김민성 Minsung Kim , 강지혜 Ji-hye Kang , 구경헌 Kyung Heon Koo , 이경순 Kyung-soon Lee

DOI: JANT Vol.28(No.3) 254-261, 2024

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Accurate guidance during landing and take-off is important, and instrument landing system (ILS) has been used for stability and verification. Regular inspections are conducted for stable operation, and there is research to perform inspection using drones in addition to ground vehicles and measurement aircraft. Using SDR and single board computer, which can receive wide frequency range, we designed a small system that receives and processes localizer signals through GNU Radio. To check signal processing characteristics through GNU Radio, we simulated with MATLAB Simulink and confirmed the theoretical values. Difference in depth of modulation (DDM) and approach angle can be calculated when the aircraft enters the runway. And GNU Radio implemented real-time signal processing wirelessly using transmission control protocol (TCP). This gives the results within the error of 0.5% when the aircraft entered the runway center line and 0.27% for the angle of 1o degree. Compared to the inspecting and maintaining ILS signals using aircraft or ground vehicles, it is possible to implement a receiving system using small SDR that can be mounted for drone.

윤현만 Hyeon-man Yun , 김찬호 Chan-ho Kim , 최인수 In-soo Choi , 이성섭 Soung-sub Lee

DOI: JANT Vol.28(No.3) 262-271, 2024

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In this paper, by applying deep learning, one of the A.I. techniques, through angle information, which is optical observation data generated when observing satellites at observatories, distance information from observatories is learned to predict range data, thereby increasing the precision of satellite's orbit determination. To this end, we generated observational data from GMAT, reduced the learning data error of deep learning through preprocessing of the generated observational data, and conducted deep learning through MATLAB. Based on the predicted distance information from learning, trajectory determination was performed using an extended Kalman filter, one of the filtering techniques for trajectory determination, through GMAT. The reliability of the model was verified by comparing and analyzing the orbital determination with angular information without distance information and the orbital determination result with predicted distance information from the model.

장동관 Dong-kwan Jang

DOI: JANT Vol.28(No.3) 272-277, 2024

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In most countries, instrument flight procedures are designed by applying one of the following standards: the International Aviation Organization's DOC 8168, Air Navigation Services and Operation Procedures (PANS-OPS), or the US Federal Aviation Administration’s TERPS, Terminal Procedures. In particular, the circling approach procedure has many differences between the two standards, and the US terminal procedure (TERPS) has become more complicated since 2013 by applying expanded standards depending on altitude. The circling approach procedures are more risky than straight-in approach procedures because it involves maneuvering the aircraft close to the ground at low energy for landing. In order to accurately understand these differences, this study provides to distinguish by what criteria the circling approach procedure is designed according to individual domestic airports in Korea, to calculate the radius for the range of circling approach areas that guarantee minimum obstacle avoidance during circling approach maneuvers, and to present methods for performing safe circling approach procedures.

오택근 Taeckkeun Oh , 이유상 You-sang Lee , 이대현 Dae-hyun Lee , 이온수 Onsoo Lee

DOI: JANT Vol.28(No.3) 278-287, 2024

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In this paper, telemetry link budget model for small launch vehicle is proposed, and telemetry link budget simulator is implemented. The proposed link budget model consist of geometry model and propagation loss model. The geometry model is calculation of look angle between ground station and small launch vehicle. The propagation loss model consist of free space loss, polarization loss, and de-pointing loss which are appropriate to the small launch vehicle flight environment. The proposed propagation loss model can be calculate propagation loss without complex calculation of propagation environments. The link budget simulator is implemented in MATLAB. The simulator calculate look angle, free space loss, polarization loss parameter, de-pointing loss and received signal level in ground station by using position of ground station, routing of small launch vehicle, 3-D radiation patterns of antennas.

프라스티우토모-푸구 Prastyoutomo Puguh , 이광병 Kwang-byeng Lee

DOI: JANT Vol.28(No.3) 288-299, 2024

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Indonesia's Keplauan Liau region is facing limitations in the development of connected transportation infrastructure due to its archipelago nature, budget constraints, and lack of land. Transportation demand is increasing due to its strategic location in the Malacca Strait Business Triangle and many tourist visits from Singapore and Malaysia. However, due to the nature of connecting many islands, the establishment of transportation infrastructure has not been achieved. This paper aims to predict the innovations that can be brought about by the introduction of advanced air mobility (AAM) with an electric vertical take-off and landing (e-VTOL) system through analysis and application consideration of the actual situation in Indonesia's Kepulauan Liau region. In addition, it intends to contribute to national-level review and policy establishment on the establishment of innovative transportation infrastructure using AAM, reflection in infrastructure construction plans, and active global cooperation.

구본수 Bon-soo Koo , 최인호 In-ho Choi , 황재욱 Jaewook Hwang

DOI: JANT Vol.28(No.3) 300-308, 2024

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Urban air mobility (UAM) is emerging as a revolutionary transportation solution to urban congestion and environmental issues. Especially, electric vertical take-off and landing (eVTOL) aircraft are expected to enhance urban mobility, reduce traffic congestion, and decrease environmental pollution. However, the successful implementation and operation of UAM systems heavily rely on advanced technological infrastructure, particularly in sensor technology. Among these, 3D light detection and ranging (LiDAR) systems are essential for detecting obstacles and generating pathways in complex urban environments. This paper focuses on the challenges of developing LiDAR-based perception solutions, emphasizing the importance and performance of object detection capabilities using 3D LiDAR. It integrates LiDAR data processing algorithms and object detection methodologies to experimentally validate the effectiveness of perception solutions that contribute to the safe navigation of aircraft. This research significantly enhances the ability of aircraft to recognize and avoid obstacles effectively within urban settings.

조성희 Sung-hee Cho , 정성재 Seong-jae Jeong , 김민선 Min-seon Kim , 남덕우 Deok-woo Nam , 정다나 Da-na Jung , 김준형 Jun-hyoung Kim

DOI: JANT Vol.28(No.3) 309-314, 2024

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Avionics Intercom performs communication between pilot, co-pilot and crews in aircraft. In the case of developing intercom in the aircraft modification development project, additional communication equipment or avionics equipment is configured to link the existing intercom with the headsets. Newly designed intercom needs a configuration that receives an aircraft headset microphone and transmits a microphone signal to the existing intercom, and these signals are required to perform signal quality above a certain level. To satisfy these requirements, microphone transmitter circuit has designed and tested, but quality factors of signal were not suitable. In order to avoid the issue, eliminate transmitter and apply signal bridge circuit considered with load effect, and it meets requirements. In this paper, the test results for the signal quality for each configuration are reviewed.

김건희 Geon-hee Kim , 김복기 Bokki Kim

DOI: JANT Vol.28(No.3) 315-322, 2024

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In this paper, we proposes real-time operating system based PCM encoder for telemetry system that must transmit frames within a set time. In the case of large aircraft, the complexity of the system is increasing because a lot of state information is measured from each sensor and peripheral device. In addition, as the amount measurement data increases, the role of PCM encoder to transmit frames within a set time is becoming important. Existing encoder is inflexible when changing specifications or implementing additional features. Therefore, a design is needed to supplement this. We propose a PCM encoder design applying uC/OS-II. In order to confirm the validity, a simulation was performed to measure the execution time of the task to confirm the performance.

양승필 Seung Pil Yang , 고강민 Kangmin Ko

DOI: JANT Vol.28(No.3) 323-330, 2024

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The purpose of this study is to analyze the effect of self-esteem on the safety culture and safety behavior of airline pilots and to confirm whether job satisfaction has a mediating effect in these relationships. It was examined whether self-esteem directly affects safety culture and safety behavior, and indirectly through job satisfaction. As a result of the study, self-esteem did not have a direct significant effect on safety culture, but indirectly had a positive effect through job satisfaction. In addition, self-esteem had a direct significant positive effect on safety behavior, and job satisfaction partially mediated this relationship. This suggests that pilots with higher self-esteem practice safety behavior more actively, and job satisfaction can promote such behavior. These results show the importance of organizational support such as programs and support for enhancing pilots' self-esteem, fair compensation for improving job satisfaction, improving working environment, and providing career development opportunities in airlines, and are intended to be used as basic data for this.

한동건 Dong-geon Han , 김윤근 Yun-geun Kim

DOI: JANT Vol.28(No.3) 331-337, 2024

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Mission autonomy system should be embedded on UAV (unmanned aerial vehicle) for mosaic warfare where UAVs autonomously assign tasks to themselves. UxAS (unmanned x-systems autonomy service) proposed by Air force research laboratory is mission autonomy system for unmanned platforms. UxAS has extensible structure composed of numerous module services. We have developed mission autonomy system based on UxAS that performs mission allocation and path planning. In this paper, We present a method of analyzing and evaluating the mission autonomy software according to the performance evaluation index.

김다니엘 Daniel Kim , 조희덕 Hee-duk Cho , 이승우 Seung-woo Lee , 김재우 Jae-woo Kim

DOI: JANT Vol.28(No.3) 338-347, 2024

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This paper deals with the study of bird collision avoidance measures in UAM operations from an operator's perspective. Urban air traffic is defined as a next-generation transportation system that uses environmentally friendly electric vertical take-off and landing (eVTOL) aircraft to provide transportation services between key points within and around urban centers. For the successful establishment of the UAM industry, it is necessary to ensure safety issues that determine public acceptance. Among the hazards that can occur in aviation operations, preventing bird collisions in urban environments is a measure that can greatly secure operational safety and public acceptance. In addition to physical measures, procedural control measures are required to prevent bird strikes. In order to ensure the safety of UAM operations, this study aims to provide a direction for the establishment of UAM bird collision prevention measures by categorizing bird collision prevention measures into physical and procedural methods and flight sections such as takeoff, landing, and corridor sections. Through this, we hope to contribute to the improvement of the safety of the urban air traffic operation system.

