• 한국해양공학회지
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• 제34권3호
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• pp.227-236
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• 2020

Underwater acoustics, which is the domain that addresses phenomena related to the generation, propagation, and reception of sound waves in water, has been applied mainly in the research on the use of sound navigation and ranging (SONAR) systems for underwater communication, target detection, investigation of marine resources and environment mapping, and measurement and analysis of sound sources in water. The main objective of remote sensing based on underwater acoustics is to indirectly acquire information on underwater targets of interest using acoustic data. Meanwhile, highly advanced data-driven machine-learning techniques are being used in various ways in the processes of acquiring information from acoustic data. The related theoretical background is introduced in the first part of this paper (Yang et al., 2020). This paper reviews machine-learning applications in passive SONAR signal-processing tasks including target detection/identification and localization.

• 로봇학회논문지
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• 제9권4호
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• pp.232-241
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• 2014

This paper proposes an underwater localization algorithm using probabilistic object recognition. It is organized as follows; 1) recognizing artificial objects using imaging sonar, and 2) localizing the recognized objects and the vehicle using EKF(Extended Kalman Filter) based SLAM. For this purpose, we develop artificial landmarks to be recognized even under the unstable sonar images induced by noise. Moreover, a probabilistic recognition framework is proposed. In this way, the distance and bearing of the recognized artificial landmarks are acquired to perform the localization of the underwater vehicle. Using the recognized objects, EKF-based SLAM is carried out and results in a path of the underwater vehicle and the location of landmarks. The proposed localization algorithm is verified by experiments in a basin.

• 한국군사과학기술학회지
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• 제9권3호
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• pp.33-40
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• 2006

In towed array passive sonar system, sonar operators cannot detect and track the all targets simultaneously in the omni-directional area by just Operator Initiated Tracking(OIT). In this paper, omni-directional automatic target detection and tracking algorithm is described and optimize the parameters through ocean data to overcome the drawbacks of OITs. The algorithm is verified through sea trials with submarines.

• 한국군사과학기술학회지
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• 제16권2호
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• pp.118-129
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• 2013

Since the obstacles and mines are of the risk factors for operating ships and submarines, the active sonar system is inevitably used to avoid the hazards in ocean environment. In this paper, modeling and simulation algorithm is used for active sonar systemto quantify the measure of mission achievability, which is known as Measure of Effectiveness(MOE), specifically for detection in this study. MOE for detection is directly formulated as a Cumulative Detection Probability(CDP) calculated from Probability of Detection(PD) in range and azimuth. The detection probability is calculated from Transmission Loss(TL) and the sonar parameters such asDirectivity Index (DI) calculated from the shape of transmitted and received array, steered beam patterns, and Reverberation Level (RL). The developed code is applied to demonstrating its applicability.

• 한국군사과학기술학회지
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• 제18권5호
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• pp.532-537
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• 2015

In this paper, we propose target range estimation method using ghost target in the submarine linear array sonar. Usually, when submarine detect target, they use passive sonar detection to avoid self-disclosure by active sonar transmission. But, originally, passive linear array sonar have limitation for target range estimation and additional processing is required to get target range information. For the case of near-field target, typical range estimation method is using multiple information by multipath effect in underwater environment. Acoustic signal generated from target are propagated along with numerous multipath in underwater environment. Since multipath target signals received in the linear array sonar have different conic angles each other, ghost target is appeared at the bearing different with real target bearing and sonar operator can find these information on the operation console. Under several assumption, this geometric properties can be analysed mathematically and we get the target range by derivation of this geometric equations using measured conic angles of real target and ghost target.

• 한국음향학회지
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• 제41권5호
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• pp.481-491
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• 2022

능동 소나 송신시스템은 전기신호를 증폭하여 출력해주는 송신기와 증폭된 전기신호를 음향신호로 변환해주는 수중 음향 트랜스듀서로 구성된다. 일반적으로 송신기 출력 특성은 부하 임피던스에 의존적이며 송신기 부하인 수중 음향 트랜스듀서는 구동 시 전기적 임피던스가 주파수에 따라 크게 변화하는 특성을 갖는다. 이러한 가변 임피던스 조건에서는 능동 소나 송신시스템의 출력이 불안정해질 수 있다. 이에 본 논문에서는 능동 소나 송신시스템에서 수중음향 트랜스듀서의 가변 임피던스 조건에서도 안정적인 송신 신호를 전송하기 위한 소나 송신기의 설계 및 제어 기법을 제안하였다. 수중 음향 트랜스듀서의 전기적 임피던스 특성은 실험적 방법으로 분석하였고, 소나 송신기는 단상 풀브릿지 인버터, LC 필터와 정합회로로 구성하였다. 실시간으로 부하 특성이 변하는 Linear Frequency Modulation(LFM) 신호를 송신하면서 송신기와 트랜스듀서를 보호하고 안정적으로 출력 전압 특성을 확보할 수 있는 소나 송신기의 설계 및 출력 제어 기법을 제안하였으며, 시뮬레이션과 실험을 통해 타당성을 검증하였다.

