An emergency locator beacon is a radio beacon, a battery powered radio transmitter, used to locate airplanes, vessels, and persons in distress and in need of immediate rescue. Various types of emergency locator beacons are carried by aircraft, ships, vehicles, hikers and cross-country skiers. In case of an emergency, such as the aircraft crashing, the ship sinking, or a hiker becoming lost, the transmitter is deployed and begins to transmit a continuous radio signal, which is used by search and rescue teams to quickly find the emergency and render aid.
COSPAS-SARSAT 406 MHz Distress Beacons
Defined officially as emergency position-indicating radiobeacon stations in the ITU Radio Regulations (Section IV. Radio Stations and Systems – Article 1.93), these transmit a coded data burst once every 50 seconds, conforming to the specification, C/S T.001 Specification for COSPAS-SARSAT 406 MHz Distress Beacons, and are designed to be detected and located by an international set of search-and-rescue transponders on various satellites. The different types include:
- ELTs (emergency locator transmitters) signal aircraft distress
- EPIRBs (emergency position-indicating radio beacons) signal maritime distress
- SEPIRBs (submarine emergency position-indicating radio beacons) are EPIRBs designed only for use on submarines
- SSASes (ship security alert system) are used to indicate possible piracy or terrorism attacks on sea-going vessels
- PLBs (personal locator beacons) are for personal use and are intended to indicate a person in distress who is away from normal emergency services; e.g., 9-1-1. They are also used for crewsaving applications in shipping and lifeboats at terrestrial systems. In New South Wales, some police stations and the National Parks and Wildlife Service provide personal locator beacons to hikers for no charge.
Auxiliary maritime beacons
- ENOS Rescue-System
- A rescue beacon system designed for use by divers who have drifted away from their dive boats.
- Search and rescue transponder (SART)
- A specialized radar beacon (RACON) that emits a string of 12 dots (replaced by arcs and circles when closer) for display on an X-band radar screen when scanned.
- MSLDs (Maritime Survivor Locator Devices) are a man-overboard signalling device, first standardized in 2016.
- A Maritime Survivor Locator Device (MSLD) is a man-overboard locator beacon. In the U.S., rules were established in 2016 in 47 C.F.R. Part 95. A MSLD may transmit on 121.500 MHz, or one of these: 156.525 MHz, 156.750 MHz, 156.800 MHz, 156.850 MHz, 161.975 MHz, 162.025 MHz (bold are Canadian-required frequencies).
- A hand-held automatic identification system (AIS) transmitter that emits only an emergency beacon. Misnamed because it does not have a receiver and thus cannot be a transponder.
SEND—Satellite Emergency Notification Devices
- TracPlus (Reliable Land, Maritime and Aviation beacons)
- Mountain Locator Unit
- Automatic Packet Reporting System
- Crash position indicator
- Transponder (aeronautics)
- Can be used as an emergency beacon of sorts by setting it to squawk 7700, the distress code
- Survival radio
- Direction finding
- Global Maritime Distress and Safety System
- Search and rescue
- Survival craft station