Types of Radars
GENERAL RADAR DISPLAY TYPES
There are two types of radar displays in common use today. RAW VIDEO Raw video 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 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.
TGT 1
TGT 2
ANGEL TGT 3 (GHOST)
ANGEL (GHOST) - see text TGT 3
NOISE
TGT 2
TGT 1
RAW VIDEO SYNTHETIC VIDEO
Figure 1. Radar Display Types
5-5.1
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.
TRACKING RADARS Usually use some combination
There are two types of radar displays in common use today. RAW VIDEO Raw video 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 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.
TGT 1
TGT 2
ANGEL TGT 3 (GHOST)
ANGEL (GHOST) - see text TGT 3
NOISE
TGT 2
TGT 1
RAW VIDEO SYNTHETIC VIDEO
Figure 1. Radar Display Types
5-5.1
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.
TRACKING RADARS Usually use some combination