Advances in the Measurement and Human Response to Noise of Unmanned Aircraft Systems 2023-01-1108

As the commercial applications of Unmanned Aircraft Systems (UAS) continue to grow the need for a robust environmental noise assessment methodology becomes more urgent. It is already understood that UAS pose a unique problem when compared to many conventional aircraft owing to their complex sound signature and their operational profiles. These complexities also mean the measurement procedures and assessment metrics used for conventional aircraft may not be appropriate for UAS. This paper describes work undertaken investigating appropriate UAS acoustic field measurement techniques and human response to noise. Firstly, the paper discusses a field measurement campaign using state-of-the-art measurement methods and how that data is being used to characterise the spectral and directivity content of different drone operations. Secondly, a listening experiment assessing the response to different drone operations when the listener is simulated to be in different outdoor and indoor environments. This experiment was designed to answer three questions. I) How is the perceived loudness and annoyance effected when the listener is in an outdoor or indoor position; II) what are the operational procedures perceived as louder and more annoying; and III) to what extent can conventional metrics such as LAmax and SEL be used to assess UAS noise annoyance and perceived loudness.