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  • Lokmane Hamdani

What is Radar?

Surveillance refers to the methods used to keep track of aircraft. The surveillance function, which is implemented through sensors, a display system, and operational procedures, provides air traffic controllers with the position of aircraft to manage separation and effectively manage given airspace. It is one of the most important domains in aviation security that no plane can fly without air navigation equipment.

Radar is now taking an important place in surveillance, It is widely used for marine and air navigation, national defense, and weather forecasting. Whether it is air traffic control, airport authorities, or pilots at the controls of their aircraft. They all use radar data to cope with the rapidly changing air traffic situation for a complete and efficient system.

Radar (RAdio Detection And Ranging) is a system that uses electromagnetic waves to detect the presence and determine the position and speed of objects such as aircraft, ships, or rain. It is a system that illuminates a portion of space with an electromagnetic wave and receives the waves reflected by the objects in it.

Historically, radars were first developed as military tools. It is for this primary reason the most common radar systems classification is the letter or band designation originally used by the military during and after World War II.


In surveillance, there are two types of radar (Primary and Secondary radar):

Primary Surveillance Radar (PSR) is a radar system that uses radio waves to detect the presence and location of an object in the air. It works by sending out a signal that bounces off the object and returns to the radar antenna. The time it takes for the signal to return is used to calculate the distance to the object. This information is used to create a radar image that displays the location and movement of the object.

PSR Principle Function


Secondary Surveillance Radar (SSR): Secondary radar is a radar system that works in conjunction with a transponder on the aircraft. The transponder sends a signal to the secondary radar system, which receives and decodes it to display information such as the aircraft's altitude, speed, and identification code. This allows air traffic controllers to track and identify individual aircraft more accurately than with primary radar alone.

SSR Principle Function


There are other sensors used in surveillance such as ADS-C and ADS-B, but Radar is one the most important equipment in terms of detection and surveillance.


Radar: Introduction to Radar Systems — Online Course. (n.d.). MIT Lincoln Laboratory.

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