Degraded visual environments are a cause of problems for surveillance systems and other sensors due to the reduction in contrast, range, and signal. Fog is a concern because of the frequency of its formation along our coastlines; disrupting border security, shipping, surveillance, and sometimes causing deadly accidents. Fog reduces visibility by scattering ambient/active illumination light obscuring the environment and limiting operational capability. Sandia has created a fog facility for the characterization and testing of optical and other systems. This facility is a 180 ft. by 10 ft. by 10 ft. chamber with temperature control that can be filled with a fog-like aerosol using 64 agricultural spray nozzles. We will discuss the physical formation of fog and how that is affected by the environmental controls at our disposal. We have recently made several improvements to the facility including temperature control and will present the results of these improvements on the aerosol conditions. We will discuss the characterization of the fog and instrumentation used for the characterization. In addition, we will present preliminary results from work at Sandia, that leveraged this facility to investigate using polarized light to enhance the range of optical systems in fog conditions. This capability provides a platform for performing optical propagations experiments in a known, stable, and controlled environment where fog can be made on demand.
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