Fixing Occlusion Problems - Wavetronix SmartSensor V User Manual

Note. A good rule of
thumb is that 50%
of a vehicle must
be visible above
any barrier in order
to be detected.
SmartSensor V User Guide
14
•
Normal
detection
Signal that doesn't
return to sensor is
scattered
Figure 5. Left: direct path return; right: 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 the 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 occlusion problems

Move the sensor higher on the pole (keeping it within the rec-
˿
ommendations in the mounting guidelines table).
Move the sensor to another spot on the freeway if possible,
˿
away from obstructions.
If there's a very large barrier in the median, you could do the
˿
following:
Use one sensor on either side of the road, pointing in (be
̀
sure to give the two sensors a 120-ft./36.6-m lateral offset
and put them on different RF channels).
Put two sensors on the same pole in the middle of the
̀
median, both pointing out (put them on different RF chan-
nels), but this would mean they are next to the barrier in the
median and that could cause multipath problems.
Signal bouncing off
wall causes false
detection