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Definition: Radar |
RadarNoun1. Measuring instrument in which the echo of a pulse of microwave radiation is used to detect and locate distant objects. Source: WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved. |
| Domain | Definitions |
Aerospace | (From radio detection and ranging). 1. 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. 2. The electronic equipment or apparatus used to generate, transmit, receive, and, usually, to display radio scanning or locating waves; a radar set.The terms primary radar and secondary radar may be used when the return signals are, respectively, by reflection and by the transmission of a second signal as a result of triggering responder beacon by the incident signal. (references) |
Food & Agriculture | A navigational aid which uses radio waves of very short wavelength sent out as a narrow beam by a highly directional aerial. The aerial rotates sending the beam out through a full 360°. Any solid object of reasonable size will reflect the beam and be detected on the radar screen as a bright spot. Source: European Union. (references) |
Health | A system using beamed and reflected radio signals to and from an object in such a way that range, bearing, and other characteristics of the object may be determined. (references) |
Post & Telecom | The use of radio waves, reflected or automatically retransmitted, to gain information concerning a distant object. Source: European Union. (references) |
| A radio detection device which provides information on range, azimuth and/or elevation of objects. Source: European Union. (references) | |
Public Administration | A set or system that uses beamed and reflected radio waves for locating objects:navigation, homing, measuring distance, bombing, etc. Source: European Union. (references) |
Source: compiled by the editor from various references; see credits. | |
(From Wikipedia, the free Encyclopedia)
Radar is a recently-coined acronym for radio detection and ranging. It is a system used to detect, range (determine the distance) and map objects such as aircraft and rain. Strong radio waves are transmitted, and a receiver listens for reflected echoes. By analysing the reflected signal, the reflector can be located, and sometimes identified. Although the amount of signal returned is tiny, radio signals can easily be detected and amplified.
Radar radio waves can be easily generated at any desired strength, detected at even tiny powers, and then amplified many times. Thus radar is suited to detecting objects at very large ranges where other reflections, like sound or visible light, would be too weak to detect.
Radar sets attempt to reflect electromagnetic waves, notably radio waves and microwaves, from target objects. This reflection is then detected using a radio receiver.
Electromagnetic waves reflect from any large change in the dielectric or diamagnetic constants. This means that a solid object in air or vacuum, or other significant changes in atomic density, will usually reflect radar waves. This is particularily true of electrically-conductive materials such as metal, making radar particularily well suited to the detection of aircraft and ships.
Radar waves reflect in a variety of ways depending on the size of the radio wave and the shape of the target. If the radio wave is much shorter than the reflector's size, the wave will bounce off in a way similar to the way light bounces from a mirror. Early radars used very long wavelengths that were larger than the targets and received a vague signal, whereas modern systems use shorter wavelengths (a few centimetres) that can image objects the size of a loaf of bread or larger.
Radio waves always reflect from curves and corners, in a way similar to glint from a rounded piece of glass. The most reflective targets have 90-degree angles between the reflective surfaces.
Polarization is the direction that the wave vibrates. Radars use horizontal, vertical and circular polarization to detect different types of reflections. For example, circular polarization is used to minimize the interference caused by rain. Linear polarization returns usually indicate metal surfaces, and help a search radar ignore rain. Random polarization returns usually indicate a fractal surface like rock or dirt, and are used by navigational radars.
Radars in the frequency range of 2.4GHz are strongly absorbed by water. This is useful for a microwave oven but is typically avoided otherwise. Frequencies like those used in commercial TV (50-900 MHz) can pass through rock and earth, and are used for ground penetrating radar.
The easiest way to measure the range of an object is to broadcast a short pulse of radio signal, and then time how long it takes for the reflection to return. The distance is one-half the round trip time (because the signal has to travel to the target and then back to the receiver) divided by the speed of the signal, which in this case is the speed of light.
The receiver cannot detect the returned reflection (also just called a return) while the signal is being sent out – there's no way to tell if the signal it hears is the original or the return. This means that a radar has a distinct minimum range, which is the length of the pulse divided by the speed of light, divided by two. In order to detect closer targets you have to use a shorter pulse length.
A similar effect imposes a specific maximum range as well. If the return from the target comes in when the next pulse is being sent out, once again the receiver cannot tell the difference. In order to maximize range, one wants to use longer times between pulses, the inter-pulse time.
These two effects tend to be at odds with each other, and it is not easy to combine both good short range and good long range in a single radar. This is because the short pulses needed for a good minimum range broadcast less total energy, making the returns much smaller and the target harder to detect. You could offset this by using more pulses, but this would shorten the maximum range again.
