Young Jae Lee

Korea University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Sangkyung Sung

Konkuk University

Jongsun Ahn

Korea Advanced Institute of Science and Technology

Dae Hee Won

Korea Aerospace Research Institute

Sebum Chun

Korea Aerospace Research Institute

Sukchang Yun

Konkuk University

Taesam Kang

Konkuk University

Byungjin Lee

Konkuk University

Eunsung Lee

Seoul National University

Moon-Beom Heo

Korea Aerospace Research Institute

Gyu-In Jee

Konkuk University

Cooperative Institutions

Konkuk University

Konkuk University Medical Center

Seoul National University

Yonsei University

Korea Advanced Institute of Science and Technology

Kyungpook National University

Korea University

Daegu Gyeongbuk Institute of Science and Technology

Korea Aerospace Research Institute

Samsung (South Korea)

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Addition of High-inclination, High-eccentricity Orbit Satellites to Improve QZSS Performance

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES (2023)

Jiyeon WOO JinHyeok Jang Dana Park Sangkyung Sung Young Jae Lee

At present, Global Navigation Satellite System (GNSS) satellites operate in medium Earth orbits (MEOs), geostationary orbits (GEOs), or inclined geosynchronous orbits (IGSOs). The QZSS consists of GEO and IGSO satellites. When we considering the QZSS skyplot in Japan and its surrounding areas, there are no satellites in the northern sky. This results in a geometric placement imbalance, and thereby, causes position errors. The fundamental method to solve this problem is to position a satellite in the vacant northern area. Therefore, in this research, the addition of navigation satellites with a high-inclination, high-eccentricity orbit (a new type of orbit) is proposed. The vacant northern area can be filled effectively by adding a satellite using this orbit. Three satellites with this orbit were added to the QZSS in a simulation. Thereby, satellites were positioned effectively in the vacant northern area of the skyplot for Tokyo and Seoul. In addition, the improvement in performance was verified quantitatively through Horizontal Dilution of Precision (HDOP) and Vertical Dilution of Precision (VDOP). Accordingly, the addition of a satellite with a high-inclination, high-eccentricity orbit to the QZSS would enable more accurate positioning in Japan and its surrounding areas.

Quasi-Zenith Satellite System

Dilution of precision

Ground track

Orbit (dynamics)

Medium Earth orbit

Sun-synchronous orbit

10.2322/tjsass.66.244

Cite

Citations (0)

Design and performance test of relative navigation of a low cost inertial SLAM

2009 ICCAS-SICE (2009)

Sukchang Yun Sangkyung Sung Young Jae Lee

Despite its precise positioning performance, a GPS based navigation system may require the reference or augmentation station in close boundaries and is liable to be affected by satellite observation environments. Thus, this paper presents an INS/vision sensor integrated system, which in principle uses purely unknown feature points in previous epochs in order to cope with the limited GPS/INS integration environment. For the implementation of three-dimensional navigation using feature points, the presented system takes advantage of a robust image extraction and tracking algorithm, data association, and inertial SLAM filter algorithm. Finally, experimental results verified the performance of integrated navigation system, through which the performance enhancement in estimating relative position of the vehicle is demonstrated effectively.

GPS/INS

Position (finance)

Feature (linguistics)

Navigation System

Source

Cite

Citations (4)

Performance Improvement of GNSS Added with Non-Legacy Orbit

Proceedings of the Satellite Division's International Technical Meeting (Online)/Proceedings of the Satellite Division's International Technical Meeting (CD-ROM) (2022)

Jiyeon Woo Jinhyeok Jang Dana Park Sangkyung Sung Young Jae Lee

The geometric placement of current GNSS has a common problem. When the skyplot is drawn in the northern hemisphere where most of the world’s population is distributed, an area without satellites exists in the north. The area is created due to the limitation of the inclination angle of navigation satellite orbit. The inclination angle of GPS, Galileo, and BeiDou is 55 – 56°. The area leads to an imbalance in satellite placement. Therefore, the DOP performance cannot be improved above a certain level. As a fundamental solution, a satellite needs to be arranged in the northern area where existing navigation satellites do not pass through. Satellites with large inclination angle and eccentricity of orbit such as the Molniya satellites are added at this time. The satellite is used as a new navigation satellite by slightly modifying the orbital parameter of the Molniya satellites. A newly designed high-inclination and high-eccentricity orbit satellite was applied to GPS for a simulation. DOP performance was improved to a greater extent than conventional GPS. The high-inclination and high-eccentricity orbit can also be applied to other GNSS. The GNSS with a new orbit will help users of GNSS of the northern hemisphere to obtain more accurate position results.

