Fast computation of radio wave diffraction effects

Unmanned aerial vehicle operations are quickly gaining ground due to rapid global market penetration. While on one hand, novel technologies that bridge communication networks to aviation industry are yet to be explored, on the other hand, their development requires highly scalable systems to enable beyond visual line-of-sight missions. This requirement imposes a big bottleneck in terms of computation complexity. This paper presents a method for fast computation of multiple diffraction of radio waves over knife-edge obstacles based on the Deygout technique and some offline computation steps, including a ground profile analysis. We prove that this algorithm is equivalent to the original Deygout algorithm for all non-line-of-sight points, show heuristics confirming that it is mostly applicable in the line-of-sight case. The computational and memory complexity of our algorithm is approximately $O\left(\sqrt{N}\right)$, compared to $O\left(N\right)$ for the original Deygout algorithm. Finally we discuss how to apply the approach to the Epstein-Peterson technique and the Giovanelli technique, and how to use it to compute clutter-loss.