Decatur Electronics G3 - Radar Interference and Remedies; Common Interference Sources and Remedies

G3
™
User’s & Installation Manual
7/October/2020
52
• TheDopplertoneiscorruptedwithnoise.
• Speedsareirregularanddonotprovidevalidtrackinghistory.
• Erroneousspeedsappeartotrackwiththeenginespeeds.
8.2.1 Angular Interference (Cosine Eect)
When operating in the Stationary Mode, the cosine eect causes the
radar to display a speed, which is lower than the actual motor vehicle
speed. This condition exists when the target motor vehicle’s path is
not parallel to the antenna, including conditions such as the motor
vehicle traveling on a curve or a hill.
As the angle between the beam of the antenna and the target motor
vehicle increases, the displayed speed decreases. Ideally, an angle
of zero (0) degrees is preferable, because the displayed speed is the
actual target motor vehicle speed. However, in all uses of police radar,
the radar device is always at a slight angle to the target motor vehicle
to avoid collisions.
Figure 8.2.1a
An angle between the antenna and the target motor vehicle
causes the cosine eect.