• Journal of The Korean Association of Information Education
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• v.2 no.2
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• pp.252-259
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• 1998

Vehicle navigation systems employ a certain route planning algorithm that provides the shortest path between the starting point and the destination point. The performance of a given route planning algorithm is measured through the degree of optimal route selection and the time cost to complete searching an optimal path. In this paper, various route planning algorithms are evaluated through computer simulation based on a real digital map database. Among those algorithms evaluated in this paper, the Modified Bi-directional A${\ast}$ algorithm is found to be the best algorithm for use in vehicle navigation systems.

• Journal of the Korea Convergence Society
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• v.2 no.2
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• pp.7-12
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• 2011

In this study, we investigate on location optimization algorithm of radio-navigation transmitter. The DOP for an each receiver is decided by the location of a transmitter. We provide various results that give an optimum DOP according to propagation characteristics. We use the DTED(Digital Terrain Elevation Data) to improve the accuracy.

• 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.

• 한국지형공간정보학회:학술대회논문집
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• 1995.10b
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• pp.33-40
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• 1995

In this paper, we developed the prototype of Car Navigation Information System which uses GPS to determine the current location. Car Navigation Information System is the one which can determine and display the current location and direction through the display monitor, search the destination point, calculate and check out the shortest path to the destination. The system we developed can determine the current location using GPS data, search the destination point in various ways, calculate the shortest path, serve the driver all the above mentioned data, and display the raster and vector data. To testify the system, we made the vectorized data about Taejeon area. Then we testified the system performance by installing the system to the notebook computer.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.267-267
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• 2019

The purpose of this study is to understand the risk of chemical product, Styrene Monomer(SM), shipped in a vessel. SM is harmful chemical product which can make injury, explosion and/or fire in a vessel. The understand of SM risk is very important to protect seafarer's body and vessel safety. This research can be expected that the understanding of SM risk by a seafarer's to prevent accidents by SM explosion/fire. In this study we used event tree analysis method using chemical reaction cased by explosion. As a result, we founded various chemical reaction and visualization for explosion path.

• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.304-311
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• 2022

Although the SEAD(suppression to enemy air defenses) mission is a strategically important task in modern warfare, the high risk of direct exposure to enemy air defense assets forces to use of unmanned aerial vehicles. this paper proposes a path planning algorithm for SEAD mission for an unmanned aerial vehicle and a method for calculating the mission effectiveness on the planned path. Based on the RRT-based path planning algorithm, a low-altitude ingress/egress flight path that can consider the enemy's short-range air defense threat was generated. The Dubins path-based Intercept path planning technique was used to generate a path that is the shortest path while avoiding the enemy's short-range anti-aircraft threat as much as possible. The ingress/intercept/egress paths were connected in order. In addition, mission effectiveness consisting of fuel consumption, the survival probability, the time required to perform the mission, and the target destruction probability was calculated based on the generated path. The proposed techniques were verified through a scenario.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.663-668
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• 2010

In driving a car, turns such as left turns, right turns, or u-turns, make the speed of the car decrease considerably. A more straight path, therefore, is probably faster to arrive at the destination than zig-zag path with same distance. In this paper, we have newly proposed the turn heuristic to make more straight path. The path navigation algorithm with turn heuristic(called as TA* algorithm) could enhance the straightness of a path by putting the turned-edges to the turn cost. It requires higher cost to use TA* algorithm than traditional A* algorithm because the straight-edge first searching have increased the search space. We have improved the TA* algorithm into the variable TA* algorithm(called as VTA* algorithm) which adopt the turn-heuristic during the a portion of the whole path.

• Journal of Positioning, Navigation, and Timing
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• v.2 no.2
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• pp.115-121
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• 2013

For the auto-landing operation of an air vehicle, the possibility of auto-landing operation should be first evaluated by testing the navigation performance through a flight test. In general, navigation performance is tested by analyzing north/east/down (NED) errors relative to reference equipment whose precision is about 8~10 times higher than that of a navigation system. However, to evaluate the auto-landing operation of an air vehicle, whether the air vehicle approaches a glide path aligned with the runway, within a specific error, needs to be examined rather than examining the north/east errors of the navigation system. Therefore, the longitudinal/lateral errors of air vehicle heading need to be analyzed. In this study, a method for analyzing the longitudinal/lateral errors of a navigation system was proposed as the navigation performance test method for evaluating the safety during the auto-landing of an air vehicle. Also, flight tests were performed six times, and the safety of auto-landing was examined by analyzing the performance using the proposed method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.827-830
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• 2008

The Center Based Navigation System(CBNS) used real time road data searches an optimal path. The other hand, the Terminal Based Navigation System(TBNS) used embedded road data searches a path that has less qualitative than the CBNS. But the TBNS has been favored, because it has no additional fees. Generally, TBNS has not used real time road data but it is recently able to use it with technique such as TPEG. However, it causes to increase a cost of exploring by using real time road data for improvement qualify of a path, because of limited performance. We propose a path-finding algorithm using a Maximum peed Dynamic Heuristic to improve quality and reduce a cost of exploring. Proposed method is to use a maximum road speed of appropriate region as dynamic heuristic for path-finding.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.4006-4011
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• 2013

Reverse parking guidance system help driver's safe reverse parking with display of the expected reverse path of the car on portable navigation device or rear-view camera display. In this paper, we suggest a reverse path prediction method of vehicle which reflect the differences in steering angle according to various types of vehicles and calibrate easily the distance error according to the property and the installation position of rear-view camera and we developed reverse parking guidance system with the our reverse path prediction method. This system can be applied to various types of vehicles, a variety of characteristics and installation of rear-view camera and navigation support systems, or portable devices are compatible and easily detachable, can be configured easily.