Orbit (dynamics)

Sun-synchronous orbit

Medium Earth orbit

Galileo (satellite navigation)

Ground track

Orbital inclination

Eccentricity (behavior)

10.33012/2022.18314

Cite

Citations (0)

Performance Analysis of GNSS Ephemeris Fault Detection Algorithm Based on Carrier-Phase Measurement

Journal of the Korean Society for Aeronautical & Space Sciences (2014)

Jongsun Ahn Hyang-Sig Jun Gi-Wook Nam Chan-Hong Yeom Young Jae Lee

본 논문에서는 위성항법시스템의 무결성 저해 요인 중, 항법메시지에 담겨 전송되는 궤도력 (Ephemeris) 정보의 고장 여부를 판단할 수 있는 알고리즘을 분석 및 성능 평가를 수행하였다. 알고리즘은 반송파 측정값과 두 지상 기준국간의 기저벡터 정보가 활용된다. 주요 특징으로 기준국 기저선과 위성이 이루는 기하학적 조건 기저선 길이에 따라 동일 궤도력 고장에 대해 알고리즘의 성능의 편차가 발생할 수 있음을 확인하였다. 또한 알고리즘 적용이 적합한 GBAS의 지상 기준국 안테나 배치 방안 및 제주국제공항에 운용되었을 때의 한계치 및 성능 지표 (MDE : Minimum Detectable Error)를 계산하였다. We analyze fault detection algorithm of ephemeris included in navigation message, which is one of the GNSS risk factors. This algorithm uses carrier-phase measurement and baseline vector of two reference stations and is alternative method for uncertainty condition of previous ephemeris. Even though same ephemeris fault is occurred, the geometry condition, between baseline vector of reference stations and satellites, effects on performance of algorithm. Also, we introduce the suitable geometry of reference stations, threshold and performance index (MDE : Minimum Detectable Error) in jeju international airport.

Ephemeris

Baseline (sea)

GNSS augmentation

10.5139/jksas.2014.42.6.453

Cite

Citations (1)

Performance Comparison of Resampling Algorithms for Heading Angle Estimation using Magnetometer and IMU

한국항공우주학회 학술발표회 논문집 (2010)

Zin Mar Lwin Younjeong Heo Eunsung Lee Young Jae Lee Sangkyung Sung

In this paper, performance of resampling algorithms are explored and analyzed based on the simulation of particle filter for the flight heading error estimation using magnetometer and IMU. Development of resampling method plays an important role in particle filter implementation because the effects of degeneracy problem found in particle filter can be reduced by using resampling method. The main goal of this paper is to compare the resampling methods and to investigate the most efficient resampling method to increase the speed and to improve the quality of particle filter for an advanced application.

Resampling

Auxiliary particle filter

Source

Cite

Citations (0)

GBAS Ground Testing and Performance Analysis at Gimpo International Airport

The Journal of Advanced Navigation Technology (2015)

Myeong-Sook Jeong Yunjung Choi Youngsun Yun Joong-Won Bae Hyang-Sig Jun

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. Ground based augmentation system (GBAS) is a next generation radio navigation aids to support precision approach of aircraft. Recently, airports installing GBAS and providing GBAS service are increasing all over the world. For the first time in Korea, SLS-4000 which is the GBAS ground equipment of Honeywell had been installed at Gimpo International Airport in 2013, and evaluated its functionality and performance of through the ground testing. This paper introduces a ground test and evaluation criteria on the CAT-I GBAS system, and describes testing methods for GBAS ground testing of Gimpo International Airport. In addition, detail testing methods and analysis results on major five of 12 ground test items are described.

