• Journal of the Korean Institute of Navigation
• /
• v.18 no.1
• /
• pp.39-61
• /
• 1994

GMDSS(the Global Maritime Distress and Safety System), which is utilizing recently developed systems such as satellite communications and positioning system, digital communication system, computer and microelectronics technology, etc., has been adopted by International Maritime Orgnization(IMO) and coordina-ted with such organization as the International Telecommunication Union(ITU), World Meteorological Organizatoion(WMO), etc. This system took effect partly on February 1st 1992 according to the 1988 SOLAS Amemdments and, after some more complementary measures, will be fully operational by February 1st 1999. Comparing with the existing communication system, the new system is mainly based on the latest scientific technologies, and therefore overall countermeasure will be necessary to accept the system reasonably. GMDSS will transform the current communication system basically and be the major factor to change the demand and supply of personnel for radio communication. To cope with the system assertively, regulations relating to the radio installation, the posting of radio operators, the bounds of their duty, etc. must be established and the demand and supply of radio operators to meet the system must be accomplished pertinently. Moreover, the technique and quality of the person-nel responsible for the system must be upgraded to carry out the obligations by international regulations as well as to ensure the safety of life and property at sea. Looking into the actual situations of our country, every regulation relating to the GMDSS has been improved, but the concerned educational institutions and administrations have not yet prepared the rational and concrete schemes on the educational methods and adquate procedures for the system. Therefore, in this thesis, the author intends to propose directions for improving the courses and contents of education of the relating educational institutions and to suggest rational schemes for balancing the demand and supply of personnel to the administrative anthorty concerned.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2006.04a
• /
• pp.93-98
• /
• 2006

2008년 서비스 제공을 목표로 진행 중인 유럽의 Galileo 시스템은 최초의 순수 민간 목적으로 제작되는 광역위성항법시스템(GNSS: Global Navigation Satellite System)이다. 현재 GPS의 SA는 제거되었지만, 군사 목적뿐만 아니라 차량 및 항공 항법, 토목 건설 분야, 텔레메틱스를 통한 민간 활용의 증가로 인해 위성측위에 있어 미국의 의존도는 그 어느 때보다 높은 실정이다. 이에 따른 전략적, 기술적 의존은 절대적이며 잠재적인 위험 요소를 포함하고 있다 이에 본 논문에서는 자체 개발한 소프트웨어를 이용하여 향후 제공될 유럽의 Galileo 시스템을 국내 적용 시뮬레이션하였으며 그 결과를 바탕으로 GPS 단독 처리의 한계를 제시하며 이를 극복할 수 있는 대안으로 Galileo 시스템에 대하여 연구하였다. 이를 통하여 러시아의 GLONASS를 포함하여 다원화되어가는 광역위성항법시스템의 안정적인 측위 환경에 대한 연구가 그 목적이다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.36 no.1
• /
• pp.9-15
• /
• 2018

Precise regional geoid heights on and around Mount Jiri were calculated and were compared to the KNGeoid14 (Korean National Geoid 2014) model. In this study, gravimetric geoid heights were calculated by using RCR (Remove-Compute-Restore) technique and then hybrid geoid heights were calculated by using the LSC (Least Square Collocation) method in the same area. In addition, gravity observation and GNSS(Global Navigation Satellite System) surveying performed in this study were utilized to determine gravimetric geoid heights and to compute hybrid geoid heights, respectively. The results of the study show that the post-fit error (mean and standard deviation) of hybrid geoid heights was evaluated as $0.057{\pm}0.020m$, while the mean and standard deviation of the differences were -0.078 and 0.085 m, respectively for KNGeoid14. Therefore, hybrid geoid heights in this study show more considerable progress than KNGeoid14.

• Bulletin of the Korean Space Science Society
• /
• 2008.10a
• /
• pp.24.3-24.3
• /
• 2008

The signals transmitted from satellites of Global Navigation Satellite System (GNSS) interact with the plasma of the ionosphere. To study the impact of the ionospheric plasma on GNSS applications a comprehensive knowledge of the ionosphere is required. Especially the correct measurement of the ionosphere such as the peak height of the F2 layer peak electron density (hmF2) is important for the GNSS ionospheric model. Anyang ionosonde station ($37.39^{\circ}N$, $126.95^{\circ}E$) has been operating from October 2000 and the accumulated data for 8 years may allow us to obtain climatological characteristics of middle latitude ionospheric F region for GNSS application. We analyzed the variations of the hmF2 and NmF2 over Anyang station for different conditions of solar activity, geomagnetic activity, season, and local time, and we compared our results with the IRI model.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.9
• /
• pp.977-983
• /
• 2014

