Non-stationary sea clutter: Impact on disturbance covariance matrix estimate and detector CFAR

In this paper we present an analysis of sea clutter non-stationarity with respect to clutter covariance matrix estimation and its impact on the constant false alarm rate (CFAR) property of the normalized adaptive matched filter (NAMF). Three estimators have been considered in the analysis, the sample covariance matrix (SCM), the normalized sample covariance matrix (NSCM), and the fixed point (PF) estimators. The impact of non-stationarity, that emerges in the statistical analysis of the clutter data, is measured in terms of differences between NAMF nominal probability of false alarm (PFA) and probability of detection (PD) and quantified by processing measured clutter data recorded by the X-band IPIX radar.