In today's vehicles, sensors for monitoring tire pressure, rain sensors and automatic driving lights switching on at dusk are standard. This offers a significant improvement in road safety. However, the automatic light control can run the risk of incorrectly detecting emerging obstructions to the view due to fog, smog or smoke, because these can also occur during the day.
Standardized automatic light systems only control the low and/or high beam, front and rear fog lights still have to be switched on manually in the absence of special sensors. Preh plans to solve these problems with a new type of visibility sensor that makes use of the optical backscattering principle. Placed behind the windshield and emitting a beam of light invisible to the human eye with a wavelength of 850nm, microparticles, such as those found in fog, are illuminated and reflect this light. Microparticle concentration enables conclusions to be drawn about the concentration of water droplets in the air. This visibility sensor was extensively tested both in the laboratory and during real test drives and produced very good results. In addition, the visibility sensor was confronted with disruptive factors such as rain, snow, tunnels and forest sections. The sensor system remained fully functional even under these different environmental conditions.
Preh's visibility sensor can make a contribution to road safety in fog by enabling the lighting required to be switched on automatically. In the future, when vehicles are networked, the sensor data can also be passed on to the traffic behind, for early detection and avoidance of hazards.
To Article (German version only)
