A5090079222- GNSS positioning and interference
- Geophysics and Gravity Measurements
- Ionosphere and magnetosphere dynamics
- Inertial Sensor and Navigation
- Earthquake Detection and Analysis
- Space Satellite Systems and Control
- Advanced Frequency and Time Standards
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Spacecraft Dynamics and Control
- Infrared Target Detection Methodologies
- Satellite Communication Systems
- Fault Detection and Control Systems
- Indoor and Outdoor Localization Technologies
- Impact of Light on Environment and Health
- Aerospace Engineering and Control Systems
- Atmospheric aerosols and clouds
- Magnetic confinement fusion research
- Optical Systems and Laser Technology
- Innovation in Digital Healthcare Systems
- earthquake and tectonic studies
- Marine and Coastal Research
- Statistical and numerical algorithms
- Spacecraft Design and Technology
Korea Astronomy and Space Science Institute
2011-2023
Yonsei University
1999-2005
Astronomy and Space
1999
In this study, global positioning system (GPS)-derived precipitable water vapor (PWV) and microwave radiometer (MWR)-measured integrated (IWV) were compared their characteristics analyzed. Comparing those two quantities for years from August 2009, we found that GPS PWV estimates larger than MWR IWV. The average difference over the entire test period was 1.1 mm standard deviation 1.2 mm. When discrepancies between IWV analyzed depending on season, 0.7 1.9 in winter summer months,...
The Korean government has a plan to build new regional satellite navigation system called the Positioning System (KPS). initial KPS constellation is designed consist of seven satellites, which include three geostationary Earth orbit (GEO) satellites and four inclined geosynchronous (IGSO) satellites. will provide an independent positioning, navigation, timing (PNT) service in Asia-Oceania region can also be compatible with GPS. In simulation for KPS, we employ 24 GPS as initially 7 Compared...
In this study, we compared the precipitable water vapor (PWV) data derived from radiosonde observation at Sokcho Observatory and PWV Global Positioning System (GPS) provided by Korea Astronomy Space Science Institute, for years of 2006, 2008, 2010, analyzed seasonal, diurnal bias according to sensor types. scatter diagram daytime nighttime GPS data, dry was found in as known previous study. Overall, tendency that wet increased decreased increased. The quantitative analysis error showed mean...
Covers advancements in spacecraft and tactical strategic missile systems, including subsystem design application, mission analysis, materials structures, developments space sciences, processing manufacturing, operations, applications of technologies to other fields.
Kinematic global positioning system precise point (GPS PPP) technology is widely used to the several area such as monitoring of crustal movement and orbit determination (POD) using dual-frequency GPS observations. In this study we developed a kinematic PPP applied 3-pass (forward/backward/forward) filter for stabilization initial state parameters be estimated. For verification results, obtained data sets from six international reference stations (ALGO, AMC2, BJFS, GRAZ, IENG TSKB) processed...
Ionosphere is one of the largest error sources when navigational signals produced by Global Positioning System (GPS) satellites are transmitted. Therefore it very important to estimate total electron contents (TEC) in ionosphere precisely for navigation, precise positioning and some other applications. When we provide ionospheric TEC values real-time, its application can be expanded areas. In this study have used data obtained from nine Navigation Satellite (GNSS) reference stations which...
The real-time kinematic (RTK) is one of precise positioning methods using Global Positioning System (GPS) data. In the long baseline GPS RTK, ionospheric and tropospheric delays are critical factors for accuracy. this paper we present RTK algorithms baselines more than 100 km with estimating delays. state vector estimated by extended Kalman filter. We show experimental results various (162.10, 393.37, 582.29, 1283.57 km) Korea Astronomy Space Science Institute data International GNSS Service...
The Earth is not perfectly spherical and its rotational axis fixed in space, these geophysical kinematic irregularities work as dominant perturbations satellite orbit propagation. International Rotation Service (IERS) provides the Conventions guidelines for using Earth's model reference time coordinate systems defined by Astronomical Union (IAU). These are directly applied to orbital dynamics of satellites. In present work, effects latest conventions released 2010 on propagation investigated...
이 논문의 목적은 이온층의 대표적인 교란현상인 Equatorial Spread F(ESF)가 GPS 관측 값을 이용한 저궤도위성의 상대궤도결정에 미치는 영향을 분석하는 것이다. 궤도결정은 우주기반의 Differential GPS(DGPS)방법을 이용했으며, 궤도결정 성능의 분석을 위해 ESF가 발생하지 않는 시점인 2004년 10월 한 달간에 대해 GRACE 두 위성의 상대궤도를 결정하였다. 정밀도를 검증하기 상대궤도 정보로부터 계산된 기선거리를 K-Band Ranging 값과 비교하였고, 그 결과 기선거리의 평균오차는 약 2~3mm(<TEX>$1{\sigma}$</TEX>)였다. 결과를 바탕으로 하여 우주기반 DGPS 자료처리에 분석하기 자주 발생한 2003년과 거의 않은 2004년에 2주씩 자료처리를 수행하였다. 2003년의 2주간 평균 기선 거리 오차는 15mm로 2004년의 3.5mm보다 상대적으로 켰으며, 센서를 통해 당시의 ESF로 보이는 교란현상이 많이...
