Archives of Acoustics, 44, 1, pp. 185–194, 2019
10.24425/aoa.2019.126364

An Experiment of the Actual Vertical Resolution of the Sub-bottom Profiler in an Anechoic Tank

Fangqi WANG
First Institute of Oceanography, State Oceanic Administration
China

Lifeng DONG
First Institute of Oceanography, State Oceanic Administration
China

Jisheng DING
First Institute of Oceanography, State Oceanic Administration
China

Xinghua ZHOU
First Institute of Oceanography, State Oceanic Administration
China

Changfei TAO
First Institute of Oceanography, State Oceanic Administration
China

Xubo LIN
First Institute of Oceanography, State Oceanic Administration
China

Guanhui LIANG
First Institute of Oceanography, State Oceanic Administration
China

Sub-bottom profiler (SBP) is an acoustic instrument commonly used to survey underwater shallow geological structure and embedded objects whose most important performance parameter is the actual vertical resolution. This paper presented a methodology to measure and evaluate the actual vertical resolution of SBP based on an experiment in an anechoic tank, which was divided into three components: building of artificial geological model, measurement of acoustic parameters, and determination of actual vertical resolution of the acoustic profiles. First, the wedge-shaped geological model, whose thickness could be accurately controlled, was designed and built in an anechoic tank to try to directly measure the vertical resolution of SBP. Then, the acoustic pulse width of SBP was measured to calculate the theoretical general vertical resolution and extreme vertical resolution. Finally, based on the acoustic profiles obtained in the experiment, the method which was used to evaluate the actual vertical resolution by measuring the duration of reflection event was put forward. Due to comparing measurement data of different parameter settings of the SBP, the study has revealed that the SBP had the lowest resolution in the 4 kHz-500 μs setting, which was 226.5 μs, or 36.2 cm, and the highest resolution in the 15 kHz-67 μs setting, which was 72.7 μs, or 11.6 cm. The vertical resolution decreased with the increase of the pulse width. The results also showed that the actual resolution was close to the theoretical general resolution and far from the extreme resolution.
Keywords: sub-bottom profiler (SBP); pulse width (PW); vertical resolution; duration of reflection event (DRE)
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References

Blondel P., Pace N.G. (2009), Bistatic sonars: sea trials, laboratory experiments and future surveys, Archives of Acoustics, 34, 1, 95–109.

Chronis A., Hasiotis T., Lowag J. (2013), Rlationship between gas-bearing sediments and biogenic mounds in the Kalloni Gulf, Lesvos Island, Greece, Proceedings of the 6th Workshop “Seabed Acoustics”, pp. 16, Rostock.

Godø O.R., Foote K.G., Dybedal J., Tenningen E., Patel R. (2010), Detecting Atlantic herring by parametric sonar, Journal of the Acoustical Society of America, 127, 4, EL153–159.

Grelowska G., Kozaczka E. (2010a), Sounding of Layered Marine Bottom–Model Investigations, Acta Physica Polonica A, 118, 66–70.

Grelowska G., Kozaczka E. (2010b), The examination of the structure of the upper layers of the seabed by the means of the parametric sonar, Proceedings of 20th International Congress on Acoustics, ICA, pp. 23–27, Sydney.

Grelowska G., Kozaczka E. (2014), Underwater Acoustic Imaging of the Sea, Archives of Acoustics, 39, 4, 439–452.

Grelowska G., Kozaczka E., Kozaczka S., Szymczak W. (2013), Laboratory investigation with subbottom parametric echosounder SES-2000 standard with an emphasis on reflected pure signals analysis, Proceedings of Meetings on Acoustics, pp. 7, Montreal.

Kozaczka E., Grelowska G., Kozaczka S., Szymczak W. (2012), Processing data on sea bottom structure obtained by means of the parametric sounding, Polish Maritime Research, 19, 4, 3–10.

Kozaczka E., Grelowska G., Kozaczka S., Szymczak W. (2013), Detection of objects buried in the sea bottom with the use of parametric echosounder, Archives of Acoustics, 38, 1, 99–104.

Levchenko O.V. (2006), Survey of underwater gas pipelines on the Ob River with parametric sediment echosounder SES, International Hydrographic Conference, Hydro’06-Evolutions in Hydroigraphy, pp. 206–210, Antwerpen.

Maushake C. (2013), How deep does an anchor penetrate the seafloor?, Proceedings of the 6th Workshop “Seabed Acoustics”, pp. 12, Rostock.

Smith G.S., Best J., Zinger J., Orfeo O., Vardy M. (2013), Imaging river dune and bar deposits using a parametric echo sounder, examples from the Rio Parana and Rio Bermejo, Argentina, Proceedings of the 6th Workshop “Seabed Acoustics”, pp. 13, Rostock.

Wang Q., Xiao F.M., Bao J.Y., Yin X.D., Xu W.M. (2013), Vertical Layer Surveying Performance Analysis for Sub-bottom Profiler [in Chinese], Hydrographic Surveying and Charting, 33, 2, 30–33.

Wunderlich J., Müller S. (2003), High-resolution sub-bottom profiling using parametric acoustics, International Ocean Systems, 7, 4, 6–11.

Wunderlich J., Wendt G., Müller S. (2004), Detection of embedded archaeological objects using nonlinear sub-bottom profilers, Proceddings of the 7th European Conference on Underwater Acoustics, ECUA 2004, pp. 6, Delft.




DOI: 10.24425/aoa.2019.126364

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