• Journal of Positioning, Navigation, and Timing
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• v.4 no.3
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• pp.97-105
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• 2015

A navigation signal based on orthogonal tiered polyphase code was proposed. For the proposed signal, tiered polyphase code was used as the code of a pilot channel. Tiered polyphase code is a complex number type code, and thus the pilot channel and data channel were separated using the Walsh code which makes the correlation between different codes become 0. The results of the simulation indicated that the correlation characteristics and signal acquisition performance of the proposed signal were identical to those of tiered polyphase code, and that the disadvantage of tiered polyphase code could be supplemented through a data channel in terms of signal tracking.

• Journal of the Korea Society of Computer and Information
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• v.23 no.8
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• pp.95-99
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• 2018

This research is related to GPS(global positioning system) enabled device navigation service and consists of two parts. The first is the logic that records the route guidance video and records GPS information in time, and the second is the logic that outputs the created video data based on real time GPS. The recording logic first determines the origin and destination, records the video from the origin to the destination and it adjusts the speed of the image in a specific area so that the user can see it easily. And insert ancillary information and advertisements that can help guide the route. In the output logic, we provide navigation services using the video and GPS data tables we created, and it receives user's GPS information in real time and corrects it based on the recent user location to reduce errors. This provides local guidance services to people who lack language skills like foreigners.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.10 no.4
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• pp.281-286
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• 2010

We propose a space and time based sensor fusion method and a robust landmark detecting algorithm based on sensor fusion for mobile robot navigation. To fully utilize the information from the sensors, first, this paper proposes a new sensor-fusion technique where the data sets for the previous moments are properly transformed and fused into the current data sets to enable an accurate measurement. Exploration of an unknown environment is an important task for the new generation of mobile robots. The mobile robots may navigate by means of a number of monitoring systems such as the sonar-sensing system or the visual-sensing system. The newly proposed, STSF (Space and Time Sensor Fusion) scheme is applied to landmark recognition for mobile robot navigation in an unstructured environment as well as structured environment, and the experimental results demonstrate the performances of the landmark recognition.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1998.10b
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• pp.65-73
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• 1998

Ship's positino data obtaining method is ine of the very important factor innavigation . Nowadays, GPS(Global Positioning System) using the earth orbiting satellites are equipped and operated for the position finding. Because it provides more precise position information than other equipments and is very convenient for navigator. In this study, it is designed to develop the GPS simulator for everybody being able to proactise the GPS operating skill like as navigation planning, navigation calculating etc. And also, it can be operated with personal computer without real GPS receiver. This simulation system is based on the real GPS receiver system and built by the visual basic 5.0 program. And it displays the ship's position and navigating information and plots the ship's moving track on the screen in real time according as initial setup data-main engine's rpm, rudder angle, depature position and waypoint.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.11
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• pp.79-90
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• 2003

In this paper, we propose a multisensor-based navigation algorithm for a mobile robot, which is intelligently searching the goal location in unknown dynamic environments using multi-ultrasonic sensor. Instead of using “sensor fusion” method which generates the trajectory of a robot based upon the environment model and sensory data, “command fusion” method by fuzzy inference is used to govern the robot motions. The major factors for robot navigation are represented as a cost function. Using the data of the robot states and the environment, the weight value of each factor using fuzzy inference is determined for an optimal trajectory in dynamic environments. For the evaluation of the proposed algorithm, we performed simulations in PC as well as experiments with IRL-2002. The results show that the proposed algorithm is apt to identify obstacles in unknown environments to guide the robot to the goal location safely.

• International Journal of Ocean System Engineering
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• v.1 no.2
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• pp.102-109
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• 2011

This paper describes the implementation of a precise underwater navigation solution using a multiple sensor fusion technique based on USBL, GPS, DVL and AHRS measurements for the operation of a remotely operated mine disposal vehicle (MDV). The estimation of accurate 6DOF positions and attitudes is the key factor in executing dangerous and complicated missions. To implement the precise underwater navigation, two strategies are chosen in this paper. Firstly, the sensor frame alignment to the body frame is conducted to enhance the performance of a standalone dead-reckoning algorithm. Secondly, absolute position data measured by USBL is fused to prevent cumulative integration error. The heading alignment error is identified by comparing the measured absolute positions with the DR algorithm results. The performance of the developed approach is evaluated with the experimental data acquired by MDV in the South-sea trial.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.458-458
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• 2000

Quick evaluations of two in-plane orbit maneuvers using small see of real-time CPS navigation solutions were peformed lot the KOMPSAT-1 spacecraft operation. Real-time GPS navigation solutions of the KOMPSAT-1 were collected during the Korean Ground Station(KGS) pass. Only a few sets of position and velocity data after completion of the thruster firing were used for the quick maneuver evaluations. The results were used for antenna pointing data predictions for the next station contact. Normal orbit maneuver evaluations using large see of playback GPS navigation solutions were also performed and the result were compared with the quick evaluation results.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.247-250
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• 2006

Integrating a GPS based vehicle navigation system and the latest optimal algorithms, this research aims to develop a real-time decision support platform for concrete plant to provide the optimal solutions for ready mixed concrete delivery. The platform includes fleet tracking system, simulation and optimization tools, and visual interface which is useful to monitor delivery progress, to obtain crucial historical and real-time data for simulation, and to improve the efficiency of the plant operation. This paper presents configuration of the system and performance evaluation based on operational data.

• Journal of Navigation and Port Research
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• v.43 no.5
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• pp.302-309
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• 2019

This study introduces the navigational environment database(DB) compiling water depth, sediment type and marine managed areas (MMAs) in coastal waters of South Korea. The water depth and sediment data were constructed by combining their sparse points of electronic navigation chart and survey data with high spatial resolution using the inverse distance weighting and natural neighbor interpolation method included in ArcGIS. The MMAs were integrated based on all shapefiles provided by several government agencies using ArcGIS because the areas should be used in an emergency case of ship. To test the validity of the constructed DB, we conducted a test application for grounding and anchoring zones using a ship accident case. The result revealed each area of possible grounding candidates and anchorages is calculated and displayed properly, excluding obstacle places.

• Journal of Ocean Engineering and Technology
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• v.31 no.4
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• pp.315-323
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• 2017

This paper presents an integrated navigation system that combines ultra-short baseline (USBL), Doppler velocity log (DVL), and heading measurements for a deep-sea remotely operated vehicle, Hemire. A navigation model is introduced based on the kinematic relation of the position and velocity. The system states are predicted using the navigation model and corrected with the USBL, DVL, and heading measurements using the Kalman filter. The performance of the navigation system was confirmed through re-navigation simulations with the measured data at the Southern Mariana Arc submarine volcanoes. Based on the characteristics of the measurements, the design process for the parameters of the system modeling error covariance, measurement error covariance, and initial error covariance are presented. This paper reviews the influence of the outliers and blackout of the USBL and DVL measurements, and proposes an outlier rejection algorithm that is robust to USBL blackout. The effectiveness of the method is demonstrated with re-navigation for the data that includes USBL blackouts.