Gamma分布在海面目标检测中的应用

Applications of Gamma Distribution in Sea Clutter Modelling and Maritime Target Detection

本文通过对大量实测数据的处理与定量分析,证明Gamma分布可用于X波段雷达海杂波幅度分布的建模,并介绍了两种适用于Gamma分布杂波背景的恒虚警(CFAR)检测器:基于最大似然估计的MLG-CFAR和基于加权幅度循环迭代的WAI-CFAR。理论分析证明,MLG-CFAR检测器对Gamma分布的杂波平均功率估计值是渐进有效的,且在形状参数已知的前提下,该检测器对尺度参数具有恒虚警特性,在均匀、非均匀杂波背景中的检测性能仿真结果验证了该检测器在Gamma杂波中的最优性;WAI-CFAR检测器综合了均值类和有序统计量类CFAR算法的优点,在均匀杂波背景中具有较好的性能,在非均匀杂波背景中可通过灵活设定加权系数,获得较强的目标检测能力和鲁棒的虚警控制能力。

The Gamma distribution is demonstrated to be promising to model the amplitude distribution of sea clutter based on experimental results.Furthermore,two CFAR detectors,namely the MLG-CFAR based on maximum likelihood estimation and the WAI-CFAR based on weighted amplitude iteration,are provided for Gamma-distributed background.Theoretical analysis shows that the derived estimator of the MLG-CFAR is an asymptotically efficient estimator of the mean power of the Gamma clutter.With a known shape parameter,the MLG-CFAR is demonstrated to maintain CFAR property with respect to the scale parameter of the Gamma distribution.Simulation results validate the superiority and generality of the MLG-CFAR in homogenous Gamma-distributed background.The WAI-CFAR is proposed by combining the advantages of cell averaging class CFAR detectors and ordered statistic class CFAR detectors.The superiority of the WAI-CFAR,which is applicable to different clutter scenarios with corresponding weighting factors,is investigated and verified by simulations.