identification, friend or foe

In telecommunications, identification, friend or foe (IFF) is a crypto identification system designed for command and control. A system that enables military, and national (civilian located ATC) interrogation systems to distinguish friendly aircraft, vehicles, or forces, and to determine their bearing and range from the interrogator.
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Secondary Surveillance Radar (SSR) is a radar system used in air traffic control (ATC), which not only detects and measures the position of aircraft but also requests additional information from the aircraft itself such as its identity and altitude. Unlike primary radar systems, which measure only the range and bearing of targets by detecting reflected radio signals, rather like seeing an object in a beam of light, SSR relies on its targets being equipped with a radar transponder, which replies to each interrogation signal by transmitting its own response containing encoded data. SSR is based on the military Identification Friend or Foe (IFF) technology originally developed during the second world war, and the two systems are still compatible today.
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A system using electromagnetic transmissions to which equipment carried by friendly forces automatically responds, for example, by emitting pulses, thereby distinguishing themselves from enemy forces. [JP1] Note: The secondary surveillance radar (SSR) system used in modern air traffic control systems is an outgrowth of the military IFF system used during World War II. The IFF equipment carried by modern military aircraft is compatible with the transponder system used for civilian air traffic control.

A system using electromagnetic transmissions to which equipment carried by friendly forces automatically responds, for example, by emitting pulses, thereby distinguishing themselves from enemy forces. Commonly called "IFF". See also detection; identification; recognition. 1/8/82

Système utilisant des émissions électromagnétiques auxquelles le matériel transporté par des forces amies répond automatiquement, en émettant par exemple des impulsions, ce qui les distingue des forces ennemies. Communément appelé "IFF". Voir aussi détection; identification; reconnaissance. 1/8/82