A new maximum a posteriori CFAR based on stability in sea clutter state-space model

A new constant false alarm rate (CFAR) for the marine environment based on a stability in sea clutter state-space model is proposed. In this CFAR, based on observation samples in the reference window, a maximum a posteriori (MAP) estimation for clutter power in the test cell is utilized for setting a threshold. The compound K model is the best model for high resolution sea clutter that includes a phenomenological insight into clutter formation, and it is most frequently cited in the literature. The compound model for sea clutter is considered to be the multiplication of two independent processes. This multiplicative model is linearized to form a state-space model for the sea clutter evolution. This state-space model is established in the logarithmic domain. By introducing a stable distribution for innovations in the state-space model as a priori, we derive a new MAP estimator for the clutter power. The performance of the new CFAR, named SLMAP-CFAR (stable linear MAP CFAR), is then compared to the existing LMAP.