• Journal of Advanced Marine Engineering and Technology
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• v.29 no.1
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• pp.124-131
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• 2005

This paper suggests LOS(Line-Of-Sight) guidance system of a surface vessel in straight-line navigation under ocean currents An LOS vector from the vessel to a point on the path between two way-points is decided and a heading angle is calculated to converge to follow the desired path based on the LOS vector This guidance system is called LOS guidance system. The suggested LOS guidance law has parameters to be properly chosen according to navigational environment. Parameters of LOS guidance system are optimized to reduce propulsive energy and/or position error between desired Position and present position of a ship using genetic algorithm which is a strong optimization algorithm with adaptational random search The effectiveness of the suggested LOS guidance system is assured through computer simulations.

• Journal of Satellite, Information and Communications
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• v.11 no.1
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• pp.21-25
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• 2016

In this paper, we propose an algorithm for optimal selection of communications for smart lighting in heterogeneous networks. The smart lighting can be used for information communications and lighting simultaneously. To improve BER performance of smart lighting in heterogeneous networks, it adaptively selects a communication method among OCC, Wi-Fi, BLE based on distance between sensors and smart lightings, low power consumption for user requirements, operating time of smart lighting in Line-of-Sight(LOS)/Non-LOS channels. Thus, simulation results demonstrate effectiveness of the proposed algorithm contrary to baseline methods in LOS/NLOS channels.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.100-102
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• 2023

항로추종성능은 자율운항선박(MASS)의 중요한 자율제어기능 중 하나이다. 이는 선박의 안전성을 보장하기 위해 중요하며, 자율운항선박의 설계 단계에서 사전 평가가 필수적이다. 본 연구는 자율운항선박의 항로추종성능 평가를 위한 전산유체역학(CFD) 모델과 LOS 알고리즘 연계 방안을 제안한다. 먼저, 자율운항선박의 정수 중 거리 이탈 편차를 이용한 항로 추종 성능 평가 모델 개발에 관하여 기술했다. 먼저, 항로 추종을 수행하는 선박 주변의 난류 흐름은 비압축성 뉴턴 유체의 가정하에 비정상 RANS(Reynolds Averaged Navier-Stokes) 법을 이용하여 수치적으로 계산되었다. 중첩격자계법을 CFD 모델에 적용함으로써 거리 이탈 편차를 이용하는 LOS(Line-of-Sight) 가이던스 알고리즘에 의한 타의 회전 및 이에 따른 선체의 6 자유도 움직임을 CFD 환경에서 구현하였다. 개발된 자유 항주 선박 CFD 모델을 이용하여 항로 추종 시뮬레이션 평가 결과, 설정된 항로에서 선박의 정수 중 항로 추종 제어는 파도, 조류, 및 바람과 같은 외부 교란의 부재로 LOS 알고리즘에 의한 우현/좌현 측 변침뿐만 아니라 직진 경로의 추종도 성공적으로 수행됨을 확인하였다. 선체, 프로펠러, 타의 복잡한 상호작용을 정도 높게 해석할 수 있는 자유 항주 선박 CFD 모델과 LOS 알고리즘의 결합은 자율운항선박의 항로 추종 성능 평가를 정량적으로 평가하는 데 기여할 것으로 기대된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.8
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• pp.1643-1654
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• 2015

With standardization of IEEE 802.11n, APs with the 2.4GHz and 5GHz dual-band capability have widely been deployed over a metropolitan area by individuals and internet service providers. Moreover, due to the increasing attentions on indoor-localization technique using Wi-Fi, the need for LOS and NLOS determination scheme is increasing to enhance accuracy of the localization. In this paper, we propose a novel LOS/NLOS determination technique by using different radio attenuation characteristics in different frequency bands and different mediums. Based on this technique, we designed a LOS/NLOS-aware indoor localization scheme. The proposed LOS/NLOS determination algorithm can be used when the distance between an user device and an AP is unknown, and the proposed localization scheme provides very accurate room-level position information. We validated the proposed scheme by implementing it on Android smart phones.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.10
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• pp.1395-1400
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• 2018

