• Journal of Advanced Navigation Technology
• /
• v.22 no.6
• /
• pp.591-601
• /
• 2018

This paper discusses methods to effectively operates and evaluates an infrastructure system for lane-level positioning based on satellite navigation. The lane-level positioning infrastructure provides correction information on range measurements with integrity information on the correction to a user with a single frequency (cheap) satellite navigation receiver in order to perform lane-level positioning and integrity monitoring on the position estimate. The architecture and configuration of the lane-level positioning system are described from the systematic level in order to provide a comprehensive insight of the system. The operation/evaluation system for the integrated infrastructure is then presented. The evaluation results of the real implemented system are provided. Based on the results, we discuss requirements to increase the system stability from the operation perspective.

• Journal of Advanced Navigation Technology
• /
• v.22 no.2
• /
• pp.49-56
• /
• 2018

As the energy generated by earthquake, tsunami, etc. propagates through the air and disturbs the electron density in the ionosphere, the perturbation can be detected by analyzing the ionospheric delay in satellite signal. The electron density in the ionosphere is affected by various factors such as solar activity, latitude, season, and local time. To distinguish from the anomaly, therefore, it is required to inspect the normal trend of the ionosphere. Also, as the perturbation magnitude diminishes by distance it is necessary to develop an appropriate algorithm to detect long-distance disturbances. In this paper, normal condition ionosphere trend is analyzed via IONEX data. We selected monitoring value that has no tendency and developed an algorithm to effectively detect the long-distance ionospheric disturbances by using the lasting characteristics of the disturbances. In the end, we concluded the $2^{nd}$ derivative of ionospheric delay would be proper monitoring value, and the false alarm with the developed algorithm turned out to be 1.4e-6 level. It was applied to 2011 Tohoku earthquake case and the ionospheric disturbance was successfully detected.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.8 no.3
• /
• pp.467-475
• /
• 2018

Recently earthquakes have been increasing worldwide, and the largest earthquake of 5.8 on the Richter scale occurred on September 12, 2016 in the Gyeongju area. After the earthquake, more than 200 aftershocks have occurred from January 2017 to December 2017. The largest earthquake in 2017 was a 4.3-magnitude earthquake near Pohang on November 15. In this study, we tried to analyze the coordinate change due to the earthquake using the data of the CORS(Continuously Operating Reference Station) in Korea. In order to analyze the change of coordinates due to the earthquake in Pohang area on November 15, 2017, data processing was performed by kinematic method. And from January 2017 to December 2017, observation data of 9 stations in Korea were analyzed by relative positioning method and the change of coordinates due to earthquake was analyzed. As a result of the study, it was possible to estimate the instantaneous coordinate change due to the earthquake through the kinematic positioning, and it was suggested that there is no change in the coordinates of the domestic CORS by the relative positioning results. After the 2017 Gyeongju earthquake, aftershocks continue to occur, and it is necessary to monitor the area continuously.

• Journal of Environmental Policy
• /
• v.14 no.2
• /
• pp.149-170
• /
• 2015

The purpose of this paper is to figure out the research direction and information regarding Mt. Baekdu in Korea through analyses of the research field and trends. Firstly, we made inventory of journal papers, conference proceedings, and research reports published related to Mt. Baekdu. A total of 255 data, spanning the 34 years from the 1980s to the middle of 2014, were acquired and classified into categories according to the year, field, contents and study area. Results show that research on Mt. Baekdu has been performed more than twice since 2010 and study regarding prediction has been carried out in 54.7% cases. In addition, the importance of geo-spatial information is expected to increase in order to study Mt. Baekdu. Secondly, we made and analyzed a geospatial information using inventory of 234 detailed research contents in research reports by Korea Meteorological Administration (KMA) and National Institute of Meteorological Research (NIMR). Statistics on categories show that research regarding prediction accounted for 81.6% of cases and the study of geo-spatial information utilization accounted for 54.7% of cases. However, the focus on studying the Mt. Baekdu region accounted for only 20.1% of cases. Thus, this indicates that it is necessary to do research at Mt. Bakdu itself. If the directly available geo-spatial information system is developed related to Mt. Baekdu, it will save research costs and analysis time. This study can be used to manage information about the research field of Mt. Baekdu by analysing inventory of research references and geospatial information using inventories when the Mt. Baekdu area is the focus of future research.

• Korean Journal of Remote Sensing
• /
• v.37 no.5_1
• /
• pp.1135-1147
• /
• 2021

In order to geometrically correct high-resolution satellite imagery, the sensor modeling process that restores the geometric relationship between the satellite sensor and the ground surface at the image acquisition time is required. In general, high-resolution satellites provide RPC (Rational Polynomial Coefficient) information, but the vendor-provided RPC includes geometric distortion caused by the position and orientation of the satellite sensor. GCP (Ground Control Point) is generally used to correct the RPC errors. The representative method of acquiring GCP is field survey to obtain accurate ground coordinates. However, it is difficult to find the GCP in the satellite image due to the quality of the image, land cover change, relief displacement, etc. By using image maps acquired from various sensors as reference data, it is possible to automate the collection of GCP through the image matching algorithm. In this study, the RPC of KOMPSAT-3A satellite image was corrected through the extracted matching point using the UAV (Unmanned Aerial Vehichle) imagery. We propose a pre-porocessing method for the extraction of matching points between the UAV imagery and KOMPSAT-3A satellite image. To this end, the characteristics of matching points extracted by independently applying the SURF (Speeded-Up Robust Features) and the phase correlation, which are representative feature-based matching method and area-based matching method, respectively, were compared. The RPC adjustment parameters were calculated using the matching points extracted through each algorithm. In order to verify the performance and usability of the proposed method, it was compared with the GCP-based RPC correction result. The GCP-based method showed an improvement of correction accuracy by 2.14 pixels for the sample and 5.43 pixelsfor the line compared to the vendor-provided RPC. In the proposed method using SURF and phase correlation methods, the accuracy of sample was improved by 0.83 pixels and 1.49 pixels, and that of line wasimproved by 4.81 pixels and 5.19 pixels, respectively, compared to the vendor-provided RPC. Through the experimental results, the proposed method using the UAV imagery presented the possibility as an alternative to the GCP-based method for the RPC correction.