Plan position indicator
Alternative term: P.P.I. display
An intensity-modulated radar display in which a radial scan rotates on the cathode ray tube in synchronism with the rotating antenna.
The display indicates, as on a map, the positions of echo-producing objects, and is generally one of two main types, relative display or true motion display.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM