• Journal of Positioning, Navigation, and Timing
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• 제4권2호
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• pp.43-55
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• 2015

In the case of satellite navigation positioning, the shielding of satellite signals is determined by the environment of the region at which a user is located, and the navigation performance is determined accordingly. The accuracy of user position determination varies depending on the dilution of precision (DOP) which is a measuring index for the geometric characteristics of visible satellites; and if the minimum visible satellites are not secured, position determination is impossible. Currently, the GLObal NAvigation Satellite system (GLONASS) of Russia is used to supplement the navigation performance of the Global Positioning System (GPS) in regions where GPS cannot be used. In addition, the European Satellite Navigation System (Galileo) of the European Union, the Chinese Satellite Navigation System (BeiDou) of China, the Quasi-Zenith Satellite System (QZSS) of Japan, and the Indian Regional Navigation Satellite System (IRNSS) of India are aimed to achieve the full operational capability (FOC) operation of the navigation system. Thus, the number of satellites available for navigation would rapidly increase, particularly in the Asian region; and when integrated navigation is performed, the improvement of navigation performance is expected to be much larger than that in other regions. To secure a stable and prompt position solution, GPS-GLONASS integrated navigation is generally performed at present. However, as available satellite navigation systems have been diversified, finding the minimum satellite constellation combination to obtain the best navigation performance has recently become an issue. For this purpose, it is necessary to examine and predict the navigation performance that could be obtained by the addition of the third satellite navigation system in addition to GPS-GLONASS. In this study, the current status of the integrated navigation performance for various satellite constellation combinations was analyzed based on 2014, and the navigation performance in 2020 was predicted based on the FOC plan of the satellite navigation system for each country. For this prediction, the orbital elements and nominal almanac data of satellite navigation systems that can be observed in the Korean Peninsula were organized, and the minimum elevation angle expecting signal shielding was established based on Matlab and the performance was predicted in terms of DOP. In the case of integrated navigation, a time offset determination algorithm needs to be considered in order to estimate the clock error between navigation systems, and it was analyzed using two kinds of methods: a satellite navigation message based estimation method and a receiver based method where a user directly performs estimation. This simulation is expected to be used as an index for the establishment of the minimum satellite constellation for obtaining the best navigation performance.

• 한국항공우주학회지
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• 제37권8호
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• pp.759-766
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• 2009

본 논문은 INS/vSLAM 통합 항법 시스템의 성능 향상을 위한 기초 연구로써, 비전 센서의 영상처리 성능을 향상을 위한 알고리즘 개발에 목표를 두고 있다. 비전센서의 영상처리알고리즘으로 SIFT 알고리즘을 사용하였으며, SIFT 알고리즘의 특징점 정합 성능을 개선하기 위해 특징점 정합 필터를 적용하였다. 본 논문에서 제안한 알고리즘을 이용하여 기존의 SIFT 알고리즘을 파라미터 조절한 경우보다 향상된 결과를 얻을 수 있었다. 차후 실시간 통합 항법 시스템에 적용하기 위해서 알고리즘의 속도를 향상시키는 작업이 필요하다.

• 한국항공우주학회지
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• 제36권5호
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• pp.462-471
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• 2008

비행기록장치는 사고원인 분석이나 사고방지를 위한 용도로 사용되고 있는데 비행 기록장치의 해석에서 가장 중요한 변수는 항공기의 위치 추정방법으로, 일반적인 항법과는 달리 항공항법에서는 정밀한 위치 추정이 쉬운 일은 아니다. 이에 본 논문에서는 정확한 항공기의 위치 추정을 위해 센서들의 특성과 비행기록장치 제한사항을 분석하였고 이를 바탕으로 비행기록장치 기반의 최상의 추정조건을 추출하여 복합항법알고리즘을 구성하고 시뮬레이션을 수행하여 기준 위치에 근사화된 위치를 추정해 낼 수 있음을 증명하였다.

• 한국군사과학기술학회지
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• 제18권5호
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• pp.602-611
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• 2015

Even though GNSS provides highly accurate navigation information all over the world, it is vulnerable to jamming in the electronic warfare due to its weak signal power. The United States and Korea have plans to use terrestrial navigation systems as back-up systems during outage of GNSS. In order to develop back-up systems of GNSS, an M&S software platform is necessary for performance evaluation of various vehicle trajectories and integrated navigation systems. In this paper a design method of an M&S software is proposed for evaluation of multiple radio positioning integration systems. The proposed M&S software consists of a navigation environment generation part, a navigation algorithm part, a GUI part and a coverage analysis part. Effectiveness of the proposed design method is shown by implementing an M&S software for the GPS, DME and eLoran navigation systems.