Each radar has a particular type of signal they use. Long range radars tend to use long pulses with long delays between then, and short range radars use smaller pulses with less time between them. This pattern of pulses and pauses is known as the Pulse Repetition Frequency (or PRF), and is one of the main ways to characterize a radar. As electronics have improved many radars now can change their PRF.
Speed is the change in distance to an object with respect to time. Thus the existing system for measuring distance, combined with a little memory to see where the target last was, is enough to measure speed. At one time the memory consisted of a user making grease-pencil marks on the radar screen, and then calculating the speed using a slide rule.
However there is another effect that can be used to make much more accurate speed measurements, and do so almost instantly (no memory required), known as the Doppler effect. The Doppler effect is the change in frequency of any signal due to the finite speed at which the signal travels compared to the motion of the object. For instance, sound travels at the fairly slow speed of around 300m/s, which is why you hear the Doppler effect of an ambulance siren as it passes you at 3m/s or so. Although this results in a small 1% change in frequency, the human ear is very good at detecting this change.
In the case of radar the speed of light is much faster than sound and thus the resulting shift much smaller. However modern electronics are even better at detecting this change than the human ear is for sound. Speeds as slow as a few centimeters per second can be easily measured, an accuracy typically much better than for the measurement of distance. Practically every modern radar system uses this principle, and is generally referred to as Pulse Doppler Radar.
The major use of Doppler is to separate moving objects from clutter. It's common for Doppler radars to have a frequency range adjust control to reject low speeds. Another form color-codes returns by their speed.
Doppler measures the speed only along the direction from the reflection to the radar antenna. In order to measure the object's true speed and direction, the radar set or operator had to remember a return's location. Military organizations traditionally used a manual plotting board for this purpose. Computers in the radar systems have made this even more convenient.
It is possible to make a radar without any pulsing, known as a Continuous Wave Radar (or CW), by sending out a very pure signal of a known frequency. Return signals from targets are shifted away from this base frequency via the Doppler effect, so they can be picked up at another antenna even if it is physically close to the broadcaster.
The main advantage of the CW radars is that they have no pulsing, and thus no minimum or maximum ranges (although the broadcast strength imposes a practical limit on the later) as well as maximizing power on the target. However they also have the disadvantage of only being able to detect moving targets, as motionless ones (along the line of sight) will not cause a Doppler shift and the signal from such a target will be filtered out. Such systems thus find themselves being used at either end of the range spectrum, as radio-altimeters at the close-range end (where the range may be a few feet) and long distance early-warning radars at the other.
CW radars have the disadvantage that they cannot measure distance, because there are no pulses to time. In order to correct for this problem, the signal can be changed in frequency subtly over time. When a reflection is received the frequencies can be examined, and by knowing when in the past that particular frequency was sent out, you can do a range calculation similar to using a pulse. It is generally not easy to make a broadcaster that can send out random frequencies cleanly, so instead these Frequency Modulated Continuous Wave Radar (FMCW), use a smoothly varying "ramp" of frequencies up and down. For this reason they are also known as a chirped radar.
Radio signals broadcast from a single antenna will spread out in all directions, and likewise a single antenna will received signals equally from all directions. This leaves the radar with the problem of deciding where the target object is located.
Early systems tended to use omni-directional broadcast antennas, with directional receiver antennas which were pointed in various directions. For instance the first system to be deployed, CH, used two straight antennas at right angles for reception, each on a different display. The maximum return would be detected with an antenna at right angles to the target, and a minimum with the antenna pointed directly at it (end on). The operator could determine the direction to a target by rotating the antenna so one display showed a maximum while the other shows a minimum.
Another method of steering is used in phased array radar. It uses the radio signal's interference with itself. One can broadcast a signal from mulitple antennas. The result is a single beam with the waves in the rest of space cancelling each other. In order to point the beam, computer-controlled delay lines adjust the delay to each antenna. Instead of constructing a single large antenna, such a system has a number of small omni-directional antennas referred to as elements, usually arranged in a flat plate.
Phased array radars require no physical movement. The beam can be steered by electronically adjusting the delay lines to each antenna. This means that the beam can scan at thousands of degrees per second, fast enough to irradiate many individual targets, and still run a wide-ranging search periodically. By simply turning some of the antennas on or off, the beam can be spread for searching, narrowed for tracking, or even split into two or more virtual radars.
Phased array radars were originally used for missile defense. On ships, they are the heart of the Aegis combat system, and are increasingly used in other areas because the lack of moving parts makes them more reliable, and sometimes permits a much larger effective antenna.
