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Radar is a system that uses radio waves to determine the distance (ranging), direction (azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method [1] used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain.
A Doppler radar is a specialized radar that uses the Doppler effect to produce velocity data about objects at a distance. [1] It does this by bouncing a microwave signal off a desired target and analyzing how the object's motion has altered the frequency of the returned signal.
The history of radar (where radar stands for radio detection and ranging) started with experiments by Heinrich Hertz in the late 19th century that showed that radio waves were reflected by metallic objects. This possibility was suggested in James Clerk Maxwell 's seminal work on electromagnetism.
Radar ranges and bearings can be very useful for navigation. Radar navigation is the utilization of marine and aviation radar systems for vessel and aircraft navigation.When a craft is within radar range of land or special radar aids to navigation, the navigator can take distances and angular bearings to charted objects and use these to establish arcs of position and lines of position on a ...
Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the intensity of the ...
Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or three-dimensional reconstructions of objects, such as landscapes. [1] SAR uses the motion of the radar antenna over a target region to provide finer spatial resolution than conventional stationary beam-scanning radars.
The pulse width ( ) (or pulse duration) of the transmitted signal is the time, typically in microseconds, each pulse lasts. If the pulse is not a perfect square wave, the time is typically measured between the 50% power levels of the rising and falling edges of the pulse. The pulse width must be long enough to ensure that the radar emits ...
Once the radar is known to be in the area, the next step is to find its location. Simplified spectrum analyzer display of superheterodyned , amplitude modulated signals. If operators know the probable frequencies of transmissions of interest, they may use a set of receivers, preset to the frequencies of interest.