Primary Surveillance Radar (PSR)

Primary Surveillance Radar (PSR) is a radar system that detects aircraft by transmitting radio pulses and receiving the reflections (returns) from aircraft skin. Unlike SSR, PSR requires no transponder in the aircraft — it detects any large metal object.

PSR vs. SSR

• PSR (Primary): Detects aircraft by skin reflection; shows position only; no altitude, identification, or speed data
• SSR (Secondary): Interrogates the aircraft transponder; provides precise position, altitude, identification (squawk), and speed data

PSR in Canada

PSR is used primarily in terminal areas. En route, SSR is the primary surveillance tool. PSR is valuable in detecting aircraft without functioning transponders (NORDO) and for surface movement radar (SMR) at large airports.

Related Terms

See also: SSR, RADAR, Transponder.