Atmospheric emission supervision - by laser beam with intermediate reflectors preceding terminal reflector

摘要

An area is supervised for atmospheric pollution, esp. for the emission of noxious substances in the environment, by a laser which radiates a coherent light across the area and by several terminal reflectors at the boundary of the area. The reflected signals are evaluated to determine the approximate source of any emission. Intermediate reflectors which are mounted across the laser path to each terminal at certain distances consist either of semi-transparent mirrors or of retroreflectors with a cross-section smaller than that of the laser beam. This results in a better resolution in depth and in a more precise location of any trouble.