Modeling and Parameter Representation of Sea Clutter Amplitude at Different Grazing Angles

Abstract

Study on sea clutter is highly important in the field of maritime surveillance. The physical mechanism of sea clutter is complex and there are many influencing factors, among which the grazing angle is one of the most important. To address the problem of determining the suitability of models of sea clutter, this study performed a comprehensive goodness-of-fit (GoF) analysis of six sea clutter models using five methods at different grazing angles, bands, and azimuths. Furthermore, to improve the description of sea clutter amplitude, we proposed a new parameter representation method. The proposed new parameters can be used to analyze the characteristics of sea clutter amplitude and evaluate the GoF of sea clutter models at different grazing angles. Experimental data were obtained using airborne radar at a low grazing angle and spaceborne synthetic-aperture radar at medium–high grazing angles. The results indicate that the characteristics of sea clutter amplitude are various with different azimuths and grazing angles, whereas there are no significant differences between the ${X}$ and ${C}$ bands. In detail, ${K}$ distribution and generalized gamma distribution ( $\text{G}\Gamma \text{D}$ ) are recommended in side-looking, while ${G}^{0}$ and ${K}$ distributions are recommended in forward-looking at low grazing angle; at medium–high grazing angle, ${K}$ , $\text{G}\Gamma \text{D}$ , and Weibull distributions are recommended for the ${X}$ band, while ${K}$ and ${G} ^{0}$ distributions are recommended for the ${C}$ band. Compared with mean-square error, Kullback–Leibler, Bhattacharyya distance, threshold error, and graphical GoF methods, the proposed method was demonstrated to be simple and efficient in evaluating the GoF of sea clutter models.