Radar
16 definitions

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An instrument useful for remote sensing of meteorological phenomena. It operates by sending radio waves and monitoring those returned by such reflecting objects as raindrops within clouds.

FK Reading Ease
23.9

FK Grade Level
College
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    An electronic radio detection and ranging system that determined the location, speed, and number of water vessels and/or the azimuth, location, height, speed, and number of aircraft. RA in RAdio, D in Detection, A in And, and R in Ranging.

    FK Reading Ease
    45.7

    FK Grade Level
    High School
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    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 transmitted pulses.

    • Primary Radar− A radar system in which a minute portion of a radio pulse transmitted from a site is reflected by an object and then received back at that site for processing and display at an air traffic control facility.
    • Secondary Radar/Radar Beacon (ATCRBS)− A radar system in which the object to be detected is fitted with cooperative equipment in the form of a radio receiver/transmitter (transponder). Radar 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 reply transmission, rather than a reflected signal, is then received back at the transmitter/receiver site for processing and display at an air traffic control facility.
    FK Reading Ease
    17.5

    FK Grade Level
    Graduate School
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    A radio detection device which provides information on range, azimuth and/or elevation of objects.

    • Primary Radar− Radar system which uses reflected radio signals.
    • Secondary Radar− Radar system wherein a radio signal transmitted from a radar station initiates the transmission of a radio signal from another station.
    FK Reading Ease
    14.5

    FK Grade Level
    College
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    An electronic instrument used for the detection and ranging of distant objects of such composition that they scatter or reflect radio energy.

    A radar consists of a transmitter, receiver, antenna, display, and associated equipment for control and signal processing. The most common radars are monostatic radars, which use the same antenna for both transmission and reception. These radars depend on backscattering to produce a detectable echo from a target. Bistatic radars have the transmitter and its antenna at one location and the receiver and its antenna at a remote location. These radars depend upon forward scattering to produce a detectable signal. Radio energy emitted by the transmitter and focused by the antenna of a monostatic radar propagates outward through the atmosphere in a narrow beam. Objects lying in the path of the beam reflect, scatter, and absorb the energy. A small portion of the reflected and scattered energy, called the target signal, travels back along the same path through the atmosphere and is intercepted by the receiving antenna. The time delay between the transmitted signal and the target signal is used to determine the distance or slant range of the target from the radar. The direction in which the focused beam is pointing at the instant the target signal is received (i.e., the azimuth and elevation angles of the antenna) determine the direction and height of the target. This information is presented visually as echoes on different types of radar displays. Because hydrometeors scatter radio energy, weather radars, operating in certain radar frequency bands, can detect the presence of precipitation and other weather phenomena at distances up to several hundred kilometers from the radar, depending upon meteorological conditions and the type of radar. MST radars and wind profilers, which operate at longer wavelengths than weather radars, are able to detect echoes from optically clear air that are caused by spatial fluctuations of refractivity. Additional information provided by a radar about a target may include the radial velocity or rate of change of range, as measured by a Doppler radar, or the depolarizing characteristics of the target, as measured by a polarimetric radar.

    FK Reading Ease
    29.7

    FK Grade Level
    College
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    A radio determination system based on the comparison of reference signals with radio signals reflected, or retransmitted, from the position to be determined.

    FK Reading Ease
    3.3

    FK Grade Level
    Graduate School
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  • "radar": A method, system or technique of using beamed, reflected, and timed radio waves for detecting, locating, or tracking objects (such as rockets), for measuring altitude, etc., in any of various activities, such as air traffic control or guidance. The electronic equipment or apparatus used to generate, transmit, receive, and usually, to display radio scanning or locating waves, a radar set. Used for radio detection and ranging.
    FK Reading Ease
    30.7

    FK Grade Level
    College
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  • An instrument useful for remote sensing of meteorological phenomena. It operates by sending radio waves and monitoring those returned by such reflecting objects as raindrops within clouds.

    FK Reading Ease
    23.9

    FK Grade Level
    College
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  • An instrument used to detect precipitation by measuring the strength of the electromagnetic signal reflected back. (RADAR= Radio Detection and Ranging)

    FK Reading Ease
    14.9

    FK Grade Level
    College
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  • This definition has not yet been approved by a moderator.

    Portable unit used by officers to determine speeds of approaching vehicles in the field.

    FK Reading Ease
    35.5

    FK Grade Level
    High School
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