• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.269-277
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• 2022

In this paper, we overview the system development status of the national maritime precise point positioning-real-time kinematic (PPP-RTK) service in Korea, also known as the Precise POsitioning and INTegrity monitoring (POINT) system. The development of the POINT service began in 2020, and the open service is scheduled to start in 2025. The architecture of the POINT system is composed of three provider-side facilities-a reference station, monitoring station, and central control station-and one user-side receiver platform. Here, we propose the detailed functionality of each component considering unidirectional broadcasting of augmentation data. To meet the centimeter-level user positioning accuracy in maritime coverage, new reference stations were installed. Each reference station operates with a dual receiver and dual antenna to reduce the risk of malfunctioning, which can deteriorate the availability of the POINT service. The initial experimental results of a testbed from corrections generated from the testbed network, including newly installed reference stations, are presented. The results show that the horizontal and vertical accuracies satisfy 2.63 cm and 5.77 cm, respectively. For the purpose of (near) real-time broadcasting of POINT correction data, we designed a correction message format including satellite orbit, satellite clock, satellite signal bias, ionospheric delay, tropospheric delay, and coordinate transformation parameters. The (near) real-time experimental setup utilizing (near) real-time processing of testbed network data and the designed message format are proposed for future testing and verification of the system.

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.524-533
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• 2015

In this paper, results for an installation and operation of a GPS jammer localization system were analyzed. The jammer localization system was developed by Korea Aerospace Research Institute and it consists of 4 Receiver Stations, a Central Tracking Station, and a Monitoring Station. The system was installed at Incheon International Airport in November 2014; each Receiver Stations were installed at rooftop of buildings apart from 4km, and the Central Tracking Station and a Monitoring Station were installed at indoor. Results of the operation can be monitored through web-browser in real-time, Korea Aerospace Research Institute and Incheon International Airport Corporation are continuously monitoring them. So far, there is no jamming signal which affects GPS receivers around the airport, however, some abnormal signals were frequently received at Receiver Stations. Therefore, the characteristics of those signals were also analyzed in this paper.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.37-44
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• 2009

In this paper, we propose an efficient method which improves the performance of transmission of PGA which is essential data for real-time earthquake monitoring system. Currently, above 120 earthquake stations were installed nationwide and additional installation is expected because the social interesting of earthquake hazard is rising. Real-time earthquake monitoring system checks earthquake occurrence by using PGA were calculated from acceleration data of each seismic station. An efficient method of PGA data transmission is key factor of real-time monitoring. The key idea of proposed method is to deal with each seismic station using an unique ID, to assign one bit to indicate whether a packet include a station's data or not. Proposed method can contain more station data and decrease the data loss compared to current method. To verify proposed method, we investigate the turnaround time and ratio of data loss using above 91000 packets. As results of experiment. the proposed method is proven that the method need more time about 50% but reduce the data loss about 87% as compared to previous method.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2422-2429
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• 2011

The main function of station is supplying the convenient environment to the passengers as a vehicle waiting place. Smart station is networked based on the station which has been combined with additional functions like effective operation and real time monitoring and power control. Smart station network for the operation has been concerning about the communication security and the data transmission distance between vehicle and station. Smart station can be useful for the ubiquitous data communication place where the people can use their personal communication instruments very easily and quickly. This is the smart station.

• Particle and aerosol research
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• v.16 no.2
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• pp.31-47
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• 2020

Although interest in air quality has increased due to the frequent occurrence of high-concentration fine particulate matter recently, the official fine particulate matter measuring network has failed to provide spatial detailed air quality information. This is because current measurement equipment has a high cost of installation and maintenance, which limits the composition of the measuring network at high resolution. To compensate for the limitations of the current official measuring network, this study constructed a spatial high density measuring network using the fine particulate matter simple measuring device developed by Observer, W-Station. W-Station installed 48 units on Jeju Island and measured PM_2.5 for six months. The data collected in W-Station were corrected by applying the first regression equation for each section, and these measurements were compared and analyzed based on the official measurements installed in Jeju Island. As a result, the time series of PM_2.5 concentrations measured in W-Station showed concentration characteristics similar to those of the environmental pollution measuring network. In particular, the results of comparing the measurements of W-Station within a 2 km radius of the reference station and the reference station showed that the coefficient of determination (R²) was 0.79, 0.81, 0.67, respectively. In addition, for W-Station within a 1 km radius, the coefficient of determination was 0.85, 0.82, 0.68, respectively, showing slightly higher correlation. In addition, the local concentration deviation of some regions could be confirmed through 48 high density measuring networks. These results show that if a network of measurements is constructed with adequate spatial distribution using a number of simple meters with a certain degree of proven performance, the measurements are effective in monitoring local air quality and can be fully utilized to supplement or replace formal measurements.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.847-859
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• 2011

This paper presents an alarm system for the integrated monitoring and control station of waterworks in Daegu City. An alarm system informs the operator or other responsible individuals about the abnormality in the process so that an appropriate action can be taken. In practice, operators receive far more false and nuisance alarms than valid and useful alarms. Too many false and nuisance alarms can distract the operator from operating the plant, and thus critical alarms may be ignored. This problem can lead to the point that the operator no longer trusts the alarms or even shuts down the whole monitoring system. This paper proposes an efficient method to reduce false and nuisance alarms by prioritizing every fault using the Fault Tree Analysis (FTA) technique. The effectiveness of the proposed method is evaluated with a set of computer simulation under various faulty conditions.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.553-558
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• 2008

Advancement in information technology have enabled applying vision sensor to railway, such as CCTV. CCTV has been widely used in railway application, however the CCTV is a passive system that provide limited capability to maintain safety from boarding platform. The station employee should monitor continuously CCTV monitors. Therefore immediate recognition and response to the situation is difficultin emergency situation. Recently, urban transit operators are pursuing applying an unattended station operation system for their cost reduction. Therefore, an intelligent monitoring system is need for passenger's safety in railway. The paper proposes a vision based monitoring system and object detection algorithm for passenger's safety in railway platform. The proposed system automatically detects accident in platform and analyzes level of danger using image processing technology. The system uses stereo vision technology with multi-sensors for minimizing detection error in various railway platform conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.68-69
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• 2014

At the present, ship traffic monitoring and management are focused on the harbor area and the specified coastal zone in South Korea. It, however, is required that the Jurisdictional Sea Area of South Korea is monitored from two viewpoints: Safety and Security. Through a safe sea line (transport route) over the world, it is possible to expand our ocean economical territory. As a first step, we have been in field campaigns for integrated ship monitoring on the Ieodo Ocean Research Station in November 2013 after the first test in Gyunggi Bay.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1776-1786
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• 2010

Intelligent distribution automation system have total monitoring and control capability. The system covers substation, distribution network, distributed generations and customers at HV system. Various intelligent distribution facilities installed at distribution systems have voltage sensor, current sensor, aging monitoring sensor. Intelligent Feeder Remote Terminal Unit (IFRTU) tied to intelligent distribution facilities process information from facilities and it checks information of fault, power quality and aging of distribution facilities. The information is transmitted to master station through communication line. The master station have remote monitoring system covers substation, distribution network, distributed generations and customers. It also have various application programs that maintain optimal network operation by using information from on-site devices.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.4
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• pp.405-420
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• 2006

This study was conducted to understand the change of spatial environmental factors including populations, air pollution source and land-use in Busan, during the period of 1995 and 2004. Firstly, the grids (5 km $\times$ 5 km) were divided using the TM coordinates of Busan and the statistical data of populations and land-use were marked on each grid during studying period. Secondly, the SO$_2$, NO$_2$ and O$_3$ concentrations of areas where air quality monitoring station was not established were estimated on the basis of these air pollutants measured at close air quality monitoring station by kriging method. In order to understand spatial change of air pollution and to investigate duplication and reduction of existing stations, semivariogram, correlation and cluster analysis were carried out. This study showed that the population increased in 2004 only on 8 grids compared to in 1995. The spatial change of SO$_2$, NO$_2$ and O$_3$ was investigated by semivariogram in Busan area. As the results of semivariogram, the spatial change of 502 become smaller and simpler, while that of NO2,03 become larger and more complex in 2004 than in 1995, According to the result of correlation and cluster analysis, the reduction of measurement item or the relocation of air quality monitoring station can be needed in the high dense grid area.