Radar
Radar – a device or system for finding the position or speed of objects, such as aircraft, that cannot be seen, by measuring the direction and timing of short radio waves that are sent out and reflect back from the objects [Cambridge Dictionary].
–A method of detecting distant objects and determining their position, velocity, or other characteristics by analysis of very high-frequency radio waves reflected from their surfaces.
–The equipment used in such detection [Collins English Dictionary].
A radar is an electromagnetic sensor for detecting, locating, tracking, and recognizing objects of various kinds at considerable distances. It operates by transmitting electromagnetic energy toward objects, commonly referred to as targets, and observing the echoes returned from them. The targets may be aircraft, ships, spacecraft, automotive vehicles, astronomical bodies, birds, insects, and rain. Besides determining the presence, location, and velocity of such objects, radar can also obtain their size and shape. What distinguishes radar from optical and infrared sensing devices is its ability to detect faraway objects under adverse weather conditions and to determine their range, or distance, with precision. A radar is an “active” sensing device with a source of illumination (a transmitter) for locating targets. It typically operates in the microwave region of the electromagnetic spectrum—measured in hertz (cycles per second), at frequencies extending from about 400 megahertz (MHz) to 40 gigahertz (GHz). It has, however, been used at lower frequencies for long-range applications (frequencies as low as several megahertz, which is the HF [high-frequency] or shortwave band) and at optical and infrared frequencies (those of laser radar or lidar). The circuit components and other hardware of radar systems vary with the frequency used, and systems range in size from those small enough to fit in the palm to those so enormous that they would fill several football fields [Britanicca].
RADAR | English meaning. Cambridge Dictionary. Retrieved from: https://dictionary.cambridge.org/dictionary/english/radar
Radar definition and meaning. Collins English Dictionary. Retrieved from: https://www.collinsdictionary.com/dictionary/english/radar
Radar | Definition, Invention, History, Types, Applications, Weather, & Facts. Britanicca. Retrieved from: https://www.britannica.com/technology/radar