• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.152-153
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• 2005

Side scan sonar System occupies an important position as one of marine survey equipments. The purpose of this research is to express sonar' scan images in underwater and compare with the measured size, shape and the quality of the material. Also we confirm the effectiveness of obtained images using the Side scan sonar.

• 센서학회지
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• 제17권1호
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• pp.53-60
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• 2008

Localization is the most important functions in mobile robots. There are so many approaches to realize this essential function in wheel based mobile robots, but it is not easy to find similar examples in small underwater robots. It is presented the sonar localization system using ubiquitous sensor network for a fish robot in this paper. A fish robot uses GPS and sonar system to find exact localization. Although GPS is essential tool to obtain positional information, this device doesn't provide reasonable resolution in localization. To obtain more precise localization information, we use several Ubiquitous Sensor Networks (USN) motes with sonar system. Experimental results show that a fish robot obtains more detailed positional information.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.961-964
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• 2016

본 논문은 쏘나 영상 촬영을 위한 무인자율항법(AUSV Autonomous Unmanned Surface Vehicle) 시스템 개발에 관한 연구이다. 자율항법 시스템은 선체에 모션센서, DGPS에 의한 현재 경위도 좌표와 목표지 경위도 좌표의 차를 가지고 선체의 추진체(Thrusters)를 FF-PID 알고리즘으로 제어한다. 실험결과, 목적지 좌표에 대한 제어좌표 오차는 전체 항법거리 1km 에서 6 meter 이하이며, 자율항법 모드에서의 Sonar Image 촬영 결과물은 유인선 촬영 결과물과의 차이는 12 pixel 이하로 전체 영상 차이는 거의 식별할 수 없이 동일하다. 개발된 시스템은 유인선으로 촬영 불가능한 해저 지형에 대한 Sonar Image 촬영을 위한 새로운 방법으로 활용 가능하다.

• 한국지구과학회지
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• 제24권5호
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• pp.467-476
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• 2003

사이드 스캔 소-나를 이용한 해저면 음향영상자료의 처리과정에서 가장 첫 번째 단계는 수중예인체의 절대위치를 결정하는 것이다. 예인체를 조사선박에 부착하지 않고 후미에서 수중예인하기 때문이다. 수중에서 음향을 이용하여 위치를 추적하는 장치나 예인체의 움직임을 관측하는 추가적인 지원장비 없이도 절대위치를 계산할 수 있는 기술적인 알고리즘이 제안되었다. 예인항적으로 작성된 모자이크 결과도면에서, 인접한 측선 간의 불일치나 모호하게 접합되는 해저형태를 발견할 수 없었다. 절대위치 계산과정에서 수중예인체의 진행방향이 부드럽게 되는 부차적인 효과가 있다. 그 결과 진행방향에 대하여 수직으로 분포하는 영상자료의 펼침형태가 안정적으로 배열되며 음향조사역(音響照射域)의 평면투영에서 자료의 유실현상도 현저하게 줄어든다. 수중에서 예인하는 방식의 다른 분야 해양조사에서도 이 연구결과의 적절한활용이 기대된다.

• 한국군사과학기술학회지
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• 제21권1호
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• pp.40-46
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• 2018

In order to successfully detect and identify underwater targets located on the seabed, unmanned surface vehicles (USVs) typically acquire acoustic signals with a side-scan sonar device and reconstruct information about the target from the processed images. As the quality of the side-scan sonar images acquired by USVs depends on the environment and operating parameters, using modeling and simulation techniques to design side-scan sonar devices can help optimize the reconstruction of the sonar images. In this work, we study a side-scan sonar design for use in USVs, that takes the movement of the platform into account. First, we constructed a simulated seabed environment with underwater targets, and specified the maneuvering conditions and sonar systems. We then generated the acoustic signals from the simulated environment using the sonar equation. Finally, we successfully imaged the simulated seabed environment using simple signal processing. Our results can be used to derive USV side-scan sonar design parameters, predict the resulting sonar images in various conditions, and as a basis for determining the optimal sonar parameters of the system.