Some years later a German engineer, Chistian Huelsmeyer, proposed the use of radio echoes to avoid collisions in marine navigation. In 1904 he completed construction of a device he called the telemobiloscope, which consisted of a simple spark gap aimed using a funnel-shaped metal antenna. When a reflection was seen by the two straight antennas attached to the receiver, a bell sounded. Although very simple, the system could detect shipping accurately up to about 3 km. Nevetheless the naval world seemed uninterested in his invention, and it was not put into production.
The invention of modern radar is generally credited to Sir Robert Watson-Watt. In 1915 he joined the Royal Aircraft Factory at Ditton Park as a meteorologist, where he attempted to use radio signals generated by lightning strikes to map out thunderstorms. The difficulty in pinpointing the direction of these high-speed signals led to the use of rotating directional antennas, and in 1923 the use of oscilloscopes in order to display them in 2-D. At this point the only missing part of a functioning radar was the broadcaster.
Nikola Tesla, in August 1917, first established principles regarding frequency and power level for the first primitive RADAR units in 1934. In the 1917 The Electrical Experimenter, Tesla stated the principles of modern military radar in detail. Tesla's study of high voltage, high frequency alternating currents led to this development. Tesla had formed the concept of using radio waves to detect objects at a distance.
Tesla stated,
In 1934, Watson-Watt was well established in the area of radio, and was approached by H.E. Wimperis from the Air Ministry, who asked about the use of radio to produce a 'death ray'. While he knew this to be unlikely, he did mention Meanwhile attention is being turned to the still difficult, but less unpromising, problem of radio detection and numerical considerations on the method of detection by reflected radio waves will be submitted when required. Watson-Watt and his assistant Arnold Wilkins published a report on the topic in February 1935, titled The Detection of Aircraft by Radio Methods.
Meanwhile in Germany, Hans Eric Hollmann had been working for some time in the field of microwaves, which were to later become the basis of almost all radar systems. In 1935 he published Physics and Technique of Ultrashort Waves, which was then picked up by researchers around the world. At the time he had been most interested in their use for communications, but he and his partner Hans-Karl von Willisen had also worked on radar-like systems.
In the autumn of 1934 their company, GEMA, built the first commercial radar system for detecting ships. Operating in the 50 cm range it could detect ships up to 10 km away, similar in purpose to Huelsmeyer's earlier device. In the summer of 1935 a pulse radar was developed with which they could spot the ship the Königsberg 8 km away, with an accuracy of up to 50 m, enough for gun-laying. The same system could also detect an aircraft at 500 m altitude at a distance of 28 km. The military implications were not lost this time around, and construction of land and sea-based versions took place as Freya and Seetakt.
At this point both England and Germany knew of the ongoing efforts by their "competition". Both nations were intensely interested in the other's developments in the field, and engaged in an active campaign of espionage and false leaks about their respective equipment. But it was only in Britain that the usefulness of the system became obvious, so while the German systems had the edge technologically (operating on much shorter wavelengths) only Britain started true mass deployment of both the radars and the control systems needed to support them.
Shortly before the outbreak of World War II several radar stations known as Chain Home (or CH) were constructed in the south of England. As one might expect from the first radar to be deployed, CH was a simple system. The broadcast side was formed from two 300' (100 m) tall steel towers strung with a series of cables between them. The output of a powerful 50 MHz radio of about 200 kW (up to 800 kW in later models) was fed into these cables, pulsed at about 50 times a second. A second set of 240' (73 m) tall wooden towers were used for reception, with a series of crossed antennas at various heights up to 215' (65 m). In fact most stations had more than one set of each antenna, tuned to operate at different frequencies.
The CH radar was read with an oscilloscope. When a pulse was sent out into the broadcast towers, the scope was triggered to start its beam moving horizontally across the screen very rapidly. The output from the receiver was amplified and fed into the vertical axis of the scope, so a return from an aircraft would deflect the beam upward. This formed a spike on the display, and the distance from the left side - measured with a small scale on the bottom of the screen - would give the distance to the target. By rotating the receiver antennas to make the display disappear, the operator could determine the direction (this is the reason for the cross shaped antennas), the size of the vertical displacement indicated something of the number of aircraft involved, and by comparing the strengths returned from the various antennas up the tower, you could determine the height.
CH proved highly effective during the Battle of Britain, and are often credited with allowing the RAF to defeat the much larger Luftwaffe forces. Whereas the Luftwaffe had to hunt all over to find the RAF fighters, the RAF on the other hand knew exactly where the Luftwaffe bombers where, and could converge all of their fighters on them.
Very early in the battle the Luftwaffe made a series of small raids on a few of the stations, but they were eventually returned to operation in a few days. In the meantime the operators took to broadcasting radar-like signals from other systems in order to fool the Germans into believing that the systems were still operating. Eventually they gave up trying to bomb them. The Luftwaffe apparently never understood the importance of radar to the RAF's efforts, or they would have assigned them a much higher priority -- it is clear they could have knocked them out continually if they wished.
