• Journal of Advanced Navigation Technology
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• v.24 no.4
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• pp.251-260
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• 2020

Unlike manned aerial vehicles, because an unmanned aerial vehicle (UAV) has a limitation which allows only remote test during flights, it is very important to maintain the high reliability of the vehicle through pre- and post-flight tests. To this end, this paper designed an air vehicle test equipment (AVTE) for UAV which meets the derived hardware and software requirements. Based on this design, the AVTE was implemented in accordance with the actual test scenario. The implemented AVTE has the advantage of reducing the time and cost required for the test of UAV by allowing the operator to perform automatic or manual tests for necessary parts in various situations such as before and after starting engine and pre- and post-flight tests. Furthermore, this study is expected to help with the design and implementation of AVTE for other UAVs.

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.72-80
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• 2021

Albatross uses dynamic soaring technique to obtain energy from horizontal winds and fly long distances without flapping. These dynamic soaring technique can be applied to manned/unmanned aircraft to reduce the components required for the aircraft and achieve light weight and small volume to effectively perform a given task. In this paper, to simulate the dynamic soaring technique of Albatross, we defined the optimization problem and set each boundary condition to derive the optimal flight trajectory and carry out simulations to follow it. In particular, to model dynamic soaring simulations more closely with reality, we proposed a horizontal wind model that changes every moment. This identifies and analyzes the effect of the time-variable horizontal wind model on the dynamic soaring mission of unmanned aircraft.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.77-86
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• 2024

'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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.597-606
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• 2020

Because the USV(Unmanned Surface Vehicle) is capable of remote control or autonomous navigation at sea, it can secure the superiority of combat power while minimizing human losses in a future combat environment. To plan the technology for the development of USV, the trend analysis of related technology and the selection of promising technology should be preceded, but there has been little research in this area. The purpose of this paper was to measure and evaluate the technology trends quantitatively. For this purpose, this study analyzed the technology trends and selected promising/declining technologies using topic modeling of papers and patent data. As a result of topic modeling, promising technologies include control and navigation, verification/validation, autonomous level, mission module, and application technology, and declining technologies include underwater communication and image processing technology. This study also identified new technology areas that were not included in the existing technology classification, e.g., technology related to research and development of USV, artificial intelligence, launch/recovery, and operation, such as cooperation with manned and unmanned systems. The technology trends and new technology areas identified through this study may be used to derive key technologies related to the development of the USV and establish appropriate R&D policies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.568-573
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• 2018

UAV(Unmanned Aerial Vehicle) is widely used in space information construction, agriculture, fisheries, weather observation, communication, and entertainment fields because they are cheaper and easier to operate than manned aircraft. In particular, UAV have attracted much attention due to the speed and cost of data acquisition in the field of spatial information construction. However, ortho image images produced using UAVs are distorted in buildings and forests. It is necessary to solve these problems in order to utilize the geospatial information field. In this study, fixed wing, rotary wing, vertical take off and landing type UAV were used to detect distortions of ortho image of UAV under various conditions, and various object areas such as construction site, urban area, and forest area were captured and analysed. Through the research, it was found that the redundancy of the unmanned aerial vehicle image is the biggest factor of the distortion phenomenon, and the higher the flight altitude, the less the distortion phenomenon. We also proposed a method to reduce distortion of orthoimage by lowering the resolution of original image using DTM (Digital Terrain Model) to improve distortion. Future high-quality unmanned aerial vehicles without distortions will contribute greatly to the application of UAV in the field of precision surveying.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.8
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• pp.682-687
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• 2013

