目标雷达截面积(RCS)的统计特性研究是雷达进行目标检测、成像识别的基础。文中基于Ku 波段固定翼无人机全极化实测数据,分析了不同频率、不同方位的无人机目标RCS 在HH、VH、HV 和VV 极化下的均值、方差等特性。研究发现,同极化方式下无人机的RCS 均值较交叉极化方式下的RCS 均值大9 dBsm。为进一步定性描述RCS 起伏特性的统计分布,选取12 GHz、14 GHz 两个频点,以最大似然估计量为初值,通过非线性最小二乘准则对参数进行微调,实现了Ku 波段不同极化方式下无人机RCS 的分布特性拟合。结果表明:Gamma 分布可以较好地拟合无人机同极化方式下RCS 的统计分布,Weibull 分布可以较好地拟合无人机交叉极化方式下RCS 的统计分布。

The research on the radar cross section(RCS) statistical characteristics is the foundation for radar image, target recognition and detection. On basis of the fully polarimetric radar experimental data of fixed-wing unmanned aerial vehicles(UAV) in Ku band, this paper analyzed the mean, variance and other statistical characteristics of UAV RCS at HH, VH, HV and VV polarization with different frequencies and directions. The research reveals that the RCS mean value of fixed-wing UAV in the co-polarization mode is 9 dBsm greater than that in the cross-polarization mode. In order to describe qualitatively the statistical distribution of the RCS fluctuation characteristics, we selected the frequency in 12 GHz and 14 GHz, took the maximum likelihood estimator as the initial value, and fine-tuned the parameters by using the nonlinear least squares criterion to achieve distribution characteristics fitting of UAV RCS with different polarization mode in Ku band. The results show that the Gamma distribution can describe preferably the statistical distribution of the UAV RCS at the co-polarization mode, and the Weibull distribution can fit well the RCS statistical distribution of the UAV at the cross-polarization mode.

TN959

国家自然科学基金资助项目(61490690,61490692,61871385)