In order to avoid the CH system the Luftwaffe adopted other tactics. One was to approach Britain at very low levels, below the sight line of the radar stations.
This was countered to some degree with a series of shorter range stations built right on the coast, known as Chain Home Low (CHL). These radars had originally been intended to use for naval gun-laying an known as Coastal Defense (CD), but their narrow beams also meant they could sweep an area much closer to the ground without seeing the reflection of the ground (or water) itself. Unlike the larger CH systems, CHL had to have the broadcast antenna itself turned, as opposed to just the receiver. This was done manually on a pedal-crank system run by WAAFs until more reliable motorized movements were installed in 1941.
Similar systems were later adapted with a new display to produce the Ground Controlled Intercept stations starting in late 1941. In these systems the antenna was rotated mechanically, followed by the display on the operators console. That is, instead of a single line across the bottom of the display from left to right, the line was rotated around the screen at the same speed as the antenna was turning.
The result was a 2-D display of the air around the station with the operator in the middle, with all the aircraft appearing as dots in the proper location in space. These so-called Plan Position Indicators (PPI) dramatically simplified the amount of work needed to track a target on the operator's part. Such a system with a rotating, or sweeping, line is what most people continue to associate with a radar display.
Rather than avoid the radars, the Luftwaffe took to avoiding the fighters by flying at night and in bad weather. Although the RAF was aware of the location of the bombers, there was little they could do about them unless the fighter pilots could see the opposing planes. However, just this eventuallity had already been forseen, and Watson-Watt (likely at the urging of Tizzard) had already started work on a miniaturized radar system suitable for aircraft, the so-called AI (airborne interception) set. Initial sets were available in 1941 and fitted to Bristol Blenheim aircraft, replaced quickly with the better performing Bristol Beaufighter, which quickly put an end to German night- and bad-weather bombing over England.
The next major development in the history of radar was the invention of the cavity magnetron by Randall and Boot of Birmingham University in early 1940. This was a small device which generated much more powerful microwaves than previous devices, which in turn allowed for the detection of much smaller objects and the use of much smaller antennas. The secrecy of the device was so high that it was decided in 1940 to move production to the USA, which resulted in the creation of the MIT Radiation Lab to develop the device further.
German developments mirrored those in England, but it appears radar received a much lower priority until later in the war. The Freya was in fact much more sophisticated than its CH counterpart, and by operating in the 1.2 m wavelength (as opposed to ten times that for the CH) the Freya was able to be much smaller and yet offer better resolution. Yet by the start of the war only eight of these units were in operation, offering much less coverage.
However the Germans did not have an airborne system of any sort deployed until 1942, leaving them with the problem of having to get their fighterss into that 300m range solely with ground-based equipment. To fill this need another system known as Wuerzburg was deployed, starting in 1941.
Unlike other systems, the Wuerzburg was mounted on a highly directional parabolic antenna that was sensitive in only one direction. This made it useless for finding the targets, but once guided to one by an associated Freya it could track it with extreme accuracy: later models were accurate to 0.2 degrees or less. In order to do this the radar sent out two lobes and the return of each was shown on the display. By keeping the returns from both the same strength, the operator kept the Wuerzburg pointed directly at the target.
The downfall of the German radar network was that it could only track a single aircraft per Wuerzburg. In fact the system required two Wuerzburgs per interception, one for the target, and one for the fighter. This meant that as a raid developed, only a few night fighters could be directed at any one time, as only a small number of the eventual 5,000 Wuerzburgs would be within their 25 km range at any one time.
Compared to the British PPI systems, the German system was far more labour intensive. This problem was compounded by the lacksidasical approach to command staffing. It was several years before the Luftwaffe had a command and control system nearly as sophisticated as the one set up by Watt before the war, after seeing the confusion too much information caused during one test.
German airborne radar units followed a similar pattern. Early Lichtenstein BC units were not deployed until 1942, and as they operated on the 2 m wavelength they required large antennas. By this point in the war the British had become experts on jamming German radars, and when a BC-equipped Ju 88 night fighter landed in England one foggy night, it was only a few weeks before the system was rendered completely useless. By late 1943 the Luftwaffe was starting to deploy the greatly improved SN-2, but this required huge antennas that slowed the planes as much as 50 km/h. Jamming the SN-2 took longer, but was accomplished. A 9 cm wavelength system known as Berlin was eventually developed, but only in the very last months of the war.
