radio direction finding

Direction finding (DF) refers to the establishment of the direction from which a received signal was transmitted. This can refer to radio or other forms of wireless communication. By combining the direction information from two or more suitably spaced receivers, the source of a transmission may be located in space via triangulation. This is called a cross-cut or fix.
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A radio direction finder (RDF) is a device for finding the direction to a radio source. Due to radio's ability to travel very long distances "over the horizon", it makes a particularly good radio navigation system for ships and aircraft that might be flying at a distance from land.
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Radio-location in which only the direction of a station is determined by means of its emissions. 1/11/68

Radiorepérage permettant seulement de déterminer la direction d'une station radio au moyen de ses émissions. 1/11/68