Method for determining visibility distance in thick fog and visibility sensor

摘要

The invention relates to a method for determing the visibility in thick fog, by means of a lidar and a visibility sensor. A pulsed laser beam is transmitted by a first transmission channel, and laser light scattered back from the fog is received by a first receiving channel, the first transmission channel and the first receiving channel being aligned parallel to one another. Laser light scattered back is additionally received by the lidar, by means of a second receiving channel, and this second receiving channel is aligned at a divergent, acute tilt angle with respect to the first transmission channel. This results in it being possible to separate the laser light which has been scattered once from the laser light which has been scattered a plurality of times and in consequence makes it possible to draw conclusions on the type of fog, and, finally, on the visibility. Further conclusions are possible as a result of investigating the depolarisation of the back-scattered laser light in accordance with an advantageous development. IMAGE