Modelling Microwave Propagation in Natural Caves using LiDAR and Ray Tracing

Abstract

Limited work has previously been conducted into microwave communication in natural caves, and although modal analysis has given acceptable results in some cave passages, multiple bends and highly irregular passages remained problematic. Recent advances in rapid capture laser scanning technology have permitted accurate 3-D models of cave passages to be created, prompting this article into modeling by ray tracing. Issues of model simplification and handling of roughness have been studied. The technique has been used in several cave passages-one in which modeling by modal analysis was especially unsuccessful-at three frequencies and the experimental results are obtained. Acceptable correlation was demonstrated despite the difficulty in accurately measuring or estimating average roughness.