• Journal of Institute of Control, Robotics and Systems
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• v.18 no.6
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• pp.594-600
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• 2012

Accurate localization is very important to stable navigation of a mobile robot. This paper deals with local localization of a mobile robot especially for outdoor environments. The GPS information is the easiest way to obtain the outdoor position information. However, the GPS accuracy can be severely affected by environmental conditions. To deal with this problem, the GPS and wheel odometry can be combined using an EKF (Extended Kalman Filter). However, this is not enough for safe navigation of a mobile robot in outdoor environments. This paper proposes a novel method using lane features from the road image. The pose data of a mobile robot can be corrected by analyzing the detected lane features. This can improve the accuracy of the localization process substantially.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.517-522
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• 2011

Global Navagation Satellite System(GNSS) is divided into Local Area Differential GNSS and Wide Area Differential GNSS. Wide Area DGNSS has more complicated structure and massage type. And transfer rate is limited, so efficient message scheduling algorithm is needed to guarantee user's accuracy and integrity. There are about 30 message types in Wide Area DGNSS. Each message type has different update interval. In this paper, the performances of message scheduling algorithm for Wide Area Differential GNSS are investigated. For all message types, results show that max update time interval requirement is satisfied.

• The Journal of Korea Robotics Society
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• v.15 no.3
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• pp.277-285
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• 2020

A differential drive wheeled robot is a kind of mobile robot suitable for indoor navigation. Model predictive control is an optimal control technique with various advantages and can achieve excellent performance. One of the main advantages of model predictive control is that it can easily handle constraints. Therefore, it deals with realistic constraints of the mobile robot and achieves admirable performance for trajectory tracking. In addition, the intention of the robot can be properly realized by adjusting the weight of the cost function component. This control technique is applied to the local planner of the navigation component so that the mobile robot can operate in real environment. Using the Robot Operating System (ROS), which has transcendent advantages in robot development, we have ensured that the algorithm works in the simulation and real experiment.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1636-1645
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• 2016

In navigation systems that use collected trajectory for routing, the number and diversity of trajectory data are crucial despite the infeasible limitation which is that all routes should be collected in person. This paper suggests an algorithm combining trajectories only by collected GPS data and generating new routes for solving this problem. Using distance between two trajectories, the algorithm estimates road intersection, in which it also predicts the correlated direction of them with geographical coordinates and makes a decision to combine them by the correlated direction. With combined and generated trajectory data, this combination way allows trajectory-based navigation to guide more and better routes. In our study, this solution has been introduced. However, the ways in which correlated direction is decided and post-process works have been revised to use the sequential pattern of triangles' area GPS information between two trajectories makes in road intersection and intersection among sets comprised of GPS points. This, as a result, reduces unnecessary combinations resulting redundant outputs and enhances the accuracy of estimating correlated direction than before.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.861-864
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• 2023

Recently, V2X (vehicle-to-everyting) communication has established itself as an essential technology for cooperative autonomous driving. V2X communication currently includes DSRC (dedicated short range communication) communication technology, which is a WLAN (wireless local area network) based communication technology, and C-V2X (cellular-V2X) communication technology, which is a Cellular-based communication technology. Since these two communication methods are not compatible with each other, various studies and experiments are being conducted to select one of the two communication methods. In the case of C-V2X communication, there are LTE-V2X (long term evolutionV2X) communication technology, which is an initial version, and 5G-V2X communication technology, which is a next-generation version. 5G-V2X communication technology has been completed only until standardization, so LTE-V2X communication technology is mainly used. In this paper, we introduce trends related to various issues in V2X communication, including communication method decisions.

