The range-height indicator (rhi)
scope, shown in figure 3, is used with height-finding search radars
to obtain height information. The rhi is a two-dimensional
presentation indicating target range and height. The sweep
originates in the lower left side of the scope It moves across the
scope, to the right, at an angle that is the same as the angle of
transmission of the height-finding radar. The line of sight to the
horizon is indicated by the bottom horizontal line. The area
directly overhead is straight up the left side of the scope. Target
echoes are displayed on the scope as vertical PIPS or BLIPS (spots
of increased intensity that indicate a target location). The
operator determines height by adjusting a movable height line to the
point where it bisects the center of the blip. Target height is then
read directly from an height dial or digital readout. Vertical range
markers are also provided to estimate target range.