General Description
Electromagnetics
Reflection
Polarization
Frequency
Distance Measurement
Signals
Speed Measurement
Doppler effect
Continuous Wave
Position Measurement
Early systems
Phased array
Types and uses of radar
Radar Equation
The amount of power Pr returning to the receiving antenna is given by the radar equation:
where
In the common case where the transmitter and receiver are at the same location, Rt = Rr and the term Rt² Rr² can be replaced by R4, where R is the range. This shows that the received power declines as the fourth power of the range, which means that the reflected power from distant targets is very, very small.History
1800s
In 1887 the German physicist Heinrich Hertz began experimenting with radio waves in his laboratory. He found that radio waves could be transmitted through some materials, and were reflected by others. Although this was predicted earlier by James Clerk Maxwell, his work was not widely known as the time and much of the research became known through Hertz. In fact today we use his name as the SI unit of frequency, the hertz, often abbreviated to Hz.1900s
Modern radar
Tesla proposed to use electromagnetic waves to determine the relative position, speed, and course of a moving object and other modern concepts of radar. Tesla had proposed that it might help find submarines (for which it isn't well-suited), though it was first applied successfully to find aircraft (after their later proliferation) and surface ships during World War II. Emil Girardeau, working with the first French radar systems, stated he was building radar systems "conceived according to the principles stated by Tesla".Microwaves
England and Germany
Chain Home
Later adaptions
Magnetron
German developments
Wuerzburg
Comparison
Specific radar systems
See also: LIDAR, sonar air defense artilleryExternal links
Further reading
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Radar."
| The following table is compiled from various sources, across various languages. When English abbreviations or acronyms come from a non-English source, this is noted. | |||
| Entry | Source | Expression | Field |
RADAR | English | Random Access Dump And Reload | N/A |
| Racon | English | Radar beacon | Military & Defense |
| RAAL | French | Radar visée latérale | Post & Telecom |
Source: compiled by the editor, based on several corpora (additional references). | |||
Synonyms: RadarSynonyms: microwave radar (n), radio detection and ranging (n), radiolocation (n). (additional references) |
| Context | Synonyms within Context (source: adapted from Roget's Thesaurus). |
Measurement | Bathometer, galvanometer, heliometer, interferometer, odometer, ombrometer, pantometer, pluviometer, pneumatometer, pneumometer, radiometer, refractometer, respirometer, rheometer, spirometer, telemeter, udometer, vacuometer, variometer, viameter, thermometer, thermistor (heat), barometer (air), anemometer (wind), dynamometer, goniometer (angle) meter; landmark; (limit); balance, scale; (weight); marigraph, pneumatograph, stethograph; rain gauge, rain gage; voltmeter(volts), ammeter(amps); spectrophotometer (light absorbance); mass spectrophotometer(molecular mass); geiger counter, scintillation counter(radioactivity); pycnometer (liquid density); graduated cylinder, volumetric flask (volume); radar gun (velocity); radar (distance); side-looking radar (shape, topography); sonar (depth in water); light meter (light intensity); clock, watch, stopwatch, chronometer (time); anemometer (wind velocity); densitometer (color intensity). |
Velocity | Log, log line; speedometer, odometer, tachometer, strobe, radar speed detector, radar trap, air speed gauge, wind sock, wind speed meter; pedometer. |
Warning | Radar, AWACS, spy satellite, spy-in-the-sky, U plane, spy plane. |
| Source: adapted from Roget's Thesaurus. | |
| Domain | Usage | |
Screenplays | I want him manning a radar tower in Alaska by the end of the day. Just mail him his clothes. (Mission: Impossible; writing credit: David Koepp and Robert Towne. Based on the television series) We're not productive anymore. We don't make things anymore. It's all automated. What are we for then? We're consumers, Jim. Yeah. Okay, okay. Buy a lot of stuff, you're a good citizen. But if you don't buy a lot of stuff, if you don't, what are you then, I ask you? What? Mentally ill . Fact, Jim, fact - if you don't buy things - toilet paper, new cars, computerized yo-yos, electrically-operated sexual devices, servo systems with brain-implanted headphones, screwdrivers with miniature built-in radar devices, voice-activated computers - (Twelve Monkeys; writing credit: David Webb Peoples) A nest of lasers and radar. (Rupan sansei: Kariosutoro no shiro; writing credit: Hayao Miyazaki; Monkey Punch) We're coming in from the north, below their radar. (Airplane!; writing credit: Jim Abrahams; David Zucker) Radar, turn on the news. (M*A*S*H; writing credit: Larry Gelbart) | |
Lyrics | Livin' like a lover with a radar phone ("Pour Some Sugar On Me"; performing artist: Def Leppard) We've got a thing that's called Radar Love ("Radar Love"; performing artist: Golden Earring) Uhh, okay, you on my radar, I got you too bitch ("Guilty Until Proven Innocent"; performing artist: Jay-Z) It's a radar scope in all silver and all platinum lights ("Birdland"; performing artist: Patti Smith) Underneath your radar screen ("Steve McQueen"; performing artist: Sheryl Crow) | |
