• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1728-1735
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• 2011

In this paper, satellite data link waveform is proposed which is based on the waveform of Link-16 but LDPC code is studied instead of CCSK code in order to be optimized to satellite nonlinear channel environment and transmission characteristics. And the DSM (Demux, Selective CH switch, and Mux) transponder structure is suggested which can remove all of the jamming signal out of the transmission signal band and convert uplink hopping frequency to desired ones of downlink. The results of BER and anti-jamming performance analysis shows that the required Eb/No and processing gain in the worst case partial band jammer of the proposed waveform are 2.5dB and 52dB respectively and the anti-jamming capacity improvement of DSM transponder is maximum 2dB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.4
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• pp.721-728
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• 1994

In this paper, we analyzed the performances of system considering diversity for FH/CPFSK system with limiter-discrimicator detection and integrate-and-dump post-detection filtering. And, we considered thermal noise and partial-band jamming noise, intersymbol interference for all eight of the possible adjacent bit data patterns, FM noise clicks for evaluation systems. In result, the performance of FH/CPFSK system with diversity under the worst-case partial band jamming noise degraded about 5dB rather than that of without diversity when we considered the thermal noise but improved about 16dB rather than of without diversity when we ignored the thermal noise.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.2
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• pp.278-286
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• 2019

Conventional methods for selecting jamming techniques in electronic warfare are based on libraries in which a list of jamming techniques for radar signals is recorded. However, the choice of jamming techniques by the library is limited when modified signals are received. In this paper, we propose a method to predict the jamming technique for radar signals by using deep learning methods. Long short-term memory(LSTM) is a deep running method which is effective for learning the time dependent relationship in sequential data. In order to determine the optimal LSTM model structure for jamming technique prediction, we test the learning parameter values that should be selected, such as the number of LSTM layers, the number of fully-connected layers, optimization methods, the size of the mini batch, and dropout ratio. Experimental results demonstrate the competent performance of the LSTM model in predicting the jamming technique for radar signals.

• Journal of IKEEE
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• v.22 no.1
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• pp.162-167
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• 2018

In this paper, we propose a method to classify radar signals according to the jamming technique by applying the machine learning to parameter data extracted from received radar signals. In the present army, the radar signal is classified according to the type of threat based on the library of the radar signal parameters mostly built by the preliminary investigation. However, since radar technology is continuously evolving and diversifying, it can not properly classify signals when applying this method to new threats or threat types that do not exist in existing libraries, thus limiting the choice of appropriate jamming techniques. Therefore, it is necessary to classify the signals so that the optimal jamming technique can be selected using only the parameter data of the radar signal that is different from the method using the existing threat library. In this study, we propose a method based on machine learning to cope with new threat signal form. The method classifies the signal corresponding the new jamming method for the new threat signal by learning the classifier composed of the hidden Markov model and the neural network using the existing library data.

• Journal of the Korea Institute of Military Science and Technology
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• v.1 no.1
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• pp.219-226
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• 1998

군 위성통신 시스템의 생존성 향상을 위한 대전자전기능 설계기법으로 Dehop/Rehop 중계기를 사용하는 FH-FDMA 위성통신방식 설계구조를 제안하고 성능을 분석하였다. Dehop/Rehop방식은 적의 재밍조건하에서 필수적 통신링크를 보장하는 설계기법으로 Bent-Pipe방식에서의 Power Robbing, Hard-limiter에 의한 소신호 감쇄 등이 거의 없으며 광대역 도약으로 항재밍 능력의 개선이 가능하다. 본 연구에서는 75bps-2048kbps의 LDR/MDR/HDR 데이터 전송이 가능한 중계기 구조를 설계하고, SHF대역에서 도약대역폭에 따른 항재밍 성능분석과 Bent-Pipe방식 대비 Dehop/Rehop방식의 채널별 항재밍 성능분석결과 9-l0㏈내외의 성능개선이 가능함을 보였다.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.3
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• pp.239-250
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• 2022

In this paper, we analyze the performance of an FM radio based passive radar in the presence of deception jamming such as false-target generation. To do this, we examine the effects of applying the deception jamming signal to the passive radar through the derivation of the construction of the amplitude-range-Doppler(ARD) plot. The analysis results show that applying the deception jamming signal with the low power similar to the target echo signal generates false targets at positions set by the jamming variables compared to the real target position in the ARD plot. Also, it is possible to induce the jamming effect so that only false targets are detected by selecting appropriate jamming power. Simulations are included to verify the theoretical results and to discuss on the effectiveness of the deception jamming on the FM radio based passive radar.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.2
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• pp.51-57
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• 2024

The tracking radar system is a pulsed tracking system that searches, detects, and tracks targets in real time for ships operating in the ocean. Ships defend themselves through soft kill operations to confuse or deceive the tracking radar. Soft Kill operations include passive chaff and active noise jamming. This paper understands the basic concepts of electronic warfare and explains various deception systems in operation on ships. In addition, each deception The radar system design to respond to the system is explained.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.4
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• pp.256-265
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• 2018

We herein analyze the survivability of an airborne platform when an active decoy delivers jamming attacks against an active RF seeker system that operates based on the proportional navigation guidance law. In encounter scenarios with various conditions, such as platform maneuvering, the decoy's RF specification, and the seeker's approaching range and angles, the missed distance of the RF seeker is evaluated. By comparing the missed distance with the proximity of the fuze range, the platform's survivability is determined and the survival area of the platform is drawn on several encounter scenarios.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.551-561
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• 2009

FH system is very robust to the jamming interference. OFDM system is very good for the high speed communication system. But, it has high PAPR. SC-FDMA system based on OFT-spread OFDM was proposed to reduce high PAPR. Therefore, in this paper, we like to introduce the FH system into SC-FDMA system, which can be best solution to the jamming hostile environment and for the high power efficiency. Also, OFDM is very sensitive to ICI. Especially, ICI generated by frequency offset and phase noise breaks the orthogonality among sub-carriers, which seriously degrades the system performance. We analyze the performance of the FH SC-FDMA system in the PBJ and MTJ channel. In this paper, the ICI effects caused by phase noise, frequency offset and Doppler effects are analyzed and we like to propose the PNFS algorithm in the equalizer to compensate the ICI influences. Through the computer simulations, we can confirm the performance improvement.

• Journal of IKEEE
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• v.8 no.1 s.14
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• pp.39-46
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• 2004

This paper presents the realization schemes for a multipurpose coherent mono-pulse radar Simulator with extendable features. We developed and installed the TSG(Timing Signal Generator) board which can simulate a mechanically rotate signal of antenna, an operation timing signal of pulse radar and target signal, to operate the simulator without real target in the indoor environment. Also, with the insertion of the radar signal processor, it came to be easy to achieve the addition of radar function algorithms, to rebuild or extend the multi-DSP Architecture into the simulator. Throughout the simulation results, we verified that the designed coherent mono-pulse radar simulator can exactly display a moving target on the realistic monitor(RD 9800).