• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.113-124
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• 2022

In wartime conditions, the communication system of military aircraft is exposed to jamming, and it is necessary to mount communication equipment with high anti-jamming performance in order to perform air operations smoothly even in an environment where jamming attempts are made. In this paper, we check in detail the jamming and anti-jamming technology that can be applied to wireless communication, and the data disclosed on the difference in specifications of the next-generation anti-jamming radio with frequency hopping method and the improvement of anti-jamming performance according to these changes. It was briefly analyzed within the scope. In addition, the points to be considered when designing a new domestic aircraft and the possibility of installing the next-generation anti-jamming communication equipment on the currently operating aircraft were confirmed, and the tactical usefulness of improving the anti-jamming capability of the next-generation anti-jamming communication equipment was confirmed.

• Journal of Satellite, Information and Communications
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• v.10 no.4
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• pp.46-51
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• 2015

In this paper, I design a linear array antenna simulator for anti-jamming GPS systems and perform various performance analysis by simulation. First, I generate simulated transmission signals through the analysis of GPS satellite signal structure, and analyze SNR(Signal to Noise power Ratio) performance of linear array antenna according to number of arrays under noise environments. In addition, I analyze the performance of the anti-jamming beam pattern using MMSE(Minimum Mean Square Error) signal processing method, and also analyze the anti-jamming performance considering antenna calibration problem when there are different delays between arrays.

• The Journal of the Korea Contents Association
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• v.15 no.12
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• pp.1-7
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• 2015

These anti-jamming GPS systems are verified using large anechoic chamber or field-test until now. When using a large anechoic chamber, Independent verification from external enviroments like noise is an advantage but high cost and availability of chamber are disadvantages. And in case of field test, verification under real propagation enviroment is an advantage but security problem of military equipments and problem of making same test condition are disadvantages. This paper presents an newly developed anti-jamming GPS test system. This test system mainly consists of small anechoic chamber, jamming divider, jamming signal generator and satellite simulator. The small anechoic chamber is installed many jamming antennas to transmit multi jamming signals and the jamming divider is newly developed to control multi jamming signals. According to self performance test and combined test with Anti-jamming GPS receiver, we verified our system's reliability.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.12
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• pp.1216-1227
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• 2013

GNSS(Global Navigation Satellite System) is now being widely used in both civilian and military applications where accurate positioning and timing information are required and it is considered as a representative convergence technique in IT-Military application techniques. However, GNSS has low sensitivity level of GNSS receivers and is vulnerable to jamming signal, since the signals come from the satellite located at approximately 20,000 Km above the earth. The studies for the anti-jamming techniques in military applications have been passively performed in the domestic, because the information related GNSS are dependent on the countries that have GNSS. In this paper, we show the effect of jammer ERP by analyzing the link budget of GPS J/S power as a function of distance between jammer and receiver. Also, we categorize the anti-jamming techniques based on the functional block diagram of GNSS receiver structure and analyze the recent anti-jamming GNSS products and their technologies developed in domestic and foreign countries.

• Journal of Advanced Navigation Technology
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• v.20 no.3
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• pp.218-225
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• 2016

Null steering and beam steering are known well as anti-jamming methods in GPS anti-jamming system. Null steering gets a noise attenuation effect for the direction of jamming and beam steering earns additional gain synthesis for the direction of satellite signals. According to the research in the article for signal processing, it expresses that the N array antenna is effective for N-1 number of jamming signal by math public interest, however, the two algorithms analysis is not unknown for the operating condition of the realistic vehicle. In this paper, we modeled anti-jamming system using 4 and 7 array antenna and showed the two algorithms performance (PM, LCMV) when considering the number of antenna array, jammers and vehicle position (horizontal, vertical). In result, we showed that the case of vertical position of the vehicle which has large tilt angle for the relative position of satellites and jammers, has about 10 dB gain more in comparison with one of vertical position in spite of same JSR condition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.8
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• pp.988-995
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• 2019

In this paper, we propose the Tile Based Frequency Hopping - Chirp Spread Spectrum(TBFH-CSS) technique, which has excellent Low Probability of Intercept(LPI)/Anti-Jamming(AJ) performance. Conventional Frequency Hopping - Chirp Spread Spectrum(FH-CSS) technique uses only single chirp signal, that makes the follower jammer easy to find and jam. However, proposed TBFH-CSS uses various kind of chirp signals which are generated according to the structure of basis tile, it is composed the basis time unit and the basis bandwidth unit. The TBFH-CSS signal has variety signal period and signal bandwidth. Therefore, the follower jammer hard to find and difficult to jam the TBFH-CSS signal. We analysis the LPI/AJ performance of the TBFH-CSS technique when the follow jamming attack exist and compared with the performance of the conventional FH-CSS technique. From the analysis, we can see the proposed TBFH-CSS technique has better LPI/AJ performance than conventional technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1105-1112
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• 2010

Link-16 is a up-to-date tactical data link used in the armed forces of U.S. and NATO. In order to guarantee the required capabilities of anti-jamming and low probability of detection, