• Journal of Convergence for Information Technology
• /
• v.10 no.3
• /
• pp.16-21
• /
• 2020

This paper describes the jamming characteristics of a stand-off jammer jamming the LPI radar. The LPI radar reduces the side lobes of the receiving antenna to reduce the effect of jamming. It is easy a radar to predict the effect of jamming on a self-protection jammer where the jammer is in the same position as the target. However, for stand-off jammer jamming at different locations from the target, the prediction of jamming effect is complex. In this paper, the jamming effect of LPI radar is analyzed using signal to jamming ratio and burn-through range. Also, when the antenna's side lobe decreases below -30 dB, the stand-off jamming effect in the side lobe direction is weak. So we proposed a new jamming method for the main lobe and analyzed the jamming effect. This study is expected to be useful for the design and operation of aircraft jammers.

• Journal of Convergence for Information Technology
• /
• v.9 no.5
• /
• pp.125-129
• /
• 2019

This paper describes the jamming effect of phase-coded pulse compression(PCPC) radar. Barker code radar, a typical PCPC radar, separates transmission pulses into 13 or 31 small pulses and phase modulates and transmits each pulse signal to increase radar detection efficiency and reduce the influence of jamming. Generally, when the radar is subjected to jamming, the detection distance becomes shorter and the detection error rate becomes higher. In the case of noise jamming or carrier jamming on the PCPC radar, the jamming effect is very small for no phase-coded convergence. However, the jamming effect is large in the case of synchronous jamming using the pulse-coded signal as a jamming signal with DRFM. It can be seen that the jamming effect increases when the storage time of the pulse-coded signal is prolonged. This study is considered to be useful for PCPC radar and EW jamming system design.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.15 no.10
• /
• pp.868-878
• /
• 1990

Upon introducing satellite communication system to Korea, one of the important problems to cope with is the effect from the probable intentional interference I.e. jamming. In this paper we have investigated how much the performance of ordinary PSK signal and Directed Sequence Spread Spectrum PSK signal degrade by the effect of jamming in the satellite communication system. In analysis we have consider the M ary PSK signal and the liniter type nonlinear satellite transponder in an environment of uplink tone or noise jamming plus Gaussian noise and downlink Gaussian noise. Using the derived error rate equation we have evaluated the error performance of BPSK and QPSK systems and compared this with that of DS BPSK system. Form the results, we know that the nonlinear satellite system is degraded more severely by the effect of noise jamming than tone jamming and the effect of tone jamming on the error rate performance can be reduced more remarkably by increasing the process gain in DS BPSK system rather than increasing carrier to jamming noise power ratio in conventional BPSK system.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.8 no.4 s.23
• /
• pp.91-101
• /
• 2005

In this paper, a technique for the quantitative analysis of the noise jamming effect is proposed. This technique based upon the mathematical modeling for noise jammers and the probability theory for random processes analyses the jamming effect by means of the modeling of the relationship among jammer, radar variables and radar detection probability under noise jamming environment. Computer simulation results show that the proposed technique not only makes the quantitative analysis of the jamming effect possible, but also provides the basis for quantitative analysis of the electronic warfare environment.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.12 no.6
• /
• pp.776-784
• /
• 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
• /
• v.13 no.2
• /
• pp.304-312
• /
• 2010

The function of IRCM(Infrared Countermeasures) jamming is to cause the missile to miss its intended target by disturbing the seeker tracking process. This paper analyzes the jamming effect of IRCM jamming for a stationary reticle seeker. The phase error containing the azimuth angle information of target is analyzed for the intensity, frequency and duty ratio variation of the jammer pulse signal. We confirmed that the more the jammer frequency is similar to the spinning frequency of the stationary seeker, the more jamming effect is high.

• The Journal of Korea Robotics Society
• /
• v.12 no.3
• /
• pp.332-338
• /
• 2017

As an interpretation of existing jamming effects, the main variables affecting the increase in stiffness due to jamming are known as system density, jamming density, pressure, and particulate temperature. The main variable, jamming density, is closely related to the distribution of particle size and contact properties such as particle shape and friction. However, the complexity of these variables makes it difficult to fully understand the mechanism of the jamming effect. In this paper, we focus on the jamming effects of particles that have more elastic properties than particles such as sand and coffee powder, which are commonly used as constituent particles of existing jamming, in order to reduce complicated factors such as temperature and concentrate on jamming effects based on elastic characteristics of particles. It was experimentally explored the possibility of increasing stiffness by mixing particles of different sizes rather than simply increasing the bending stiffness by controlling the particle size. Through simulations and experiments, we found a case where the stiffness of each particle size distribution is larger than the stiffness of each particle size.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1987.04a
• /
• pp.212-218
• /
• 1987

The error rate equations of digital modulatuon techniques(M-ary PSK MSK Multi-level QAM) have been derived in the environment of Qaussian noise and Jamming And the results are shown in the figures as parameters of carrier power to noise power ration(CNR) carrier power to Jamming power ration(CJR) Jamming power to carrier power ration(JCR) alteration figure of envelope of Jamming(M) As the results of analysis the system performance is more degreeded by Qau-ssian Famming than Tone Famming In case that envelope of Famming has m-distribution, the s/stem parformance is desreeded in the deep alteration of envelope

• Journal of Positioning, Navigation, and Timing
• /
• v.10 no.4
• /
• pp.353-361
• /
• 2021

This paper presents the jamming effect on the L5 band of Global Navigation Satellite System (GNSS) by analyzing real data collected via measurement campaigns in Korea region. In fact, the L5 band is one of the dedicated bands for various satellite navigation systems such as Global Positioning System (GPS), Galileo, BeiDou (BDS), and Quasi Zenith Satellite System (QZSS). And this band is also allocated along with various systems used for aeronautical radio navigation systems (ARNS). Among ARNS, the Distance Measuring Equipment (DME) and the Tactical Air Navigation System (TACAN) are systems that transmit and receive strong power pulse signals, which may cause unintentional jamming in the reception of GNSS signals. In this paper, signals in the main lobe of GPS L5, Galileo E5a, BDS B2a, and QZSS L5 are collected in Korean region to confirm whether the jamming effect exists in the band. And then, the pulse blanking technique, which is a simple signal processing technique capable of responding to pulsed jamming, is applied to analyze the jamming effect of DME/TACAN on the L5 band.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.9A
• /
• pp.1609-1613
• /
• 2001

본 논문에서는 실시간 자기 상관 관계를 이용하여 주파수 도약 시점을 찾아내는 epoch 추정기를 소개하고 이것의 성능을 tone jamming 환경 하에서 분석해 보았다. 주파수 도약 방법을 이용하는 시스템은 주로 군 관련 시스템이므로 jamming 환경 하에서의 성능이 매우 중요하다. Jamming이 있을 경우 epoch 추정기는 실제 값보다 작은 값을 나타내는 것을 알 수 있었다. 분석 과정을 수학적으로 유도하였고, 컴퓨터 실험으로 결과를 확인하였다.