A radar is an electronic installation
A radar is an installation that has been made to search the environment for targets (in the air, on land or at sea). A goal can be an airplane, or a car or rocket. There are also soil radars that can locate objects from the air (often from an airplane) at certain depths. The images are made visible using a monitor. The word radar comes from the English: Radio Detection and Ranging (detecting and locating distance using radio technology). Radar images were used for the first time in the shipping industry, the large metal ships can reflect the radio waves well. Radar technology became popular around 1930, when Europe and the United States thought they could use the technology to detect attacks. The technology is now so far that computers can display situation summaries that are very accurate. A radar emits radio waves and receives them back after the objects reflect them (echo). Something that is very closely reflected earlier, so the distance can be determined by the time it takes for the radio wave to return again.
How Does ATC Aviation Radar work [YouTube]-FTYnWID3DI [/youtube]