Clever | The microwave was invented after a researcher walked by a radar tube and a chocolate bar melted in his pocket. (references; author: unknown) | |
Movie/TV Titles | UFO Contatto radar. Stanno atterrando. (1974) Radar Station (1953) | |
Song Titles | Radar Love (performing artist: Golden Earring) Radar Love (performing artist: Under Suspicion) | |
Source: compiled by the editor from various references; see credits. | ||
| Domain | Title | ||
References | |||
Books | |||
Periodicals |
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Theater & Movies | |||
Music |
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High Tech |
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Source: compiled by the editor from various references; see credits. | |||
| Thumbnail | Description & Credit | Thumbnail | Description & Credit |
 | Closeup of Shoran antenna mounted on radar antenna Shoran array installed by party off of LYDONIA.Credit: Coast & Geodetic Survey Historical Image Collection. |  | Shoran antenna installed on radar tower Shoran array installed by party off of LYDONIA.Credit: Coast & Geodetic Survey Historical Image Collection. |
 | Current buoys with lights, radar reflectors, and F.M. transceivers C&GS surveys followed Good Friday Alaska earthquake of 1964 Current surveys conducted with hydrographic surveys Investigations off of HODGSON.Credit: Coast & Geodetic Survey Historical Image Collection. |  | Commander Maurice A. Hecht at left - first instructor for radar ranging class Observation battalion training in use of radar to determine enemy gun location.Credit: Coast & Geodetic Survey Historical Image Collection. |
 | New Ensigns helping calibrate the radar The tinfoil both helps reflect the radar and protect brain from radar pulses On the NOAA Ship WHITING.Credit: Coast & Geodetic Survey Historical Image Collection. |  | A drift buoy with radar reflector for studying surface currents.Credit: Paths Less Taken - NOAA at the Ends of the Earth. |
 | Radar display of multiple contacts of lobster pot moorings ALBATROSS IV had to find clear spot to trawl through.Credit: Paths Less Taken - NOAA at the Ends of the Earth. |  | Shaded relief map of Antarctica developed from RADARSAT Synthetic Aperture Radar data. RADARSAT is a Canadian satellite.Credit: Paths Less Taken - NOAA at the Ends of the Earth. |
 | Forester uses radar gun to survey.Credit: D. Huntington. | ||
Source: compiled by the editor from various references; see credits. | |||
| Play | Caption |
 | Alarm; alert; balefire; beam; bonfire; flare; guidepost; heliograph; lamp; lantern; lighthouse; lodestar; pharos; radar; rocket; rocket; sign; signal fire; smoke signal; beacon; warning signal; watchtower. |
| Source: compiled by the editor from various references; see credits. | |
| Subject | Topic | Quote |
Business | NATAM is also responsible for aircraft navigation, radar systems and equipment. (references) | |
All services are upgrading radar systems and introducing new Command, Control, Communications and Computer (C4I) equipment. (references) | ||
The Czechs have a long industrial history of producing high quality aircraft and heavy equipment, as well as sophisticated technologies for radar. (references) | ||
Economic History | France | France is the leading European exporter of radar and communication equipment. (references) |
Bulgaria | The modernization of the Varna airport also includes upgrading its radar equipment. (references) | |
Egypt | Radar, airport equipment, and navigational equipment will be required for the development of both existing and new airports. (references) | |
Human Rights | Lebanon | On July 1, Israeli warplanes destroyed a Syrian army radar base in the Biqa' Valley, wounding three Syrian and one Lebanese soldier. (references) |
Lebanon | For the first time in more than 10 years, Israel responded against a Syrian target in Lebanon, bombing a Syrian radar station in Mudayrej and killing three Syrian soldiers. (references) | |
Trade | Argentina | TDA offered to train air traffic controllers at FAA facilities if a project to modernize the national radar system favors a U.S. supplier. (references) |
Travel | Bahrain | Radar and speed detection cameras are installed by some traffic lights. (references) |
Source: compiled by the editor from ICON Group International, Inc.; see credits. | ||
| "Radar" is generally used as a noun (singular) -- approximately 97.89% of the time. "Radar" is used about 616 times out of a sample of 100 million words spoken or written in English. Its rank is based on over 700,000 words used in the English language. Some parts-of-speech are not covered due to the samples used by the British National Corpus. (note: percents less than one-hundredth of one percent have been omitted) |
| Parts of Speech | Percent | Usage per 100 Million Words | Rank in English |
| Noun (singular) | 97.89% | 603 | 10,628 |
| Noun (proper) | 1.94% | 12 | 101,599 |
| Noun (common) | 0.16% | 1 | 339,140 |
| Total | 100.00% | 616 | N/A |
Source: compiled by the editor from several corpora; see credits.
