• Journal of Positioning, Navigation, and Timing
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• v.10 no.1
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• pp.43-48
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• 2021

Most existing studies on the wide-area differential global positioning system (WADGPS) used standard positioning service (SPS) receivers in their observation reference stations which provide the central control station global positioning system (GPS) measurements to generate augmentation data. In the present study, it is considered to apply a precise positioning service (PPS) receiver to an observation reference station which is located in the threatened jamming area. Therefore, the reference station network consists of a PPS receiver based observation reference station and SPS receiver based observation reference stations. In this case, to maintain correction performance P1C1 differential code bias (DCB) should be compensated. In this paper, P1C1 DCB estimation algorithm was applied to the PPS/WADGPS system and performance test results using measurements in the Korean Peninsula were presented.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.3
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• pp.307-314
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• 2023

Wide-Area Differential Global Positioning System (WADGPS) is a system that operates a number of reference stations to provide correction information to improve the accuracy of GPS users, and it is available to service users within the area where the wide-area reference stations are installed. Recently, as positioning information has been used in various applications, the need for WADGPS for precise navigation in long-distance spaced areas where the wide-area reference stations cannot be installed has been raised. This paper tested the user navigation performance outside the wide-area reference stations of the WADGPS system, which serves both GPS Precise Positioning Service (PPS) and Standard Positioning Service (SPS) users. Static and dynamic tests were conducted using vehicles, and as a result, position accuracy improvement through WADGPS was confirmed even at points hundreds of kilometers outside the network area of the wide-area reference stations. Through this, the performance of the PPS/SPS correction system and the possibility of expanding the service area were confirmed.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.4
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• pp.349-358
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• 2023

The Satellite-Based Augmentation System (SBAS) plays a significant role in the fields of aviation and navigation: it corrects signal errors of the Global Navigation Satellite System (GNSS) and provides integrity information to facilitate precise positioning. These SBAS systems have been adopted as international standards by the International Civil Aviation Organization (ICAO). In recent SBAS system design, the Minimum Operational Performance Standards (MOPS) defined by the Radio Technical Commission for Aeronautics (RTCA) must be followed. In October 2014, South Korea embarked on the development of a Korean GPS precision position correction system, referred to as Korea Augmentation Satellite System (KASS). The goal is to achieve APV-1 Standard of Service Level (SoL) service level and acquisition of CAT-1 test operating technology. The first satellite of KASS, KASS Prototype 1, was successfully launched from the Guiana Space Centre in South America on June 23, 2020. In December 2022 and June 2023, the first and second service signals of KASS were broadcasted, and full-scale KASS correction signal broadcasting is scheduled to start at the end of 2023. The aim of this study is to analyze the precision of both the GNSS system and KASS system by comparing them. KASS is also compared with Japan's Multi-functional Satellite Augmentation System (MSAS), which is available in Korea. The final objective of this work is to validate the usefulness of KASS correction navigation in the South Korean operational environment.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.9
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• pp.818-826
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• 2002

Since multipath phenomenon frequently occurs when a Global Positioning System receiver is placed in urban area crowded with large buildings, efficient mitigation of multipath effects is necessary to resolve. In this paper, we propose a new multipath detection technique that is useful in real-time positioning with a general Global Positioning System receiver. The proposed technique is based on a channelwise multipath test statistic that efficiently indicates the degree of fluctuations induced by multipath error. The proposed multipath test statistic is operationally advantageous because it does not require any specialized hardware nor any pre-computation of receiver position, it is directly related to standard $\chi$$^2$-distributions, and it can adjust the detection resolution by increasing the number of successive measurements. Simulation and experiment results verify the performance of the proposed multipath detection technique.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.87-90
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• 2004

Telematics is an emerging industrial field made up of the convergence of technologies. The key technologies for Telematics are server-side technology, terminal-side technology, communication-related technology, and positioning technology. Standardization in Telematics is now getting more notice these days. Domestic situation is explained for several related facilities such as ETRI, TTA, and Telematics Standardization Forum. In this paper, we will focus especially on the standard reference model that is the most fundamental framework of Telematics technology standardization. In the reference model, the Telematics system is composed of Telematics client part, communication part, and Telematics server part. The Telematics client part consists of terminal, positioning device, and car electronic devices. Communication part can be composed of various telecommunication channels such as CDMA, WLAN, DMB, WiBro, etc. which can guarantee the seamless two-way communication. Telematics server part is composed of TSP(Telematics Service Provider) server and CP(Contents Provider) servers gathering and managing the various Telematics services. This Telematics reference model is expected to be utilized as the base architecture in developing the technology and standards from now on.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2623-2626
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• 2003

GPS provides two services which include SPS(Standard Positioning Service) and PPS(Precise Positioning Service). While SPS users can navigate in more precise due to cancellation of SA(Selective Availability), SPS users has still less precision navigation than PPS users. L1/L2CS integrated receiver can provide more precise navigation to SPS users because the delay of Ionosphere will be cancelled by using two frequencies (L1 and L2). This paper designs an integrated L1/L2CS digital correlator to prepare the L2C signal that will be provided in 2003. Also L2CS transmitter is designed to confirm L2CS correlator.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.208-213
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• 2011

This paper analyzes potential interference effects of Ultra Wide Band(UWB) on Global Positioning System(GPS) which is providing safety service. For the interference analysis, positioning error method is used to determine the minimum protection distance to meet positioning error of 2.5 m below and Minimum Coupling Loss(MCL) method is used to determine the required protection ratio(I/N) from the protection distance of UWB transmitter and GPS receiver to meet positioning error of 2.5 m below. In a result, the minimum protection distance to meet positioning error of 2.5 m below was about 10 m and the protection ratio to meet positioning error 2.5 m below was -20 dB. The protection ratio proposed in this paper is the same value of the protection ratio of safety service proposed by ITU-R. The obtained protection ratio can be used for the protection standard of domestic GPS system for the safe of life service.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2285-2291
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• 2015

At present, available positioning satellites are not only the GPS, but also GLONASS, GALILEO, QZSS, BeiDou. However, the differential GPS, the augmentation service for increase the positioning accuracy, is follow the RTCM version 2.3 standard. So, it can service the correction information about only GPS. For solve this problem, RTCM is making the new version of RTCM message standard that can service the correction information for all of available GNSS. In South Korea, the software DGNSS RSIM system was installed at almost the whole DGNSS reference station. In this reason, that can cope with the new RTCM version 2.4 quickly. However, the DGNSS Reference Station based RSIM 1.3 can not make the GNSS's PRC simultaneously and can not support RTCM version 2.4. Thus, in this paper, the version of RTCM 2.4 is analyzed and the RTCM version 2.4 message generating module's architecture for software DGNSS reference station is designed.

• Journal of Information Technology and Architecture
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• v.11 no.4
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• pp.441-448
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• 2014

The application of spatial information has drawn significant attention from a wide range of industries. Railway spatial information facilitates the cooperation among related parties and improves the efficiency of asset management and operations. This study proposes the structure of Railway Object IDentifier(ROID) on railway spatial information. Current facility management and train operation are based on relative positioning system. Despite many advantages, relative positioning system causes serious problems such as the entire reconfiguration of positioning in the case of line change. Another major concern is the interface compatibility between individual facilities with different relative positioning. ROID based on absolute positioning addresses these issues, allowing the information exchange and convergence between independent parties. This study proposes ROID based on OID standard with object IDentifier and service object-oriented reference system. Our ROID employs the absolute positioning and the unique identifier, maintaining the compatibility with existing management system.