RADAR (RADIO DETECTION AND RANGING)
A device which, by measuring the time interval between transmission and reception of radio pulses and correlating the angular orientation of the radiated antenna beam or beams in azimuth and or elevation, provides information on range, azimuth and / or elevation of objects in the path of the transmited pulses. [Radar Beacon (secundary radar) - A Radar system in which the object to be detected is fitted with cooperative equipment in the form of a radio receiver / transmitter (transponder). Radio pulses transmitted from the searching transmitter receiver (interrogator) site are received in the cooperative equipment and used to trigger a distinctive transmission from the transponder. This latter transmission rather than a reflected signal is then received back at the transmitter / receiver site]