Comparison of a trans-horizon littoral clutter model with shipboard radar data

Standard radar clutter reflectivity models such as the GIT sea clutter model (Ewell G.W. et al., 1979) (Horst M.M. et al., 1978) and the Billingsley land clutter model (2002) are based upon many measurements, in part to remove the effects of varying propagation environment, in order to predict radar reflectivity for standard propagation. It has been known for some time that radars on ships operating in regions near land are often subject to clutter amplitudes that vary significantly from these models, and this is due to anomalous propagation, or ducting. This paper describes the littoral clutter model (LCM) developed by Naval Surface Warfare Center Dahlgren Division and its validation against recorded radar data. LCM includes propagation modeling and is an extension of both the GIT sea clutter, and Billingsley land clutter models. The model compares favorably to measured land and sea clutter amplitudes in the presence of ducting.