Radar, which stands for radio detection and ranging, is a system that uses radio waves to detect the presence, position, and speed of distant objects. The history of radar started with experiments by Heinrich Hertz in the late 19th century that showed that radio waves were reflected by metallic objects. The development of systems able to produce short pulses of radio energy was the key advance that allowed modern radar systems to come into existence. By timing the pulses on an oscilloscope, the range could be determined and the direction of the antenna revealed the angular location of the targets. The two, combined, produced a "fix", locating the target relative to the antenna.
During the 1934-1939 period, eight nations developed independently and in great secrecy, systems of this type. A radio-based device for remotely indicating the presence of ships was built in Germany by Christian Hülsmeyer in 1904. The British called it Radio Direction Finding (RDF). While today radar is considered a standard piece of equipment in many industries, it was regarded as a top-secret project before the Second World War.
The method of measuring information about objects using radar is done through pulses of high-frequency electromagnetic waves. The pulse is sent out into the head of the ship, aircraft, or other object and when detected, bounces off the object and reflects to the antenna of the radar for processing . Doppler radar is a types of radar system that can detect and track hidden objects by using indirect reflections or a measurement of a faint signal.
The Duga radar was a top-secret project built in the Soviet Union in the 1970s to mitigate long-range missile threats. It was a huge over-the-horizon-radar that would bounce signals off the ionosphere to peer over the Earth's curvature. Despite the gigantic scale of the project, the scientists lacked full understanding of how the ionosphere works, dooming it to failure before it was even built . The Duga radar was only a signal receiver, and the transmitting center was built some 60 kilometers away in a town called Lubech-1, now also abandoned.
How is radar used in aviation and air traffic control?
Radar is an essential tool in aviation and air traffic control. Here are some ways radar is used in aviation and air traffic control, as well as other applications of RADAR system:
Tracking aircraft: Area Radars, Surveillance Radars, and Approach Radars allow controllers to track aircraft within their area of responsibility. Precision Approach Radars (PAR) enable controllers to provide precision approach guidance to aircraft landing in instrument conditions
. Airport Surveillance Radar (ASR) is an approach control radar used to detect and display an aircraft's position in the terminal area.
Surface movement: Surface Movement Radar enables controllers to track the movement of aircraft and vehicles on an aerodrome surface.
Weather monitoring: Weather Radar gives pilots situational awareness of hazardous weather, especially Thunderstorms.
Secondary Surveillance Radar: Secondary Surveillance Radar enables aircraft to pass additional information, such as identification and flight level, back to the interrogating radar.
Military applications: Radar is also used in military applications, such as detecting and tracking incoming missiles.
Modern air traffic control radars use the Doppler effect to discriminate moving aircraft from stationary targets and to measure storm movement. Air Traffic Control Radar (ATC-Radar) is the umbrella term for all radar devices used to secure and monitor civil and military air traffic in Air Traffic Management (ATM). While today radar is considered a standard piece of equipment in many industries, it was regarded as a top-secret project before the Second World War.
