Localization of acoustic source from a landing aircraft with a microphone array

Abstract

Acoustic source two-dimensional localization was performed during flyover tests with an Airbus A340 in Tarbes, France, in 1997. The method combined a cross-shaped array of 29 microphones developed by ONERA to a D-GPS tracking system operated by Aerospatiale. These tests aimed to validate the method and evaluate its precision and performance. The signal processing used a 32-channel digital tape recorder, where both D-GPS synchronization tops and the acoustic signals were recorded on the ground while DGPS information was recorded on board. The aircraft performed flyovers above the array at altitudes between 40 and 180 meters and for different flight configurations. An acoustic emitter producing tone noise placed on the aircraft nose has helped for the method calibration. The source is clearly localized with a bias on position that can be lower than 50 cm. The method interest for extended and multiple sources is also confirmed : a few examples of airframe noise source maps are presented for configurations with landing gears and high-lift devices extended.