• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.6
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• pp.776-784
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• 2009

The function of DIRCM(Directed Infrared Countermeasures) jamming is to cause the missile to miss its intended target by disturbing the seeker tracking process. The DIRCM jamming uses the pulsing flashes of IR energy and its frequency, phase and intensity have influence on the missile guidance system. In this paper, we analysis the DIRCM jamming effect of spin-scan reticle seeker. Simulation results show that the jamming effect is greatly influenced by frequency, phase and intensity of the jammer signal.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.3
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• pp.95-100
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• 2006

The pulse compression technique using Linear FM signal is commonly used for improving the performance of both the detection range and range resolution in radar system. In general, the compressed LFM waveform has relatively large sidelobe level which may prevent a target from being detected when strong jammer or clutter signal is near the target signal. In this paper, we propose a new weighting method which uses the square-root weight to suppress the sidelobe level. Typical applications are missile seekers and tracking radar systems where target tracking range is available prior to the signal processing. By computer simulation, we show that the performance of the proposed method is better than that of the conventional weighting methods in terms of sidelobe suppression.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.1
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• pp.106-113
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• 2011

This paper describes Data Acquisition & Analysis System(DAS) for analysis of the multi-function radar. There are various information - beam probing data, clutter map data, plot data, target tracking data, RT tracking data, radar signal processing data, interface data - this device saves. The most important thing of data analysis is that a researcher gets a view of the whole data. The DAS intergrates with all of the data and provides overall information on the time matters occur. This is very useful advantage for approaching the matter easily. System algorithms of multi-function radar are improved by using this advantage. As a result of, range blank region have fallen about 72% and it is able to keep track in jammer environment.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.2
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• pp.252-257
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• 2010

SAR has pulse compression gain through the process including range and azimuth. Efficient jammers against the SAR with simulated elements are evaluated in the view of power and SAR image. In this paper, J/S is analysed for SAR with RF propagation equation firstly. Several jamming signals on SAR signal are made into SAR image through pulse compression process. Objective jamming performance is evaluated using euclidean distance.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.5
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• pp.34-41
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• 2008

This paper describes the design of SP3T PIN diode switch which has a 500W high power handling capability in $20{\sim}400MHz$ frequency range. Design factors were investigated and it was confirmed by simulation that the characteristics of insertion loss, VSWR, and isolation met design goal. Also, the capability to handle 500W high power with very fast switching speed of less than $26{\mu}s$ was confirmed and insertion loss of less than 1dB, VSWR of less than 1.4:1, and isolation of higher than 60dB were obtained by experiments.

• Journal of Positioning, Navigation, and Timing
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• v.9 no.1
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• pp.7-13
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• 2020

As a countermeasure against the threat of jamming which can disrupt operation of the Global Positioning System (GPS) receivers, various kinds of technique to estimate the Direction-Of-Arrivals (DOAs) of incoming jamming signals have been widely studied, and among them, the MUltiple SIgnal Classification (MUSIC) algorithm is known to provide very high resolution. However, since the previous studies regarding the MUSIC algorithm does not consider the orientation of each antenna element of antenna arrays, there is a possibility that DOA estimation performance degrades in the case of a misaligned antenna array whose antenna elements are not oriented along the same direction. As an effort to solve this problem, there exists a previous work which presents an MUSIC-based method for DOA estimation. However, the error between the real and measured values of each antenna orientation is not taken into consideration. Therefore, in this paper, the effect of the aforementioned error on the DOA estimation performance in the case of a misaligned antenna array is analyzed by simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1756-1758
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• 2016

Pseudorange is the pseudo distance between a GPS satellite and a GPS receiver to determine the receiver's position. The closer the distance between jammer and victim receiver is, the more effective a repeat-back jamming is. In this letter, we analyze the pseudorange difference between adjacent GPS receivers using real GPS pseudorange data to understand the effects by the repeat-back jamming.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.3
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• pp.304-306
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• 2016

In this letter, we investigate the performance of coherent free-space optical(FSO) systems under pulsed noise jamming conditions. In particular, we derive the average bit error probability of the coherent FSO systems with the pulsed noise jamming in a closed-form. Also, we derive the optimal fraction of symbol time of the jammer. We confirm the derived average error probability expressions by the exactly matching Monte-Carlo simulation results.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.26-38
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• 2000

전파 방해장치(jammer)의 핵심 부품이라 할 수 있는 광대역 고출력 증폭기는 초소형화, 초고주파화 및 초고출려고하하는 다양성을 각각 다른 형태의 증폭장치에서 실현하고 있다. 이 논문에서는 먼저 진공 고출력 증폭기를 반도체 증폭기와 비교하며 각각의 영향권에서 대해 비교하였다. 본론에서는 첫째로 초소형화되어가는 광대역 TWT와 MMIC와 같은 반도체소자와 연합하여 효율이 높은 초소형 고출력(>100W CW) 증폭기의 혁신을 일으키는 MPM(Microwave Power Module)을 소개하였고 둘째로는 고출력(>kW)으로 초고주파화(밀리미터파) 되어가는 Gyro-TWT를 소개하였다. 세째로 원리적으로는 현재 무기체계의 전면적인 수정을 불가피하게 할지 모르는 초고출력화(>GW) 되어가는 HPM(High Power Microwaves)이 소개되었다. 마지막으로 한국에서의 고출력 증폭기에 관련된 연구개발 상황과 TWT국산화에 대한 현황이 소개되었다.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.1
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• pp.30-35
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• 2010

As of today, Frequency Hopping techniques are widely used for over-channel interference and anti-jamming communication systems. In this paper, analysis the performance of robustness on the focus of some general jamming channel. In FH/SS systems, usually SFH(Slow Frequency Hopping) and FFH(Fast Frequency Hopping) are took up on many special communication systems, the SFH, FFH are also combined with a channel diversity algorithm likes NED(Normalized Envelop Detection), EGC(Equal Gain Combines) and Clipped Combines to overcome jammer's attack. This paper propose Adaptive-NED and shows A-NED will be worked well than the others in the some general jamming environments.