Ascertaining range of vision of car driver in fog - using range finder transmitting signals and receiving those reflected from road surface not covered by fog

摘要

A distance-measuring device (2) consisting of a transmitter and a receiver is fastened at the front of a car (1) so that it can be swung, in equal steps, a to j, over the length being measured, immediately in front of the car by moving in a vertical plane. The signals transmitted from the device however are reflected back from the points on the road (3) to the receiver only when they are not concealed by fog (5). When the road is covered by fog, signals do not return to the receiver. USE/ADVANTAGE - Ascertaining visibility in fog using mostly readily available equipment.