracking”. Retrieved June 4, 2009 from www.sarsat.noaa.gov/emerbcns.html NASA Search and Rescue Mission Office. December 2008. “Emergency Beacons.” Retrieved June 4, 2009 from http://searchandrescue.gsfc.nasa.gov/beacons/index.html. Federal Emergency Management Agency. May 1994. “Community Emergency Response Team.” Retrieved June 4, 2009 from http://www1.va.gov/emshg/apps/kml/docs/CERT_Manual.pdf. Cospas-Sarsat. 2007. “Cospas-Sarsat Distress Alerts during 2007.” Retrieved June 4, 2009 from http://www.cospas-sarsat.org/Status/saves.htm. National Oceanic and Atmospheric Administration. November 2000. “Satellite Processing of 121.5/243 MHz Emergency Beacons to be Terminated On Feb. 1, 2009.” Retrieved June 4, 2009 from http://www.sarsat.noaa.gov/121phaseout.pdf. International Civil Aviation Organization. August 2007. “ICAO/IMO Joint Working Group on Harmonization of Aeronautical and Maritime Search and Rescue.” Retrieved June 4, 2009 from http://www.icao.int/icaoimojwg/meetings/jwg14/docs/JWG_SAR14wp13.pdf. National Oceanic and Atmospheric Administration. November 2000. “SARSAT System Overview.” Retrieved June 4, 2009 from http://www.sarsat.noaa.gov/. Read More