We research the characteristics of detecting of small sea targets with a small radar cross section, located on the rough sea surface, with respect to the coherent pulse radar with high resolution. As a result of mathematical modeling based on the technical parameters of the radar "Fregat- MAE -4K " and conditions close to real environmental conditions, it was found that the detection performance in advanced Gaussian noise model based on the Rayleigh distribution of the envelope of the reflected signal from the rough sea surface is considerably more optimistic than the detection characteristics for the most appropriate for high-resolution radar non-Gaussian noise model based on K- distribution envelope radar reflections.