EO TGP(Electro-Optical Targeting Pod) is an optical tracking system which has various functions such as target tracking and image stabilization and LOS(Line of Sight) change. Especially, it is very important to move the LOS into a interest point for joystick command. When pilot move joystick in order to observe different scene, EO TGP gimbals should be operated properly. Generally, most EOTS just operate corresponding gimbal for joystick command. For example, if pilot input horizontal command in order to observe right hand screen, it just drive azimuth gimbal at any position. But in the screen, the image dosen't move in a horizontal direction because gimbal structure is Euler angle. And image rotation is occurred by elevation gimbal angle. So we need to move Pitch gimbal. So in the paper, we designed LOS moving algorithm which convert LOS command to gimbal velocity command to move LOS properly. We modeled a differential kinematic equation and then change the joystick command into velocity command of gimbals. This algorithm generate velocity command of each gimbal for same horizontal direction command. Finally, we verified performance through MATLAB/Simulink.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.1
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• pp.72-82
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• 2023

The EOTS(Electro Optical Tracking System) must have stabilization performance to provide high-quality images under disturbance environment. In this paper, we present a controller that can minimize the LOS error and has a simple structure. Hence, to evaluate the performance of this controller, analysis in the frequency domain and LOS error measurement are performed. In order to measure the LOS error without a 'rate table' that requires a lot of facility investment, we propose a design method for disturbance model that considers the operating environment of the EOTS. Finally, the performance of the stabilization algorithm is evaluated by the proposed disturbance model.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.873-875
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• 2008

In sensor network, the elimination of NLOS information is a necessity to improve the accuracy of the localization. For this reason, we proposed an algorithm iteratively eliminating the NLOS information to enhance the accuracy of the localization of a tag location, and simulated the proposed algorithm to confirm the performance. The proposed algorithm can estimate the location of the error distance within 3.5m when it has 10 LOS coordinates with LOS information. In addition, it can enhance the accuracy according to decreasing NLOS coordinates.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.359-362
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• 1996

The guidance system which uses the line-of-sight(LOS) rate to guide the missile towards its target has been used to the conventional differential game, such as the pursuer-evader game. Proportional navigation guidance and its derivatives have been shown to be an effective LOS rate guidance system. In this paper, we have used the genetic algorithm to construct the guidance system for the pursuer-evader type differential game. Also we have proposed the prediction model to obtain the informations about the intention of future actions of the pursuer and the evader.

• Journal of Advanced Navigation Technology
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• v.10 no.4
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• pp.385-393
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• 2006

In this paper, we proposed a location estimation algorithm considering an extension of searching area in 2.45GHz band RTLS and analyzed its performance in terms of an average estimation error distance. The extendable searching area was assumed to be square of $300m{\times}300m$ and 2 dimensions. The arrangement shape of available readers was considered circle, rectangle, and shrinkage rectangle for extendable searching area. Also, we assumed that propagation path was LOS (Line-Of-Sight) environment, and analyzed the estimation error performance as a function of the number of received sub-blink considering an arrangement shape of available readers in searching area. From the results, compared with rectangle shape, circle shape showed the higher estimation accuracy. Also, we confirmed that the proposed location estimation algorithm provided high estimation accuracy in the shrinkage rectangle shape that was suitable for extension of searching area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.7
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• pp.1524-1532
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• 2012

The calibration method using the existing environmental characteristics is to correct taking advantage of the data that is followed Judgement on the environment. If a decision is not made on the environmental judgement, the use of traditional methods may increase rather than errors. In this paper, UWB-based localization system is utilized. We propose Location Correction Algorithm which is available on if you can not make a judgment about any circumstances for location estimation system. Reference Points was selected to observe the characteristics of the localization system. This paper searched the characteristics of the localization system in LOS environment and NLOS environment, and used data correcting the location information of the moving object by combining the two environmental characteristics. The Location Correction Algorithm is applied to the location measured from the location estimation system. This algorithm corrects for the location information of the object. As a result, the location accuracy improvement were observed.