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A plan position indicator (PPI) is a type of radar display that represents the radar antenna in the center of the display, with the distance from it and height above ground drawn as concentric circles. As the radar antenna rotates, a radial trace on the PPI sweeps in unison with it about the center point. It is the most common type of radar ...
The constant altitude plan position indicator, better known as CAPPI, is a radar display which gives a horizontal cross-section of data at constant altitude. It has been developed by McGill University in Montreal by the Stormy Weather Group [1] to circumvent some problems with the PPI: Altitude changing with distance to the radar.
This image shows a modern PPI display in use, with the islands and ground surrounding the ship in green. The current direction of the radar can be seen as the dotted line pointing northwest. The PPI display provides a 2-D "all round" display of the airspace around a radar site. The distance out from the center of the display indicates range ...
Plan position indicator (PPI) display showing polar display and radar sweep. A real radar display would show hard terrain features and look recognizably map-like, and from the sea, match well with land features of local nautical charts matching and sending strong clean radar echos back to the ship at sea.
Unlike the earlier system where radar data was forwarded by telephone and plotted on a map, GCI radars combined all of these functions into a single station. The PPI was in the form of a 2D top-down display showing both the targets and the intercepting night fighters. Interceptions could be arranged directly from the display, without any need ...
In radar systems, the blip-to-scan ratio, or blip/scan, is the ratio of the number of times a target appears on a radar display to the number of times it theoretically could be displayed. [1] Alternately it can be defined as the ratio of the number of scans in which an accurate return is received to the total number of scans.
Consider the following example : if the radar antenna is located at around 15 m above sea level, then the distance to the horizon is pretty close, (perhaps 15 km). Ground targets further than this range cannot be detected, so the PRF can be quite high; a radar with a PRF of 7.5 kHz will return ambiguous echoes from targets at about 20 km, or ...
PPI may refer to: Science and technology ... Plan position indicator, radar display; Polymethylene polyphenylene isocyanate; Business and organizations