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• A reading appears when no target is in the operational range of
the antenna .
• A target entering the operational range overrides the
interference signal, causing the display speed to change
suddenly to the target’s speed .
• Speeds are irregular and do not provide a valid tracking history .
6.2.1 Angular Interference (Cosine Effect)
The cosine effect causes the system to display a speed which is
lower than the actual target's speed . This condition occurs when
the target’s path is not parallel to the antenna, including conditions
such as a vehicle traveling on a curve or hill .
As the angle between the beam of the antenna and the target
vehicle increases, the displayed speed decreases . Ideally, an angle
of zero (0) degrees is preferable, because the displayed speed is the
actual target speed . However, in all uses of radar, the radar device is
always at a slight angle to the target to avoid collisions .
Velocity
Vector
Angle
Radar
Figure 6 .2 .1
An angle between the antenna and the
target causes the cosine effect .