时间域航空电磁一维阻尼特征参数反演方法

1D inverse method based on damped eigenparameter for airborne time domain electromagnetic data

时间域航空电磁数据反演是当前航空电磁领域的研究热点和难点,甚至一维反演问题仍然没有得到很好的解决.本文应用阻尼特征参数算法对时间域航空电磁数据一维反演进行研究,即将阻尼因子与相对奇异值结合,通过改变相对奇异值修正阻尼因子,达到约束反演过程的目的.由于阻尼特征参数算法综合了奇异值截断和马奎特方法的优点,所以具有较高的计算效率和精度.为了验证该反演方法的有效性,使用MAXWELL软件中的2.5D正演方法获得反演所需的模拟数据.实验主要对三层和四层地电模型的模拟数据进行反演,结果表明该方法收敛稳定,对低阻体的反演结果较好.

The inverse problem of time-domain airborne electromagnetic data is still one of the hot and difficult spots in the field of airborne electromagnetic prospecting,even onedimensional inverse problems cannot be solved very well.In this paper,the inverse problems of one-dimensional electromagnetic data may be solved by the damped eigenparameter method,which constrains the inverse process by combining the damping factors with the relative singular values and correcting iteratively damping factor.The method proposed is with low computational cost and high accuracy because it integrates the advantages of the Marquardt and Truncation estimates.Synthetic data generated by the 2.5Dmodeling program of the MAXWELL software are applied to demonstrate the validity of the inverse method shown.The experiments upon the typical geoelectric models with the three-layer and the four-layer media respectively show that the proposed method is with high accuracy and stable convergence speed,especially for low resistivity object.