• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.1
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• pp.88-93
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• 2011

In order to ensure the safety, regularity and efficiency of air transportation, ICAO has established the international standards for air navigation systems since 1940s. In 1991, ICAO announced the concept of New CNS/ATM systems and recommended States to carry out the development of the sub systems as well as propose the standards due to many problems caused by service limitations and considerable errors from the conventional systems. As a result, international standards for 21 systems have been established. However, many problems have also been raised. In this paper the problems on new international standard establishment are analyzed and the measures to cure them are suggested.

• Journal of Advanced Navigation Technology
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• v.20 no.3
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• pp.203-209
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• 2016

Among the various fields in the communications, navigation, and surveillance/air traffic management (CNS/ATM) scheme, the surveillance field, which includes an automatic dependent surveillance - broadcast (ADS-B) system and a multilateration (MLAT) system, is implemented using satellite and digital communications technology. These systems provide better performance than radar, but still incur position error. To reduce the error, we propose an efficient information fusion method called the reweighted convex combination method for ADS-B and MLAT systems. The reweighted convex combination method improves aircraft tracking performance compared to the original convex combination method by readjusting the weights given to these systems. In this paper, we prove that the reweighted convex combination method always provides better performance than the original convex combination method. Performance from the fusion of ADS-B and MLAT improves an average of 51.51% when compared to the original data.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.1
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• pp.216-239
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• 2021

The present work addresses the challenging problem of coordinating power allocation with interference management in multi-robot networks by applying the promising expansion capabilities of multiple-input multiple-output (MIMO) and full duplex systems, which achieves it for maximizing the throughput of networks under the impacts of Doppler frequency shifts and external jamming. The proposed power allocation with interference coordination formulation accounts for three types of the interference, including cross-tier, co-tier, and mixed-tier interference signals with cluster head nodes operating in different full-duplex modes, and their signal-to-noise-ratios are respectively derived under the impacts of Doppler frequency shifts and external jamming. In addition, various optimization algorithms, including two centralized iterative optimization algorithms and three decentralized optimization algorithms, are applied for solving the complex and non-convex combinatorial optimization problem associated with the power allocation and interference coordination. Simulation results demonstrate that the overall network throughput increases gradually to some degree with increasing numbers of MIMO antennas. In addition, increasing the number of clusters to a certain extent increases the overall network throughput, although internal interference becomes a severe problem for further increases in the number of clusters. Accordingly, applications of multi-robot networks require that a balance should be preserved between robot deployment density and communication capacity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5377-5391
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• 2017

In this paper, we propose a new scheme to suppress the narrowband interference (NBI) in OFDM-based systems. The scheme utilizes code division multiple access (CDMA) and weighted-type fractional Fourier transform (WFRFT) domain preprocessing technologies. Through setting the WFRFT order, the scheme can switch into a single carrier (SC) or a multi-carrier (MC) frequency division multiple access block transmission system. The residual NBI can be eliminated to the maximum extent when the WFRFT order is selected properly. Final simulation results show that the proposed system can outperform MC and SC with CDMA and frequency domain preprocessing in terms of the narrowband interference suppression.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.33-37
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• 2006

Since 1993, the civil aviation community through RTCA (Radio Technical Commission for Aeronautics) and the ICAO (International Civil Air Navigation Organization) have been working on the definition of GNSS augmentation systems that will provide improved levels of accuracy and integrity. These augmentation systems have been classified into three distinct groups: Aircraft Based Augmentation Systems (ABAS), Space Based Augmentation Systems (SBAS) and Ground Based Augmentation Systems (GBAS). The last one is an implemented system to support Air Navigation in CAT-I approaching operation. It consists of three primary subsystems: the GNSS Satellite subsystem that produces the ranging signals and navigation messages; the GBAS ground subsystem, which uses two or more GNSS receivers. It collects pseudo ranges for all GNSS satellites in view and computes and broadcasts differential corrections and integrity-related information; the Aircraft subsystem. Within the area of coverage of the ground station, aircraft subsystems may use the broadcast corrections to compute their own measurements in line with the differential principle. After selection of the desired FAS for the landing runway, the differentially corrected position is used to generate navigation guidance signals. Those are lateral and vertical deviations as well as distance to the threshold crossing point of the selected FAS and integrity flags. The Department of Applied Science in Naples has create for its study a virtual GBAS Ground station. Starting from three GPS double frequency receivers, we collect data of 24h measures session and in post processing we generate the GC (GBAS Correction). For this goal we use the software Pegasus V4.1 developed from EUROCONTROL. Generating the GC we have the possibility to study and monitor GBAS performance and integrity starting from a virtual functional architecture. The latter allows us to collect data without the necessity to found us authorization for the access to restricted area in airport where there is one GBAS installation.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.1
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• pp.45-50
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• 2010

Air Traffic Management aims to fulfill the requirement of the aviation demander by constructing the most effective and safety aviation systems for providing safety and cost-effective service. All concerned parties of aviation present the needs of improving Air Traffic Management system for solving the issue of the current system and the air traffic capacity in the 21st century, and introduce the significant improvements from the conventional technology and method for the past 40 years. Accordingly, ICAO promotes the development of innovative procedures and technologies to solve the problems and meet the demands. It is the concept of Performance based Navigation(PBN) based on Communication, Navigation, and Surveillance/Air Traffic Management(CNS/ATM). This study defines differences between RNAV and RNP RNAV as methods of air navigation based on the CNS/ATM, and needs and requirements of PBN as an emerging global standard. It also outlines basic elements supporting and implementing the PBN concept.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.456-461
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• 1993

In this paper, a new guidance law for a short-range air-to-air missile with constant thrust is presented. It is essentially based on the concept of proportional navigation. First, the theoretical guidance law is derived. Then, we show the technique for practical implementation of the guidance law. By a computer simulation, it is shown that the new guidance law gives better performance than the conventional proportional navigation.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.3
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• pp.273-278
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• 2007

In this paper, a performance comparison between CLOS(Command to Line-of-Sight) guidance law and PN(Proportional Navigation) guidance law is made, based on a short range surface-to-air missile simulation program called KNUCLOS. This simulation program has a full nonlinear aerodynamic missile model, a tracker model for missile and target, and target model. According to the simulation results, the PN guidance law has a better performance than CLOS guidance law under various target speed.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.699-709
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• 2023

As the global air traffic volume has shown a rapid increase, doubling every 15 years since 1977, domestic and international air traffic control services and air navigation safety facility operation management system and status review It is necessary to present the feasibility of establishing an air traffic control agency with integrated functions and establish an operating system for an independent dedicated agency to provide advanced air traffic control services in preparation for the future air transport environment. In particular, in 2021, the national ATM reformation and enhancement (NARAE) a customized comprehensive plan for operations, facilities, and systems to handle air traffic safely and efficiently by actively reflecting changes in the navigation environment such as international policies and standards as this is established, the role of the air traffic control agency becomes more important, and an improved action plan for the control and navigation operating system must be promoted.

• Journal of the Korean Institute of Navigation
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• v.18 no.4
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• pp.147-154
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• 1994

A practical application of a fuzzy control system is described for an air-conditioning system. Air-hadling units are being widely used for improving the performance of central air-conditioning systems. The fuzzy control system has two controlled variables, temperature and humidity, and three control elements, cooling, heating, and humidification. In order to achieve high efficiency and economical control, especially in large offices and industrial buildings, two controllable parameters, temperature and humidity, must be adequately controlled by the three final controlling elements. In this paper a fuzzy control system was described for controlling air-conditioning systems efficiently and economically.