There are two types of radar displays in common use today.
displays are simply oscilloscopes that display the detected and amplified target return signal (and the receiver
noise). Raw video displays require a human operator to interpret the various target noise and clutter signals.
On the left hand display of Figure 1, an operator could readily identify three targets and a ghost (a ghost is a
phony target that usually fades in and out and could be caused by birds, weather, or odd temporary reflections -
also referred to as an angel). Target 3 is a weak return and hidden in the noise - an operator can identify it as
a target by the "mouse under the rug" effect of raising the noise base line.
Synthetic video displays use a computer to clean up the display by eliminating noise and clutter and creating it's
own precise symbol for each target. On the right hand display target 1 comes and goes because it is barely
above the receiver noise level - notice that it is quite clear on the raw video. Target 3 wasn't recognized by the
computer because it's to far down in the noise. The computer validated the ghost as a target. The ghost might be a
real target with glint or ECM characteristics that were recognized by the computer but not the operator.
Figure 1. Radar Display Types
SEARCH AND ACQUISITION RADARS
They generally use either a PPI or a sector PPI
display as shown in Figure 2. PPI displays can be either raw video or synthetic video.
PPI scope (plan
position indicator). Polar plot of direction and distance. Displays all targets for 360 degrees.
Sector PPI scope. Polar plot of direction and distance. Displays all targets within a
specific sector. Origin may be offset so that "your" radar position may be off the scope.
Usually use some combination of A, B, C, or E scope displays. There are many other
types of displays that have been used at one time or another - including meters - but those listed here are the
most common in use today.
Figure 2. Common Radar Displays
Target signal amplitude vs. range or velocity.
Displays all targets along
pencil beam for selected range limits.
Displays tracking gate. Usually raw video. Some modern radars have
raw video a-scopes as an adjunct to synthetic video displays.
Must be used with a separate azimuth and
elevation display of some sort.
Also called a range scope (R-Scope).
Range vs. azimuth or elevation. Displays targets within selected limits.
Displays tracking gate. May be raw
or synthetic video.
Surface radars usually have two. One azimuth/one elevation which can result in
confusion with multiple targets.
Azimuth vs. elevation. Displays
targets within selected limits of az and el.
Displays tracking gate. May display bull's-eye or aim dot.
May have range indicator inserted typically as a marker along one side. Usually synthetic video.
Pilots eye view and very common in modern fighter aircraft heads up displays for target being tracked.
Could be used in any application where radar operator needs an "aiming" or "cross hair" view like a rifle scope.
Elevation vs. Range similar to a B-scope, with elevation replacing