• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.341-342
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• 2012

현재 운영 중인 DGPS RSIM은 서비스 측면에서 GPS 보정정보 만을 제공 하고 있으며, GLONASS 보정서비스는 아직까지 실시하고 있지 않다. 또한 운영적, 기술적인 측면에서 국외 기술에 많이 의존하고 있는 실정이다. 본 논문에서는 DGPS 기준국 고도화와 기술적, 운영적 독립을 위한 실질적인 대응으로서 DGNSS 통합 소프트웨어 RSIM 기술개발에 대해 다룬다. DGNSS RSIM 국산화 기술개발 및 그 성능고도화를 위하여 GPS/GLONASS 보정서비스가 가능한 DGNSS 통합 소프트웨어 RSIM 기술개발과 실제 기준국 환경에서 성능평가를 수행한 결과를 제시한다.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.95-100
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• 2013

Several observation equipments are being used for determination of the water vapor content and precipitable water vapor (PWV) because the water vapor is highly variable temporally and spatially. In this study, we used GNSS systems such as GPS and GLONASS in standalone and combined modes to compute PWV and validated their accuracy with respect to the results of other water-vapor monitoring systems. The other systems used were radiosonde and microwave radiometer, and the comparisons were convenient because all three systems were collocated at the test site. The differences of PWW were in the range of 0.6-3.4 mm in the mean sense, and their standard deviations were 1.0-3.8 mm. The relatively large difference of GNSS compared with the other two systems were believed to be caused by the fact that the GNSS antenna used in this study was the kind for which the international standard of phase center variations (PCV) calibration is not available. We expect better accuracy of PWV determination and improved availability of it through integrated data processing of GPS/GLONASS when an appropriate antenna with PCV correction model is used.

• Journal of Positioning, Navigation, and Timing
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• v.5 no.4
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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.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2002.04a
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• pp.93-102
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• 2002

도로상에서 발생되는 교통사고의 많은 부분이 도로의 선형불량에 기인된다. 이러한 도로의 개량설계를 위하여서는 도로의 선형을 정확히 분석할 필요가 있으며, 도로의 설계도와 주요점의 좌표가 필요하게 된다. 따라서, 본 연구에서는 현재 많이 연구되고 있는 인공위성중 RTK GPS/GLONASS의 조합에 의하여 획득된 3차원 자료를 기존 설계도의 제원을 근거로 하여 위치정밀도를 비교하며, 이렇게 재현된 도로의 선형을 평가함으로써 인공위성을 이용한 도로의 선형정보체계를 보다 효율적이고 실용적으로 사용하기 위한 한 접근방법을 제시하고자 한다.

• TTA Journal
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• s.135
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• pp.26-27
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• 2011

지금 세계는 미국, 러시아, 유럽 등 우주강국들의 '제2의 우주전쟁'이라고 할 수 있는 'GPS 개발 경쟁'이 치열하다. 미국은 전 세계를 대상으로 GPS(Global Positioning System) 서비스를 무료로 제공하고 있기 때문에 세계 모든 나라가 이를 이용하고 있다. 지난 2월 26일에는 러시아 국방부가 글로벌위성항법시스템 (GNSS: Global Navigation Satellite System)인 글로나스(GLONASS) 구축을 위해 23번째 통신위성(GLONASS-K)을 정상궤도에 쏘아 올렸다. 글로나스는 미국의 위성위치확인시스템 GPS와 동일한 러시아판 GPS다. 러시아는 글로벌위성항법시스템 완성을 위해 올해 중 24번째의 인공위성을 쏘아 올려 24개의 인공위성과 2개의 예비위성을 모두 갖추고 운영할 예정이다. 그렇다면 세계는 왜 이토록 위치 확인에 관심을 쏟으며 경쟁을 벌이고 있는 것일까?

