Aircraft are one of the major noise sources affecting residents close to airports. Classical metrics for noise assessment are usually derived from energy-based quantities, such as known from noise maps. Thus, they only consider human perception in a very basic manner. To investigate the impact of aircraft noise in a more accurate way, it is desired to conduct experiments focusing on human perception by presenting audible signals. This can be achieved in virtual acoustic environments. In this context, auralization is an approach to synthesize these audio signals based on virtual scenarios.

One important requirement for auralization is a model for sound propagation from the aircraft to the listener. Typical aircraft auralization approaches use the simplification of a homogeneous medium and a flat ground. However, the atmosphere is generally inhomogeneous and moving leading to sound propagating along curved paths. Furthermore, sound generally interacts with urban structures within residential areas, e.g. leading to reflections and diffraction or occlusion of the direct sound.

This work aims to overcome these simplifications in order to allow the consideration of aircraft noise in more realistic acoustic virtual environments. For this purpose, an aircraft auralization approach considering curved sound propagation in the atmosphere is proposed. This includes a computationally efficient method to simulate the curved sound paths connecting a source and a receiver, while still assuming a flat ground. It is based on a ray tracing algorithm for inhomogeneous, moving media and uses a divide-and-conquer routine to significantly reduce the number of calculated rays. Furthermore, a procedure for scheduling these simulations and interpolating respective results is presented, which enables to perform such auralizations in real time.

Finally, an interface method is introduced allowing to combine the presented curved propagation approach with urban auralization methods. Such methods consider the interaction with urban structures but assume straight-path propagation. The proposed interface finds a virtual source position for the urban auralization in order to maintain the acoustic properties resulting from the curved propagation through the atmosphere, e.g. incident direction at the receiver and propagation delay. The method was applied to a street canyon scenario. The auralization result highlights the relevance of considering sound interaction with urban structures. This is especially prominent when the direct sound is occluded and therefore, reflected and diffracted sound paths have a significant effect on the localization of the aircraft.

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