Fig. 1. An example of deployment for the shipping noise measurement.[4]
Fig. 2. Cepstrum analysis numerical example : (a) half space environment, (b) spectrum of direct arrival and received signals, (c) cepstrum.
Fig. 3. Concept of the acoustic inversion through comparison between (a) cepstrum of measured data and (b) cepstrum of simulated data.
Fig. 4. Definition of the positions which represent surface buoy, hydrophone, ship DGPS and ship acoustic center in 2-D coordinates parallel to the sea surface.
Fig. 5. Definition of two coordinates which shows the relation between (Δxs, Δys) and (Δls, Δbs).
Fig. 6. Description of URN measurement test : (a) test site and (b) measured underwater sound speed profile.
Fig. 7. Cepstrum images of data measured from 01:00 to 04:00 on March 4, 2016.
Fig. 8. Scatter plots of the VFSR search for the cepstrum data of 90 % MCR 1st run.
Fig. 9. Comparison of slant ranges. The blue line is estimated from the DGPS data of ship and surface buoy and the red line is estimated from inversion. Cepstrums are also shown in the figure. Time differences between direct arrival and bottom reflected signal are given as red lines on the cepstrums.
Table 1. Ship acoustic center positions relative to the ship DGPS and hydrophone position relative to the surface buoy DGPS converted from inversion results. Depths of the acoustic center and the hydrophone are also given in the table.
References
- IMO MEPC.1/Circ.833, Guidelines for the Reduction of Underwater Noise from Commercial Shipping to Address Adverse impacts on Marine Life, 2014.
- IWC Scientific Committee. "Report of the workshop on acoustic masking and whale population dynamics," International Whaling Commission, IWC/SC/66B/REP 10, Rep., 2016.
- ISO 7208-1:2016(E), Underwater acoustics -Quantities and procedures for description and measurement of underwater sound from ships -Part 1: Requirements for precision measurements in deep water used for comparison purposes, 2016.
- DNVGL-RU-SHIP Pt.6 Ch.7, Rules for classification: Ships, 2017.
- BV NR614, Underwater Radiated Noise (URN), 2014.
- A. Tolstoy, Matched Field Processing for Underwater Acoustics (World Scientific, NJ, 1993), pp. 1-10.
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- L. Ingber, "Very fast simulated reannealing," Math. Comput. Modeling, 12, 967-993 (1989). https://doi.org/10.1016/0895-7177(89)90202-1
- D. C. Kim, G. Y. Kim, H. I. Yi, Y. K. Seo, G. S. Lee, J. H. Jung, and J. C. Kim, "Geoacoustic provinces of the South Sea shelf off Korea," Quaternary International, 263, 139-147 (2012). https://doi.org/10.1016/j.quaint.2012.02.035
- Ocean buoy data of Korea Hydrographic and Oceanographic Agency, www.khoa.go.kr, 2016.