昆虫雷达散射截面积特性分析

Analysis of Insect RCS Characteristics

昆虫雷达是观测昆虫迁飞最有效的工具。研究昆虫的雷达散射截面积(RCS)特性对于昆虫雷达目标识别有着重要意义。该文将分析昆虫的静态RCS特性和动态RCS特性。首先,基于实测的X波段全极化昆虫RCS数据,分析昆虫的静态RCS特性,包括水平和垂直极化RCS随体重变化规律以及昆虫极化方向图随体重的变化规律。其次,总结当前通过电磁仿真研究昆虫RCS特性所用到的介质和几何形状模型,并对比了水、脊髓、干皮肤和壳质与血淋巴混合物4种介质和等体型扁长椭球体、等质量扁长椭球体和三轴椭球体3种几何模型组成的12种介质模型,经过电磁仿真结果与实测数据相对比发现脊髓介质等质量扁长椭球体模型与实测昆虫RCS特性最接近。然后,基于Ku波段高分辨昆虫雷达外场实测昆虫回波数据,分析了昆虫动态RCS的起伏特性,将实测昆虫动态RCS起伏数据与4种经典的RCS起伏分布模型χ2,Log-normal,Weibull和Gamma分布分别进行了拟合分析,从最小二乘拟合误差和拟合优度检验结果可以看出,相比于其他3种模型,Gamma分布可以较好地描述昆虫目标RCS起伏的统计特性。最后,综述了昆虫RCS特性在昆虫雷达测量昆虫朝向、体重等参数测量的应用。

Insect radar is the most effective tool for insect migration observation.In order to realize target recognition of insect radar,it is important to study the RCS characteristics of insects.This paper will analyze the static and dynamic Radar Cross Section(RCS)characteristics of insects.Firstly,based on the measured Xband fully-polarimetric RCS data,the static RCS characteristics of insects are analyzed,including the variations of horizontal and vertical polarization RCS with body weight respectively,and the variation of insect polarization pattern with body weight.Secondly,the dielectrics and geometric models currently used to study the RCS characteristics of insects are summarized by electromagnetic simulation.Twelve dielectric models consisting of four dielectrics(including water,spinal cord,dry skin,and chitin and hemolymph mixture)and three geometric models(including equivalent size prolate spheroid,equivalent mass prolate spheroid and triaxial prolate spheroid)are compared,and it be found that the RCS characteristics of equivalent mass prolate spheroid are closest to that of the real insects.Then,the fluctuation characteristics of insect dynamic RCS are analyzed based on the insect echo data measured in field by a Ku-band high-resolution insect radar.The measured insect dynamic RCS fluctuation data are fitted with four classical RCS fluctuation distribution models(χ2,Log-normal,Weibull and Gamma distribution),respectively.It can be seen from the least square error of fitting and goodness of fit test that Gamma distribution gives the best description of the statistical characteristics of insect RCS fluctuations.Finally,the application of insect RCS characteristics to insect orientation,mass and body length measurements for insect radars is summarized.