• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.3
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• pp.431-440
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• 2017

HF communications are used as a last means of long distance communications without any relay node in NLOS (Non Line-Of-Sight) environment. Conventional analog voice communication in the HF band is vulnerable to security as well as severe background noise. To overcome these shortcoming, digital voice was introduced into HF radios in the early 1980s. In this paper, we analyze avaliable digital voice communication ground wave range of HF radios that applied MELPe CODEC and MIL-STD-188-110B physical layer standard using GRWAVE program. And we evaluate usefulness of digital voice communication in HF band.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.12
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• pp.2549-2554
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• 2011

This paper describes on development of integrated interface and applications to support stable digital data communication service for small and midium sized crafts exploiting SSB modems and HF wireless sets. Firstly, integrated interface module between GPS (Global Positioning System) and communication devices was developed. Secondly, maritime map was implemented into a display terminal to provide location tracking service and voyage planning function. In addition, condition monitoring service of crafts and fishing report functions as well as alarm functions were developed to support secure fishery. Results of performance measure on developed application services shows that error rate was less than 3% and communication delay was shorter than 1 second when a message length was less than 1 Kbyte along with one-to-many communication type.

• Defense and Technology
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• no.11 s.297
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• pp.56-61
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• 2003

Longbow Apache의 밀리미터파 사통 레이더는 최첨단의 광학 체계조차 장님으로 만드는 연기와 날씨도 침투한다. 애초에 특수 작전용 Black Hawk와 Chinook에 탑재된 통합 RF Countermeasures는 대공 레이더를 식별하고 위치확인 후 교란한다. IDM(Improved Data Modem), 내장된 GPS 관성 항법장치 그리고 초지평선 HF 무전기가 헬기편대에 포함되서 미래전투체계(FCS)와 UAV(Unmanned Aerial Vehicle)의 정보를 실시간으로 이용할 수 있게 한다. 게다가 AWACS와 JSTARS같은 공군의 공중 레이더, 혹은 해군의 네트워크 중심의 전장 공간 같은 데 있는 해상 센서를 통해 전체적으로 파악된 영상까지도 가능하게 될 것이다.

• Journal of Aerospace System Engineering
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• v.13 no.5
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• pp.87-93
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• 2019

This study suggests the development of the ALE (Automatic Link Establishment) system for the long-range communication with a helicopter at the lands or marines by HF (High Frequency) radios. In the condition of LOS or more than 35 NM, the communication success rate is significantly lowered when the frequency is manually selected because of the reduced transmission power and various strong RF environment noise signals. In this paper, we make an effort to overcome the difficulties of choosing the optimal frequency when the operating frequency selection is manually operated in long-distance communication or LOS uncertain environment. The ALE system is designed based on the frequency analysis propagation software and is verified that the communication success rate is increased by applying the proposed system. The ALE system was applied to the helicopter system and the ground/flight test was conducted. As a result, the superiority and efficiency of the proposed system were verified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.10
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• pp.1990-1998
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• 2017

The success of naval operation prioritizes the implementation of a robust communication network that delivers accurate and prompt communications to one another. The satellite, which is the main communication network of the military, is required to construct a preliminary communication network because of the enemy radio disturbance and weak point of fixed antenna. The military operational communication network has been in transition from voice-centered wireless communication network to text message-based communication network. In this paper we suggest an enhanced communication method built on Roll Call, the main communication method of ROK Navy operating tactical data link called Link-11. Simulation results display that the proposed method reduces the transmission time per unit frame by 4.3 times compared to the Roll Call and 6.3 times compared with the Round Robin & Broadcasting; it is also proved that the higher the direct reception rate, the shorter the transmission time required by 1.6 times maximum.