| The following table summarizes the usage of "radar" based on a population census conducted in the United States. Ranks and frequencies are based on all names reported and classified. |
| Name | Usage/Gender | Usage per 100 million Persons | Rank in USA |
| Radar | Last name | 170 | 45,776 |
| Source: compiled by the editor from several corpora; see credits. | |||
Expressions using "radar": 3d radar ♦ aeronautical radar beacon ♦ air search radar ♦ air to surface vessel radar ♦ airborne weather radar ♦ directional radar prediction ♦ Doppler radar ♦ Dual Auroral Radar Network ♦ early warning radar ♦ fine grain radar ♦ fire control radar ♦ gap filler radar ♦ get caught in a radar trap ♦ imaging radar ♦ microwave radar ♦ microwave search radar ♦ naval radar ♦ navigational radar ♦ precision approach radar ♦ primary radar ♦ projected radar beam ♦ radar advisory ♦ radar altimeter ♦ radar altimeter area ♦ radar angels ♦ radar approach ♦ radar beacon ♦ radar beam ♦ radar beam reflection ♦ radar blip ♦ radar blip identification ♦ radar bombsight ♦ radar camouflage ♦ radar clutter ♦ radar contact ♦ radar control ♦ radar controller ♦ radar countermeasures ♦ radar coverage ♦ radar cross section area ♦ radar danning ♦ radar dish ♦ radar display ♦ radar dome ♦ radar echo ♦ radar fence ♦ radar fire ♦ radar fix ♦ radar girl ♦ radar heading ♦ radar homing ♦ radar horizon ♦ radar identification ♦ radar imagery ♦ radar jamming ♦ radar map ♦ radar monitoring ♦ radar net ♦ radar netting ♦ radar netting station ♦ radar observation ♦ radar operator ♦ radar parallax ♦ radar picket ♦ radar plot ♦ radar position symbol ♦ radar reconnaissance ♦ radar response ♦ radar return ♦ radar scanner ♦ radar scope ♦ radar scope overlay ♦ radar scope photography ♦ radar screen ♦ radar separation ♦ radar service ♦ radar set ♦ radar silence ♦ radar sonde observation ♦ radar sonobuoy ♦ radar station ♦ radar target ♦ radar trace ♦ radar track position ♦ radar tracking ♦ radar transfer of control ♦ radar trap ♦ radar unit ♦ radar vectoring ♦ radar wind observation ♦ search radar ♦ secondary radar ♦ secondary surveillance radar ♦ side looking airborne radar ♦ station keeping radar ♦ surface search radar ♦ surveillance radar ♦ surveillance radar element ♦ transfer of radar identification ♦ vertical looking radar ♦ weather radar. Additional references. | |
| Hyphenated Usage | |
Beginning with "radar": radar-blinding, radar-controlled, radar-dark, radar-dependent, radar-evading, radar-guided, radar-imaging, radar-like, radar-ranging, radar-screening, radar-sonde, radar-tracking. | |
Ending with "radar": anti-radar, sub-radar. | |
Containing "radar": non-radar separation. | |
| Source: compiled by the editor from various references; see credits. | |
| The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com. |
| Expression | Frequency per Day |
radar detector | 4,867 |
weather radar | 3,419 |
doppler radar | 1,984 |
radar | 1,751 |
radar gun | 605 |
local weather radar | 264 |
escort radar | 233 |
radar detector review | 233 |
rocky mountain radar | 205 |
radar jammer | 196 |
| Source: compiled by the editor from various references; see credits. | |
| Language | Translations for "radar"; alternative meanings/domain in parentheses. | |
Albanian | radiolokim, radar. (various references) | |
Arabic | كشف عن طريق الرادار, جهاز لتحديد وجود شئ بواسطة الموجات اللاسلكية, رادار. (various references) | |
Bulgarian | радар (radiolocation, radiolocator). (various references) | |
Chinese | 雷达, 雷" . (various references) | |
Czech | radar. (various references) | |
Danish | radar. (various references) | |
Dutch | radar, raderwerk (train). (various references) | |
Esperanto | radaro. (various references) | |
Farsi | رادار. (various references) | |
Finnish | tutka. (various references) | |
French | radar. (various references) | |
German | Radar. (various references) | |
Greek | ραντάρ. (various references) | |
Hebrew | ר"ר. (various references) | |
Hungarian | radar (radiolocation, radiolocator), lokátor. (various references) | |
Icelandic | ratsjá. (various references) | |
Indonesian | radar. (various references) | |