A repeat-back jamming signal is an intentionally re-broadcasted GNSS (Global Navigation Satellite System) interference. In this paper, a novel repeat-back jamming detection scheme is proposed. The proposed scheme uses a combined pseudo random noise signal (C-PRN) and is available for a generic GNSS receiver with a single antenna. The C-PRN signal is made by combining several received pseudo random noise signals that had been transmitted from the visible GNSS satellites. Through a Monte-Carlo simulation, the detection probability of a repeat-back jamming signal detected with the proposed scheme is presented.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1533-1534
• /
• 2008

회전 항체용 GNSS(Global Navigation Satellite System) 수신기의 회전 추적 루프를 제안하였다. 제안하는 회전 추적 루프는 항체의 회전속도와 회전각을 추적하는 회전 추적 루프가 반송파 추적 루프에 추가되는 형태이다. 회전 추적 루프에서 수신기의 상관기 출력값을 이용하여 항체의 회전 속도를 추정하고 이를 이용하여 회전 변조된 반송파의 위상과 주파수를 추적할 수 있도록 하였다. 제안하는 GNSS 수신기의 회전 추적 루프는 모의실험을 통하여 검증하였으며, 이 루프를 사용함으로써 회전 변조된 신호를 GNSS 수신기에서 추적할 수 있음을 확인하였다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.15 no.2
• /
• pp.81-87
• /
• 1990

International time comparisons using a commercial GPS receiver, with the common-view program of GPS satellite time links, have been carried out between Korea Standards Research Institute(KSRI) and Communications Research Laboratory(CRL) of Japan, and also between KSRI and United Stated Neval Observatory(USNO). The frequency stability is about 1.5 parts in $10^-13$ for the averaging time of 1day. The result of time comparisons obtained by the GPS common-view technique was about 10 times better than that by the LORAN-C(Long Range Navigation) ground wave technique.

• Annual Conference of KIPS
• /
• 2024.10a
• /
• pp.839-840
• /
• 2024

위성측위시스템(GNSS, Global Navigation Satellite System)은 지구 궤도 상에 위치한 위성군을 이용하여 전 지구상에서 사용자의 위치를 제공해 주고 있다. 실외 자율주행로봇 또는 자율주행차량의 경우 기존에 알고 있지 않은 환경에서 대상의 절대 위치 확보 시 용이하고 효율적인 주행을 가능하게 하므로, 이러한 영역에서 GNSS의 활용이 많은 도움을 줄 것으로 기대된다. 본 논문에서는 RTK(Real-time Kinematic Positioning) 기술을 이용하여 얻은 보정된 GNSS 위치 정보를 획득하고, 이 정보를 근간으로 자율주행로봇의 경로계획에 사용하는 방법을 제시한다. 그리고 이 방법을 기반으로 제작된 자율주행로봇으로 실시한 실험을 통해 제안한 방법의 적합성을 확인한다.

• Journal of Astronomy and Space Sciences
• /
• v.37 no.2
• /
• pp.105-115
• /
• 2020

The Korean Institute of Technology Satellite (KITSAT-1) is the first satellite developed by the Satellite Technology Research Center and the University of Surrey. KITSAT-1 is orbiting the Earth's orbit as space debris with a 1,320 km altitude after the planned mission. Due to its relatively small size and altitude, tracking the KITSAT-1 was a difficult task. In this research, we analyzed the tracking results of KITSAT-1 for one year using the Midland Space Radar (MSR) in Texas and the Poker Flat Incoherent Scatter Radar (PFISR) in Alaska operated by LeoLabs, Inc. The tracking results were analyzed on a weekly basis for MSR and PFISR. The observation was conducted by using both stations at an average frequency of 10 times per week. The overall corrected range measurements for MSR and PFISR by LeoLabs were under 50 m and 25 m, respectively. The ionospheric delay, the dominant error source, was confirmed with the International Reference of Ionosphere-16 model and Global Navigation Satellite System data. The weekly basis orbit determination results were compared with two-line element data. The comparison results were used to confirm the orbital consistency of the estimated orbits.

• Journal of Advanced Navigation Technology
• /
• v.20 no.6
• /
• pp.503-510
• /
• 2016

In recent years, owing to the growing user demand for the two-way internet service based on the move global broadband communications, a new type of satellite terminal has developed, known as earth station in motion (ESIM). This service was required by Resolution 158 (WRC-15) to study on the coexistence with the co-primary fixed service (FS) in 27.5-29.5 GHz as a FSS uplink. In this paper, four scenarios was introduced to account for the antenna pointing error and the azimuth for an analysis on the sharing between ESIM and FS. From analysis results, the required separation distance between two systems should be about 32~52 km according to the elevation angles of $20^{\circ}{\sim}40^{\circ}$ using thresholds of 5% and 10% outage probability. Therefore, it is necessary to control the azimuth angle due to a moving terminal as well as the pointing error of ESIM to minimize the required separation distance and to protect the co-primary FS.