The Journal of the Acoustical Society of Korea (한국음향학회지)

The Acoustical Society of Korea (한국음향학회)
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A study on the acoustical inversion method using cepstrum analysis of underwater ship radiated noise

선박 수중방사소음의 셉스트럼 분석을 이용한 음향역산법 연구

  • 박철수 (선박해양플랜트연구소 친환경운송연구본부) ;
  • 김건도 (선박해양플랜트연구소 친환경운송연구본부) ;
  • 임근태 (선박해양플랜트연구소 친환경운송연구본부) ;
  • 문일성 (선박해양플랜트연구소 친환경운송연구본부)
  • Received : 2018.10.24
  • Accepted : 2019.01.23
  • Published : 2019.01.31
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Abstract

This paper proposes an acoustical inversion method using cepstrum analysis of underwater ship noise. Through the cepstrum analysis, multipath structure can be extracted from the recorded ship noise. The multipath structure comes from interferences between a direct arrival and multiple reflections from the sea surface and the bottom. The acoustic inversion is the optimization process to find the best parameters which show good correlation between cepstrums of the measured signal and the replica. The inversion method was applied to the underwater ship radiated noise data measured at Straits of Korea in order to estimate the acoustic center of the ship and the hydrophone position. The inversion results showed good agreement with the measured information.

본 논문에서는 선박 수중방사소음의 셉스트럼(cepstrum) 분석을 이용한 음향역산법을 제안하였다. 셉스트럼 분석을 통해 수중 청음기에서 계측된 선박 소음으로부터 직접 도달파와 해수면과 해저면에서 반사파와의 간섭에서 기인한 음파의 다중반사 구조를 추출할 수 있다. 음향학적 역산은 계측 신호의 셉스트럼과 모의 신호의 셉스트럼을 비교하여 최적의 역산인자를 찾는 방식으로 구성되었다. 본 논문에서 제안된 역산기법을 대한해협에서 계측한 선박 수중방사소음 데이터에 적용하여 대상 선박의 음원중심과 수중청음기의 위치를 추정하였다.

Keywords

GOHHBH_2019_v38n1_73_f0001.png 이미지

Fig. 1. An example of deployment for the shipping noise measurement.[4]

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Fig. 2. Cepstrum analysis numerical example : (a) half space environment, (b) spectrum of direct arrival and received signals, (c) cepstrum.

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Fig. 3. Concept of the acoustic inversion through comparison between (a) cepstrum of measured data and (b) cepstrum of simulated data.

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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.

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Fig. 5. Definition of two coordinates which shows the relation between (Δxs, Δys) and (Δls, Δbs).

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Fig. 6. Description of URN measurement test : (a) test site and (b) measured underwater sound speed profile.

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Fig. 7. Cepstrum images of data measured from 01:00 to 04:00 on March 4, 2016.

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Fig. 8. Scatter plots of the VFSR search for the cepstrum data of 90 % MCR 1st run.

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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.

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References

  1. IMO MEPC.1/Circ.833, Guidelines for the Reduction of Underwater Noise from Commercial Shipping to Address Adverse impacts on Marine Life, 2014.
  2. IWC Scientific Committee. "Report of the workshop on acoustic masking and whale population dynamics," International Whaling Commission, IWC/SC/66B/REP 10, Rep., 2016.
  3. 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.
  4. DNVGL-RU-SHIP Pt.6 Ch.7, Rules for classification: Ships, 2017.
  5. BV NR614, Underwater Radiated Noise (URN), 2014.
  6. A. Tolstoy, Matched Field Processing for Underwater Acoustics (World Scientific, NJ, 1993), pp. 1-10.
  7. C. Park, W. Seong, P. Gerstoft, and W. S. Hodgkiss, "Time-domain geoacoustic inversion of short-range acoustic data with fluctuating arrivals" (in Korean), J. Acoust. Soc. Kr. 32, 308-316 (2013). https://doi.org/10.7776/ASK.2013.32.4.308
  8. R. B. Randall, "A history of cepstrum analysis and its application to mechanical problems," Mechanical Systems and Signal Processing, 97, 3-19 (2017). https://doi.org/10.1016/j.ymssp.2016.12.026
  9. B. P. Bogert, M. J. R. Healy, and J. W. Tukey, "The quefrency analysis of time series for echoes: cepstrum, pseudo-autocovariance, cross-cepstrum, and saphe cracking," Proc. the Symposium on Time Series Analysis, 209-243 (1963).
  10. P. O. Fjell, "Use of the cepstrum method for arrival times extraction of overlapping signals due to multipath conditions in shallow water," J. Acoust. Soc. Am. 59, 209-211 (1976). https://doi.org/10.1121/1.380849
  11. G. V. Krishnakumar, M. Padmanabham, B. Sudhakar, C. Pavani, and M. Naik, "Transiting ship's slant range estimation using single hydrophone in shallow waters," Proc. Underwater Technology, 1-3 (2015).
  12. L. An and L. Chen, "Underwater acoustic passive localization base on multipath arrival structure," Proc. Inter-noise (2014).
  13. M. Porter, "The BELLHOP manual and user's guide," HLS Research, 2011.
  14. L. Ingber, "Very fast simulated reannealing," Math. Comput. Modeling, 12, 967-993 (1989). https://doi.org/10.1016/0895-7177(89)90202-1
  15. 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
  16. Ocean buoy data of Korea Hydrographic and Oceanographic Agency, www.khoa.go.kr, 2016.