• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.455-458
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• 2006

The Real Time Kinematic (RTK) technique is the most productive and accurate GPS positioning method today, as it can be determinate position within few centimeters instantly. This method is widely used for applications such as surveying, structure monitoring and machine guidance etc. In order to perform RTK processing for large scale systems (i.e. precise vehicle monitoring with many rovers), many expensive RTK receivers and same number of bidirectional communication units have to be installed to collect observation data communicate with the reference site and monitor its RTK solutions. Moreover, if applications require remote control or apply sensing instruments, we have to install computers at each rover. To limit expense and complexity of system management with a large number of rovers, we have developed server based RTK processing platform to share RTK function for all rovers. The system can be process many GPS stations with a single personal computer. we have also developed a specialized dual frequency GPS receiver unit without on-board RTK processing capability to reduce receiver cost in order to demonstrate the advantage of our server based RTK platform. This paper describes the concept of our server based RTK platform and specialized GPS receiver unit with existing applications in Japan.

• 천문학회보
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• 제44권1호
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• pp.74.3-75
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• 2019

Recent Integral Field Spectroscopy (IFS) studies revealed that not only late type galaxies (LTGs) but also early type galaxies (ETGs) have various kinds of kinematic rotation. (e.g. not clearly detectable rotation, disk-like rotation, kinematically distinct core (Cappellari 06)) Among the various studies about galactic kinematics, one of the most notable anomalies is the star-gas misalignment. The gas forms stars and stars release gas through mass-loss. In this process, their angular momentum is conserved. Therefore, kinematic decoupling between stars and gas can occur due to external gas inflow or perturbation of components. There are some possible origins of misalignment: cold gas from filaments, hot gas from outer halo, interaction or merging events with galaxies and environmental effects. Misalignment, the black box from mixture of internal and external gas, can be an important keyword for understanding further about galaxies' kinematics and external processes. Using both SAMI IFS data(Sydney-AAO Multi-object Integral field spectrograph Galaxy Survey, Croom+12) and Horizon-AGN simulation(Dubois+14), we examined misaligned galaxies properties and distribution. Because the simulation has lots of galaxies at various z, we were able to study history of formation, evolution and extinction of misalignment, which was hard to be done with observation only.

• 천문학회보
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• 제44권2호
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• pp.75.4-75.4
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• 2019

We present a quantitative analysis of the relationship between the gas dynamics and star formation history of DDO 210 which is an irregular dwarf galaxy in the local Universe. We perform profile analysis of an high-resolution neutral hydrogen (HI) data cube of the galaxy taken with the large Very Large Array (VLA) survey, LITTLE THINGS using newly developed algorithm based on a Bayesian Markov Chain Monte Carlo (MCMC) technique. The complex HI structure and kinematics of the galaxy are decomposed into multiple kinematic components in a quantitative way like 1) bulk motions which are most likely to follow the underlying circular rotation of the disk, 2) non-circular motions deviating from the bulk motions, and 3) kinematically cold and warm components with narrower and wider velocity dispersion. The decomposed kinematic components are then spatially correlated with the distribution of stellar populations obtained from the color-magnitude diagram (CMD) fitting method. The cold and warm gas components show negative and positive correlations between their velocity dispersions and the surface star formation rates of the populations with ages of < 40 Myr and 100~400 Myr, respectively. The cold gas is most likely to be associated with the young stellar populations. Then the stellar feedback of the young populations could influence the warm gas. The age difference between the populations which show the correlations indicates the time delay of the stellar feedback.

• 천문학회보
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• 제45권1호
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• pp.60.3-61
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• 2020

We perform disk-halo decomposition of the Large Magellanic Cloud (LMC) using a novel HI velocity field extraction method, aimed at better deriving its HI kinematics and thus the dark matter density profile. For this, we use two newly developed galaxy kinematic analysis tools, BAYGAUD and 2DBAT which have been used for the kinematic analysis of resolved galaxies from Australian Square Kilometre Array (ASKAP) observations like WALLABY which is an all-sky HI galaxy survey in southern sky. By applying BAYGAUD to the combined HI data cube of the LMC taken with the Australia Telescope Compact Array (ATCA) and Parkes radio telescopes, we decompose all the line-of-sight velocity profiles into an optimal number of Gaussian components based on Bayesian MCMC techniques. From this, we disentangle turbulent non-circular gas motions from the overall rotation of the galaxy. We then derive the rotation curve of the LMC by applying 2DBAT to the separated circular motions. The rotation curve reflecting the total kinematics of the LMC, dark and baryonic matters is then be combined with the mass models of baryons, mainly stellar and gaseous components in order to examine the dark matter distribution. Here, we present the analysis of the extracted HI gas maps, rotation curve, and J, H and K-band surface photometry of the LMC.

• 한국지형학회지
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• 제28권4호
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• pp.41-52
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• 2021

With the popularization of drones and the ease of use of the Global Navigation Satellite System (GNSS), drone photogrammetry for terrain information has been widely used. Drone photogrammetry enables the realization of high-accuracy three-dimensional topography for the entire area with less effort and time compared to the past direct survey using GNSS or total station. From 3-D topographic data, various topographical analysis is possible. To improve the accuracy of drone photogrammetry, direct GCP surveying in the field is essential, and the numbers and reasonable positioning of GCPs are very important. In the case of beaches or tidal flats on the west coast of Korea, the numbers and location of GCPs are important factors in efficient drone photogrammetry because of the size of the area, difficulties of movement, and the risk from tides. If the RTK (Real-time kinematic) or PPK (Post-processed kinematic) method is used, the increased accuracy of the drone's location enables high-accuracy photogrammetry with a small number of GCPs. This study presents an efficient drone photogrammetry method in terms of time and economy by comparing and analyzing the results of drone photogrammetry using Non-PPK with low-cost PPK-Kit, based on the tests of various numbers and locations of GCPs in the university field including various slopes and structures like coastal terrain.

