• 한국공간정보시스템학회:학술대회논문집
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• 2007.06a
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• pp.324-328
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• 2007

텔레매틱스 분야에서 가장 널리 서비스되고 있는 내비게이션 시스템의 최신 동향은 주행중 운전자의 정보 인지를 쉽게 하도록 하는 것이다. 실감 내비게이션 기술은 운전자의 시야와 동일한 전방 영상을 카메라로부터 획득하여 운전자에게 필요한 정보를 그 위에 오버레이하여 직접 전달하는 기술이다. 이러한 실감 내비게이션을 위하여 기존 방식과는 다른 빠르고 효과적인 정보전달 방식이 필요하며, 어떤 정보를 사용자에게 어떻게 전달하느냐에 따라 다른 효과를 가져올 수 있다. 본 논문에서는 실감 내비게이션에서의 정보 표현을 위한 화면 배치, 가상객체의 디자인 안, 정보량의 적정수준 등 디자인 방향과 고려사항을 논의하고 사용자 평가에 의한 디자인 최적 대안을 제시한다.

• 한국공간정보시스템학회:학술대회논문집
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• 2007.06a
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• pp.188-193
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• 2007

본 논문에서는 실사영상을 기반으로 동작하는 내비게이션에서 핵심적인 역할을 담당하고 있는 모듈 가운데 하나인 도로객체인식 모듈의 기능에 대해서 살펴보고자 한다. 이 모듈은 기존의 맵 기반의 내비게이션에서 찾아볼 수 없는 부분이며, 실사 영상위에 차량의 경로를 안내하기 위해서는 이 모듈을 통해 다양한 도로객체를 인식해야 하는데, 주행차선인식, 주행차로인식 및 신호등 인식이 필요하며 경우에 따라서는 건물인식이 여기에 포함될 수 있다.

• Spatial Information Research
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• v.15 no.4
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• pp.385-395
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• 2007

As the growth of performance of the computer and the development of the Internet are exponential, sharing and using the information illegally have also increased to the same proportion. In this paper, we proposed a novel method on the vector map data among digital contents. Vector map data are used for GIS, navigation and web-based services etc. We embedded watermark into the coordinate of the vector map data using bit operation and extracted the watermark. This method helps to protect the copyright of the vector map data. This watermarking method is a spatial domain method and it embeds the watermark within an allowable error. Our experiment shows that the watermark produced by this method is resistant to simplification and translation.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.321-324
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• 2005

In these days, the management and visualization of 3D geo-spatial information is regarded as one of an important issue in GiS and remote sensing fields. 3D GIS is considered with the database issues such as handling and managing of 3D geometry/topology attributes, whereas 3D visualization is basically concerned with 3D computer graphics. This study focused on the design and implementation for the OpenGL API-based rendering system for the complex types of 3D geo-spatial features. In this approach 3D features can be separately processed with the functions of authoring and manipulation of terrain segments, building segments, road segments, and other geo-based things with texture mapping. Using this implementation, it is possible to the generation of an integrated scene with these complex types of 3D features. This integrated rendering system based on the feature-based 3D-GIS model can be extended and effectively applied to urban environment analysis, 3D virtual simulation and fly-by navigation in urban planning. Furthermore, we expect that 3D-GIS visualization application based on OpenGL API can be easily extended into a real-time mobile 3D-GIS system, soon after the release of OpenGLIES which stands for OpenGL for embedded system, though this topic is beyond the scope of this implementation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.385-390
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• 2006

This paper examines the sampling and jitter specifications and considerations for Global Navigation Satellite Systems (GNSS) software receivers. Software radio (SWR) technologies are being used in the implementation of communication receivers in general and GNSS receivers in particular. With the advent of new GPS signals, and a range of new Galileo and GLONASS signals soon becoming available, GNSS is an application where SWR and software-defined radio (SDR) are likely to have an impact. The sampling process is critical for SWR receivers, where it occurs as close to the antenna as possible. One way to achieve this is by BandPass Sampling (BPS), which is an undersampling technique that exploits aliasing to perform downconversion. BPS enables removal of the IF stage in the radio receiver. The sampling frequency is a very important factor since it influences both receiver performance and implementation efficiency. However, the design of BPS can result in degradation of Signal-to-Noise Ratio (SNR) due to the out-of-band noise being aliased. Important to the specification of both the ADC and its clocking Phase- Locked Loop (PLL) is jitter. Contributing to the system jitter are the aperture jitter of the sample-and-hold switch at the input of ADC and the sampling-clock jitter. Aperture jitter effects have usually been modeled as additive noise, based on a sinusoidal input signal, and limits the achievable Signal-to-Noise Ratio (SNR). Jitter in the sampled signal has several sources: phase noise in the Voltage-Controlled Oscillator (VCO) within the sampling PLL, jitter introduced by variations in the period of the frequency divider used in the sampling PLL and cross-talk from the lock line running parallel to signal lines. Jitter in the sampling process directly acts to degrade the noise floor and selectivity of receiver. Choosing an appropriate VCO for a SWR system is not as simple as finding one with right oscillator frequency. Similarly, it is important to specify the right jitter performance for the ADC. In this paper, the allowable sampling frequencies are calculated and analyzed for the multiple frequency BPS software radio GNSS receivers. The SNR degradation due to jitter in a BPSK system is calculated and required jitter standard deviation allowable for each GNSS band of interest is evaluated. Furthermore, in this paper we have investigated the sources of jitter and a basic jitter budget is calculated that could assist in the design of multiple frequency SWR GNSS receivers. We examine different ADCs and PLLs available in the market and compare known performance with the calculated budget. The results obtained are therefore directly applicable to SWR GNSS receiver design.

