정다님 Da-nim Jung , 이수민 Soo-min Lee , 이찬희 Chan-hee Lee , 김의호 Eui-ho Kim , 최헌호 Heon-ho Choi

DOI: JANT Vol.28(No.1) 1-14, 2024

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Global navigation satellite system (GNSS) providing position, navigation and timing (PNT) services consist of satellite, ground, and user systems. Monitoring stations, a key element of the ground segment, play a crucial role in continuously collecting satellite navigation signals for service provision and fault detection. These stations detect anomalies such as threats to the signal-in-space (SIS) of satellites, receiver issues, and local threats. They deliver received data and detection results to the master station. This paper introduces the main monitoring algorithms and measurement pre-processing processes for quality assessment and fault detection of received satellite signals in current satellite navigation system monitoring stations. Furthermore, it proposes a strategy for the development of components, architecture, and algorithms for the new regional navigation satellite system (RNSS) monitoring stations.

한준영 Junyoung Han

DOI: JANT Vol.28(No.1) 15-20, 2024

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The utilization of small unmanned aerial vehicles (UAVs) has expanded into both military and civilian domains, increasing the necessity for research to ensure operational safety and the efficient utilization of airspace. In this study, the calculation of minimum separation distances for the safe operation of small UAVs at low altitudes was conducted. The determination of minimum separation distances requires a comprehensive analysis of the total system errors associated with small UAVs, necessitating sensitivity analysis to identify key factors contributing to flight technology errors. Flight data for small UAVs were acquired by integrating the control system of an actual small UAV with a flight simulation program. Based on this data, operational scenarios for small UAVs were established, and the minimum separation distances for each scenario were calculated. This research contributes to proposing methods for utilizing calculated minimum separation distances as crucial parameters for ensuring the safe operation of small unmanned aerial vehicles in real-world scenarios.

김도현 Do-hyun Kim , 이경한 Kyung-han Lee , 장효석 Hyo-seok Chang , 이승준 Seung-jun Lee

DOI: JANT Vol.28(No.1) 21-26, 2024

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Urban air mobility (UAM) is being considered as an alternative to transportation in urban areas where traffic congestion is increasing. It is judged that it will be difficult to manage the complex UAM operation environment with the existing Air Traffic Service, which is a person-centered service. Therefore, an advanced information processing-based traffic management system for UAM (UATM) is needed. Airspace management is essential to establish a systematic UAM traffic management (UATM) environment. In particular, the establishment of exclusive corridors where UAM aircraft can operate safely can provide opportunities to operate UAM aircraft without violating the minimum flight altitude regulations. This study conducted an empirical analysis using a helicopter of similar size to UAM to establish the cross-track dimension of the corridor for UAM operation. The research results can be used as a guideline when designing UAM corridors.

강남선 Nam-seon Kang , 손금준 Gum-jun Son , 박래천 Rae-chon Park , 이창식 Chang-sik Lee , 유성상 Seong-sang Yu

DOI: JANT Vol.28(No.1) 27-36, 2024

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In this paper, we analyze the unified requirements of international association of classification societies - cyber resilience of ships, ahead of implementation of the agreement on July 1, 2024, and respond to ship cyber security and resilience programs based on 5 requirements, 17 details, and documents that must be submitted or maintained according to the ship's cyber resilience,. Measures include document management such as classification certification documents and design documents, configuration of a network with enhanced security, establishment of processes for accident response, configuration management using software tools, integrated network management, malware protection, and detection of ship network security threats with security management solutions. proposed a technology capable of real-time response.

김기연 Ki Yeon Kim , 이장룡 Jang Ryong Lee

DOI: JANT Vol.28(No.1) 37-43, 2024

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National aircraft are subject to exceptions under the International Civil Aviation Convention. Each country must ensure the safety of civil aircraft through reasonable consideration (due regard). Accordingly, the Aviation Safety Act of Korea also includes an exception for national aircraft. However, Korea Coast Guard aircraft are legislated to be subject to the law on five provisions. As Korea Coast Guard aircraft operate under the application of these provisions of international and domestic laws, they will be required to control flight procedures from China's civil air traffic control when flying over provisional action zone, which is international waters in the West Sea. China's demand is a major limiting factor in protecting the safety of the people of Korea, which is the original mission of Korea Coast Guard aircraft, and through this study, countermeasures to solving these problems at the national level were suggested.