• 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.

• 한국군사과학기술학회지
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• 제15권3호
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• pp.272-287
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• 2012

The optimal use of sonar systems for detection is a practical problem in a given ocean environment. In order to quantify the mission achievability in general, measure of effectiveness(MOE) is defined for specific missions. In this paper, using the specific MOE for detection, which is represented as cumulative detection probability(CDP), an integrated software package named as Optimal Acoustic Search Path Planning(OASPP) is developed. For a given ocean environment and sonar systems, the discrete observations for detection probability(PD) are used to calculate CDP incorporating sonar and environmental parameters. Also, counter-detection probability is considered for vulnerability analysis for a given scenario. Through modeling and simulation for a simple case for which an intuitive solution is known, the developed code is verified.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.575-576
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• 2014

The Hull Mounted Sonar Dome housing the sonar sensor array is a ship's structure protruded from ship bottom, which is under turbulent flow. The flow of sonar surface is highly disturbed and turbulent. In this case the wall pressure fluctuations within the turbulent boundary layer are one of the most important flow induced self noise sources of the SONAR system. We investigate the characteristics of the wall pressure fluctuations of the hull mounted sonar dome through the model test in the cavitation tunnel. This paper contains the wall pressure fluctuation spectra at various free stream velocities.

• 한국음향학회지
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• 제39권6호
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• pp.541-548
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• 2020

수상함용 선체부착형소나의 한계를 극복하기 위해서 해상작전헬기용 디핑소나를 많은 나라에서 운용중이다. 디핑소나는 탐지거리가 짧지만 수상함의 생존성을 보장하고, 해양환경에 따라 심도를 조절하여 탐지성능을 향상시킬 수 있는 장점이 있다. 본 논문에서는 최적화 알고리즘을 적용하여 해상작전헬기용 디핑소나의 최적심도를 산출하는 방법을 제안하였다. 또한, 소나의 성능을 평가하기 위해 해양환경, 표적의 심도, 디핑소나의 심도를 고려하도록 소나성 능함수를 정의하였다. 계산시간 단축을 위해 최적화 알고리즘중 하나인 Simulated Annealing(SA)를 적용하여 최적 심도를 산출하였다. 알고리즘의 정확도 검증을 위하여 최적화 기법을 적용하여 산출한 최적심도를 목적함수 계산 결과와 비교하였다. 또한, 우리나라 동해해역에서 해양환경에 따른 최적심도를 산출하였다.

• 로봇학회논문지
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• 제16권2호
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• pp.94-102
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• 2021

This study addresses a method for 3D reconstruction using acoustic data with heterogeneous sonar devices: Forward-Looking Multibeam Sonar (FLMS) and Profiling Sonar (PS). The challenges in sonar image processing are perceptual ambiguity, the loss of elevation information, and low signal to noise ratio, which are caused by the ranging and intensity-based image generation mechanism of sonars. The conventional approaches utilize additional constraints such as Lambertian reflection and redundant data at various positions, but they are vulnerable to environmental conditions. Our approach is to use two sonars that have a complementary data type. Typically, the sonars provide reliable information in the horizontal but, the loss of elevation information degrades the quality of data in the vertical. To overcome the characteristic of sonar devices, we adopt the crossed installation in such a way that the PS is laid down on its side and mounted on the top of FLMS. From the installation, FLMS scans horizontal information and PS obtains a vertical profile of the front area of AUV. For the fusion of the two sonar data, we propose the probabilistic approach. A likelihood map using geometric constraints between two sonar devices is built and a monte-carlo experiment using a derived model is conducted to extract 3D points. To verify the proposed method, we conducted a simulation and field test. As a result, a consistent seabed map was obtained. This method can be utilized for 3D seabed mapping with an AUV.