地海交界环境与其上方双目标复合散射的混合算法研究

Composite electromagnetic scattering from double targets above ground and near sea in adjacent region using hybrid method

采用蒙特卡罗方法建立地海交界分区域复合粗糙面模型,陆地区域采用高斯谱模拟,近海海面区域采用基于变浅系数的北海海浪工程(joint North Sea wave project,JONSWAP)谱模拟;提出了基于分形理论的边界赋形方法,并运用多种反正切权函数处理实现了线型、月牙型、峡谷型和分形型边界的地海交界环境;基于矩量法和基尔霍夫近似的混合算法研究了地海交界环境与其上方双目标的复合电磁散射特性,对比了双目标分别位于两种典型环境和地海交界环境上方时的复合散射系数曲线,研究了复合散射系数随入射角、陆地区域参数、海面参数、边界形状、双目标参数及双目标类型的变化情况,并做了详细分析与讨论。结果表明该混合算法的高效性和准确性,数值仿真结果对地海交界环境上方目标的探测、遥感及成像具有借鉴意义。

The Monte-Carlo method is applied to construct composite rough surface model for describing ground and near sea in adjacent region. The Gauss spectral function is introduced to simulate actual ground surface. Based on the shallow coefficient, the joint North Sea wave project (JONSWAP)spectral function is used to simulate actual near sea surface. A new shaping method based on fractal theory is proposed. Different weighted inverse tangent functions are introduced to realize diverse actual environments, such as ground and near sea in adjacent region with linear boundary, crescent boundary, valley boundary and fractal boundary. The composite electromagnetic scattering from double targets above ground and near sea in adjacent region is investigated by using the hybrid method-the method of moment with the Kirchhoff approximation. The curves of composite scattering coefficient of double targets above two kinds of traditional environment and the composite environment are compared. The composite scattering coefficient which varies with incident angle, the parameters of ground region and near sea region, the shape of boundary, and the parameters and category of double targets is studied in detail. The high efficiency and high precision of the hybrid method are verified. The numerical results show the composite scattering characteristics of double targets above ground and near sea in adjacent region, which can be a reference for target detection, remote sensing and imaging in this kind of composite environment.