Sount source detection and noise measurement methods for aircraft noise monitoring in presence of background noise

Resumen

The objective of the present thesis is to design a method for aircraft noise monitoring in presence of background noise. Such a method is not dependant on radar data in order to perform source detection, and that provides a background noise free record of aircraft noise. At this aim the use of microphone array techniques in aircraft noise monitoring have been deeply studied by designing and testing a microphone linear array specially designed for aircraft noise measurements. Simulation, indoor tests, and outdoor tests revealed good performance. However, the results point out that 12 microphones at least are needed in each measuring terminal. Given that, a less resources demanding measurement method is designed. Such a method requires a single microphone in every measurement site, and is able to locate the source by using the relation between the Doppler Effect shift that affects every receiver and the aircraft position. It also takes advantage of the fact that a common signal is present in all receive's record (the aircraft noise signal) buried in the specific background noise of each site, to obtain a background noise free record of the aircraft noise. The theoretical development of this method is presented in this document, as well as simulation and practical tests results. Simulated results in the case of locating a moving source in a linear path have been compared with experimental results in the same situation. Since obtained simulated and experimental results satisfactorily agreed for this simple case, simulation has been used in order to analyze the more complex case of aircraft noise monitoring, because the real testing of that situation demanded resources not available for this study. The simulation of such an application reveals that this method could be a good alternative to the classical methods because it gives better features without increasing the number of material resources.