θφ5dcReal-time map viewer and report creatorThe AS-51 aircraft noise management software enables collection, compilation, visual representation, and output of data measurements by the aircraft noise monitoring system. This data can be collected via LAN communication or a modem or saved directly to an external storage drive. The most notable feature is the real-time map viewer function. A map displayed when noise is detected indicates the source location and noise fluctuation over time. Daily, monthly, and annual reports can also be created easily.Overhead sound identification using the correlation methodThe AN-39D sound arrival direction identification unit detects the overhead sound as follows: Two microphones (M1 and M2) are arranged perpendicular to each other as shown in Figure 1, separated by distance d. When the sound from an aircraft arrives with an elevation angle θ, the equation shown on the left applies, where τ is the time difference between the arrival time of the sound at the two microphones, and c is the speed of sound in air. By tracking changes in this angle θ once a sound event is detected, we can distinguish aircraft noise from other sounds. Furthermore, we can calculate the sound arrival direction vectors (elevation angle, azimuth angle) by arranging four microphones in a three-dimensional, Cartesian configuration as shown in Fig. 2 to obtain more accurate information on the direction the sound source is moving in.Y axisElevation angle θ and azimuth angle φ can be calculated by correlation of 3-axis data.Keishi SakodaField Engineering Department, Environ-mental Instruments DivisionSince joining the company in 1998, he has dedicated himself to researching air-craft noise measurement, analysis tech-nology, and developing solutions in the development department. As a field en-gineer, he travels worldwide to conduct inspections of on-site instruments, en-suring their peak performance.Aya IshidaS&V Measuring Instrument International Sales Section, Environmental Instru-ments DivisionSince joining Rion in 2014, she has been in charge of regions including India and South Asia and, since 2016, Vietnam. She hopes to help people in need facing sound and vibration problems using Ri-on’s superior technology.Figure 1Figure 2Z axis3-axis direction identification systemX axisproject steadily evolve from there.“When preparing the measurement and evaluation manual, we were espe-cially careful to let the Vietnamese side take the lead instead of imposing our own method,” recalls Sakoda. “In Japan, we have a manual that complies with the Environmental Quality Standards for Aircraft Noise established by the Minis-try of the Environment. But we didn’t want to translate that into Vietnamese. We believed that unless the Vietnamese people made their own decisions for their own country, it wouldn’t really take root. Another hurdle in setting up the mea-surement system was the inability to access the airport flight logs, due to secu-rity concerns. Since we didn’t have infor-mation on whether noise was from a long-haul international flight or a short-haul domestic flight, we couldn’t defini-tively match the noise data obtained at a certain time to its source. The Vietnam-ese members on the team wanted to obtain data analysis results according to the airline and aircraft type, but this remained an issue to be resolved.”“Since Rion needs to expand its business overseas. I think this project has helped cultivate a new market for us,” comments Sakoda. “I learned a lot about what is required from meetings where many stakeholders with different posi-tions and intentions get together. I also understood that a project on a scale as large as this one couldn’t have gotten off the ground without the cooperation of experts, researchers, and other associated parties not just within our company, but from outside. Now I have a renewed sense of the significance of creating coopera-tive relationships with experts outside the company and a new appreciation of nurturing and maintaining the relation-ships I’ve made.”“This project gave me a clear sense of accomplishment based on our success in solidifying relations with the Civil Avia-tion Authority of Vietnam, the Ministry of Transport, and the airport companies in Vietnam,” says Ishida. “My hope is that Rion’s aircraft noise monitoring system will find wide use in Vietnam and benefit those who suffer from aircraft noise.”Project seminar for reviewing the actual situation of the airport noise environmentThe most memorable part of the proj-ect for the team was the third project seminar, held in Hanoi. The first and sec-ond seminars focused on introducing the results in Japan, while the main theme of the third seminar was to report on the actual situation in Vietnam (the mea-surement and analysis results for Noi Bai International Airport).“The reaction from participants at the third seminar was totally different from the previous seminars,” says Ishida. “When the project participants and gov-ernment officials realized and under-stood that the measurement data matched the actual aircraft flight data, they let out a collective cheer: ‘Wow!’ That was a very moving moment for me.” The JICA-aided project in Vietnam was completed successfully according to the initial schedule. Now, planning is underway for the second round of tech-nical joint efforts.M1M0M2M3τ=× sin (θ)
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