• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.1
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• pp.67-76
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• 2011

An exact curved path has to be fixed and velocity profile for travelling on the curved path is required by a moving stage. In this study, we decide the curved path on the basis of the information on three point locations. The path of the moving stage is traced by simulating the designed curve path and the velocity profile, and the results are compared with the given three points to determine how closely the moving stage follows the given path. Further, we propose a method to calibrate a curved path and velocity profile. The proposed moving paths were evaluated by performing experiments. Finally, the designed curved path and the actual path were compared.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.4
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• pp.81-90
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• 2016

As an autonomous driving vehicle (AV) need to cope with external road conditions by itself, its perception performance for road environment should be better than that of a human driver. A vision sensor, one of AV sensors, performs lane detection function to percept road environment for performing safe vehicle steering, which relates to define vehicle heading and lane departure prevention. Performance standards for a vision sensor in an ADAS(Advanced Driver Assistance System) focus on the function of 'driver assistance', not on the perception of 'independent situation'. So the performance requirements for a vision sensor in AV may different from those in an ADAS. In assuming that an AV keep previous steering due to lane detection failure, this study calculated lane departure distances between the AV location following curved road alignment and the other one driving to the straight in a curved section. We analysed lane departure distance and time with respect to the allowance of lane detection malfunction of an AV vision sensor. With the results, we found that an AV would encounter a critical lane departure situation if a vision sensor loses lane detection over 1 second. Therefore, it is concluded that the performance standards for an AV should contain more severe lane departure situations than those of an ADAS.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.2
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• pp.180-187
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• 2010

In this paper, a GNSS-based AGV system was designed, and steering tested on a golf cart using electric wires in order to confirm the control efficiency of the low speed vehicle which used only position information of GNSS. After analyzed the existing AGVs system, we developed controller and steering algorithm using GNSS based position information. To analyze the performance of the developed controller and steering algorithm, straight-type and circle-type trajectory test are executed. The results show that steering performance of GNSS-based AGV system is ${\pm}\;0.2m$ for a reference trajectory.

• The Journal of the Acoustical Society of Korea
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• v.40 no.6
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• pp.546-554
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• 2021

In the signal processing of synthetic aperture sonar, it is subject that the platform in which the sensor array is installed moves along the straight line path. In practical operation in underwater, however, the sensor platform will have trajectory disturbances, diverting from the line path. It causes phase errors in measured signals and then produces deteriorated SAS images. In this study, in order to develop towed SAS, as tools to remove the phase errors associated with the trajectory disturbances of the towfish, motion compensation technique using Redundant Phase Center (RPC) and also Phase Gradient Autofocus (PGA) method is investigated. The performances of these two approaches are examined by means of a simulation for SAS system having a sway disturbance.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.2
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• pp.68-78
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• 2000

This paper suggests a new map-matching algorithm for matching traveling trace of vehicle, which is measured by GPS receiver, to the road of a digital map This eventually brings the Improvement of positioning accuracy of the vehicle with GPS receiver After representing the travelling vehicle's motion by state equations using Singer's model, the proposed map-matching algorithm places the position of a vehicle right on the road and also improves the positioning accuracy of the vehicle using a Kalman filter In the crossroad, since it is difficult to determine precisely a current travelling road, we take linear regression to the estimated values from Kalman filtering This gives the direction angle of turning vehicle, then we can determine the correct route direction after comparing with each route-direction angle at the intersection.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.5
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• pp.183-193
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• 2019

This study developed a shockwave detection and prediction of their extinction point method based on continuous wavelet transform using trajectory data from probe vehicles equipped with automotive sensors.. To analyze the effectiveness of the proposed method, this paper proposed two measures which are a distance error between the extinction points of the predictor and an time-location error of the extinction points. The proposed concept was proved using the micro simulation based experiment with three exogenous variables of traffic volume, lane-close duration, market penetration of probe vehicles. The analysis results show that the proposed method is capable of detecting the traffic shockwaves as well as predicting their extinction point, and also that the accuracy of the proposed method is highly dependent on the rate of the probe vehicles.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.4
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• pp.14-27
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• 2009

Collection of invaluable real-time traffic data becomes available under ubiquitous transportation sensor networks (UTSN). Various research efforts have been made to utilize such useful data for deriving more accurate and reliable traffic information. This study presented a novel concept of decentralized traffic information and method to process traffic data which are obtained from inter-vehicle communications under the UTSN. In addition, an experimental evaluation to investigate the feasibility of the proposed method using probe vehicle data. Predictive travel times were estimated and evaluated for the feasibility investigation. Technical issues were derived and discussed to fully implement the proposed system. The outcomes of this study would be used as a guideline in designing better next-generation traffic information systems.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.6
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• pp.33-42
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• 2010

Travel speed is an important parameter in measurement of road traffic. UTIS(Urban Traffic Information System) was developed as a type of section detector. However, UTIS incur errors caused by irregular vehicle trajectories, wireless communication range and so on. This paper suggests a new model that use an error-filtering algorithm to improve the accuracy of travel speed measurements. In the field test, the variance of the percent errors measured by the new model was reduced. Therefore, it can be concluded that the proposed model significantly improves travel speed measuring accuracy.

• Journal of Advanced Navigation Technology
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• v.23 no.6
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• pp.515-521
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• 2019

The C-ITS requires the lane level positioning of the vehicle in the land transportation environment, and it is most effective to utilize the global navigation satellite system. In the precision positioning system based on satellite navigation, the evaluation of dynamic environment of lane level positioning performance should be accompanied and the evaluation system configuration should be preceded. In addition, performance analysis must be performed according to various environments that change according to traffic or road conditions in a dynamic environment. In this paper, we describe with the performance of traffic and road environment through the evaluation system of lane positioning precision positioning user system based on satellite navigation system. The numerical performance evaluation was carried out based on the data collected by carrying out the actual driving. The performance evaluation by the actual driving trajectory and driving image comparison was performed to derive and analyse evaluation results of positioning performance according to driving condition.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.54-66
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• 2018

In this study, vehicle speeds at acceleration and deceleration lanes of rest areas for drowsy drivers were investigated to analyze effects of acceleration and deceleration lane lengths, grades and curve radius. In addition, we used VISSM to analyze proper lengths of rest area's acceleration and deceleration lanes. Several VISSIM scenarios with different lengths of acceleration and deceleration lane were constructed. Through VISSIM simulation, we collected individual vehicle speed data to analyze speed changes by different lengths of acceleration and deceleration lanes. As a result of the vehicle speed change investigation, grades and curve radii of the rest area affected the speed, most of all lengths of acceleration and deceleration lane showed a great effect on the vehicle speed. In the case of short lengths of acceleration and deceleration lane, speed variation among vehicles was significant. If the deceleration lane length is short, the vehicle enters a state in which the speed is not sufficiently reduced, and if the acceleration lane length is short, the vehicle enters a state in which the speed is not sufficiently accelerated showing high risks of conflicts and accidents. It is recommended that 245m length of deceleration lane and 370m length of acceleration lane should be installed at least to secure safety and manage conflicts relevantly.