Effects of small clutter cell statistics on probability of detection

In this study, the effects of decreasing clutter cell size on radar system performance are analyzed. The mean and variance of the clutter cross section for small clutter cells, characteristic of high resolution radar, are calculated. Typically, the statistical distribution of the clutter cross section is assumed to be exponential. As the clutter cell size decreases, however, the statistical distribution of the clutter cross section is no longer well modeled by an exponential distribution. The variance increases as the clutter cell size decreases. The calculated means and variances for small cell sizes were used as input parameters to four clutter cross section distribution functions and the effect on system performance examined. Because a definitive statistical distribution of the clutter cross section for small clutter cells has not been identified, four common distribution functions were used to represent the clutter statistics: the exponential; Weibull; chi-squared and log-normal. Detection probabilities were found to decrease as the cell size decreased due to the non-Gaussian clutter characteristics of small cells. In some cases, order of magnitude reductions in the probability of detections were observed