The Federal Aviation Administration (FAA) defines radar targets as the electronic representations of aircraft observed on a radar display. Radar targets are created by the reflection of radar signals off the surface of an aircraft. These targets provide information to air traffic controllers about the position, altitude, and sometimes the identity of aircraft in a given airspace.
¶ Surveillance Radar Systems
Primary Surveillance Radar (PSR) and Secondary Surveillance Radar (SSR) are two distinct radar systems used in air traffic control and aviation for different purposes.
¶ Primary Surveillance Radar (PSR)
- PSR operates by emitting radio waves and listening for the reflections (echoes) from objects in the radar's coverage area.
- It provides information about the position (range and azimuth) and relative speed (Doppler shift) of detected targets.
- PSR can detect any object that reflects radio waves, including aircraft, birds, and weather phenomena.
- PSR does not provide detailed information about individual aircraft, such as their identity or altitude.
¶ Secondary Surveillance Radar (SSR)
- SSR is designed to provide additional information about aircraft in addition to their position.
- It functions by sending out interrogations to aircraft transponders, which then respond with specific information.
- SSR provides the aircraft's unique identification code (squawk code), altitude, and mode (e.g., Mode A for squawk code, Mode C for altitude).
- SSR allows for positive identification of aircraft and assists in maintaining safe altitude separation.