Irish | radar. (various references) | |
Italian | radar (radars). (various references) | |
Japanese Kanji | 電探 , 電波探知器 , 電波探知機 , レース編み (lacework, radar gun, reason for living). (various references) | |
Japanese Katakana | レーダー , で"た" (leaflet), で"ぱた"ちき. (various references) | |
Korean | 이다. (various references) | |
Manx | radar. (various references) | |
Pig Latin | adarray.(various references) | |
Portuguese | radar (radio location, radiolocator). (various references) | |
Romanian | radiolocaţie (radiolocation), radar. (various references) | |
Russian | радар (radar scope), радиолокатор (radiolocator, radio-locator). (various references) | |
Serbo-Croatian | radar (doppler radar, radiolocation, radiolocator). (various references) | |
Spanish | radar. (various references) | |
Swedish | radar. (various references) | |
Thai | เร"าร์. (various references) | |
Turkish | radar (radar set, speed trap). (various references) | |
Ukranian | радіолокація (radiolocation), радіолокаційний, радіолокатор (radiolocator), радарний, радар. (various references) | |
| Source: compiled by the editor from various translation references. | ||
Derivations | |
Words beginning with "radar": radars, radarscope, radarscopes. (additional references) | |
Words ending with "radar": antiradar. (additional references) | |
| |
"Radar" is suggested in spellcheckers for the following: Adyar, Arandar, arar, ardar, Ardmair, ardua, Arrad, Badar, dadar, Erada, fadar, Gadara, ladar, Madar, Padarn, Praedrag, raad, raargh, radah, Radal, Radda, Radday, radek, Radev, Radha, rador, radoz, radu, raeda, ragar, Rajaori, ramar, Ramdac, randan, randor, Ravar, rder, Redab, Redfarn, redr, rhaeadr, Riada, ridar, ridda, ridor, ridur, rizar, rodar, rodor, Roudbar, rudjak, ruiari, rurar, sadar. (additional references) | |
| Source: compiled by the editor, based on several corpora (additional references). | |
Scrabble® Enable2K-Verified Anagrams | |
| Words within the letters "a-a-d-r-r" | |
-2 letters: rad. | |
-3 letters: aa, ad, ar. | |
| Words containing the letters "a-a-d-r-r" | |
+1 letter: radars, sardar. | |
+2 letters: abrader, airward, arrased, arrayed, awarder, drawbar, parader, parador, radular, sardars, yardarm. | |
+3 letters: aardvark, abraders, arranged, awarders, barnyard, barraged, brassard, demerara, diarrhea, disarray, drawbars, farmyard, garboard, gerardia, hardware, harridan, labrador, larboard, marauder, narrated, paraders, paradors, paradrop, radiator, railroad, rearward, tramroad, yardarms. | |
+4 letters: aardvarks, aberrated, adversary, afterward, antiradar, armatured, arraigned, arrogated, arrowhead, awkwarder, barnyards, barracked, barracuda, barricade, barricado, brassards, cardboard, cardsharp, carronade, dartboard, daytrader, deaerator, demeraras, diarrheal, diarrheas, diarrhoea, disarrays, dramaturg, earmarked, earthward, farmyards, garboards, gerardias, graduator, graveyard, graybeard, guardrail, hadrosaur, hardboard, hardwares, harridans, irradiate, labradors, larboards, marauders, paradores, paradrops, radiators, radicular, radiogram, railroads, ramparted, rearguard, rearwards, regardant, reradiate, retardant, retardate, starboard, trademark, tramroads, warranted. | |
+5 letters: adjuratory, aerobraked, afterwards, arbitraged, arbitrated, arrowheads, astarboard, barbarized, bardolater, bardolatry, bargeboard, barracudas, barramunda, barramundi, barrelhead, barricaded, barricades, breadboard, cardboards, cardiogram, cardplayer, cardsharps, carronades, dartboards, daydreamer, daytraders, deaerators, diarrhoeas, disarrange, disarrayed, disparager, dramaturge, dramaturgs, dramaturgy, dysarthria, earthwards, eradicator, fairleader, graduators, graveyards, graybeards, guardrails, hadrosaurs, handbarrow, hardboards, irradiance, irradiated, irradiates, irradiator, mandragora, microfarad, narrowband, paperboard, parricidal, pericardia, prodromata, quadrature, radarscope, radiograms, radiograph, railroaded, railroader, reappeared, rearranged, reradiated, reradiates, retardants, retardates, rewardable, ritardando, starboards, tardigrade, tetrahedra, threadbare, tradec | |
