• 제어로봇시스템학회논문지
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• 제12권9호
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• pp.898-904
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• 2006

Ionospheric storms, caused by the interaction between Solar and geomagnetic activities, may degrade the differential GNSS(Global Navigation Satellite Systems) performance significantly, and the importance of the ionospheric storm research is growing for the GBAS(Ground-Based Augmentation System) and SBAS(Satellite-Based Augmentation System) development. In order to support Korean GNSS augmentation system development, a software tool for analyzing the regional ionosphere is being developed and its preliminary results are discussed. After brief description of the ionosphere and ionospheric storm, the research topics on the GBAS applications are discussed. The need for ionospheric spatial gradient analysis is described and some results on the ionospheric spatial gradient during recent storm periods are discussed.

• 한국항공운항학회:학술대회논문집
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• 한국항공운항학회 2007년도 추계학술대회
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• pp.106-109
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• 2007

• 한국항공운항학회:학술대회논문집
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• 한국항공운항학회 2007년도 추계학술대회
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• pp.101-105
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• 2007

• 한국항행학회논문지
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• 제19권1호
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• pp.22-32
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• 2015

위성항법지역보강시스템(GBAS)은 항공기 정밀접근을 지원하는 차세대 항행안전무선시설로, 최근 GBAS 설치 및 서비스를 제공하는 공항들이 전 세계적으로 증가하고 있다. 한국도 2013년 김포국제공항에 국내 최초로 미국 Honeywell사의 GBAS 지상장비인 SLS-4000을 설치하였으며, 지상시험을 통해 설치된 장비의 기능 및 성능을 점검하였다. 본 논문에서는 GBAS 지상시험에 대한 국내 GBAS CAT-I 시험평가 기준 및 방법을 소개하고, 김포국제공항에서 진행된 GBAS 시험평가 방법에 대해 기술하였다. 또한 GBAS 지상시험의 12개 시험항목 중 주요 5개 시험항목에 대한 상세한 시험평가 방법 및 분석 결과를 기술하였다.

• 한국항공우주학회지
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• 제43권1호
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• pp.49-61
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• 2015

GBAS는 Differential GPS(DGPS) 개념을 활용하여 공항근처 23NM 반경 이내에 위치한 항공기에 정밀위치서비스와 정밀접근서비스를 제공하는 시스템으로, GBAS 지상장비는 공항에 설치된 이후에 지상 및 비행시험평가를 통해 그 기능 및 성능을 검증하도록 되어있다. 본 논문에서는 김포국제공항에 설치된 GBAS 지상장비에 대해 비행검사용 항공기를 이용한 비행시험 방법 및 결과를 분석하여 기술하였다. 시험 결과 김포공항의 GBAS 신호통달범위 내에서 VDB 데이터가 오류 없이 정상적으로 수신되었으며, VDB 전계강도, 보호수준, 코스정렬 정확도 등도 평가 요구조건을 충분히 만족시키는 것을 확인하였다.

• Journal of Positioning, Navigation, and Timing
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• 제13권2호
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• pp.189-197
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• 2024

Galileo is a European Global Navigation Satellite System (GNSS) that has offered the Galileo Open Service since 2016. Consequently, the standardization of GNSS augmentation systems, such as Satellite Based Augmentation System (SBAS), Ground Based Augmentation System (GBAS), and Aircraft Based Augmentation System (ABAS) for Galileo signals, is ongoing. In 2023, the European Union Space Programme Agency (EUSPA) released prior probabilities of a satellite fault and a constellation fault for Galileo, which are 3×10^-5 and 2×10^-4 per hour, respectively. In particular, the prior probability of a Galileo constellation fault is significantly higher than that for the GPS constellation fault, which is defined as 1×10^-8 per hour. This raised concerns about its potential impact on GBAS integrity monitoring. According to the Global Positioning System (GPS) Standard Positioning Service Performance Standard (SPS PS), a constellation fault is classified as a wide fault. A wide fault refers to a fault that affects more than two satellites due to a common cause. Such a fault can be caused by a failure in the Earth Orientation Parameter (EOP). The EOP is used when transforming the inertial axis, on which the orbit determination is based, to Earth Centered Earth Fixed (ECEF) axis, accounting for the irregularities in the rotation of the Earth. Therefore, a faulty EOP can introduce errors when computing a satellite position with respect to the ECEF axis. In GNSS, the ephemeris parameters are estimated based on the positions of satellites and are transmitted to navigation satellites. Subsequently, these ephemeris parameters are broadcasted via the navigation message to users. Therefore, a faulty EOP results in erroneous broadcast ephemeris data. In this paper, we assess the conventional ephemeris fault detection monitor currently employed in GBAS for wide faults, as current GBAS considers only single failure cases. In addition to the existing requirements defined in the standards on the Probability of Missed Detection (PMD), we derive a new PMD requirement tailored for a wide fault. The compliance of the current ephemeris monitor to the derived requirement is evaluated through a simulation. Our findings confirm that the conventional monitor meets the requirement even for wide fault scenarios.

