量化秩非参数CFAR检测器在杂波边缘中的性能分析

人们常用均匀背景、多目标和杂波边缘3种典型背景来衡量雷达目标检测器的性能，但在现有文献中缺乏量化秩（Rank Quantization，RQ）非参数检测器在杂波边缘中虚警概率的理论模型，缺乏RQ非参数检测器与经典的参量型检测器在杂波边缘中虚警控制能力的比较.本文给出了RQ检测器在杂波边缘中虚警概率的解析表达式，并比较了它与非相干积累CA （Cell Averaging），GO （Greatest Of），OS （Ordered Statistic）恒虚警方法在杂波边缘中的虚警控制能力.可以看出，采用高秩量化门限的RQ检测器的虚警控制能力要优于低秩量化门限的情况，在瑞利分布杂波边缘情况下，RQ检测器的虚警控制能力与非相干积累OS方法接近.但是当强杂波变为长拖尾分布的非高斯杂波时，非相干积累CA，GO和OS参量型检测方法的虚警概率产生了3个数量级以上的上升，且不能降回到原始设定的虚警概率.而RQ检测器显示出了非参量检测器的优势，即当杂波背景的分布类型发生变化后，它仍然可以保持虚警概率的恒定.

Performance Analysis of Rank Quantization Nonparametric CFAR Detector at Clutter Edge

The performance evaluation of radar target detector is often carried out in 3 typical environments of homogeneous background, multiple targets situation and clutter edge.However, there is a lack of the mathematical model of the false alarm rate for the rank quantization (RQ) nonparametric detector at clutter boundaries, and lack of a comparison of the ability for the RQ detector to control the rise of the false alarm rate at clutter edges to that of the conventional parametric CFAR schemes.The analytic expression of the false alarm rate P_fa for the RQ nonparametric detector at clutter edges was derived in this paper, and the ability of the RQ nonparametric detector to control the rise of the false alarm rate at clutter edges was compared to that of the cell averaging (CA) CFAR, the greatest of (GO) CFAR and the ordered statistic (OS) CFAR with incoherent integration.It is shown that a high rank quantization threshold results in a low rise of the false alarm rate at clutter edges, and the rise of the RQ nonparametric detector at clutter edges is close to that of the OS-CFAR with incoherent integration in the Rayleigh distributed clutter environment.However, when a non-Gaussian distributed clutter with a long tail moves into the reference window, the rise of the CA-CFAR, the GO-CFAR and the OS-CFAR with incoherent integration reaches a peak of more than 3 orders of magnitude, and can not return to the pre-designed P_fa in Rayleigh noise situation.But the RQ nonparametric detector exhibits its inherent advantage in such situation, it can maintain constant false alarm rate even the distribution type of clutter changes to a different one.