Radar Glossary







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    Airborne Radar.  An airborne radar is carried by an aircraft.

    Airport Radar.  Airport radar provides information to air traffic controllers on aircraft in the local air space.

    Anti-radiation Missile (ARM).  An anti-radiation missile is able to guide itself to destroy a radar using the signal transmitted by the radar. Destruction of the radar or intimidation of the operators is the most positive electronic attack (EA) tactic

    ARM.  See Anti-radiation Missile.

    AWACS.  The AWACS (Airborne Warning and Control System) is a system mounted in a Boeing E3 aircraft that provides airborne surveillance and command and control (C2) functions.

    Barrage Jamming.  Barrage jamming is used when there is a need to jam over a wide bandwidth simultaneously. Barrage jamming is an attractive technique because a range of different radars (including frequency agile radars) can be jammed continuously and simultaneously.

    Bistatic Radar.  A bistatic radar system uses different antennas for transmission and reception.

    Blind Range.  Targets falling within the blind range range from the radar system are not detected.

    Chaff.  Chaff refers to large quantities of passive reflecting material deployed in the atmosphere to counter or confuse enemy radar. Chaff was (almost) simultaneously introduced during World War II (1943) by the Germans and the British. The British called their version of chaff window.

    Continuous Wave Radar (CW Radar).  Continuous wave (CW) radar continually transmits energy in the direction of the target and receives back reflection of the continuous wave.

    CW Radar.  See Continuous Wave Radar.

    Digital Radar.  Surveillance radar is used to detect targets within range of the radar.

    Digital Radio Frequency Memory (DRFM).  Digital radio frequency memory is an approach being adopted by modern electronic attack (EA) systems to combat pulse-compression radar. A digital radio frequency memory system receives radar pulses, stores these in a digital delay line, and retransmits then some time later.

    Doppler Blind Speed.  Doppler blind speed is a major weakness of moving target indicator (MTI) radar. Each time the Doppler shift is an integral multiple of the radar pulse-repetition frequency (PRF), the moving target indicator (MTI) radar receiver returns a zero response

    Doppler Radar.  Doppler radar allows the speed of a target to be measured using the Doppler effect.

    DRFM.  See Digital Radio Frequency Memory.

    EA.  See Electronic Attack.

    ECCM.  See Electronic Counter Counter Measures.

    ECM.  See Electronic Counter Measures.

    Electronic Attack (EA).  Electronic attack (EA), previously known as electronic counter measures (ECM), is conducted on radar systems to reduce or prevent the radarís use of the electromagnetic spectrum.

    Electronic Counter Counter Measures (ECCM).  See electronic protection.

    Electronic Counter Measures (ECM).  See electronic attack.

    Electronic Protection (EP).  Electronic protection (EP) aims to ensure continued friendly use of the electromagnetic spectrum despite adversary EA and ES.

    Electronic Support (ES).  Electronic Support aims to gain sufficient information about radar sensors to allow an understanding of the radarís characteristics including its role, its method of operation, and its strengths and weaknesses.

    Electronic Warfare (EW).  Electronic warfare (EW) describes techniques that exploit an adversary's use of the electromagnetic spectrum or defend friendly use of the electromagnetic spectrum. There are three subdivisions of EW: Electronic Support, Electronic Attack and Electronic Protection.

    EP.  See Electronic Protection.

    ES.  See Electronic Support.

    EW.  See Electronic Warfare.

    FM CW Radar.  See Frequency Modulated Continuous Wave Radar.

    Frequency Agility.  Frequency agility refers to the radar's ability to rapidly change its operating frequency in a pseudo-random fashion to maintain a narrow instantaneous bandwidth over a wide operating bandwidth.

    Frequency Diversity.  Frequency diversity refers to the use of complementary radar transmissions or multiple radar systems operating cooperatively at different frequencies.

    Frequency Modulated Continuous Wave Radar (FM CW Radar).  Frequency modulated continuous wave radar makes use of frequency modulation to allow the range of a target to be measured.

    GPR.  See Ground Penetrating Radar.

    Ground Penetrating Radar (GPR).  Ground penetrating radar uses radar principles to image, locate and quantitatively identify changes in electromagnetic properties under the ground.

    Ground Radar.  Ground radar is used to observe targets either on the surface of the earth, or airborne targets.

    Identification Friend or Foe.  See IFF.

    IFF (Identification Friend or Foe).  The identification friend or foe (IFF) system is an example of a secondary radar system that is in wide use in the military environment.

    Inverse Synthetic Aperture Radar (ISAR).  Inverse SAR (ISAR) is a variation on the SAR theme that uses the motion of the target relative to the radar to the same effect.

    ISAR.  See Inverse Synthetic Aperture Radar.

    Jammer.  A jammer aims to degrade the operation of a radio receiver by transmitting a jamming signal that is received at higher power than other signals, and hopefully prevents them from being received at all.

    Laser Radar (LIDAR).  Laser radar (LIDAR) is a radar that uses light in place of the radio-frequency signals used in conventional radar.

    LIDAR.  See Laser Radar.

    Marine Radar.  Marine radar is used for prevention of collisions between ships and as an aid to navigation when a ship is close to shore.

    Maximum Unambiguous Range.  The pulse-repetition frequency (PRF) of a radar system determines the maximum operating range of the radar before ambiguities start to occur. This is called the maximum unambiguous range of
    the radar.

    Monostatic Radar.  A monostatic radar system transmits and receives its energy through the same antenna system or through collocated antennas.