유병선 Byeong-seon Yoo , 고강민 Kangmin Ko

DOI: JANT Vol.28(No.1) 44-50, 2024

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This study analyzed the effect of flight stress on job satisfaction and safety culture on 193 domestic civil airline pilots. As a result of the analysis, flight stress had a negative effect on job satisfaction, and pilots with low job satisfaction had a low awareness of safety culture. In particular, there was a difference in the effect of flight stress on job satisfaction and safety culture according to the airlines and rank of pilots. This suggests the necessity of developing customized stress management programs for each airline and pilot position. The study emphasizes the importance of managing pilots' stress and improving job satisfaction to reinforce the safety culture of the aviation industry. In addition, airlines should develop strategies to strengthen safety culture by reducing pilot stress and increasing job satisfaction. The result of this study is to be used as useful basic data for finding ways to manage pilots' stress and strengthen safety culture in the aviation industry.

황준혁 Jun-hyeok Hwang , 김규왕 Kyu-wang Kim

DOI: JANT Vol.28(No.1) 51-59, 2024

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Currently, the approved training organization (ATO) is being used worldwide to supply excellent pilots in the aviation industry. This system, which is used worldwide, has been transformed and utilized according to each country. In this study, the operation method and educational environment of specialized pilot training institutions in Korea were examined in detail, and the differences were compared by comparing the operation methods and flight education environments of international standards, the United States, Europe, Canada, and neighboring countries such as Japan, China, and Singapore to derive differences from the system of specialized educational institutions in Korea. Based on these comparative data, through a survey of workers in the relevant work, satisfaction with the number of department classes set by the domestic aviation safety law specialized educational institution designation standards differed greatly depending on the characteristics of the survey subjects, and the importance differed depending on the department's class subjects.

임세훈 Se-hoon Yim , 조영진 Young Jin Cho

DOI: JANT Vol.28(No.1) 60-67, 2024

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The majority of civil aviation accidents are caused by human factors, and especially for rotary-wing aircraft, accidents often occur in situations where pilots unexpectedly or unintentionally enter into instrument meteorological conditions (IIMC). This research analyzed the error rates of rotary-wing aircraft pilots under low visibility conditions from various angles to gain insights into flight characteristics and to explore measures to reduce accidents in IIMC situations. The occurrence rate of errors by pilots under low visibility conditions was examined using a flight simulator equipped with motion, with 65 pilots participating in the experiment. Flight data obtained through the experiment were used to aggregate and analyze the number of errors under various conditions, such as reductions in flight visibility, the presence or absence of spatial disorientation, and the pilot's qualifications. The analysis revealed peculiarities in flight characteristics under various conditions, and significant differences were found in the rate of error occurrence according to the pilot's qualification level, possession of instrument flight rules (IFR) qualifications, and during different phases of flight. The results of this research are expected to contribute significantly to the prevention of aircraft accidents in IIMC situations by improving pilot education and training programs.

김재현 Jae-hyeon Kim , 이동민 Dong-min Lee , 이명진 Myeong-jin Lee , 최영훈 Yeong-hoon Choi , 권지훈 Ji-hun Kwon , 나종화 Jong-whoa Na

DOI: JANT Vol.28(No.1) 68-76, 2024

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With the recent rapid growth of the domestic and international unmanned aerial vehicle (UAV) market and the increasing importance of UAV operations in urban centers, such as UAMs, the safety management and regulatory framework for human life and property damage caused by UAV failures has been emphasized. In this study, we conducted a comparative analysis of risk-cost models that evaluate the risk of an operating area for safe UAM flight path planning, and identified the main limitations of each model to derive considerations for future model development. By providing a basic model for improving the safety of UAM operations, this study is expected to make an important contribution to technical improvements and policy decisions in the field of UAM flight path planning.

