CELL-AVERAGING CFAR GAIN IN SPATIALLY CORRELATED K-DISTRIBUTED CLUTTER

The detection performance of a cell-averaging CFAR detector is analyse d for spatially correlated K-distributed clutter. In thermal noise or uniform clutter, the performance of the cell-averaging CFAR can be com pared with that of the ideal fixed threshold, but with an associated ' CFAR loss', quantified by the increase in average signal-to-clutter ra tio required to achieve a given probability of detection and probabili ty of false alarm. In some types of clutter, knowledge of the overall amplitude distribution alone is not sufficient to assess the performan ce of a cell-averaging CFAR. In particular, sea clutter may exhibit si gnificant spatial correlation, often associated with the sea swell. In such spatially varying clutter, the cell-averaging CFAR may be able t o follow the local fluctuations, giving a considerable improvement in performance compared to the 'ideal' fixed threshold. This is quantifie d as a 'CFAR gain' with the limit of such improvement given by the per formance of the 'ideal CFAR' detector. The CFAR gain or loss is illust rated in different clutter conditions for a range of cell-averager con figurations. It is shown that significant CFAR gain, compared with the commonly accepted CFAR loss, can be achieved in some circumstances.