Chapter 1: Choosing a Mounting Location
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15
Multipathing
Normal
detection
Signal that doesn’t
return to sensor is
scattered
Signal bouncing off
wall causes false
detection
Figure 10.
Top: direct path return; bottom: multipath return
Multipathing occurs when a large flat surface near the sensor inter-
feres with detection. A radar signal can bounce around several
times between the surface and any vehicles before returning to the
sensor. This can make the sensor detect a vehicle where there is
none. This can happen with:
˿
Buildings
˿
Signs
˿
Guard rails
˿
Sounding walls and more
Fixing multipath problems
˿
Move the sensor if possible; make sure it is separated from
overhead signs, overpasses, parallel walls, etc. A 30-ft. (9.1-m)
lateral separation is ideal, but even just a few feet can make a
difference.
˿
Adjust the sensor’s sensitivity thresholds in SmartSensor
Manager Matrix, as covered in chapter 6.
