关键词: 雷达, 杂波, 韦布尔分布, 目标检测, 非参数, 恒虚警率

Abstract: 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.

Key words: radar, clutter, Weibull distribution, target detection, nonparametric, CFAR