| Refractivity parameters in which the radar is operated have great theoretical significance and of great value to practical on radar, communication and electronic support measures system. When a duct is present, the radar is practically radar holes and increases the range. So,it is important to inverse the atmospheric refractivity from radar sea clutter. Compared with some other common methods, this method has many advantages.This dissertation introduces the formal condition, the classification of the atmospheric duct, and the impact on the EM-wave propagation. Some kinds of the forecast and prediction technologies of the atmospheric duct are predicted. By the atmospheric boundary layer theory, the dissertation discusses the modified refractivity profile of the different atmosphere layer in evaporation duct. Based on the Split-step Fourier transform (SSFT) and DMFT of PE model, the transmission loss in the atmospheric duct is studied, and calculates the transmission loss under the different atmospheric duct. The influence of the grazing angle on the EM-wave propagation is analyzed. This dissertation discusses two kinds of optimization algorithms -GA and PSO. Two Different atmospheric ducts are inversed. The result is more ideal and PSO is more high-efficient than GA, to restrain the speed is faster. A mix GA-PSO is put forward and inverse the atmospheric duct innovatively and superior to performing the result instead of single GA and PSO algorithm. |
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