3
SYSTEM DESCRIPTION
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8017768/12AX/2019-05-31|SICK
O P E R A T I N G I N S T R U C T I O N S | TIC
Subject to change without notice
If an axle is not detected within the first 2 meters of the vehicle, the vehicle height
one meter from the vehicle front is output with a reduced confidence level.
Accuracy
The axle counting accuracy is 97% for normal traffic on dry roads.
•
The axle counting accuracy decreases if the vehicle’s axles are difficult to detect. This
affects vehicles with a lower chassis, vehicles that are close to the edge of the lane,
and vehicles that have lots of small wheels located very close to one another.
•
When the road is very wet and there is a high level of spray, the axle counting accuracy
will reduce significantly.
•
Raised axles (about 10 cm above the ground) are generally not detected.
3.4.5
Emission of object location messages
In addition to vehicle-related information, all three system functions also deliver so-called
object location messages. These messages provide information on the time at which the
vehicle was located at a defined position in the lane. In order to integrate third-party
systems such as license plate cameras, these messages must be assigned with a time
stamp.
It is possible to define trigger lines before and after the measuring plane. If a vehicle
passes over this line during the measurement process, a message is emitted.
Stable time synchronization (NTP) is essential for this type of integration.
For the TIC102 and TIC502 system functions, the LMS Length supplies the information
about the vehicle’s location within the lane for localization. To do this, it scans the front
and rear end of the vehicle.
The time stamp for the vehicle location is sent to the Traffic Controller 20 ms after the
position line is passed for the TIC102 and 10 ms after for the TIC502.
Fig. 32: Determination of object location messages – TIC102 / TIC502
Note