Secondary surveillance radar
|Term||secondary surveillance radar|
A surveillance radar system which uses transmitters/receivers (interrogators) and transponders.
ICAO Official definition, ANNEX 10/IV Aeronautical Telecommunications — Surveillance Radar and Collision Avoidance Systems
Secondary surveillance radar (SSR), which had its beginnings in wartime Identification Friend or Foe (IFF) systems, transmits pulses of energy which trigger a response from an airborne transponder, with range and bearing obtained in the same way as primary radar. (source: ICAO, "APOSI Airports International" 1993, April, p. 28 [TF-ATM])