Related topics: nasa

Future-proofing ice measurements from space

With diminishing ice one of the biggest casualties of our warming world, it's imperative that accurate measurements continue to be made for scientific research and climate policy, as well as for practical applications such ...

A better method for measuring alpha returns

Doppler radar, the Consumer Price Index, quarterback rating—these and many other measuring tools have refined the way performance is both documented and predicted in weather, the economy and sports.

3D radargram brings new focus to Mars' north polar cap

A new enhanced 3D radar image offer a greatly improved view of the interior of the Martian north polar cap, according to a paper led by Planetary Science Institute Senior Scientist Nathaniel Putzig.

Fireworks have long-lasting effects on wild birds

Scientists at the Max Planck Institute of Animal Behavior in Konstanz, Germany, and the Netherlands Institute of Ecology GPS tracked Arctic migratory geese in Germany, Denmark, and the Netherlands over the New Year period ...

page 1 from 40

Radar

Radar 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.

This text uses material from Wikipedia, licensed under CC BY-SA