• Journal of Sensor Science and Technology
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• v.33 no.5
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• pp.391-398
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• 2024

Accurate positioning is essential for unmanned underwater vehicle (UUV) operations, particularly for long-term survey missions. To reduce the inherent positioning errors from the inertial navigation systems of UUVs, or dead reckoning, underwater terrain observations from sonar sensors are typically exploited. Within the framework of pose-graph optimization, we can generate submaps of the seafloor and use them to add loop-closure constraints to the pose graph by determining the best match between the submaps. However, this approach results in error accumulation in long-term operations because the quality of local submaps depends on the dead reckoning. Hence, we can adopt external acoustic positioning systems, such as an ultrashort baseline (USBL), to add global constraints to the existing pose graph. We assume that the acoustic transponder is installed on a UUV and that the acoustic transceiver is equipped in an unmanned surface vehicle trailing the UUV to maintain an acoustic connection between the vehicles. We simulate the terrain and USBL measurements as well as evaluate the performance of the UUV's pose estimation via online pose-graph optimization.

• Journal of Navigation and Port Research
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• v.27 no.3
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• pp.345-349
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• 2003

A theme park is a tourism destination attracting a lot of tourists. Many local authorities establish theme parks within their own territory. Busan Metropolitan City tries to host an attractive theme park, and to make the city known as the tourism destination for 21st century. The purpose of this paper is to suggest a policy and management strategy of theme park based on questionnaire analysis for international tourists visiting Busan. First, it is needed to supply low land price to reduce construction cost and to attract investors from the public and private sectors. Second, the theme park has to have attractive themes and new events for repeaters. Third, infra structures related to the theme parks should be provided for the easy accessibility. Finally more emphasis should be placed on public relation and service education for employees.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1348-1351
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• 1997

The federated Kaman filter(FKF) is being widely used in many multisensor navigatiion systems. It is know that the FKF has advantages of simplicity and fault-tolerance over other decentralized filter techniques. In this paper, optimal and suboptimal FKF configuratiions are mentioned and a covariance analysis technique for the suboptimal FKF is newly presented. The suboptimal FKF configuration, known as No-reset(NR) mode, has better fault tolerance capability than the optimal FKF coniguratioin. In the suggested technique, a suboptimal fusion process of FKF is considered a swell as suboptimal gains of local filters. An upper boun of error covariance for suboptimal FKF is derived. Also, it is mathematically shown that this bound is smaller thanexisting bound in the literatrue. A vehicle-navigaion system is designed using the FKF. In thissystem, a map constraing equation is introduced and used as a measurement equatioin of Kalman filter. Performance analysis is done by the suggested covariance analysis techniques.

• Journal of Navigation and Port Research
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• v.39 no.5
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• pp.417-422
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• 2015

Sea-ports in Northern Vietnam have experienced a rapid growth of container throughput in recent years. To accompany with such development, huge investment also has been performed to enhance not only local port capacity but also the regional logistics system. Container terminals in Northern Vietnam locate centrally along Cam river of Haiphong city, leaving 2 others in Quang Ninh province. Five out of totally 11 container terminals in the area are under the control of Vinalines - a national corporation in field of maritime industry. In this paper, those terminals are classified in terms of location and ownership. The volume of container throughput and facilities of all container terminals in Northern Vietnam from 2005 to 2014 are recorded in order to compare the performance of groups. A Data Envelopment Analysis (DEA) is then applied to evaluate the relative efficiency of such terminals. Before conclusion, number of suggestions will be contributed to related parties.

• Journal of Navigation and Port Research
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• v.37 no.3
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• pp.315-320
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• 2013

According to climate change, deficiency of usable land, large water portion of the Earth surface, and improvement of income level, floating architecture is emerging as a strong & attractive alternative. The aim of this study is to suggest some related applying ways for new building projects around waterside. New paradigm of architecture can be described as a new model and/or system of architecture with new concept and Zeitgeist like sustainability and green building. Floating building is already a new paradigm of architecture comparing with the preconception of building only on the land and current building regulations. New paradigm features from the sample projects can be summarized as new concepts of building, application of various renewable energy resources(water, solar, wind), modular construction, use of local raw material, dual purpose usage, long term and relocatable usage, and special building materials for green building.