Automatically low clouds or fog detection, based on two visibility meters and FSO

This paper is focused on the FSO link attenuation under specific elevation angle. In these conditions fog or low clouds could cause different results in attenuation. Difference in these two kinds of attenuation is essential for attenuation modeling on FSO links. The decision which kind of attenuation on FSO link occurs is based on two visibility data and attenuation info on link. Modeling method is proposed in this paper. This method is using all previously described data. Model output is computed on theoretical level of edge between two visibilities. This level we take into consideration in attenuation data filtering.