Emergency locator beacon

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 is an international humanitarian consortium of governmental and private agencies which acts as a worldwide dispatcher for search and rescue operations.

The satellites calculate the geographic location of the beacon within 2 km by measuring the Doppler frequency shift of the radio waves due to the relative motion of the transmitter and the satellite, and quickly transmit the information to the appropriate local first responder organizations, which perform the search and rescue.

Defined officially as emergency position-indicating radiobeacon stations in the ITU Radio Regulations (Section IV.