• 천문학회보
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• 제37권2호
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• pp.235-235
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• 2012

The "Widefield ASKAP L-band Legacy All-sky Blind surveY" (WALLABY) is an extragalactic HI survey which aims to examine HI properties and large-scale distribution of ~500,000 galaxies out to z ~ 0.27, covering a wide range of science goals associated with galaxy formation and evolution (P.I.: B. Koribalski & L. Staveley-Smith). The combination of ASKAP's exquisite column density sensitivity and a large primary beam will make it possible to systematically investigate the rarely explored low column-density HI in the universe. Ultimately, the largest and most homogeneous data set from WALLABY will drastically improve and broaden our knowledge on galaxy formation and evolution. ASKAP will be on-line in 2013, so to ensure timely and efficient reduction and analysis of the large WALLABY data set, we have been developing and testing reliable source finding tools and data analysis pipelines. In this talk I present recent progress of WALLABY, especially on the kinematic parameterisation pipeline for the spatially resolved galaxies detected by WALLABY.

• 한국측량학회지
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• 제17권3호
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• pp.197-203
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• 1999

GPS의 이동측량 방법을 사용하여 위치정보와 속성정보를 취득하는 경우, 대상지의 지형학적 위치와 여러가지 오차요인에 의해 이상점이 발생하게 된다. 본 연구에서는 절사평균 방법과 1차 미분을 이용한 이상점 검출 알고리즘을 작성하고, 선형보간법과 다항식보간법을 사용하여 이상점 보간을 하였다. 또한 정확하게 보간된 데이터를 이용하여 국도 30 km구간에 대해 수치지도를 제작하였으며 수치지도를 제작하는 과정에서 발생될 수 있는 문제점들을 고찰하고 문제점들의 해결을 통해 정확한 GIS 커버리지 맵을 작성하였다.

• 천문학회보
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• 제44권1호
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• pp.69.2-69.2
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• 2019

Recent high resolution IR observations reveal that molecular clouds are filamentary and such a structure is ubiquitous over various star-forming environments, and it is clear that filaments play a crucial role in the formation of cores and stars. However, the formation process of dense cores in the filaments are still unknown. To investigate this issue in detail, we have carried out TRAO FUNS (TRAO survey of nearby Filamentary molecular clouds, the Universal Nursery of Stars) toward various star forming filamentary molecular clouds. In this presentation, we will report the first look results of filaments and dense cores in MCLD 123.5+24.9 and IC 5146, which are known as a quiescent, non-star-forming region and an active, high-mass star forming region, respectively. By comparing the kinematic properties of filaments and dense cores in different star forming environments, we verified the formation scenario of filaments and dense core, i.e., gravoturbulent fragmentation via supersonic motions.

• 한국측량학회지
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• 제38권6호
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• pp.663-670
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• 2020

본 연구에서는 건물이 혼재한 준 도심 지역에서 발생할 수 있는 재난/재해를 가정하여 네트워크 RTK (Real Time Kinematic) 측위가 가능한 무인기를 이용한 항공삼각측량의 정확도를 평가하였다. 검사점 측위의 신뢰성을 확보하기 위해 검사점을 건물의 옥상에 설치하여 네 시간 이상의 GNSS (Global Navigation Satellite System) 정적 측위를 수행하였다. 객관적인 정확도 평가를 위해 소프트웨어에서 자동으로 인식 가능한 코드화된 대공 타겟을 사용하였다. 무인기에서는 네트워크 RTK 측위의 일종인 VRS (Virtual Reference Station) 방식을 이용하여 영상 취득 당시 카메라의 3차원 좌표를 측정하였고, IMU (Inertial Measurement Unit)와 짐벌 회전각 측정을 통해 카메라의 3축 회전각을 측정하였다. Agisoft Metashape를 이용하여 내·외부 표정요소를 추정·갱신한 결과, 항공삼각측량의 3차원 RMSE (Root Mean Square Error)는 영상의 중복도와 촬영 각도의 조합에 따라 크게는 0.153 m에서 작게는 0.102 m로 나타났다. 더욱 높은 수준의 항공삼각측량 정확도를 확보하기 위해서는 연직 영상의 중복도를 높이는 것이 일반적이나 경사 영상을 추가하는 것이 효과적인 것으로 나타났다. 따라서 대응 단계의 재난/재해 현장에서 긴급하게 무인기 매핑을 수행할 경우 중복도를 높이기 보다는 경사 영상도 함께 취득할 필요가 있다.

• 천문학회보
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• 제40권1호
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• pp.74.2-74.2
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• 2015

Strong outflows from active galactic nuclei (AGNs) may play a crucial role in galaxy evolution. Integral-field spectroscopy (IFS) is the most powerful tool to study the detailed kinematics of AGN outflows. We present the on-going optical 3D spectroscopic survey of ionized gas outflows. Type 2 AGN sample is uniquely selected from SDSS DR7 with a luminosity-limit (i.e., L[O III] > $10^{41.5}erg/s$) as well as strong kinematic signatures of ionized gas outflows ([O III] velocity shift > ~200 km/s or [O III] velocity dispersion (FWHM) > 1000 km/s), defining an extremely rare population (< ~0.5%). Thus, these AGNs with strong outflow signatures are one of the best suites for investigating AGN feedback. The IFS observations cover several kpc scales for the central region of the host galaxies, providing a detailed information of the kinematics and geometry of the gas outflows. In this contribution, we report the current status of the survey and the preliminary results on gas kinematics of 18 AGNs, based on the Magellan/IMACS-IFU and the VLT/VIMOS data.