• Journal of Korean Society for Geospatial Information Science
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• v.2 no.2 s.4
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• pp.81-88
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• 1994

The CNS(Car Navigation System) is used more generally in driver aid system than ALV(Auto nomous Land Vehicle) research area. In this paper we developed a new position tracking algorithm for the Global Path Planning in the CNS. In japan, CNS is already well developed and, thesedays they sell CNS products about $400{\sim}500$ thousands per year, and USA and European Communications(EC), too. In Korea, studies of the first generation CNS, which finds current location of a navigating vehicle and displays its location in a Digital-Map with real-time are progressing but still in the beginning step. Therefore a new position tracking algorithm is presented, which reduces vehicle position error dramatically by fusing GPS and dead-reckoning sensors. And the validity of our algorithm is demonstrated by the experimental results with the real car.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.469-478
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• 2000

On the advent of digital era, ECDIS has emerged as a new navigation aid that should result in significant benefits to safe navigation. More than simply a graphics display, ECDIS is a new concept navigation system capable of providing integrated information of geographical and texual data. As an official vector data for ECDIS, ENC consists of spatial and feature data to describe objects in form of points, lines and areas. IHO published International Standards for ENC, such as S-52(Specification for Chart Content and Display Aspects of ECDIS) and S-57(IHO Transfer Standard for Digital Hydrographic Data). This paper deals with the implementation of an ENC representation system which meets S-52 presentation specification and S-57 transfer standards by analyzing S-57 data structures and converting them to an appropriate internal data structures and representing them onto screen adopting S-52 presentation specification.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.375-383
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• 2018

In order to apply the Network RTK (real time kinematics) technology, which has been used for positioning of stationary points, to the navigation of vehicles, its infrastructure should provide correction data with a quality indicator that can show the expected accuracy in real time. In this paper, we analyzed various indicator generation algorithms such as I95 (ionospheric index 95) / G95 (geodetic index 95), SBI (semivariance based index) and RIU (residual interpolation uncertainty). We also applied them to the raw observables from the reference stations of National Geographic Information Institute and VRS (virtual reference station) users, and then examined its feasibility to be used as a real-time performance index of the Network RTK rover. 24 hour data analysis shows that the RIU index, which can represent the non-linearty of the correction, has the strongest correlation with the Network RTK rover accuracy. Therefore, RIU index is expected to be used as a real-time performance index of the Network RTK rover.

• The Journal of Korea Robotics Society
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• v.13 no.2
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• pp.113-120
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• 2018

To fly a drone or unmanned aerial vechicle(UAV) safely, its pilot needs to maintain high situation awareness of its flight space. One of the important ways to improve the flight space awareness is to integrate both the global and the local navigation map a drone provides. However, the drone pilot often has to use the inconsistent reference frames or perspectives between the two maps. In specific, the global navigation map tends to display space information in the third-person perspective, whereas the local map tends to use the first-person perspective through the drone camera. This inconsistent perspective problem makes the pilot use mental rotation to align the different perspectives. In addition, integrating different dimensionalities (2D vs. 3D) of the two maps may aggravate the pilot's cognitive load of mental rotation. Therefore, this study aims to investigate the relation between perspective difference ($0^{\circ}$, $90^{\circ}$, $180^{\circ}$, $270^{\circ}$) and the map dimensionality matches (3D-3D vs. 3D-2D) to improve the way of integrating the two maps. The results show that the pilot's flight space awareness improves when the perspective differences are smaller and also when the dimensionalities between the two maps are matched.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.146-150
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• 1999

On the advent of digital era, ECDIS has emerged as a new navigation aid that should result in significant benefits to safe navigation. More than simply a graphics display, ECDIS is a new concept navigation system capable of providing integrated information of geographical and texual data. As an official vector data for ECDIS, ENC consists of spatial and feature data to describe objects in form of points, lines and areas. IHO published International Standards for ENC, such as S-52(Specification for Chart Content and Display Aspects of ECDIS and S-57(IHO Transfer Standard for Digital Hydrographic Data). This paper deals with the implementation of an EUC representation system which meets S-52 presentation specification and S-57 transfer standards by analyzing S-57 data structures and converting then to an appropriate internal data structures and representing them onto screen adopting S-52 presentation specification.