A new set of measuring terrain atmospheric visibility with optical fiber

摘要

In the paper, a set for measuring terrain atmospheric visibility is put forward. Principle of the set operating is discussed. The processing of the signals in the set is analyzed. Optical fiber beams are utilized. The fiber beams act as both a field stop and a spatial filter. The errors caused by the limit of the end faces of fiber are smaller than 3.0 % in the set. The errors can be eliminated by means of adjusting the instrument constant of the set. The effect by the forward scattered light on the measuring of transmission light is cut down due to the spatial filter. The measuring of angular scattering coefficient is not affected by the change in the intensity of probing beam, and change in the properties of propagation by the depositing of dust. The set can be used in the real-time measuring of visibility. The relative error is about 3.7 % between the total scattering coefficient and that by the transmission light method.