• 한국항공우주학회지
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• 제36권4호
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• pp.393-398
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• 2008

본 논문에서는 소형 인공위성에 탑재 가능한 GPS/INS 항법 컴퓨터의 구조를 제안한다. GPS/INS 항법 시스템을 소형 인공위성에 적용하기 위해서는 우선 우주의 방사능, 미세 중력, 진공 상태 등의 극한 환경을 고려해야 한다. 또한 소형 인공위성에서 GPS/INS 항법 시스템의 궁극적인 목표는 소형 인공위성의 편대 비행이므로 실시간 처리 능력이 필요하다. 제작된 항법 보드에는 우주환경에 대한 헤리티지가 있는 PowerPC계열의 MPC860T와 KAUSAT-2의 환경시험에서 우주환경에 대한 검증을 마친 ATmega128을 사용하였다. 항법 알고리즘은 MPC860T에 포팅된 VxWorks 환경에서 동작하도록 구현하였다.

• 한국항공운항학회:학술대회논문집
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• 한국항공운항학회 2004년도 추계학술발표대회 논문집
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• pp.295-301
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• 2004

• Journal of Positioning, Navigation, and Timing
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• 제7권1호
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• pp.15-24
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• 2018

This study analyzed positioning accuracy of the multi-differential global navigation satellite system (DGNSS) algorithm that integrated GPS, GLONASS, and BDS. Prior to the analysis, four sites of which satellite observation environment was different were selected, and satellite observation environments for each site were analyzed. The analysis results of the algorithm performance at each of the survey points showed that high positioning performance was obtained by using DGPS only without integration of satellite navigation systems in the open sky environment but the positioning performance of multi-DGNSS became higher as the satellite observation environments degraded. The comparison results of improved positioning performance of the multi-DGNSS at the poor reception environment compared to differential global positioning system (DGPS) positioning results showed that horizontal accuracy was improved by 78% and vertical accuracy was improved by 65% approximately.

• 한국항행학회논문지
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• 제23권3호
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• pp.245-250
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• 2019

관성항법장치는 시간 경과에 따라 관성센서 및 초기정렬 오차로 인해 항법 오차가 발생한다. 이를 보상하기 위한 방법으로 위성항법시스템 및 속도계 등을 이용하여 보정항법을 수행한다. 수중 환경에서는 GNSS 신호가 통하지 않기 때문에, 수중운동체에 탑재한 관성항법장치는 주로 속도계 보조센서를 이용하여 보정항법을 수행한다. 속도계 보조센서는 DVL, EM-Log, RPM이 있으며, 시스템 환경에 따라서 센서 종류가 적용된다. 본 논문은 고속 및 심해 환경에서 운용되는 관성항법장치의 RPM 속도보정항법을 설계하였다. 또한 직진 방향의 성분을 갖는 RPM 속도계의 한계를 보완하며, 해조류 속도 오차를 보상하는 알고리즘을 제안하였다. 제안한 알고리즘은 몬테카를로 시뮬레이션 결과를 통해 성능을 입증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.477-479
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• 1998

This paper presents the results of the field of an improved GPS navigation algorithm. The improved GPS navigation algorithm is a modified Kalman filter which is designed to be ideally suited to car navigation in urban area where lack of GPS visibility is the major problem because of the frequent blockage of the GPS signals by tall buildings and other structures. The method allows the user to estimate its position when the number of visible GPS satellites becomes less than four by using altitude fixing and clock bias estimation techniques. The two estimation techniques are integrated with the Kalman filter in a mutually compensating manner and it is shown that the 3-dimensional position accuracy is well maintained when the number of the visible satellites drops down to two for a reasonable period of time. The post processing results are included to show the improved performance of the modified algorithm over a normal conventional GPS Kalman filter.

• 한국항해학회지
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• 제21권4호
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• pp.1-9
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• 1997

A study on theergonomic design of the automated ship's bridge and console layout was carried out through this paper. The goal of this study is to find out the effective and ergonomic optimal design solutions of bridge layout hence to reduce the duty officier's workload and increase the safety of navigation. The conventional bridge layouts and modernized Integrated bridge layouts were compared using several factors. To use human factors, an ergonomic control panel layout system based on constraint satisfaction algorithm wa squoted. And the integrated ergonomic bridge layout was converged and applied to the redesign of the navigational console layout.