If you have a controller board connected to the serial port of the radar, you may also
obtain
lane-by-lane target presence and other lane information in real-time
.
Historical Lane Counts
As of radar firmware v124 and higher (release date May 10
th
2012) the radar also counts
the number of vehicles detected in each lane during every accumulation interval.
Accumulation interval is programmed in minutes via BN variable. These counts are
stored in internal memory and may be retrieved later for analysis.
Co-located Radars
When radars are located close to each other and point in the same direction they may
interfere with each other unless their frequency sweeps are synchronized. PD420 provide
facility to synchronize two or more radars in a “single master, one or more slaves”
configuration. With this arrangement, the master initiates each sweep and slaves follow
with delayed sweeps.
As an additional benefit the sweeps will have a user defined constant time lag between
them. This fact can be put to a good use in case where an external controller is looking at
data from both radars and needs to know exact delay between measurements.
Time lag should be set to a different value in each slave. A 500 us increment from master
to slave and from slave to slave is recommended but maximum lag value should not
exceed 4000 us.
The need for synchronization should be decided on a case by case base and will depend
on radar proximity to each other and beam pointing. Please see the section Synchronizing
Multiple Radars for more information.
Radar Range Resolution
The PD420 radar features an unmatched internal range measurement resolution down to
0.25 inches (0.64cm). This is achieved by utilizing a proprietary resolution enhancement
algorithm. However, there are several factors that must be considered in order to achieve
this resolution.
1.
Signal strength. Very weak targets may not be able to achieve this resolution.
Target strength of 3 ‘RSS’ bars, as shown on the GUI plot is required for the best
performance.
2.
Multiple return signals from same target. A large target with a complex shape
such a vehicle has many contours and surfaces that return the radar energy back to
the radar with different signal strengths. Additionally, these contours are located
at different linear distances from the radar. All these reflections are merged
together into a single range reading for that target. As the vehicle is traveling