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.6
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• pp.659-667
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• 2009

In this study, an integrated GNSS Simulator called Inha GNSS Simulation System (IGSS) using 3D spatial information was developed and validated. Also positioning availability and accuracy improvement were evaluated under the integrated GNSS environment using IGSS. GPS and GLONASS satellite visibility predictions were compared with real observations, and their frequency of error were 6.4% and 7.5%, respectively. To evaluate positioning availability and accuracy improvement under the integrated GNSS environment, the Daejeon government complex area was selected to be the test site because the area has high-rise buildings and thus is susceptible to signal blockages. The test consists of three parts: the first is when only GPS was used; the second is when both GPS and GLONASS were simulated; and the last is when GPS, GLONASS, and Galileo were used all together. In each case, the number of visible satellites and Dilution Of Precision were calculated and compared.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.4
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• pp.205-211
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• 2015

The Global Navigation Satellite System (GNSS) is undergoing dramatic changes. Nowadays, much more satellites are transmitting navigation data at more frequencies. A multi-GNSS analysis is performed to improve the positioning accuracy by processing combined observations from different GNSS. The multi-GNSS technique can improve significantly the positioning accuracy. In this paper, we present a combined Global Positioning System (GPS), the GLObal NAvigation Satellite System (GLONASS), the China Satellite Navigation System (BeiDou), and the Quasi-Zenith Satellite System (QZSS) standard point positioning (SPP) method to exploit all currently available GNSS observations at Mokpo (MKPO) station in South Korea. We also investigate the multi-GNSS data recorded at MKPO reference station. The positioning accuracy is compared with several combinations of the satellite systems. Because of the different frequencies and signal structure of the different GNSS, intersystem biases (ISB) parameters for code observations have to be estimated together with receiver clocks in multi-GNSS SPP. We also present GPS/GLONASS and GPS/BeiDou ISB values estimated by the daily average.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.3
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• pp.301-308
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• 2001

Nowadays GPS play a important roles in the navigation system of vehicles, but, it doesn't determine the kinematic positions of vehicles accurately because of few satellites in the urban canyon covered with trees and high buildings. So GLONASS (GLObal Navigation Satellites System), the Russian satellites'system, operated in 1996, was introduced to overcome this drawbacks. Therefore, this study deals with the kinematic positioning of vehicles with Real-time code differential positioning methods. As a result, Real-time DGPS/GLONASS is better than Real-time DGPS in the differential corrected positions and HDOP (Horizontal Dilution of Precision). And it was shown that the combined GPS/GLONASS contributes to the precise kinematic positioning of vehicles.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.2 s.20
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• pp.29-37
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• 2002

Many of the traffic accidents on roads are a result of alignment defect of the roads. This alignment of the road needs to lie analyzed with accuracy for improving design of road, and it needs the design drawing of road, and coordinates of the main point. Accordingly, in this study the precision of location based on existing design drawing was compared with the data acquired by the combination of RTK GPS/GLONASS. The result of study is included within range 5cm, we would like to propose an effective and useful approach method to utilize the satellite for road alignment information system by evaluating the represented road alignment.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.39-46
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• 2014

Network RTK positioning, one of GNSS positioning systems, is currently very popular due to its easy operation and low cost. However, the network RTK positioning unquestioningly accepts observation result acquired with an ambiguity fixed-solution regardless of different field conditions and situations, and then it is applied to the practice. This paper, therefore, has investigated the effects of field conditions obtained network RTK survey data for the area with obstacles on the variation of positioning accuracy. Being explained in detail, after conducting survey by GPS-only positioning and combined GPS/GLONASS observations giving changes to the distance from obstacles and elevation angles, and then accuracy results of each positioning method were compared each other. As a result, while GPS-only point positioning method showed more stable results than combined GPS/GLONASS method in the areas with no obstacles, combined method gave better result than GPS-only for the areas with presence of obstacles. Based on the results of this experiment, when the further study is conducted with a variety of different field conditions affecting the survey accuracy, it can be expected that the accuracy of network RTK survey method would become to more popular.