• 한국해양공학회지
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• 제28권5호
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• pp.429-439
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• 2014

The target echoes contain information on the target such as the orientation, kinematics, and internal structure, as well as the external geometrical shape of the target. In addition, the pattern of the target echoes depends on the arrangement of the transmitters and receivers in space. Therefore, the study of the target echoes in a multi-static SONAR system can be useful for detecting and tracking submerged objects using an underwater surveillance system. For this purpose, an acoustic measuring system for multi-static target echoes was designed and tested in an acoustic water tank. Some preliminary data are presented and discussed.

• 한국해양공학회지
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• 제28권5호
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• pp.440-451
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• 2014

A multi-static SONAR system consists of the transmitters and receivers separately in space. The active target echoes are received along the transmitter-target-receiver path and depend on the shape and aspect angle of the submerged objects at each receiver. Thus, the target echo algorithm used with a mono-static system, in which the transmitter and receiver are located at the same position, has limits in simulating the target echoes for a multi-static SONAR system. In this paper, a target echo modeling procedure for a 3D submerged object in space is described based on the Kirchhoff approximation, and the SONAR system is extended to a multi-static SONAR system. The scattered field from external structures is calculated on the visible surfaces, which is determined based on the locations of the transmitter and receiver. A series of experiments in an acoustic water tank was conducted to measure the target echoes from scaled targets with a single transmitter and 16 receivers. Finally, the numerical results were compared with experimental results and shown to be useful for simulating the target echoes/target strength in a multi-static SONAR system.

• 한국산업정보학회논문지
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• 제27권5호
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• pp.49-59
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• 2022

SHAPE 알고리즘은 펄스의 스펙트럼 형태를 원하는 대로 성형하면서, 이 외의 특성에는 왜곡을 발생시키지 않도록 설계할 수 있다는 장점이 있어 기존의 능동소나 펄스 설계에 활용되었다. 본 논문에서는 다중상태 소나 시스템을 위한 펄스를 설계할 때, 주파수 대역에서 인접한 펄스 간의 상호상관도를 감소시키면서도 펄스 자체의 성능 저하를 방지하기 위해 SHAPE 알고리즘을 적용한 펄스 신호 설계 기법을 제안한다. 이를 위해서 SHAPE 알고리즘의 경계함수를 펄스 대역폭으로 제한하도록 설정하였다. 제안하는 설계 기법을 사인화 주파수 변조 펄스 신호에 적용한 결과 상호상관도를 의미하는 peak cross-correlation level (PCCL)이 44.23 dB 감소하였다. PCCL이 수십 dB 감소하였음에도 모호성 함수의 변화가 크게 관찰되지 않았으며, 부엽의 평균값을 의미하는 integrated sidelobe level (ISL)이 11.64 dB 증가하였다.