Validation of atmospheric propagation models in littoral waters

Abstract

Various atmospheric propagation effects are limiting the long-range performance of electro-optical imaging systems. These effects include absorption and scattering by molecules and aerosols, refraction due to vertical temperature gradients and scintillation and blurring due to turbulence. In maritime and coastal areas, ranges up to 25 km are relevant for detection and classification tasks on small targets (missiles, pirates). From November 2009 to October 2010 a measurement campaign was set-up over a range of more than 15 km in the False Bay in South Africa, where all of the propagation effects could be investigated quantitatively. The results have been used to provide statistical information on basic parameters as visibility, air-sea temperature difference, absolute humidity and wind speed. In addition various propagation models on aerosol particle size distribution, temperature profile, blur and scintillation under strong turbulence conditions could be validated. Examples of collected data and associated results are presented in this paper.