• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1414-1418
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• 2013

In this paper, analyzed of UAVs operation altitude and range from the point of view of the data link. UAVs operation altitude is determined by the specification of the mission equipment and operational purposes. The link-of-sight analysis of data link equipment before deciding the unmanned aircraft operation altitude conditions should be considered. If GDT=0m installation then 32dBi antenna apply 15,779 meter is operation altitude. 44dBi antenna 7,927 meters. Operating altitude perspective, high-gain antenna is recommended of the long range communication.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.11
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• pp.1031-1038
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• 2016

In the UAVs, the position error of the inertial navigation system is constantly increased when global positioning system goes wrong due to interference. It makes impossible to ensure mission and flight safety. If the data-link system provide the position of the UAV for inertial navigation system periodically, then the UAV may operate normally under malfunction of the global positioning system. In this paper, we introduce an algorithm for estimating the position of the UAV using the monopulse tracking and distance measurement of the line-of-sight data-link system. Also, we propose a method to improve the performance of position estimation. And we assured ourselves that this method can be applied in the UAVs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.783-785
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• 2013

In this paper, analyzed of UAVs operation altitude and range from the point of view of the data link. UAVs operation altitude is determined by the specification of the mission equipment and operational purposes. The link-of-sight analysis of data link equipment before deciding the unmanned aircraft operation altitude conditions should be considered. If GDT=0m installation then 32dBi antenna apply 13,724 meter is operation altitude. 44dBi antenna 6,657 meters. Operating altitude perspective, high-gain antenna is recommended of the long range communication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1528-1538
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• 2016

Common data link systems are designed to transmit the imaginary and signal intelligence data at long distance air-ground line of sight(LOS) link. In this paper, we analyze the received power variation according to the communication distance of the common data link using curved earth 2-Ray model suitable for received signal power analysis of long distance air-ground wireless channel. We propose optimal elevation angle control method of the receiving antenna to reduce a power variation caused by ground-reflected wave. Proposed method can get additional link margin compared to the conventional method without any additional hardware performance enhancement.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2541-2546
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• 2013

In this paper, we proposed on the azimuth correction method for a line-of-sight data-link tracking antenna system. Tracking antenna system is essential to maintain line-of-sight between moving object and data-link equipment. In order to calculate the azimuth and elevation between the moving object and antenna system, we used GPS data. also to match the each coordinate systems, we used geomagnetic sensor or beacon. However, the geomagnetic disturbance-prone terrain in places difficult to correct calibration. The first step, finds the location of the strongest RF signal, we should remember the difference between the reference point and the detected position of the antenna. The second step, we could communicate each other. And the azimuth angle is calculated by GPS values. Despite the geomagnetic interference, we can correct the azimuth angle quickly and easily.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1586-1594
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• 2011

LED-ID (light emitting diode - identification) technology is the new paradigm in the identification technology environment. LED-ID system typically needs line of sight (LOS) that supports narrow FOV transceivers links to achieve high data rate. On the other hand, narrow FOV reduces the coverage area. Therefore, the number of tags is increased significantly to cover the whole area. In this case number of link switching is increased when the reader moves within whole coverage area. Link switching delay is the important factor for the moving reader to maintain the communication with high data rate and better QoS. In this paper we propose in literature a new link switching scheme and measure the link switching delay time for LED-ID system. The simulation results show that the proposed link switching scheme is a possible candidate for multi-tag LED-ID system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.10
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• pp.965-976
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• 2012

Multi-Platform Image and Intelligence Common data link(MPI-CDL) systems are designed to transmit the imaginary and signal intelligence data at an aeronautical to ground line of sight(LOS) link. This paper proposes a method to predict a link availability and analyzes the required link margin to satisfy a given link availability for MPI-CDL systems. To estimate a link availability the proposed method applies the conditional probability so that both a rain attenuation and a multipath fading are considered simultaneously. Link margins to meet the link availability for MPI-CDL systems are calculated according to an operating environment including frequencies, flight altitudes and transmission ranges. The required link margins for actual unmanned air vehicle systems are also given by simulation results.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.9-14
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• 2020

In this paper, we studied on-board antenna(primary link/secondary link/satellite link) used in UAV Data-link system. As a result, it is ideal to configure the Data-link as a triple link to secure the flight stability of the UAV, but the communication link should be configured according to the operating platform. As a result of overseas R&D trend analysis, the on-board Data-link antenna is installed and operated in a location where it is easy to secure LOS. The primary link consists of a directional antenna for basic operation and an omni-directional antenna for emergency operation. The secondary link uses a monopole/dipole antenna in the UHF/C band. Satellite link has been developed to apply phased array antenna to improve UAV operability.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1169-1176
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• 2018

The C-band omni-directional antenna for drone control is mounted on the top or bottom and used to configure the communication link. The communication link is affected by the LOS depending on the mounting position of the omni-directional antenna. In this paper, two kinds of embedded antennas were designed with a commercial simulation tool CST MWS, and EM analysis was performed to consider the mounting environment. Also, we propose the PTMP ground antenna to control a large number of drones. The ground antenna has a communication link of 30km, and it consists of four sector antennas in the horizontal direction and one directional antenna at the top.

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.99-111
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• 2010

In this paper as a follow-up to Paper I, the required fade margin derived in Paper I to preserve the same service quality has been examined by analyzing system and propagation characteristics as well as measured data. The comparison of the fade margin between simulated and measured results is also performed for the actual operating line-of-sight(LOS) and non-LOS links, and practical usefulness as an analysis tool is revealed by checking service quality of M/W system relevant to frequency reallocation. According to simulated and measured results, there was a little difference for LOS link between Mt. Moodung and Mt. Mangun, but a fairly good agreement was reached for non-LOS link between Andong KBS and transmitter site.