• 한국정보통신학회논문지
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• 제13권12호
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• pp.2753-2758
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• 2009

해군에서는 수중 표적을 효과적으로 탐색하기 위한 소나운용전술을 개발하기 위해 노력하고 있다. 효율적인 소나운용전술 개발을 위해서는 먼저 다양한 소나운영전술에 대한 효과도를 분석할 수 있는 시뮬레이션 시스템이 필요하다. 시뮬레이션 시스템은 해양환경 정보, 자함 정보, 소나 정보, 그리고 수중표적의 정보를 매개변수로 입력받아 소나운용전술에 대한 시뮬레이션을 수행하며, 시뮬레이션의 진행에 따른 다양한 정보를 제공할 수 있어야 한다. 본 연구에서는 다양한 환경에서 수중표적에 대한 함정의 최적 탐색 전략을 평가할 수 있는 탐색효과도 분석용 시뮬레이션 시스템을 설계 개발하였다. 시뮬레이션 시스템은 소나방정식 및 탐지확률곡선을 이용할 수 있도록 개발되었으며, 표적의 실제적인 행동패턴을 고려하여 여러 가지 형태의 기동 패턴을 시스템에 묘사하였다. 개발된 시스템은 앞으로 수중표적에 대한 효율적인 소나운용전술을 개발하고 발전시키는데 유용하게 사용될 수 있을 것으로 판단된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.38-47
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• 2009

Scour means the erosion of bed material by flow change when a bridge is constructed in a stream. Scour is one of the critical factors of a bridge failure. There are several methods for the monitoring of scour near bridge foundations; Sounding rods, Magnetic sliding collar System, Sonar system, underwater camera system and so on. In general, Sonar system is preferred due to its convenience and good accuracy. In this study, the new scour monitoring system was developed using profiling sonar sensor. The new system can measure a line profile of a seabed and has small size due to the effectively designed data logger. The performance of the new scour monitoring system was evaluated at a bridge pier in tidal environment. The measured local scour depths were discussed with the result of the empirical formulas; CSU, Froehlich, Laursen and Neill.

• 대한조선학회논문집
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• 제42권4호
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• pp.299-306
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• 2005

To determine a guidance law which is suitable for Target Tracking System(TTS) of an underwater vehicle, the performance (hitting probability) of TTS were calculated with four different guidance schemes, considering underwater vehicle's manoeuvrability and characteristics of seeking equipment such as sonar To evaluate the performance of TTS with each guidance law, numerous target-tracking simulations of underwater vehicle were performed under the condition of target's various motion scenario. Furthermore, the effect of sonar characteristics to the performance of guidance law in TTS was studied by changing parameters of sonar such as frequency of ping and detecting error of target. The pursuit-tail guidance law showed the best performance among four different guidance laws. Complex motion of target from straight line to turning circle and zigzag movement, low frequency of sonar ping and large detecting error of target decreased the hitting probability.

• 한국정보통신학회논문지
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• 제16권11호
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• pp.2569-2574
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• 2012

초계함(천안함급)에 탑재 된 HMS(Hull Mount Sonar) 장비는 능동모드에 적합하도록 설계 되어 있다. 이에 센서 및 시스템 특성이 어뢰 탐지 주파수 대역에 적당하도록 구성되어 있지는 않다. 이에 초계함에 장착 된 기존 HMS 장비를 이용한 어뢰탐지 기능 구현을 위하여, 초계함 함 별 입력 특성을 분석하고, 입력 주파수 신호에 대한 역보상 회로 설계, 입력 신호 크기에 따른 AGC(Auto Gain Control) 기능 구현 및 함별 신호특성에 따른 대역설정 기능을 통하여 함정 별 특성 및 운용환경 특성에 맞는 어뢰방어시스템을 구현하였다.