The authors have developed a sound direction detection method based on the cross-correlation method and applied it to automatic monitoring of aircraft noise and identification of sound sources. As aircraft performance improves, noise decreases, and people are interested in and dissatisfied with low-level noise aircraft, especially in urban areas where environmental noise and aircraft noise combine to complicate the acoustic environment. Therefore, it is necessary to monitor and to measure not only aircraft noise but also environmental noise. Since our surveillance is aircraft noise, it is important to analyze noise exposure from acoustic information rather than trucks or images.
In this report, we will look back on the development process of this sound direction detection technology, show examples of helicopters and application examples of acoustic scene analysis to high-altitude aircraft, and consider the latest situation realized as acoustic environment monitoring. We believe that this analysis will make it easier to understand the noise exposure situation at the noise monitoring station. It also describes the future outlook for this method.