김종호 Jong-ho Kim , 최규식 Gyu-shik Che

DOI: JANT Vol.28(No.3) 348-355, 2024

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A current source capable of stably supplying current as a measurement medium is required in order to measure and test important facilities that require large-scale measurement current, such as a control element drive mechanism control system(CEDMCS), in case of dismantling a nuclear power plant. However, it can provides only voltage power as a source, not current, although direct voltage controlled constant current source is essential to test major equipment. That kind of source is not available to supply stable constant current regardless of load variation. It is just voltage supplier. Developing current source is not easy other than voltage source. Very large-scale current source up to ampere class more than such ten times of normal current is inevitable to test above mentioned equipment. So, we developed large-scale current source which is controlled by input DC voltage and supplies constant stable current to object equipment according to this requirement. We measured and tested nuclear power plant equipment using given real site data for a long time and afforded long period load test, and then proved its validity and verification. The developed invetion will be used future installed important equipment measuring and testing.

여준호 Junho Yeo , 이종익 Jong-ig Lee

DOI: JANT Vol.28(No.3) 356-361, 2024

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This paper deals with the design and fabrication of a coplanar waveguide (CPW)-fed super-wideband semicircular-disk-shaped dipole antenna operating in a frequency band of 2.4 GHz or higher. To feed the antenna, a CPW feed line was appended to the center of the lower arm of the semicircular-disk-shaped dipole antenna. For miniaturization, square patches were added to the ends of the two arms of the semicircular-disk-shaped dipole, whereas the slot width of the CPW feed line at the center of the dipole antenna was increased to improve impedance matching in the 5.4-6.3 GHz band. The simulated frequency band of the proposed antenna for a voltage standing wave ratio (VSWR) less than 2 was 2.369-30 GHz(170.7%), whereas the fabricated antenna was maintained VSWR less than 2 in the frequency range of 2.378-20 GHz when measured using a network analyzer operating up to 20 GHz so it can be applied as a super-wideband antenna for next-generation mobile communications.

김명생 Myeong-saeng Kim , 김동옥 Dong-ok Kim

DOI: JANT Vol.28(No.3) 362-368, 2024

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In this paper, we investigated the performance of directional and omnidirectional precoding schemes when transmitting to improve downlink performance in massive MIMO. Omnidirectional precoding was used to broadcast a common signal, such as a synchronization or control signal, to all users. The main purpose of omnidirectional precoding is to design the precoding matrix so that the signal transmitted in the downlink is the same in all directions and emitted with maximum energy. We propose a flexible omnidirectional precoding method for full-dimensional massive MIMO that can set the spatial coverage range to less than 120 degrees. The constraints of omnidirectionality of all antennas, equal transmit power, and maximum transmit rate are used to design the encoding matrix of the proposed method. The performance was evaluated in terms of spatial coverage by considering changing the spatial coverage of the antenna array by changing the distance between neighboring antennas in the antenna array.

천재성 Jae-sung Chun , 문일영 Il-young Moon

DOI: JANT Vol.28(No.3) 369-374, 2024

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This study aims to improve the accessibility and efficiency of sign language education for both hearing impaired and non-deaf people. To this end, we developed VR realistic sign language education content that integrates hand tracking technology and conversational AI. Through this content, users can learn sign language in real time and experience direct communication in a virtual environment. As a result of the study, it was confirmed that this integrated approach significantly improves immersion in sign language learning and contributes to lowering the barriers to sign language learning by providing learners with a deeper understanding. This presents a new paradigm for sign language education and shows how technology can change the accessibility and effectiveness of education.

Kyung-soon Lee , Kyung Heon Koo

DOI: JANT Vol.28(No.3) 375-378, 2024

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The instrument landing system (ILS) is an international standard established by the International civil aviation organization (ICAO) as one of the landing support facilities for aircraft. This system consists of a localizer (LOC) that provides orientation information about the runway to indicate the approach direction, a glide path (GP) that indicates the appropriate approach glide slope, and three of marker beacons (MB) that indicates the distance to the runway landing edge. In this study, we predicted the received signal strength by altitude and distance for LOC signals transmitted from the ground and analyzed the difference with the signal strength measured in the actual environment. Our objective is to develop signal strength prediction technology and apply it to the real environment.