• 한국항공우주학회지
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• 제43권2호
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• pp.125-132
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• 2015

본 논문은 한국형 위성항법시스템의 위성궤도, 위성시계 고장 검출이 가능한 UDRE에 대한 모니터링 알고리즘 분석을 수행하였다. UDRE 모니터링을 위한 의사거리 잔차 생성방법 중 대류권 지연오차와 수신기 시계바이어스 추정방법에 대해 새로운 알고리즘을 제안한다. 대류권 지연오차는 국내 기상데이터에 더욱 적합한 Saastamoinen 모델과 Neill 매핑함수의 조합 모델을 사용하였으며, 수신기 시계 바이어스 추정방법으로는 칼만필터를 사용한 기법을 사용하였다. 국내 지역에서 직접 수신한 위성데이터와 기상데이터를 사용한 UDRE 모니터링 분석을 통해 한국지역에 더욱 적합한 UDRE 모니터링 한계치(Threshold)를 도출하고 추 후 한국형 위성항법시스템의 고장검출 기법으로 활용할 수 있을 것으로 기대한다.

• 한국측량학회지
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• 제37권5호
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• pp.379-388
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• 2019

Recently, a technique for acquiring spatial information data using UAV (Unmanned Aerial Vehicle) has been greatly developed. It is a very crucial issue of the GIS (Geographic Information System) mapping system that passes way point in the unmanned airframe and finally measures the accurate image and stable localization to the desired destination. Though positioning using DGPS (Differential Global Navigation System) or RTK-GPS (Real Time Kinematic-GPS) guarantee highly accurate, they are more expensive than the construction of a single positioning system using a single GPS. In the case of a low-priced single GPS system, the stability of the positioning data deteriorates. Therefore, it is necessary to supplement the uncertainty of the absolute position data of the UAV and to improve the accuracy of the current position data economically in the operating state of the UAV. The aim of this study was to present an algorithm enhancing the stability of position data in a single GPS mode of UAV with multiple GPS. First, the arrangement of multiple GPS receivers through the center of gravity of the UAV were examined. Next, MD (Mahalanobis Distance) is applied to detect instantaneous errors of GPS data in advance and eliminate outliers to increase the accuracy of previously collected multiple GPS data. Processing procedure for multiple GPS reception data by applying the center of the triangular method were presented to improve the position accuracy. Second, UAV navigation systems integrated multiple GPS through configuration of the UAV specifications were implemented. Using the unmanned airframe equipped with multiple GPS receivers, GPS data is measured with the TCM (Triangular Center Method). In addition, UAV equipped with multiple GPS were operated in study area and locational accuracy of multiple GPS of UAV with VRS (Virtual Reference Station) GNSS surveying were compared. The result showed that the error factors are compensated, and the error range are reduced, resulting in the reliability of the corrected value. In conclusion, the result in this paper is expected to realize high-precision position estimation at low cost in UAV using multiple low-cost GPS receivers.

• Journal of Positioning, Navigation, and Timing
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• 제5권4호
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• pp.181-191
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• 2016

A Satellite Based Augmentation System (SBAS) provides differential correction and integrity information through geostationary satellite to users in order to reduce Global Navigation Satellite System (GNSS)-related errors such as ionospheric delay and tropospheric delay, and satellite orbit and clock errors and calculate a protection level of the calculated location. A SBAS is a system, which has been set as an international standard by the International Civilian Aviation Organization (ICAO) to be utilized for safe operation of aircrafts. Currently, the Wide Area Augmentation System (WAAS) in the USA, the European Geostationary Navigation Overlay Service (EGNOS) in Europe, MTSAT Satellite Augmentation System (MSAS) in Japan, and GPS-Aided Geo Augmented Navigation (GAGAN) are operated. The System for Differential Correction and Monitoring (SDCM) in Russia is now under construction and testing. All SBASs that are currently under operation including the WAAS in the USA provide correction and integrity information about the Global Positioning System (GPS) whereas the SDCM in Russia that started SBAS-related test services in Russia in recent years provides correction and integrity information about not only the GPS but also the GLONASS. Currently, LUCH-5A(PRN 140), LUCH-5B(PRN 125), and LUCH-5V(PRN 141) are assigned and used as geostationary satellites for the SDCM. Among them, PRN 140 satellite is now broadcasting SBAS test messages for SDCM test services. In particular, since messages broadcast by PRN 140 satellite are received in Korea as well, performance analysis on GPS/GLONASS Multi-Constellation SBAS using the SDCM can be possible. The present paper generated correction and integrity information about GPS and GLONASS using SDCM messages broadcast by the PRN 140 satellite, and performed analysis on GPS/GLONASS Multi-Constellation SBAS performance and APV-I availability by applying GPS and GLONASS observation data received from multiple reference stations, which were operated in the National Geographic Information Institute (NGII) for performance analysis on GPS/GLONASS Multi-Constellation SBAS according to user locations inside South Korea utilizing the above-calculated information.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 춘계학술대회
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• pp.685-688
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• 2016

위성기반 보강시스템은 위성항법시스템 사용자의 측위 정확도를 향상 시킬 수 있는 보정정보를 위성을 이용하여 방송하는 시스템으로, 특히 항행분야에서 많이 활용되고 있다. 위성기반 보강시스템을 항행분야에서 활용하기 위해서는 정확성뿐만 아니라 무결성, 지속성, 가용성, 서비스 영역 등의 요구사항을 만족해야한다. 기준국은 보정정보 생성을 위한 측정치를 수집하는 기반 시스템으로서, 기준국의 환경, 위치, 분포 등은 위성기반 보강시스템의 성능을 결정하는 중요한 요소이다. 따라서 위성기반 보강시스템의 기준국 선정을 위해서는 사이트 조사를 통한 환경 분석이 필수적이다. 본 논문에서는 우리나라 해양수산부에서 운영 중인 NDGPS 기준국을 위성기반 보강시스템의 기준국으로 공동 활용한다는 전제하에 NDGPS 기준국 사이트 중 일부의 환경 분석을 수행한다. 기준국 환경 분석은 GPS 위성의 가시성과 전파환경에 대하여 분석하며, 이로부터 기준국 사이트 조사를 위한 간략한 절차와 요구사항을 제시한다.