LIDAR ARRANGEMENT FOR MEASURING ATMOSPHERIC TURBIDITIES

摘要

The lidar arrangement (1) has a transmitter (3) forlinearly polarized radiation (12), a receiver (5) with a firstreceiving device which measures intensity of the backscatteredradiation (15) coinciding approximately with the transmittedradiation cone (12) in a polarization plane of the cone and ina perpendicular polarization plane, wherein the receiverfurther includes a second receiving device which measures theintensity of backscattered radiation (17) outside the trans-mitted cone (12), the outer backscattered radiation has theshape of a conical shell which surrounds the backscatteredconical shell of the first mentioned backscattered radiation(15) and of the transmitted cone (12), the received separateradiation cones (15 and 17) are split in a polarizationanalyzing optical element into two mutually perpendicularpartial light beams, each consisting of an inner partial beamportion (15a, 15b) and an outer partial beam portion (17a and17b), the inner and outer partial beam portions are separatelydetected and the resulting output signals are amplified by anamplification factor which depends on the distance of thelidar from a visibility obstacle, the distance-correctedamplified signals are evaluated in a signal processing unit to-1-distinguish between different kinds of the visibilityobstacle, the evaluated obstacle such as fog, rain, snow orsolid obstacle and a distance thereof are indicated on corre-sponding indicators.-2-