Acronym for radio detection and ranging. 1. A radio detection
system that transmits short bursts (pulses) of rf energy and detects their echos from objects (targets) such as aircraft or ships.
Note: The round-trip
propagation time for the
echo return may be used to determine the target's range (distance from the radar's
antenna). If the transmitting antenna has a narrow
beam (the usual case), the azimuth or elevation of the target may also be determined.
Synonym primary radar. Contrast with secondary radar. 2. A radio detection device that provides
information on range, azimuth, and/or elevation of objects. [
JP1]
3. A
radiodetermination system based on the comparison of reference signals with radio signals reflected, or retransmitted, from the position to be determined. [
NTIA] [
RR]