Setting the Necessity for a Warning

The necessity for a warning is determined by the master radar sensor (SWW). To do this, it uses the data which it has collected about road users itself, as well as information from the SWW2 radar sensor.

For the blind spot detection system, only the road users on the immediately neighboring lanes on both sides are relevant. In contrast, road users in your own lane and on other more distant lanes do not pose a danger when you are making a lane change.

The distance and approaching speed of road users in your lane change zone, i.e. of vehicles immediately behind your own vehicle, is a decisive factor as to whether a warning is issued or not. The time remaining for cancelling a lane change maneuver is calculated using the distance (in a longitudinal direction) and their approaching speed. If this time drops below a threshold value for any one of the detected road users, the system decides that it is necessary to give a warning.

Road users in the blind spot lead to a minimal amount of time being calculated for cancelling a lane change. This is why their exact position or speed relative to your own vehicle only has secondary importance. The mere presence of a road user in the blind spot therefore leads to the necessity for a warning.

The blind spot detection system must, of course, also be able to detect transitions from the lane change zone into the area of the blind spot and vice versa. A further challenge for the system is to determine the beginning and the end of the warning necessity when a vehicle in the neighboring lane is slowly overtaken by your own vehicle.

Vehicles that are overtaken very quickly cause the necessity for a warning to be suppressed or at least to end quickly.

In order to depict what the system is doing as reliably as possible to the driver, more than just the current measured values from the radar sensors are used, in particular in these special situations. In addition, the position and speed history of the other road users is taken into account. For example, based on a mathematical model, the system determines the point when an overtaking vehicle leaves the blind spot area and no longer poses a danger.

The master-radar sensor sends the result of the calculation as to whether the necessity for a warning is present or not, to the ICM control unit.