Secondary surveillance radar

Rarity: Common

The most frequent rarity: most Wikipedia articles become Commons.

Rarity follows how well known the article is: its views on the French and English Wikipedia over a year, and the number of languages it exists in.

At a glance

Class

Notion

Domain

Science and technology

In collections

Nobody has pulled it yet.

What Wikipedia says

Secondary surveillance radar (SSR) is a radar system used in air traffic control (ATC) that, unlike Primary Surveillance Radar (PSR) systems that measure the bearing and distance of targets using the detected reflections of radio signals, relies on targets equipped with a radar transponder, that reply in the same Mode that an interrogation pulse code corresponds to, by transmitting a pulse telegram containing, e.g. the identity code as a 4 digit octal number in Mode A, the aircraft's altitude from the barometric pressure sensor of an aircraft in Mode C and a unique 24-bit address and further information in other Modes.

Excerpt from the Wikipedia article “Secondary surveillance radar”, under the CC BY-SA 4.0 license. Read the article on Wikipedia

Image: c.w., CC BY-SA 3.0, via Wikimedia Commons.