• Journal of the Society of Disaster Information
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• v.1 no.1
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• pp.91-119
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• 2005

When the national disaster accident is occurred, it is difficult to maintain the mutual cooperation systems. In order to solve the problems, the construction of the national unified command wireless network is necessary. In this paper, the specified state of the characteristic frequency of the digital TRS wireless network constructed recently is investigated and analyzed. Through the analysis, the problems of the construction of the national unified command wireless network are grasped. To solve the problem, it is proposed that the digital TRS wireless network is connected with the satellite communication network, and connected with the existing wireless network, LMR. In the concretely it is proposed that the natural unified wireless network should be proceeded step by step. At first, for 2 years the existing networks of the Fire Fighting Agency, the Police, the Forest Service and so on must be utilized and prepared to link with TRS. The second, for 2 years it is carried forward a scheme to maintain the properties of the agencies concerned. Further, it must be prepared to connect with satellite network. At third, for 2 years all agencies concerned with the fire fighting and the disaster prevention must be unified, and the systems have to be promoted for the p1an of linkage of TRS network and the existing network. Next the agencies concerned have to be unified and the authority has to be intensified. When a disaster is occurred, the National Emergency Management Agency has to play a central role. In a local area it has to be given the Fire Fighting Agency an authority and a duty to get ready for each emergency situation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.813-821
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• 2000

The engineering of satellite communication systems at frequencies above 10GHz requires a method for estimating rain-caused outage probabilities on the earth-satellite path. A procedure for predicting a rain attenuation distribution from a point rainfall rate distribution is, therefore, needed. In order to predict rain attenuation on the satellite link, several prediction models such as ITU-R, Global, SAM, DAH model, have been developed and used at a particular propagation condition, they may not be appropriate to a propagation condition in Korean territory. In this paper, a new rain attenuation prediction method appropriate to a propagation condition in Korea is introduced. Based on the results from ETRI measurements, a new method has been derived for an empirical approach with an identification on the horizontal correction factor as in current ITU-R method, and the vertical correction factor has been suggested with decreasing power law as a function of rainfall rate. This proposed model uses the entire rainfall rate distribution as input to the model, while the ITU-R and DAH model approaches only use a single 0.01% annual rainfall rate and assume that the attenuation at other probability levels can be determined from that single point distribution. This new model was compared with several world-wide prediction models. Based on the analysis, we can easily know the importance of the model choice to predict rain attenuation for a particular location in the radio communication system design.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.448-451
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• 2004

MSC (Multi-Spectral Camera) system is an electro-optical camera system which is being developed to be installed on KOMPSAT-2 satellite. High resolution image data from MSC system will be transmitted to the ground-station through x-band antenna called APS (Antenna Pointing System). APS is a directional antenna which will point to the receiving antenna at ground station while the satellite is passing over it. The APS needs to be controlled accurately to provide the reliable communication with big RF link margin. The APS is controlled by ATS (Antenna Tracking Software) which is included in the MSC software. ATS uses the closed loop control algorithm which will use TPF (Tracking Parameter File) as an input for antenna position, and will use two resolve readings from APS as a feedback. ATS has been developed and verified using APS QM (Qualification Model) and all the control parameters for ATS have been tested and verified. Various kinds of maximum, nominal and realistic dynamics for the APS movement have been simulated and verified. In this paper, closed loop servo control algorithm and obtained APS position error from the verification test with APS QM will be presented in detail

• The Journal of the Acoustical Society of Korea
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• v.17 no.5
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• pp.35-41
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• 1998

본 논문에서는 다중 빔을 사용한 저궤도 위성 이동 통신시스템 환경에서 부호 분할 다중접속 및 주파수 분할 다중접속 방식의 채널 용량을 비교 분석하였다. 위성 중계기의 출 력의 효율성, 주파수 효율성, 부호화 방식 및 안테나의 EIRP나 G/T형태 등과 같은 파라미 터들을 순방향 링크와 역방향 링크에서 채널 용량을 결정하는 시스템 파라미터로서 고려하 였고, 피더 링크(feeder link)는 Ku-band를, 사용자는 링크는 L-band를 사용한 다중 스팟빔 (spot beam) 시스템을 채널 용량 분석의 모델로 적용하였다. 분석결과 도플러 현상 및 다중 경로에 강한 부호 분할 다중접속 방식이 용량면에서 주파수 분할 다중접속 방식에 비해 성 능이 우수함을 알 수 있었다.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.3
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• pp.451-456
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• 2020

In this paper, we studied the method of designing a embedded antenna for mounting on the JTDLS complete aircraft. The proposed antenna satisfies the MIDS-LVT operation frequency band and is designed as a broadband in consideration of expandability. As a result of the design, it was confirmed that the proposed antenna has similar electrical performance to the existing blade antenna and has broadband characteristics. As a result of EM analysis, the antenna was mounted on the top and bottom parts of the aircraft to check the mount of the aircraft, and it was confirmed that both the top and bottom parts had good radiation characteristics. The technology acquired through this study is judged to be applicable to the JTDLS completed aircraft.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.3
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• pp.201-210
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• 2019

This paper proposes the AMCS(Agricultural Machine Control System that distinguishes farms using satellite photos or drone photos of farms and controls the self-driving and operation of farm drones and tractors. The AMCS consists of the LSM(Local Server Module) which separates farm boundaries from sensor data and video image of drones and tractors, reads remote control commands from the main server, and then delivers remote control commands within the management area through the link with drones and tractor sprinklers and the PSM that sets a path for drones and tractors to move from the farm to the farm and to handle work at low cost and high efficiency inside the farm. As a result of AMCS performance analysis proposed in this paper, the PSM showed a performance improvement of about 100% over Dijkstra algorithm when setting the path from external starting point to the farm and a higher working efficiency about 13% than the existing path when setting the path inside the farm. Therefore, the PSM can control tractors and drones more efficiently than conventional methods.

• Journal of Information Technology and Architecture
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• v.11 no.1
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• pp.11-23
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• 2014

Kill Chain is getting attention due to North Korea's recent nuclear test and missile launches and has emerged the need for an early build up. In order to build a materialized kill chain, you should review the unique kill chain to support operations effectively using various sensors and striking weapon system. Especially, you need a suitable network to reduce a reaction time against the enemy attack under joint operations environment etc. Currently there are many communication ways(e.g. data link, voice, video and text message) used in operations through satellite, wired and wireless and so on. Now, this paper contains analysis on various means for target information exchange which are used in the kill chain. And appropriate network of the kill chain for target information transmission is addressed to confirm feasibility of its alternatives, which is developed using AHP(Analytic Hierarchy Process). Finally, this paper is suggesting network and means of its building up for target information transmission of kill chain which can be implemented under the situation of joint battle field.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.156-162
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• 2013

In the communication between satellite and ground station, data rate can be determined from the data volume and required transmission time. Increasing data rate can be limited according to the available bandwidth. For the reason, it has been popularly studying on high spectral-efficient modulation scheme in large volume data application such as digital video broadcasting service. This paper presents the conceptual design of UHRIT broadcasting in GEO-KOMPSAT-2A (GK2A) mission by using DVB-S2 standard. Based on the recently determined data rate, UHRIT bandwidth was calculated at the various modulation schemes and code rates of DVB-S2 standard. Receiving performance of global user station was also evaluated thorough link analysis by considering that user station is located at the edge of beam coverage. Finally, maximum data rate was analyzed in a situation that COMS HRIT bandwidth should be alternatively applied for UHRIT downlink.