色散有损介质土壤对电磁回波影响的不确定性分析研究

Uncertainty Analysis of the Influence of Dispersive and Lossy Soil on Electromagnetic Wave Propagation

不确定性分析是量化不确定性从而获得统计特性的过程。在数值模拟中,均值、标准差等统计特性是评价数值仿真结果是否合理的重要依据。针对探地雷达系统建模仿真输出结果的不确定性,本文提出一种改进的不确定性分析方法。该方法结合辅助微分方程时域有限差分法与广义多项式混沌展开方法,对色散有损土壤模型的不确定参数所引起的仿真输出结果的不确定性进行量化表征,从而得到输出结果的不确定度。与传统不确定性分析方法蒙特卡洛方法相比,该方法计算效率更高,显著降低计算成本。

This paper proposes an improved intrusive generalized polynomial chaos expansion(gPCE)method for uncertainty quantification(UQ)in ground penetrating radar(GPR)modeling.The uncertainty in simulation results induced by the uncertain parameters of dispersive and lossy soil is quantified with the auxiliary differential equation(ADE)finite-difference time-domain(FDTD)method combined with gPCE.To avoid the curse of dimensionality in modeling complex systems,the combination of uncertainties is incorporated into the new method to evaluate the interval of the uncertainty of the output.The results from the new method are compared against traditional UQ method Monte Carlo method(MCM).The new method shows its considerable advantage in the computational expense and speed.