AU-Ray program for modeling radio wave propagation in the ionosphere

This paper presents a numerical ray-tracing model, AU-Ray, for simulating the HF/VHF radio wave propagation in the ionosphere. AU-Ray operates in fully three-dimensional magnetoionic conditions along similar principles as applied in some other widely used ray-tracing codes (e.g., PHaRLAP and Proplab-Pro). The AU-Ray software has been developed in C++ and built entirely on open-source packages, which makes it an efficient standalone alternative for other ray-tracing models. The model can handle customized user-defined sources for the ionospheric background conditions, in addition to the well-known empirical models. Use cases for AU-Ray include analyzing satellite and ground-based measurements, investigating ionospheric anomalies, and supporting real-time operations. Validation against other ray-tracing models demonstrates that AU-Ray provides consistent results with Proplab-Pro and PHaRLAP and has similar performance in computational efficiency as PHaRLAP, which is significantly higher than that of Proplab-Pro. As an additional feature when compared to PHaRLAP's capabilities AU-Ray's photon mapping tool allows operations to solve large quantities of rays for detailed propagation maps in experimental background conditions.