• Journal of Positioning, Navigation, and Timing
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• 제12권1호
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• pp.23-35
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• 2023

Korea Augmentation Satellite System (KASS) is a satellite-based augmentation system (SBAS) that provides approach procedure with vertical guidance-I (APV-I) level corrections and integrity information to Korea territory. KASS is used to monitor navigation performance in real-time, and this paper introduces the design, implementation, and verification process of mission monitoring (MIMO) in KASS. MIMO was developed in compliance with the Minimum Operational Performance Standards of the Radio Technical Commission for Aeronautics for Global Positioning System (GPS)/SBAS airborne equipment. In this study, the MIMO system was verified by comparing and analyzing the outputs of reference tools. Additionally, the definition and derivation method of accuracy, integrity, continuity, and availability subject to MIMO were examined. The internal and external interfaces and functions were then designed and implemented. The GPS data pre-processing was minimized during the implementation to evaluate the navigation performance experienced by general users. Subsequently, tests and verification methods were used to compare the obtained results based on reference tools. The test was performed using the KASS dataset, which included GPS and SBAS observations. The decoding performance of the developed MIMO was identical to that of the reference tools. Additionally, the navigation performance was verified by confirming the similarity in trends. As MIMO is a component of KASS used for real-time monitoring of the navigation performance of SBAS, the KASS operator can identify whether an abnormality exists in the navigation performance in real-time. Moreover, the preliminary identification of the abnormal point during the post-processing of data can improve operational efficiency.

• Journal of Positioning, Navigation, and Timing
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• 제12권2호
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• pp.185-200
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• 2023

The Korea Augmentation Satellite System (KASS) is the first satellite navigation enhancement system in Korea developed in compliance with international standards. Technologies accumulated during the development process should be spread to industries such as academia and serve as the basis for developing the domestic satellite navigation field. This paper introduces the development process from design to implementation, testing, and verification of KASS control systems (KCS). First, development standards, milestones, requirements, and interface standards are presented as KCS development methods, and major functional design, physical design, and hardware/software implementation are described based on the allocated requirements. Subsequently, the verification environment, procedures, and results of the development product are covered and the developed operational and maintenance procedures are described. In addition, based on the experience gained through the development, suggestions were made for beneficial technology development and organization when promoting satellite navigation projects in the future. Since this work has important historical value for the development of domestic satellite navigation, it is expected that the development results will be shared with academia and industry in the future and be used as basic data for similar development.

• 한국위성정보통신학회논문지
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• 제8권1호
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• pp.40-44
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• 2013

본 논문에서는 지상용 GPS(Global Positioning System)와 유사한 GBAS(Ground Based Augmentation Systems)의 위치측정오차에 대해서 연구하였다. GBAS의 위치측정오차에 영향을 주는 요소는 많이 있으며 측위오차(DOP: Dilution Of Precision)도 그 중의 하나이다. 측위오차는 송신기와 수신기의 수와 기하학적 배치위치에 따라서 결정된다. 본 연구에서는 한반도 지형에 2-열로 송신기를 배치하고 수신기의 위치에 따른 고도별 DOP를 예측할 수 있는 알고리즘을 개발하였다. 본 논문은 송신기와 수신기가 배치된 3차원 공간의 DOP를 정확하게 예측할 수 있어서 항법시스템에 매우 유용하게 사용될 수 있을 것으로 판단된다.

• 한국위성정보통신학회논문지
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• 제12권4호
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• pp.72-77
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• 2017

위성항법보강시스템 (Satellite Based Augmentation System; SBAS)은 정지궤도(GEO) 위성들을 이용하여 GPS, GLONASS 등의 위성항법시스템 (Global Navigation Satellite System; GNSS) 사용자들에게 무결성 데이터 및 정정 데이터를 방송하는 데 목적이 있다. 국제민간항공기구 (International Civilian Aeronautical Organization; ICAO)의 2025년까지 SBAS 도입 권고에 따라, 국토교통부 사업으로 한국형 SBAS 시스템 개발/구축 사업이 진행 중에 있다. 한국형 위성항법보강시스템인 KASS(Korea Augmentation Satellite System)는 초정밀 GPS 오차보정시스템으로, 기준국(KASS Reference Station; KRS), 중앙처리국(KASS Processing Station; KPS), 위성통신국(KASS Uplink Station; KUS) 및 통합운영국(KASS Control Station; KCS)으로 구성된 지상시스템과 GEO 위성으로 이루어져 있다. 본 논문에서는 KASS 지상 부문과 GEO 위성간의 연동 역할을 하며 신호생성부(Signal Generator Section; SGS)와 RF부(Radio-Frequency Section; RFS)로 구성된 KASS 위성통신국에 대해 개념적 설계를 하였다.