Developing virtual acoustic terrain for Urban Air Mobility trajectory planning

Urban Air Mobility (UAM) is a transformative concept that must operate harmoniously within the constraints imposed by societal impacts. Noise-aware flight trajectory planning can address UAM's community noise concerns. However, the traditional trajectory optimization paradigm requires repetitive computations of a flight's noise footprints in complex urban environments and is computationally expensive. In this work, we propose virtual acoustic terrain, a novel concept to enable an efficient trajectory optimization paradigm. By applying acoustic ray tracing and the principle of reciprocity in a complex urban environment, we convert different noise constraints into 3D exclusion zones which UAM operations should avoid to maintain limited noise impact. It combines with the physical urban terrain to define an acceptable fly zone for non-repetitive noise-aware trajectory optimization. This framework provides a new angle to future urban area airspace management and can also accommodate other forms of societal constraints.