It is a radarscope over which the wave of an object reflecting radar shows its bearing and the distance from the radar detector by making a spot of light to appear on a screen that represents a map of the area around the detector.
( PPI) A conventional radar display of the location of targets on a horizontal plane. The display contains concentric radial distance circles centered on the radar site to indicate the range of the target and radial lines emanating from the origin to indicate the azimuth, for the determination of the direction of the target from the radar site.
(DOD, NATO) A cathode ray tube on which radar returns are so displayed as to bear the same relationship to the transmitter as the objects giving rise to them.
Also known as a PPI Scope, it is a radar indicator scope displaying range and azimuth of targets in polar coordinates.
(Abbreviated PPI.) A type of radar display on which the reflectivity or other properties of echoes are plotted in plan position, forming a maplike display, with radial distance from the center representing range and the angle of the radius vector representing azimuth angle. The PPI is usually produced by scanning the antenna in azimuth with the elevation fixed. It may be an intensity-modulated display or may use a scale of colors to represent the values of the function displayed.
The plan position indicator (PPI), is the most common type of radar display. The radar antenna is usually represented in the center of the display, so the distance from it can be drawn as concentric circles. As the radar antenna rotates, a radial trace on the PPI sweeps in unison with it about the center point.