垂直入射区雷达地面散射系数测量与特性研究

Radar Terrain Scattering Return Measurement and Characteristics Research in Vertical Incidence Region

为研究垂直入射区大地回波的散射机理,用S和8 mm波段线性调频连续波雷达散射计测量了垂直入射时农田和沙地的散射系数,建立了与雷达工作频率、高度、天线方向图、波束入射角、地面粗糙度和介电常数等相关的垂直入射区地面回波数据库,给出了回波数据处理方法,推导了粗糙地面散射系数理论模型,并对实验数据进行了拟合。实验结果表明,测量的垂直入射地面散射系数与所给模型吻合,沙地散射系数比农田强2～3 dB,8 mm散射系数平均比S波段强18～20 dB。

To study the scattering mechanism of radar terrain returned in vertical incidence region,an experimental program to measure the scattering coefficients of terrain including farmland and sand in vertical incidence region was carried out by using S and 8mm Linear Frequency Modulated Continuous Wave Radar scatterometers.A terrain scattering return database connected with radar frequency,altitude,antenna pattern,incidence angle,and the roughness and permittivity of ground surface was established.The return data processing approach is provided,the theoretical scattering model of rough terrain surface is derived,and then the measured data is fitted by the model.The experimental results show that the measured scattering coefficients agree with the given model,the radar cross section per unit area at vertical incidence of sand is 2～3dB larger than that of farmland,and the scattering coefficients at 8mm is 18～20dB larger than that at S frequency-band.