GNSS augmentation

10.12673/jant.2015.19.1.22

Cite

Citations (0)

Modeling of turbulent jet diffusion flames. 2nd report, Application of the modified .KAPPA.-.EPSILON. turbulence model to turbulent jet diffusion flames.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B (1991)

Young Jae Lee Yoshiaki ONUMA

It was examined whether the modified k-ε model, obtained from the modeling of hot air jets in the 1st report, is applicable to the numerical simulation of turbulent combustion flow fields. Calculated results were compared with experimental ones in hydrogen jet diffusion flames, and it was then revealed that the modified k-ε model represents very well flow fields with laminarization due to the existence of flames, and the model is useful for the numerical simulation of turbulent combustion fields. However, although the ordinary k-ε model also represented the large trend in turbulent flow fields of jet flames, the calculated and experimental results did not agree well. This was supposed to be due to the fact that the model cannot represent the foregoing laminarization in flames.

Turbulent diffusion

10.1299/kikaib.57.339

Cite

Citations (1)

High‐temperature meltdown characteristics of DRI‐flux mixture in a melter‐gasifier

Scandinavian Journal of Metallurgy (2000)

Young Jae Lee Chong Min Cho

The slag formation mechanism in the melter‐gasifier was examined by the meltdown test for DRI‐additive‐ash mixed bed under load and by analysis for the slag taken from the actual furnace of the two‐step ironmaking process. For the slag phase analyses, chemical analysis, SEM‐EDS and XRD pattern analysis were employed. The primary slag originated from the gangue in DRI was homogeneous. Partially‐melted secondary slag consisting of dicalcium silicate with dissolved FeO was formed under rather higher CaO/SiO 2 basicity compared to that of tapped slag. Then, these slags reacted with bottom ash resulting in the homogeneous tertiary slag with the dissolved FeO. Finally, the final slag, similar to tapped slag, was collected on the top of the metal pool. The slag had CaO/SiO 2 slightly greater than 1 in the hearth of the melter‐gasifier.

Slag (welding)

Wood gas generator

Alkalinity

Gangue

10.1034/j.1600-0692.2000.d01-30.x

Cite

Citations (1)

Analysis of Performance of the Satellite Orbit Fault Detection Method Using Inter-Satellite Link (ISL) Range Measurement and Trigonometry Law

Proceedings of the Satellite Division's International Technical Meeting (Online)/Proceedings of the Satellite Division's International Technical Meeting (CD-ROM) (2018)

JinHyeok Jang SangHoon Koo Jung Min Joo Moon Beom Heo Sangkyung Sung

Satellite coordinates are critical information in calculating the user’s location on the Global Navigation Satellite System (GNSS). This system estimates coordinates using ephemeris. Ephemeris is a value generated through satellite orbit estimation and does not indicate current satellite coordinates. When an unexpected problem or ephemeris modify problem occurs in the satellite operation, this results in a considerable error for the user. Ground reference stations apply a monitoring technique to prevent this problem. However, the current existing technique uses ground measurement estimated from ground reference stations, which inevitably incurs various errors. Error estimation can eliminate such errors, but in turn, this technique entails possible estimation error. As a result, the performance of this error detection technique decreases. Ground reference stations use distance values to detect satellite faults from the ground. This can also potentially reduce the detection performance as detection is dependent on geometrical arrangement and the direction of satellite faults. To resolve these two problems, the present study proposes a satellite orbit fault detection method using the Inter-Satellite Link (ISL) and the trigonometry law. We calculated test statistic and analyzed the sensitivity of our new method. Based on this, we identified the characteristics of our method. We calculated threshold and Minimum Detectable Error (MDE) based on statistical theories. Calculated values were tested through simulation. Finally, the performance of our method was confirmed through a quantitative comparison of sensitivity and MDE between the existing technique and our method.

Ephemeris

Orbit Determination

Orbit (dynamics)

10.33012/2018.16113

Cite

Citations (0)

A Study on the Coordinate Transformation of Cadastral map to World Geodetic System Using Thin Plate Spline Interpolation

한국지적정보학회지 (2016)

이종민 이원희 Young Jae Lee 강상구

Cadastre

Interpolation

Spline (mechanical)

Source

Cite

Citations (0)