The upper portion of the display indicates elevation, the lower portion azimuth. Controllers must be able to interpret radar returns for the azimuth as a "top view" to inform them if the aircraft is left or right of course.
In the United States PAR are used mostly by The Navy. This is because they present a more covert type of precision approach for use on Aircraft carriers. An ILS installed on a ship could provide guidance to enemy missiles but a PAR does not provide accurate guidance without controller instruction.
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