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List of radar types

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This is a list of different types ofradar.

Detection and search radars

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Search radars scan great volumes of space with pulses of short radio waves. They typically scan the volume two to four times a minute. The waves are usually less than a meter long. Ships and planes are metal, and reflect radio waves. The radar measures the distance to the reflector by measuring the time of the roundtrip from emission of a pulse to reception, dividing this by two, and then multiplying by thespeed of light.To be accepted, the received pulse has to lie within a period of time called therange gate.The radar determines the direction because the short radio waves behave like a search light when emitted from the reflector of the radar set's antenna.

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RAFBoeingE-3 SentryAEW1 (AWACS) with rotating radar dome. The dome is 30 feet across (9 m) The E-3 is accompanied by twoPanavia Tornado F3.

Targeting radars

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Main article:Fire-control radar

Targeting radars utilize the same principle but scan smaller volumes of space far more often, usually several times a second or more, while a search radar will scan a larger volume less frequently.Missile lock-ondescribes the scenario where a targeting radar has acquired a target, and the fire control can calculate a path for the missile to the target; insemi-active radar homingsystems, this implies that the missile can "see" the target that the targeting radar is "illuminating". Some targeting radars have a range gate that can track a target, to eliminate clutter andelectronic countermeasures.

Missile guidance systems

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Main article:Missile guidance

Others

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Battlefield and reconnaissance radar

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Military map marking symbolRadaras of NATO standardAPP-6a

Instrumentation radars

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Instrumentation radars are used to test aircraft, missiles, rockets, and munitions on government and private test ranges. They provide Time, Space, Position, Information (TSPI) data both for real time and post processing analysis.[2]

Repurposed NASA and military radars

Commercial off-the-shelf (COTS)

Custom

  • AN/MPS-39 Multi-Object Tracking Radar (MOTR)
  • TAMTS
  • BAE Rule
  • ROTR
  • ROSA
  • ROSA II
  • COSIP
  • Dynetics MRS

Fuzes and triggers

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Radarproximity fuzesare attached toanti-aircraft artilleryshells or otherexplosivedevices, and detonate the device when it approaches a large object. They use a small rapidly pulsing omnidirectional radar, usually with a powerful battery that has a long storage life, and a very short operational life. The fuzes used in anti-aircraft artillery have to be mechanically designed to accept fifty thousandg,yet still be cheap enough to throw away.[citation needed]

Weather-sensing radar systems

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Weather radarscan resemble search radars. This radar uses radio waves along with horizontal, dual (horizontal and vertical), or circular polarization. The frequency selection of weather radar is a performance compromise between precipitation reflectivity and attenuation due to atmospheric water vapor. Someweather radarsusesdoppler shiftto measure wind speeds and dual-polarization for identification of types of precipitations.[3][4]

  • Storm front reflectivities on a weather radar screen (NOAA)
    Storm frontreflectivitieson a weather radar screen (NOAA)
  • Wind profiling radar
    Wind profiling radar
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Main article:Radar navigation
Surface search radar display commonly found on ships

Navigational radars resemble search radar, but use very short waves that reflect from earth and stone. They are common on commercial ships and long-distance commercial aircraft.

Marine radars are used by ships for collision avoidance and navigation purposes. The frequency band ofradarused on most ships isX band(9 GHz/3 cm), butS band(3 GHz/10 cm) radar is also installed on most oceangoing ships to provide better detection of ships in rough sea and heavy rain condition.Vessel traffic servicesalso use marine radars (X or S band) for trackingARPAand provides collision avoidance or traffic regulation of ships in the surveillance area.

General purpose radars are increasingly being substituted for pure navigational radars. These generally use navigational radar frequencies, but modulate the pulse so the receiver can determine the type of surface of the reflector. The best general-purpose radars distinguish the rain of heavy storms, as well as land and vehicles. Some can superimpose sonar and map data fromGPSposition.

Air Traffic Control and navigation

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Air traffic controluses primary and secondary radars. Primary radars are a "classical" radar which reflects all kind of echoes, includingaircraftand clouds. Secondary radar emits pulses and listens for special answer of digital data emitted by an AircraftTransponderas an answer. Transponders emit different kind of data like a 4 octal ID (mode A), the onboard calculated altitude (mode C) or the Callsign (not theflight number) (mode S). Military use transponders to establish the nationality and intention of an aircraft, so that air defenses can identify possibly hostile radar returns. This military system is called IFF (Identification Friend or Foe).

Air traffic control radar atLondon Heathrow Airport

Space and range instrumentation radar systems

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Mapping radars

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Mapping radars are used to scan a large region forremote sensingandgeographyapplications. They generally usesynthetic aperture radar,which limits them to relatively static targets, normally terrain.

Specific radar systems can sense a human behind walls. This is possible since the reflective characteristics of humans are generally more diverse than those of the materials typically used in construction. However, since humans reflect far less radar energy than metal does, these systems require sophisticated technology to isolate human targets and moreover to process any sort of detailed image. Through-the-wall radars can be made withUltra Widebandimpulse radar, micro-Doppler radar,and synthetic aperture radar (SAR).[5]

Speed radar

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  • Radar gun,for traffic policing and as used in some sports

Radars for biological research

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Radar range and wavelength can be adapted for different surveys of bird andinsectmigration and daily habits. They can have other uses too in the biological field.

  • "MERLIN Avian Radar System for Bird Activity Monitoring and Mortality Risk Mitigation"(PDF).
  • Insect radar
  • Wearable radarand miniature radar systems are used as electric seeing aids for the visually impaired, as well as early warningcollision detectionandsituational awareness.
Further information:Bioradiolocation

See also

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Notes

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  1. ^"AN/PPS-5B Ground Surveillance Radar Set".Federation of American Scientists. 1998-09-12.Retrieved2009-03-15.
  2. ^Nessmith, Josh T. (November 1976). "Range Instrumentation Radars".IEEE Transactions on Aerospace and Electronic Systems.12(6): 756–766.Bibcode:1976ITAES..12..756N.doi:10.1109/TAES.1976.308354.S2CID45406364.
  3. ^"Using and Understanding Doppler Weather Radar".National Weather Service.Retrieved2023-08-08.
  4. ^"What is Dual-Pol?".National Weather Service.Retrieved2023-08-08.
  5. ^Through-the-wall radar
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