이건희 Keon-hee Lee , 이중윤 Joong-yoon Lee

DOI: JANT Vol.28(No.1) 77-86, 2024

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‘UAS flight recording system’ is a system that is mounted on an unmanned aircraft system consisting of various components and records flight-related data. The data recorded by this system should be used for aviation accident and incident investigations to prevent similar accidents. In particular, for the category of UAS with high operating risk, safety devices close to that of manned aircraft are required, and it is urgent to develop flight recording systems reflecting the characteristics of the UAS to secure airworthiness. This paper highlights the need for UAS flight recording systems for aviation accident and incident investigations and seek a method to derive flight recording system parameters for ‘Certified Category’ with high operational risk. To this end, Inter-City UAM was used as a concrete use case, and the process of approaching system parameters was devised by assuming accident occurrences and hazards from mission profiles and scenarios. As a result of the study, it was confirmed that parameters could be derived through this process.

이동렬 Dong-ryeol Lee , 김현덕 Hyeon-deok Kim

DOI: JANT Vol.28(No.1) 87-94, 2024

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Despite the development of the aviation industry, aircraft accidents due to pilots' human errors continue to occur. The cause of aircraft accidents due to human errors is that they cannot remove hazard factors that hinder flight safety in advance, leading to accidents. This study examined how job stress, fatigue, and anxiety, which psychologically and physically affect flight safety among various hazard factors, affect pilots' safety behavior for flight crew and pilots of general aviation working in domestic airlines. In addition, an empirical analysis was conducted to confirm the mediating effect of safety culture between job stress and safety behavior. According to the results of the study, job stress not only directly affects the safety behavior of pilots, but also affects the safety culture of airlines such as safety atmosphere and reporting culture. The purpose of this study is to improve the performance of the safety management system through the correlation between the pilot's job stress and safety culture and safety behavior.

김혜지 Hyeji Kim , 김정민 Jeongmin Kim , 윤다연 Dayeon Yoon , 하종준 Jongjun Ha , 이동진 Dongjin Lee , 이장호 Jangho Lee

DOI: JANT Vol.28(No.1) 95-101, 2024

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This paper aims to establish a reconfigurable flight simulation environment to conduct safety evaluation of various electric vertical take-off and landing (eVTOL) aircraft. Since the inceptor, aircraft dynamics model, and controller applied to each eVTOL aircraft are different, it was configured to be variable so that a simulation can be executed for each eVTOL aircraft. Test elements and performance indicators were set to perform safety evaluation of eVTOL aircraft. Ground auxiliary equipments were designed and implemented in a simulation environment according to test procedures for each test element. In addition, to analyze safety performance, a simulation flight data collection environment based on MATLAB/Simulink and a tool for safety performance analysis were implemented. Test flight and analysis were conducted in the implemented simulation environment in this paper. Finally, this study shows the environment was verified by confirming that it was performed normally.

권슬에 Seul-ae Gwon , 한승규 Seung-kyu Han , 정영호 Young-ho Jung

DOI: JANT Vol.28(No.1) 102-108, 2024

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In the initial stages of urban air mobility (UAM) operations, compliance with existing visual flight rules and instrument flight regulations for conventional human-crewed aircraft is crucial. Additionally, voice communication between the on board pilot and relevant UAM stakeholders, including vertiports, is essential. Consequently, very high frequency (VHF) aviation voice communication must be consistently provided throughout all phases of UAM operations. This paper presents the results of the VHF communication coverage analysis for the initial UAM demonstration areas, encompassing the Hangang River and Incheon Ara-Canal corridors, as well as potential vertiport candidate locations. By considering the influence of terrain and buildings through the utilization of a digital surface model (DSM), communication quality prediction results are obtained for the analysis areas. The three-dimensional coverage analysis results indicate that stable coverage can be achieved within altitude corridors ranging from 300 m to 600 m. However, there are shaded areas in the low-altitude vertiport regions due to the impact of high-rise buildings. Therefore, additional research to ensure stable coverage around vertiports in the lower altitude areas is required.

정영호 Young-ho Jung , 전향식 Hyangsig Jun

DOI: JANT Vol.28(No.1) 109-115, 2024

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The Concept of Operations (ConOps) document issued by the Korean Government (K-UAM ConOps) for urban air mobility (UAM) services takes into account not only aviation voice communication but also the use of 4G and 5G mobile communication to support the initial phase of UAM services. This paper studies a methodology to establish communication performance requirements for UAM traffic management and presents the analyzed results for communication performance requirements. To accomplish this, the operational scenarios of UAM developmental stages outlined in the K-UAM ConOps and FAA ConOps are scrutinized, and the diverse messages that must be communicated among various stakeholders for effective UAM operations are identified. A draft of communication performance requirements is also calculated by considering packet sizes, transmission frequencies, acceptable latencies, and availability. The outcomes of this study are expected to stand as a pioneering effort in defining communication requirements for UAM services, providing a crucial foundation for future initiatives such as the design of dedicated communication networks for UAM and the determination of required frequency bandwidth.

김수경 Su Kyung Kim , 구경헌 Kyung Heon Koo

DOI: JANT Vol.28(No.1) 116-122, 2024

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In this paper, course structure and course width were studied among the main performances of the system to derive the required performance of the modulation index, output power, and phase change specifications of the instrument landing system (ILS) localizer power amplifier. To satisfy the course structure's deviation standard (± 5 uA), the difference in depth of modulation (DDM) deviation standard of the carrier with sideband (CSB) amplifier was standardized to ± 1 uA(0.001 DDM). CSB 30 W power amplifier was designed, and through the modulation compensation circuit, sum in depth of modulation (SDM) is 40% ± 0.1% and DDM is ± 0.0005 DDM in the operating output range(45 dBm ~ 35 dBm). In addition, the course width and displacement sensitivity specifications were analyzed through simulation, and the ± 0.1° change applied during comissioning inspection, which is the most stringent standard, was applied. The output variation of the suppressed with sideband only ( SBO) amplifier was ± 2 mW or less, The phase was standardized to within ± 3 ° and the characteristics were satisfied. By applying a compensation circuit according to output power and temperature, stable modulation index, output, and phase characteristics were obtained.

이성렬 Seong-real Lee

DOI: JANT Vol.28(No.1) 123-128, 2024

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When mid-span spectral inversion (MSSI), which inverts the propagated wave into phase-conjugated wave in the middle of the entire transmission distance, is combined with dispersion-managed link, it is very effective in compensating for the wavelength division multiplexed (WDM) signal distortion due to chromatic dispersion and nonlinear effects. In this MSSI combined dispersion-managed link, the shape of the dispersion map, channel data rate, channel wavelength and wavelength spacing, etc. affect the compensation and, consequently, determine the transmission distance and capacity of the WDM signal. In this paper, the compensation according to the extinction ratio of the return-to-zero (RZ) pulse that constitutes the WDM signal in the MSSI combined distributed control link was numerically analyzed. As a result of the simulation, it was conformed that the extinction ratio to obtain the best compensation should be determined depending on the shape of the dispersion map and the size of the residual dispersion per span, which determines the specific shape of the dispersion map. These results show a significant difference from the results in a general optical transmission system, where as the extinction ratio increases, the power difference between the ‘1’ and ‘0’ signals increases, thereby improving reception performance.

김명회 Myunghoi Kim

DOI: JANT Vol.28(No.1) 129-135, 2024

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In this paper, an analytical approach for the design and analysis of an aperiodic electromagnetic bandgap (EBG)-based power distribution network (PDN) in high-speed integrated-circuit (IC) packages and printed circuit boards (PCBs) is proposed. Aperiodic EBG is an effective method to solve the noise problem of high-speed IC packages and PCBs. However, its analysis becomes challenging due to increased computation time. To overcome the problem, the proposed analytical method entails deriving impedance parameters for EBG island and the overall PDN, which includes locally placed EBG structures. To validate the proposed method, a test vehicle is fabricated, demonstrating good agreement with the measurements. Significantly, the proposed analytical method reduces computation time by 99.7 % compared to the full-wave simulation method.

