secondary radar

secondary radar

[′sek·ən‚der·ē ′rā‚där] (electronics) Radar which receives pulses transmitted by an interrogator and makes a return transmission (usually on a different frequency) by its transponder, as opposed to a primary radar which receives pulses returned from illuminated objects.

secondary radar

A radar system wherein a radio signal transmitted from the radar station initiates the transmission of a radio signal from another station (ICAO). Examples of secondary radars are IFF (identification friend or foe) and secondary surveillance radar. See identification friend or foe.