CHAOTIC DYNAMICS OF SEA CLUTTER

The notion that a deterministic nonlinear dynamical system (with relat ively few degrees of freedom) can display aperiodic behavior has a str ong bearing on sea clutter characterization: random-looking sea clutte r may be the outcome of a chaotic process. This new approach envisages deterministic rules for the underlying sea clutter dynamics, in contr ast to the stochastic approach where sea clutter is viewed as a random process with a large number of degrees of freedom. In this paper, we demonstrate, convincingly for the first time, the chaotic dynamics of sea clutter. We say so on the basis of results obtained using radar da ta. collected from a series of extensive and thorough experiments, whi ch have been carried out with ground-truthed sea clutter data sets at three different sites. The study includes correlation dimension analys is (based on the maximum likelihood principle) and Lyapunov spectrum a nalysis. The Lyapunov (Kaplan-Yorke) dimension, which is a byproduct o f Lyapunov spectrum analysis, shows that it is indeed a good estimator of the correlation dimension. The Lyapunov spectrum also reveals that sea clutter is produced by a coupled system of nonlinear differential equations of order five or six. (C) 1997 American Institute of Physic s.