半空间与其上方电大目标复合散射的时域快速算法研究

With the developments of earth observation technology of space-based radar, the accurate and fast calculation of the scattering of the complex target over the layered half-space became one of the urgent problems in target identification. The algorithms available are difficult to satisfy the need of analysis the scattering of the target in such conditions. This project is supposed to solve the problem by the method of combining analytical method and numerical calculation. The computational region can be divided in to two parts which includes target and rough surface, respectively. The incident wave can be obtained by the combination of numerical calculation and analytic method. Based on the reciprocity theorem and the Fourier transform, the far field formulation in the frequency and time domain of an arbitrarily oriented electric and magnetic dipole located above the interface of the half-space will be given to solve the fundamental problems in the calculation of the scattering of the target over layered half-space and the directional diagram. For the general framework of national supercomputers, the MPI, OpenMP and GPGPU hardware acceleration mixed parallel scheme is employed to satisfy the need for the calculation and analysis of electromagnetic scattering of complex targets over layered half space.

随着天基雷达对地观测技术的发展，半空间上方目标电磁散射的快速、精确计算成为目标探测等领域需要迫切解决的问题之一。现有的数值计算方法难以满足电大尺寸复杂目标与粗糙背景复合电磁特性精细计算和快速分析的需要。本项目拟采用解析分析和数值计算相结合的方法研究目标与背景复合散射的高效时域算法。将计算域分解为包含目标的计算子域和包含粗糙面的计算子域，目标的照射波通过数值计算和解析分析相结合的方法获得；研究弱耦合情形目标电磁散射的时域外推方法，利用互易定理给出半空间上方任意取向电、磁偶极子远区辐射场频域解析式，结合傅里叶变换获得时域场值，解决目标与背景复合散射中的基础性问题；针对我国超级计算机的通用架构，采用基于MPI、OpenMP和GPGPU硬件加速混合并行方案实现的FDTD高效、高精度计算，使之满足含层状半空间背景复杂目标电磁散射特性快速计算分析的需要。

随着天基雷达对地观测技术的发展，半空间上方目标电磁散射的快速、精确计算成为目标探测等领域需要迫切解决的问题之一。现有的数值计算方法难以满足电大尺寸复杂目标与粗糙背景复合电磁特性精细计算和快速分析的需要。本项目采用解析分析和数值计算相结合的方法研究目标与背景复合散射的高效时域算法，在时域以FDTD方法为例展开相关问题研究。将计算域分解为包含目标的计算子域和包含粗糙面的计算子域，目标的照射波通过数值计算和解析分析相结合的方法获得；研究弱耦合情形目标电磁散射的时域外推方法，利用互易定理给出半空间上方任意取向电、磁偶极子远区辐射场频域解析式，结合时域反射系数给出远区辐射场时域解析式，解决目标与背景复合散射中的基础性问题；针对我国超级计算机的通用架构，采用基于MPI、OpenMP和GPGPU硬件加速混合并行方案实现的FDTD高效、高精度计算，使之满足含层状半空间背景复杂目标电磁散射特性快速计算分析的需要。