Definition

Primary Surveillance Radar (PSR). A surveillance radar system which uses reflected radio signals.

Source: ICAO Doc 4444 PANS-ATM

Description

Principle of operation The radar antenna rotates (usually at 5-12 rpm) emits a pulse of radio wave. Upon reaching an aircraft (or other object) the wave is reflected and some of the energy is returned to the antenna.

The PSR output data uses polar coordinate system - it provides range and bearing of the targets found in respect of the antenna position. Note that the range is the slant distance from the antenna and not the horizontal distance.