Acoustic and Psychoacoustic Characterisation of Unmanned Aircraft Systems as a Function of Vehicle Mass and Flight Procedure

Previous studies have found the noise emission of Unmanned Aircraft Systems (UAS) highly dependent on the vehicle mass and flight procedure. These changes in noise emission, as well as the position of the UAS relative to the receiver, have led to changes in noise annoyance and perceived loudness. This paper presents an acoustic (i.e., amplitude, frequency and directivity) and psychoacoustic (based on Sound Quality Metrics) characterisation of a series of UAS varying in take-off mass, and for three flight conditions (i.e., flyover, landing and take-off). Important findings are the confirmation of a logarithmic increase in sound levels (measured as ��AE) with vehicle mass for flyover, take-off and landing operational procedures; and the higher roughness and impulsiveness of the sound emitted during take-off and landing operations, which might explain the higher values of annoyance reported in the literature for these operations. These results can be used to inform a vehicle classification as a key step towards the development of a modelling framework for UAS noise mapping.