Localization and tracking of aircraft with ground based 3D sound probes

Abstract: In this paper a new method is described for localizing and tracking low flying aircraft, based on compact and broadband three-dimensional sound probes. Recently, such sound probes became available based upon three orthogonally placed acoustic particle velocity sensors (Microflowns) and a single sound pressure sensor. With at least two of these sound probes, placed at a certain distance from each other, sound sources such as airplanes can be localized and tracked along its trajectory. The method is based on a triangularization technique using the particle velocity or sound intensity vectors. As an acoustic far field sound source localization technique, this approach has already been applied in wind tunnels. However, this method can also be used to localize the geometric position of a low flying aircraft along its trajectory. Simultaneously, both the perceived noise level and acoustic signature of the flying object can be determined. Thus, this method can be expected to be used for both civil and defense purposes, for instance around heliports or borderlines. The method will be clearly described and test results of both lab scale and first true outdoor applications will be presented.