• Journal of Navigation and Port Research
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• v.26 no.1
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• pp.35-42
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• 2002

The roles and importance of the application of simulator in harbor and waterway design are emphasized. On this paper Different methods of simulation and their application are described. A large-scale simulation concept, group simulation, is proposed. Requirements of the simulation for accomplishing the tasks properly and effectively are suggested. Some points on modeling of ship hydrodynamics and environmental factors. which are critical especially in waterway desing simulation, are discussed and algorisms presented.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.89-92
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• 2005

This paper describes a system for LNG carrier's loading and discharging work education This system consists of three modules(cargo work simulation, ballast work simulation and loading calculation module), and could be a useful to train mariners boarding on LNG carrier so as to take a suitable action while their ship maneuvering and cargo handling.

• The Journal of Korea Robotics Society
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• v.15 no.1
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• pp.24-31
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• 2020

Alternative navigation in underwater environments is essential to prevent accumulating drift error of dead reckoning. In case of using an external positioning system, the installation and management process of the transmission station is cumbersome, and the operation range of underwater vehicle is limited. In order to solve this problem, navigation using geophysical information such as terrain, geomagnetic field and gravity can be used. Unlike the terrain, geomagnetic field and gravity are composed of 3-D information, so continuation process is required. In this paper, we present a integrated navigation algorithm using multiple geophysical information for long-term operation of UUV. The proposed algorithm is verified through numerical simulation in an artificially generated environments. As a result, integrated navigation showed higher navigation accuracy than single alternative navigation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.108-114
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• 2014

This paper proposes a generation method of a navigation guidance direction and a fuzzy controller to achieve the autonomous navigation of a mobile robot using a particle swarm optimization(PSO) scheme in unknown environments. The proposed navigation guidance direction is the direction that leads a mobile robot to arrive a target point simultaneously with avoiding obstacles efficiently according to the surrounding local informations. It is generated by selecting the most suitable direction of the many directions in the surrounding environment using a particle swarm optimization scheme. Also, a robot can reach a target point with avoiding the various obstacles by controlling the robot so that it can move from its current orientation to the navigation guidance direction using the proposed fuzzy controller. Simulation results are presented to show the feasibility and validity of the proposed robot navigation scheme.

• Journal of Navigation and Port Research
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• v.43 no.6
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• pp.429-436
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• 2019

The eLoran system is considered the best alternative because the vulnerability of satellite navigation systems cannot be resolved as perfect. Thus, South Korea is in the process of establishing a testbed of the eLoran system in the West Sea. To provide resilient navigation services to all waters, additional eLoran transmitters are required. However, it is difficult to establish eLoran transmitters because of various practical reasons. Instead, the positioning with NDGNSS/AIS source can expand the coverage and its algorithm with applying continuous waves is under development. Using the already operating NDGNSS reference station and the AIS base station, it is possible to operate the navigation system with higher accuracy than before. Thus, it is crucial to predict the performance when each system is integrated. In this paper, we have developed a simulation tool that can predict the performance of terrestrial integrated navigation system using the eLoran system, maritime NDGNSS station and the AIS station. The esitmated phase error of the received signal is calculated with the Cramer-Rao Lower Bound factoring the transmission power and the atmospheric noise according to the transmission frequency distributed by the ITU. Additionally, the simulation results are more accurate by estimating the annual mean atmospheric noise of the 300 kHz signal through the DGPS signal information collected from the maritime NDGNSS station. This approach can further increase the reliability of simulation results.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.2
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• pp.114-121
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• 2011

Introduction: The aim of this study was to demonstrate that the simulation surgery on rapid prototype (RP) model, which is based on the 3-dimensional computed tomography (3D CT) data taken before surgery, has the same accuracy as traditional orthograthic surgery with an intermediate splint, using an optoelectronic tracking navigation system. Materials and Methods: Simulation surgery with the same treatment plan as the Le Fort I osteotomy on the patient was done on a RP model based on the 3D CT data of 12 patients who had undergone a Le Fort I osteotomy in the department of oral and maxillofacial surgery, Seoul National University Dental Hospital. The 12 distances between 4 points on the skull, such as both infraorbital foramen and both supraorbital foramen, and 3 points on maxilla, such as the contact point of both maxillary central incisors and mesiobuccal cuspal tip of both maxillary first molars, were tracked using an optoelectronic tracking navigation system. The distances before surgery were compared to evaluate the accuracy of the RP model and the distance changes of 3D CT image after surgery were compared with those of the RP model after simulation surgery. Results: A paired t-test revealed a significant difference between the distances in the 3D CT image and RP model before surgery.(P<0.0001) On the other hand, Pearson's correlation coefficient, 0.995, revealed a significant positive correlation between the distances.(P<0.0001) There was a significant difference between the change in the distance of the 3D CT image and RP model in before and after surgery.(P<0.05) The Pearson's correlation coefficient was 0.13844, indicating positive correlation.(P<0.1) Conclusion: Theses results suggest that the simulation surgery of a Le Fort I osteotomy using an optoelectronic tracking navigation system I s relatively accurate in comparing the pre-, and post-operative 3D CT data. Furthermore, the application of an optoelectronic tracking navigation system may be a predictable and efficient method in Le Fort I orthognathic surgery.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.308-313
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• 1993

In this paper, the navigation computer design of RPV(remotely piloted vehicle) using GPS is investigated, and its hardware and software structures are described. The proposed hardware adopts the common PC configuration by using 5016A micro PC card and software is divided into several modules such as navigation module, guidance module and control module, etc. The performance of the navigation computer is verified through PILS(process in the loop simulation).

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.633-638
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• 1988

In this paper, a zero-velocity update technique to improve navigation accuracy of a SDINS(Strapdown Inertial Navigation System) has been studied. An indirect feedback Kalman filter which includes SDINS error equations based on a quaternion between body-fixed frame and local level navigation frame is employed for processing zero-velocity updates in an on-board navigation filter. Simulation results for land-mobile vehicle show that the zerovelocity update technique make a significant contribution to improving SDINS performance without any external aids.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.47-52
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• 2005

This paper describes how a relatively compensate the error of position by using low cost Inertial Measurement Unit (IMU) has been evaluated and compared with the well established method based on a Kalman Filter(KF). The compensation algorithm by using IMU have been applied to the problem of integrating information from an Inertial Navigation System (INS). The KF is to estimate and compensate the errors of an INS by using the integrated INS velocity and position. We verify the proposed algorithm by simulation results.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.788-797
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• 2023

In this paper, we introduced a test environment to test a vision-aided navigation system, as an alternative navigation system when global positioning system (GPS) is unavailable, for vertical take-off and landing (VTOL) unmanned aerial system. It is efficient to use a virtual environment to test and evaluate the vision-aided navigation system under development, but currently no suitable equipment has been developed in Korea. Thus, the proposed test environment is developed to evaluate the performance of the navigation system by generating input signal modeling and simulating operation environment of the system, and by monitoring output signal. This paper comprehensively describes research procedure from derivation of requirements specifications to hardware/software design according to the requirements, and production of the test environment. This test environment was used for evaluating the vision-aided navigation algorithm which we are developing, and conducting simulation based pre-flight tests.