基于速度分析的探地雷达阻抗介电常数反演

阻抗反演是利用波阻抗与介电常数关系开展地下介质参数估计的重要技术，在探地雷达以及叠后地震资料解释中具有广泛的应用。常规阻抗反演需要钻孔或测井曲线作为约束项，约束项信息直接影响阻抗反演的估计精度。在缺少钻孔数据的实际应用中，如何开展探地雷达阻抗反演是该方法研究的重要内容之一。基于上述问题，本文提出了基于速度分析的探地雷达阻抗反演方法。其基本思想是基于多偏移距雷达数据开展速度谱分析和Dix反演，以获得不同深度的速度信息作为阻抗反演的约束项；同时，采用K-means方法自动拾取速度谱信息，大大降低了常规人工拾取误差，提高了计算效率。通过典型随机土壤介质模型，验证了本文方法在无钻孔条件下仍然可以获得较好的介电常数估计结果，并测试噪声适应能力强。最后通过美国密歇根州Wurtsmith AFB，in Oscoda区域的探地雷达数据测试了本文提出方法在探地雷达实测数据参数估计中具有较好的应用效果。

GPR Impedance Inversion of Permittivity Based on Velocity Analysis

Impedance inversion is an important technique for estimating the parameters of underground media using the relationship between wave impedance and dielectric constant, which is widely used in GPR and post-stack seismic data interpretation. Conventional impedance inversion requires drilling or logging parameters as constraints, which directly affect the estimation accuracy of the final impedance inversion. In the practical application with lack of borehole data, how to carry out GPR impedance inversion is one of the important contents of the method. To solve the above problems, the authors proposed a GPR impedance inversion method based on velocity analysis. The basic idea is to carry out velocity spectrum analysis and Dix inversion based on multiple offset radar data to obtain velocity information of different depths as the constraint term of impedance inversion. At the same time, the K-means method can automatically pick up the velocity spectrum information, so as to greatly reduce the conventional manual picking error and improve the calculation efficiency. Through a typical random soil medium model, it is verified that the method can also obtain better dielectric constant estimation results without drilling data, and can test noise adaptability effectively. Based on the GPR data acquired from Wurtsmith AFB, in Oscoda area, Michigan, the method proposed in this paper has a good application effect in the parameter estimation of GPR measured data.