Possibility of False Target Signals Induced by Reverberation Due to Internal Waves in Shallow Water

Sung Chun Lee; Sunhyo Kim; Jee Woong Choi; Donhyug Kang; Joung Soo Park; Kyeongju Park

doi:10.7776/ASK.2015.34.2.098

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Possibility of False Target Signals Induced by Reverberation Due to Internal Waves in Shallow Water 천해에서 내부파로 인해 생성되는 잔향음에 의한 허위표적 신호 발생 가능성

31 March 2015. pp. 98-107

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Abstract

It is investigated that there exists the possibility of the false target signals induced by reverberation in an active sonar system due to the internal waves in shallow water. The rays down-refracted from the internal waves may generate strong bottom-reverberation signals, which can result in false target signals. Sound waves emitted from a source propagate 3-dimensionally. Therefore, the study of internal waves on the reverberation should be studied for azimuthal direction as well as 2-dimensional (r-z) plane. Internal-wave modelling was conducted, based on solitons which were predicted with the various conditions such as, the range of source-soliton, horizontal widths of soliton. Variable depth sonar (VDS) was assumed as a source, of which the depth was located in the minimum sound speed layer in a simulation environment. Finally, the simulation on the reverberation level with time was made based on ray-based reverberation model, and the results implied that several false-target signals could be displayed on the PPI(Plan Position Indicator) scope simultaneously with range from source to soliton, and the horizontal width of soliton.

Keywords

Sound propagation

Internal waves

Soliton

Reverberation

False target

능동소나 시스템에서 천해 내부파에 의한 잔향음으로부터 유도될 수 있는 허위 표적 신호의 발생 가능성에 대하여 연구하였다. 내부파로부터 굴절된 하향 음선은 강한 해저면 잔향음 신호를 발생시켜 허위 표적 신호를 야기한다. 음원으로부터 송출된 음파는 3차원적으로 전파하므로, 2차원(r-z) 뿐만 아니라 수평방향에 대해서도 고려되어야 한다. 솔리톤(soliton)으로 구성된 내부파 모델링은 음원과 솔리톤간 거리 및 솔리톤의 수평폭과 같이 다양한 조건에서 수행되었다. 음원은 가변심도소나(VDS: Variable Depth Sonar)를 가정하여 모의 환경에서의 최소음속층에 위치시켰고, 음선 기반의 잔향음 모델을 이용하여 시간에 따른 잔향음 준위를 모의하였다. 결과적으로 음원과 솔리톤간 거리 및 솔리톤의 수평폭에 따라 여러 개의 허위표적 신호가 동시에 PPI(Plan Position Indicator) 전시기에 나타날 수 있음을 확인하였다.

키워드

음파전달

스내부파마트폰

솔리톤

잔향음

허위표적

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Information

Publisher :The Acoustical Society of Korea
Publisher(Ko) :한국음향학회
Journal Title :The Journal of the Acoustical Society of Korea
Journal Title(Ko) :한국음향학회지
Volume : 34
No :2
Pages :98-107
Received Date : 2014-12-08
Accepted Date : 2015-01-12
DOI :https://doi.org/10.7776/ASK.2015.34.2.098

The Journal of the Acoustical Society of KoreaISSN:1225-4428(Print) 2287-3775(Online)한국음향학회

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