Radar terms, and definitions

Radar: An acronym for Radio Detection And Ranging. A radio detection system that transmits short bursts (pulses) of rf energy and detects their echos from objects (targets) such as aircraft or ships.

Radar Altimeter: Airborne radar that measures the distance of the aircraft above the ground.

Radar Beam: The space in front of a radar antenna where a target can be effectively detected or tracked.

Radar Blind Range: The range that corresponds to the situation in which a radar transmitter is on and hence the receiver must be off, so that the radar transmitted signal does not saturate, i.e., does not blind, its own receiver.

Radar Blind Speed: The magnitude of the radial component of velocity of an object, i.e., a target, relative to a radar site, that cannot be measured by the radar unit.

Radar Cross Section: A measure of the radar reflection characteristics of a target. It is equal to the power reflected back to the radar divided by power density of the wave striking the target. For most targets, the radar cross section is the area of the cross section of the sphere that would reflect the same energy back to the radar if the sphere were substituted. RCS of sphere is independent of frequency if operating in the far field region.

Radar Detector: A detector that, in its simplest form, only needs to be capable of producing an output when RF energy (reflected from a target) is present at its input.

Radar Mile: A time interval of 12.36 microseconds which equals the amount of time for rf energy to travel out from a radar to a target and back to the radar; radar nautical mile.

Radar Range Equation: The radar range equation is a basic relationship which permits the calculation of received echo signal strength, if certain parameters of the radar transmitter, antenna, propagation path, and target are known.

Radar Signature: The detailed waveform of a detected radar echo.

Radar Warning Receiver: [RWR] A receiver that detects the presence of Radar signals. A radar detector.

Radiation Pattern: The variation of the field intensity of an antenna as an angular function with respect to the axis.

Radar Frequency Interference: See RFI.

Radome: The structure that protects a radar antenna; Radar Dome. A covering that conceals the pointing location of a radar.

Range: The length of a straight line between a radar set and a target.

Range Cell: In a radar, a range cell is the smallest range increment the radar is capable of detecting. If a radar has a range resolution of 50 yards and a total range of 30 nautical miles (60,000 yds), there are: 60000/50 = 1,200 range cells.

Range Gate: A movable gate used to select radar echoes from a very short-range interval. A gate voltage used to select radar echoes from a very short range interval.

Range Gate Pull Off: [RGPO] Deception technique used against pulse tracking radars using range gates. Jammer initially repeats the skin echo with minimum time delay at a high power to capture the AGC circuitry. The delay is progressively increased, forcing the tracking gates to be pulled away from the target echo.

Range-Height Indicator. A radar display on which slant range is shown along the X axis and height along the Y axis.

Range Rate: The rate at which a radar target is changing its range with respect to the radar (in feet per second for example). Note that this rate is not the same as target velocity unless the target is moving straight toward or straight away from the radar.

Range Resolution: Ability of a radar to distinguish between targets that are close together.

Range Scope: There are a number of types of Radar screens in use. See R-Scope A-Scope or PPI.

Ranging: The measurement of the distance to a remote object (target), from a known observation or reference point.