Plan Position Indicator
Abstract
In the spring of 1939 it was realized that the use of radar would be greatly facilitated by employing indicators which would present a polar coordinate map (in terms of range and bearing) of all objects "visible: to the radar system. This type of indication can be produced through the use of a radial sweep or a cathode-ray tube. In particular, an electron beam is made to sweep from the center to the outside edge of long- persistence fluorescent screen deposited on the inside face of the cathode-ray tube. To have radial distance on the face of the cathode-ray tube represent the range of an object, it is necessary to have the sweep start at the same time that a radio-frequency pulse is radiated from the directional radar antenna. To have an angle measured on the face of the cathode-ray tube represent the bearing of an object, the radial sweep is made to rotate about the center of the fluorescent screen in synchronism with the radar antenna, so that the sweep is always in a direction corresponding directly to that in which the antenna is pointing.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 30, 1942
- Accession Number
- AD1166176
Entities
People
- James J. Fleming
- Willard S. Mcvay
Organizations
- United States Naval Research Laboratory