Radar
hideRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for radio detection and ranging. The term has since entered the English language as a standard word, radar, losing the capitalization. Radar was originally called RDF (Radio Direction Finder, now used as a totally different device) in the United Kingdom.
A radar system has a transmitter that emits microwaves or radio waves. These waves are in phase when emitted, and when they come into contact with an object are scattered in all directions. The signal is thus partly reflected back and it has a slight change of wavelength (and thus frequency) if the target is moving. The receiver is usually, but not always, in the same location as the transmitter. Although the signal returned is usually very weak, the signal can be amplified through use of electronic techniques in the receiver and in the antenna configuration. This enables radar to detect objects at ranges where other emissions, such as sound or visible light, would be too weak to detect. Radar is used in meteorological detection of precipitation, measuring ocean surface waves, air traffic control, police detection of speeding traffic, and by the military.
For more information about Radar, read the full article at
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News tagged with radar
Britain shuts down UFO-hunting unit
Dec 04, 2009 |
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The British government has shut a unit which has investigated UFO sightings for more than 50 years, judging its resources better spent on more earthly threats, it said Friday.
Researchers patent enabling technology for spread-spectrum systems
Nov 17, 2009 |
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If you've ever gotten the dreaded "network busy" message while trying to make a cell phone call, you've experienced the complication of sharing a single network with numerous other users.
New algorithms for computerized, large-scale surveillance
Dec 02, 2009 |
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A recent AFOSR-funded technology should enable the Air Force to achieve advances in object and target detection technology by using sophisticated algebraic theories called groups, rings and fields.
First phase of pan-tropical forest mapping debuting at COP15
Dec 10, 2009 |
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Tropical forest loss accounts for an estimated 17% of global emissions of carbon dioxide. As part of a strategy to reduce these greenhouse gas fluxes to the atmosphere, the UNFCCC's Conference of the Parties 15 in Copenhagen ...
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TRMM sees 05B winding down off the Sri Lanka coast
Space & Earth / Earth Sciences
Dec 14, 2009 |
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Tropical Depression 05B is dissipating on the east coast of Sri Lanka today and over the next couple of days, but not before bringing some moderate and heavy rain over the next couple of days to some areas ...
Better-than-new LIDAR provides 24/7 atmospheric aerosol data
Space & Earth / Earth Sciences
Dec 08, 2009 |
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(PhysOrg.com) -- A team of researchers from eight institutions led by Pacific Northwest National Laboratory has solved a software and hardware problem that had perplexed scientists studying atmospheric aerosols ...
NASA Global Precipitation Measurement Mission Passes Major Review
Space & Earth / Space Exploration
Dec 08, 2009 |
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(PhysOrg.com) -- NASA's effort to deploy the first satellite mission to advance global precipitation observations from space moved closer to this goal when agency officials approved critical elements for the Global Precipitation ...
Turning metal black more than just a novelty
Dec 08, 2009 |
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(PhysOrg.com) -- University of Rochester optics professor Chunlei Guo made headlines in the past couple of years when he changed the color of everyday metals by scouring their surfaces with precise, high-intensity laser bursts.
Forest deal at Copenhagen must avoid creating 'carbon refugees'
Dec 03, 2009 |
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Forest dwellers must be included in the design of the upcoming forest deal at Copenhagen in order to avoid a humanitarian crisis, according to a scientist at the University of Leeds.
Typhoon Nida's cloud tops dropping as it zigzags in wind shear
Space & Earth / Earth Sciences
Dec 01, 2009 |
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Nida is battling to keep its typhoon strength in the Western Pacific Ocean as wind shear continues to tear at the storm and weaken it. NASA's CloudSat satellite noticed that Nida's cloud tops are not as high ...
Winds drive icebergs away from New Zealand
Space & Earth / Earth Sciences
Dec 01, 2009 |
4 / 5 (2) |
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(AP) -- Strong westerly winds in the southern Pacific Ocean have driven scores of icebergs originally headed toward New Zealand to the east, away from the country, an oceanographer said Tuesday.
NASA captures Typhoon Nida's clouds from 2 angles
Space & Earth / Earth Sciences
Nov 30, 2009 |
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NASA satellites capture amazing views of tropical cyclones, and the Aqua and CloudSat satellites captured a top-down look at temperatures in Typhoon Nida's clouds, and an image of what they look like from ...
Scientists explain puzzling lake asymmetry on Titan
Space & Earth / Space Exploration
Nov 29, 2009 |
4.4 / 5 (14) |
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Researchers at the California Institute of Technology (Caltech) suggest that the eccentricity of Saturn's orbit around the sun may be responsible for the unusually uneven distribution of methane and ethane ...
New radar helps monitor site of century-old tragedy
Space & Earth / Earth Sciences
Nov 27, 2009 |
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(PhysOrg.com) -- A University of Alberta researcher has turned the site of a southern Alberta rockslide tragedy into the proving ground for new equipment meant to avert such a disaster in the future.
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