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Lidar Monitoring of Infrared Target Detection Ranges Through Adverse Weather

出版	Defence Research Establishment Valcartier, 1998
URL	http://books.google.com.hk/books?id=IywzjwEACAAJ&hl=&source=gbs_api

註釋Adverse weather still constitutes an important decision factor in the efficient use of infrared sensors. The presence of fog, clouds, or precipitation affects both the infrared transmission & background properties of the atmosphere. Taking these effects into account requires the knowledge of the optical parameters of fog, clouds or precipitation which generally fluctuate too much on a scale of a few kilometers to be predictable with acceptable information for real-time on-site decision making. A promising alternative is continuous monitoring of atmospheric aerosol properties with a laser infrared radar or lidar. The method used in this study is the multiple field of view technique which takes advantage of the information contained in the multiple scattering contributions to solve for both the droplet concentration & effective diameter. These solutions can then be used to derive the atmospheric radiance & transmittance and calculate the contrast-to-noise ratio of infrared images of small targets. Using actual lidar probings, examples of performance curves of a generic surveillance sensor are obtained for two types of targets. Results show how performance can change over an interval as short as one minute.