    Phased Array Radar.  A phased array radar uses an antenna that consists of an array of antenna elements along with signal processing that allows the antenna to be steered electronically.

    Plan Position Indicator (PPI).  The plan position indicator (PPI) is possibly the best known of all radar displays where the targets are shown in a plan format.

    PPI.  See Plan Position Indicator.

    Primary Radar.  Primary radar systems receive reflections of their own transmitted signals as returned signals from the target.

    Pulse Compression Radar.  Pulse-compression radars make use of specific signal processing techniques to provide most of the advantages of extremely narrow pulses widths whilst remaining within the peak power limitations of the transmitter.

    Pulse Doppler Radar.  Pulse doppler radars make use of the Dopper shift in pulse radar to determine the relative velocity of moving targets.

    Pulse Radar.  A pulse radar transmits a sequence of short pulses of RF energy, and estimates range to the target by measuring the time delay in returned pulses.

    Radar.  Radar is used to describe systems that use electromagnetic energy to detect distant objects and possibly determine other characteristics such as direction and range.

    Radar Absorbent Material (RAM).  Radar absorbent material has electrical properties similar to free space. When radar impacts radar absorbent material, the energy acts as though it "sees" infinite free space instead of a boundary.

    Radar Altimeter.  A radar altimeter is used by an aircraft to determine its height above terrain.

    Radar Antenna.  A radar antenna is a physical object used to focus, direct and concentrate electromagnetic energy into a specific direction. The most common types of radar antenna are parabolic reflectors and phased array antennas.

    Radar Clutter.  The term clutter refers to any objects that cause unwanted reflections of a radar's electromagnetic energy to be returned to the radar receiver.

    Radar Cross Section (RCS).  The radar cross section (RCS) of a target is the projected area that would intercept the transmitted signal and reflect isotropically an amount that produces the returned signal at the receiver.

    Radar Detector.  A radar detector warns its user when it detects a radar signal.

    Radar Displays.  A means of displaying target information in a clear and concise manner.

    Radar Electronics.  Traditional radar systems have relied on dedicated, radar electronics for their processing.

    Radar GunRadar gun is a colloquial term for a type of police radar used to measure speed.

    Radar Jammer.  A radar jammer is a type of jammer designed specifically designed to jam radar receivers.

    Radar Range Equation (RRE).  The radar range equation (RRE) relates the range performance of a radar system to other radar components and their characteristics.

    Radar Receivers.  Clutter is a major practical problem in the use of radar systems. Radar receivers often incorporate special techniques to to minimise clutter.

    Radar Reflector.  A radar reflector is a passive device that is designed to be ab efficient reflector of radar signals, giving a strong return to the radar.

    Radar ScreenRadar screen is another term for radar display.

    Radar StationRadar station is a term used to describe a facility housing a ground radar.

    Radar System.  A radar system includes: a radar antenna, a radar transmitter, a radar receiver, radar signal processing, and a radar display.

    Radar Warning Receiver (RWR).  A radar warning receiver is a type of radar detector.

    RAM.  See Radar Absorbent Material.

    Range Gate Pulloff.  Targets being tracked using range gates can attempt to employ a tactic known as range-gate pull off (RGPO) or range-gate stealing.

    Range Height Indicator (RHI).  A range height indicator (RHI) is a radar display that represents the height of the target on the vertical axis, and uses the horizontal axis of the RHI to represent the target range.

    Range Resolution.  Range resolution is the ability of the radar to differentiate or resolve two targets that are close together in range.

    RCS.  See Radar Cross Section.

    RHI.  See Range Height Indicator.

    RRE.  See Radar Range Equation.

    RWR.  See Radar Warning Receiver.

    SAR.  See Synthetic Aperture Radar.

    Satellite Radar.  Satellite radar systems can be used for a variety of surveillance applications.

    Secondary Radar.  A secondary radar system is a cooperative target identification system in which the interrogator transmits an encoded signal to a target.

    Sidelobe Blanking (SLB).  Antennas with poor sidelobe performance can be improved by using sidelobe blanking techniques.

    Sidelobe Cancellation (SLC).  Sidelobe cancellation determines the direction of the jamming signal and effectively steers a null into that direction to zero out the jamming signal. Planar array antenna systems can perform this electronically by dedicating some of the array elements to function as omnidirectional antennas.

    Sidelobe Control.  Sidelobe control comes initially from good antenna design where one requirement is the minimisation of signals entering the receiver through the sidelobes.

    SLB.  See Sidelobe Blanking.

    SLC.  See Sidelobe Cancellation.

    Spot Jamming.  Spot jamming aims to concentrate the maximum amount of jammer power into the bandwidth of an individual radar system.

    Surveillance Radar.  Surveillance radar is used to detect targets within range of the radar.

    Sweep Jamming.  Sweep jamming aims to counter a number of different radar systems spread in frequency over a wide band by continuously sweeping the jamming frequency across the band.

    Swept Jamming.  See sweep jamming.

    Synthetic Aperture Radar (SAR).  Synthetic aperture radar (SAR) describes a way of synthesising a very large array antenna over a finite period of time by using a series of returns from a much smaller physical antenna that is moving relative to the target.

    Tracking Radar.  Tracking radar aims to accurately track the target in range, velocity or most commonly bearing.

    Weather Radar.  Weather radar is used as an aid to weather forecasting.

    X Band Radar.  An X band radar operates in the frequency range 8-12 GHz.


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