Navigation is a crucial capability for all types of manned or unmanned vehicles. However, vehicle navigation in underwater environments still remains a challenging problem since GPS signals for position fixes are not available in the water. Terrain-referenced underwater navigation is an alternative navigation technique that utilizes geometric information of the subsea terrain to correct drift errors due to dead-reckoning or inertial navigation. Terrain-referenced navigation requires the description of an undulating terrain surface as a mathematical function or table, which often leads to a highly nonlinear estimation problem. Recently, PFs (Particle Filters), which do not require any restrictive assumptions about the system dynamics and uncertainty distributions, have been widely used for nonlinear filtering applications. However, PF has considerable computational requirements which used to limit its applicability to problems of relatively low state dimensions. This study proposes the use of a Rao-Blackwellized particle filter that is computationally more efficient than the standard PF for terrain-referenced underwater navigation involving a moderate number of states, and its performance is compared with that of the extended Kalman filter algorithm. The validity and feasibility of the proposed algorithm is demonstrated through numerical simulations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.7
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• pp.55-62
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• 2006

This thesis describes collision avoidance using fuzzy logic based on "Right of way" rules of ICAO and FAA and pilot's experiences for Unmanned Aerial Vehicle(UAV). To apply the rules, we designed fuzzy logic based collision avoidance system. And we also designed decision logic for enable condition of collision avoidance system. Decision logic have three kinds of core key, i.e. Relative Range, Time of CPA(Closest Point of Approach) and Distance at CPA. Application of decision logic made a possible to avoid NMAC(Near Mid-Air Collision) and it has been verified through several simulations. To conclude, we proposed the method to carry out "See and Avoid" ability on UAVs, which is capability to mingle with manned aircraft in civil airspace.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.1-10
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• 2011

This is a comparative study of three inertia navigation units and focuses on the verification of reliability about GPS/INS for the SmartUAV(DGNS). Those GPS/INS have been tested using a manned aircraft and an automobile. The comparative aspect of units include details about the GPS positions and the inertia sensor performance. With the flight scenario, the DGNS guarantees the reliability of the navigation operation and performs the flight test for the development of the SmartUAV.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.4
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• pp.479-489
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• 2021

The Republic of Korea is expected to participate in the denuclearization verification activities by the International Atomic Energy Agency (IAEA) in case any neighboring countries declared denuclearization. In this study, samples for the verification of nuclear activities in undeclared areas were selected for the denuclearization of neighboring countries, and the appropriateness of the procedures was considered. If a country with nuclear weapons declares denuclearization, it must be accompanied by the IAEA's verification regarding nuclear materials and weapons in the declared and undeclared areas. The analysis of the process samples or on-site environmental samples and the verification of undeclared nuclear facilities and materials aid in uncovering any evidence of concealment of nuclear activity in undeclared areas. Therefore, a methodology was established for effective sampling and analysis in accordance with proper procedures. Preparations for sampling in undeclared areas were undertaken for various potential scenarios, such as, the establishment of zones according to radiation dose, methods of supplying electricity, wireless communication networks, targets of sampling according to characteristics of nuclides, manned sampling method, and unmanned sampling method. Through this, procedures were established for pre- and post-site settings in preparation for hazards and limiting factors at nuclear inspection sites.

• The Journal of Korea Robotics Society
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• v.18 no.3
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• pp.293-298
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• 2023

The military is facing a continuous decrease in personnel, and in order to cope with potential accidents and challenges in operations, efforts are being made to reduce the direct involvement of personnel by utilizing the latest technologies. Recently, the use of various sensors related to Manned-Unmanned Teaming and artificial intelligence technologies has gained attention, emphasizing the need for flexible utilization methods. In this paper, we propose four dataset construction methods that can be used for effective training of robots that can be deployed in military operations, utilizing not only RGB image data but also data acquired from IR image sensors. Since there is no publicly available dataset that combines RGB and IR image data, we directly acquired the dataset within buildings. The input values were constructed by combining RGB and IR image sensor data, taking into account the field of view, resolution, and channel values of both sensors. We compared the proposed method with conventional RGB image data classification training using the same learning model. By employing the proposed image data fusion method, we observed improved stability in training loss and approximately 3% higher accuracy.