Airborne weaponry noise measurements

摘要

Many aircraft noise models exist that estimate noise levels from military aircraft operations nearairbases, along training routes, and within special use airspace, but these models do not includecontributions to the noise by air gunnery and air fired missile operations. A new air-weaponrymodel is being developed to assess noise from these unique military operations. This paperdescribes the initial field measurements used to characterize air-weaponry noise sources and toevaluate propagation algorithms. Air gunnery noise data were collected from helicopter andfixed-wing aircraft operations. Missile launch noise data were collected from helicopteroperations. For the air gunnery noise, important aspects of time-dependent waveforms andspectral descriptions for muzzle blasts and ballistic waves are discussed along with theirdirectivity patterns. This analysis demonstrates that the positive impulse is the most stablemetric for describing the muzzle blast. The peak is best for describing the ballistic wave; and theCSEL is best for the missile launch and thrust noise. For the propagation algorithm, the lineargeometric theory of diffraction agrees well with the measured data. The development of an airweaponry model will be described in a companion paper.