Combination of empirical/asymptotic models to characterize sea clutter at intermediate angles

In this paper, we propose to characterize normalized reflectivity of sea clutter at intermediate angles. Two approaches are generally used to model radar signal backscatter by the sea: empirical models based on measurements and asymptotic models based on physics. We choose to interpolate an unified model which combines the Georgia Institute of Technology model (GIT model), defined for low grazing angles, and the GOSSA model, developed by the French Mediterranean Institut of Oceanography, former Fresnel Institut, defined for high angles. The curve fitting of data is made by using the Lagrange and spline interpolations. The results are compared with a set of data (Nathanson and Masuko et al.) and with two mean backscatter models, one developed by the Defence Science and Technology Organisation (DSTO) called IRSG-LIN model and the IGENCE model.