Ground-penetrating Radar (GPR) is a non-invasive technique with increasing focus on civil-engineering applications. Referring to existing constructions, the most recent International and National Codes suggest a knowledge-based approach, which is mandatory before any structural assessment or design of interventions. The knowledge-based process includes experimental investigations aimed at the detailed geometrical and structural relief as well as to the evaluation of the materials mechanical properties. However, when dealing with built Cultural Heritage, destructive techniques should be limited or even forbidden. In this context, non-destructive investigations play a key role and their effectiveness should be further studied in relation to specific applications. To this end, Ground-penetrating Radar surveys were performed in the test site of the Laboratory of Applied Geophysics, the University of Salento, Lecce (Italy), with the aim of simulating various real-life practical applications. In particular, several objects of different materials and geometries were buried in the subsurface and a small building was built in the area using different construction techniques, among them, multi-leaf masonry walls, also called sack masonry walls, were constructed. The GPR method can detect both the presence of hidden bodies and different leafs of the walls with a relative efficiency depending on the field context, the dielectric properties of the host material, and the nature and size of the bodies. In this work, a test was planned to verify 900 and 2000 MHz antenna resolutions. The data acquired with the 2000 MHz antenna were used to estimate the mean electromagnetic wave propagation velocity in the sack masonry layers of known thickness and to understand if the inner core was filled with material other than air. The authors propose a high-resolution method to improve the velocity estimation using geometrical optics laws and the sign of the reflection coefficient in order to properly select the arrivals from different interfaces.

探地雷达（GPR）是一种非侵入性技术，越来越重视土木工程应用。关于现有结构，最新的《国际和国家法规》提出了一种基于知识的方法，在进行任何结构性评估或设计干预措施之前，这种方法是强制性的。基于知识的过程包括针对详细的几何和结构浮雕以及材料力学性能评估的实验研究。但是，在处理建筑文化遗产时，应当限制甚至禁止使用破坏性技术。在这种情况下，非破坏性调查起着关键作用，应针对具体应用进一步研究其有效性。为此，在意大利莱切萨伦托大学应用地球物理实验室的测试现场进行了探地雷达调查，目的是模拟各种现实生活中的实际应用。特别是，在地下埋藏了数种不同材料和几何形状的物体，并使用不同的建造技术在该地区建造了一栋小建筑物，其中，建造了多叶砌筑墙，也称为麻袋砌筑墙。GPR方法可以根据现场环境，基质材料的介电特性以及物体的性质和尺寸，以相对效率检测隐藏物体和墙壁不同叶片的存在。在这项工作中，计划进行测试以验证900和2000 MHz的天线分辨率。使用2000 MHz天线获取的数据用于估计已知厚度的麻袋砌筑层中的平均电磁波传播速度，并了解内芯是否充满了除空气以外的其他材料。作者提出了一种高分辨率方法，利用几何光学定律和反射系数的符号来改进速度估计，以便正确地选择来自不同界面的到达信号。