여준호 Junho Yeo , 이종익 Jong-ig Lee

DOI: JANT Vol.28(No.1) 136-141, 2024

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In this paper, a broadband inset-fed microstrip patch antenna operating at 10.525 GHz band was proposed. The proposed broadband inset-fed microstrip patch antenna consists of three narrow rectangular patches. At the center of the center patch, two symmetrical side patches were connected by a strip conductor and were arranged with their centers shifted in a perpendicular direction with respect to the center patch. For performance comparison, a conventional inset-fed square microstrip patch antenna was designed. Experiment results show that the frequency band of the measured input reflection coefficient with a voltage standing wave ratio less than 2 for the broadband inset-fed microstrip patch antenna was 10.036-11.051 GHz (9.63%), whereas that for the conventional inset-fed rectangular microstrip patch antenna was 10.306-10.772 GHz (4.42%). Therefore, the input reflection coefficient frequency bandwidth of the fabricated broadband inset-fed microstrip patch antenna was increased by 2.18 times, compared to the conventional inset-fed square microstrip patch antenna.

한승진 Seungjin Han

DOI: JANT Vol.28(No.1) 142-148, 2024

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It is difficult to apply authentication methods of existing wired or wireless networks to Internet of Things (IoT) devices due to their poor environment, low capacity, and low-performance processor. In particular, there are many problems in applying methods such as blockchain to the IoT environment. In this paper, edge computing is used to serve as a server that authenticates disposable templates among biometric information in an IoT environment. In this environment, we propose a lightweight and strong authentication procedure using the IoT-edge computing (IoT-EC) system based on elliptic curve cryptographic (ECC) and evaluate its safety.

정용진 Yong-jin Jung , 오창헌 Chang-heon Oh

DOI: JANT Vol.28(No.1) 149-154, 2024

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Research on particulate matter is advancing in real-time, and various methods are being studied to improve the accuracy of prediction models. Furthermore, studies that take into account various factors to understand the precise causes and impacts of particulate matter are actively being pursued. This paper trains an LSTM model using seasonal data and another LSTM model using concentration-based data. It compares and analyzes the PM_2.5 prediction performance of the two models. To train the model, weather data and air pollutant data were collected. The collected data was then used to confirm the correlation with PM_2.5. Based on the results of the correlation analysis, the data was structured for training and evaluation. The seasonal prediction model and the concentration-specific prediction model were designed using the LSTM algorithm. The performance of the prediction model was evaluated using accuracy, RMSE, and MAPE. As a result of the performance evaluation, the prediction model learned by concentration had an accuracy of 91.02% in the “bad” range of AQI. And overall, it performed better than the prediction model trained by season.

Yongjun Lee , Heonho Choi , Byungwoon Park

DOI: JANT Vol.28(No.1) 155-158, 2024

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Multipath, a major error source in urban GNSS positioning (global navigation satellite system), pose a challenge due to its site-dependent nature, varying with the user’s signal reception environment. In our previous study, we introduced a technique generating GNSS multipath map in urban canyon. However, due to uncertainty in initial GNSS positions, applying multipath maps required generating multiple candidate positions. In this study, we present an efficient method for applying multipath maps by projecting the multipath correction in position domain. This approach effectively applies multipath maps, addressing the challenges posed by urban user position uncertainties.

Dongyeop Lee , Daesik Lim , Soojeong Woo , Youngho Moon , Minjeong Kim , Joonwon Lee

DOI: JANT Vol.28(No.1) 159-162, 2024

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This paper proposes a novel safety autonomous platform (SAP) architecture that can automatically and precisely manage on-site safety through ensemble artificial intelligence models generated from video information, worker’s biometric information, and the safety rule to estimate the risk index. We practically designed the proposed SAP architecture by the Hadoop ecosystem with Kafka/NiFi, Spark/Hive, Hue, ELK (Elasticsearch, Logstash, Kibana), Ansible, etc., and confirmed that it worked well with safety mobility gateways for providing various safety applications.