In this study, positioning results that combined the code observation information of GPS and GLONASS navigation satellites were analyzed. Especially, distribution observed in Korea GPS/GLONASS presented. The GNSS data received at two reference stations (GRAS Europe KOHG Goheung, Korea) during a day processed, mean value root square (RMS) position error calculated. analysis indicated did not show significantly improved performance compared to GPS-only positioning. This could be due...
Covers advancements in spacecraft and tactical strategic missile systems, including subsystem design application, mission analysis, materials structures, developments space sciences, processing manufacturing, operations, applications of technologies to other fields.
The Korean Multipurpose Satellite-5 (KOMPSAT-5) launched on 22 August 2013 was equipped with a global positioning system (GPS) receiver for precision orbit determination (POD). Even though the GPS of KOMPSAT-5 shares same heritage as BlackJack onboard in Gravity Recovery and Climate Experiment (GRACE) satellites, has lower orbital position accuracy (~10 cm) compared GRACE (~2 cm). reduced dynamic kinematic methods are applied POD to investigate observation quality due satellite operation...
Precise Point Positioning (PPP) is a stand-alone precise positioning approach. As the quality of satellite orbit and clock products from analysis centers has been improved, PPP can provide more accuracy reliability. A combined use Global System (GPS) Orbiting Navigation Satellite (GLONASS) in now available. In this paper, we explained about an approach for GPS GLONASS measurement processing, validated performance through comparison with GPS-only results. We also used obtained GRAS reference...
Precise Point Positioning (PPP) has been widely used in navigation and orbit determination applications as we can obtain precise Global System (GPS) satellite clock products. Kinematic PPP, which is based on the GPS measurements only from spaceborne receiver, some advantages for a simple (POD). In this study, developed kinematic PPP technique to estimate orbits of GRACE-A satellite. The comparison mean position between JPL's product our results showed differences 0.18 cm, 0.54 0.98 cm...
A strategy for geostationary orbit (or earth [GEO]) surveillance based on optical angular observations is presented in this study. For the dynamic model, precise analytical model developed by Lee et al. (1997) used to improve computation performance and unscented Kalman filer (UKF) applied as a real-time filtering method. The UKF known perform well under highly nonlinear conditions such that combines propagation tested various like different level of initial error measurement noise....
Being a torque free motion of the rotating Earth, Chandler wobble is major component in Earth’s polar with amplitude about 0.05-0.2 arcsec and period 430-435 days. Free core nutation, also called nearly diurnal wobble, exists due to elliptical core-mantle boundary Earth takes almost whole part un-modelled variation pole celestial sphere beside precession nutation. We hereby present brief summary their theories report recent features acquired from updated datasets (EOP C04 ECMWF) by using...
The Korea Astronomy and Space Science Institute is working on a project, the Republic of Imaging Test System shortly called ROKITS, which an optical system that aims to study formation occurrence aurora. main objective gain insights into changes occurring in atmosphere, particularly upper due external energy sources from outside Earth. Additionally, will investigate feasibility detecting atmospheric waves, specifically gravity spread lower atmosphere. To achieve these scientific goals, 90...
위성에 탑재된 GPS 수신기의 관측 자료를 활용하여 저궤도위성의 정밀궤도 결정을 위해서 반드시 필요한 자료 전처리에 관련된 연구를 수행하였다. 전처리 과정에서는 반송파 위상 자료와 코드 자료에 있는 사이클 슬립, 시계 오차, 불량 관측값, 이온층 지연 효과 등을 제거하거나 보정하여 일정한 간격으로 재정렬된 이중차분 생성한다. DGPS 방식을 이용하여 저궤도 위성의 정밀궤도결정을 수행하면 그 정밀도가 수 미터에서 센티미터 수준에 달하기 때문에 과정에서도 정밀도에 영향을 미치지 않을 정도로 자료의 편집이 정밀하게 수행되어야 한다. 그러나 GPS수신기가 수집하는 시간간격에 따라 분해할 한계가 달라지기 수신시간간격은 전처리의 성능과 직결된다. 또한 수신기를 탑재한 고도에 따라서 질이 달라지기도 하므로, 이 논문에서는 방식에 의한 수행하기 위한 과정에서 수신시간간격, 따른 성능을 분석하여 시간간격과 종류에 사용할 방법을 제안하였다. This article investigates the...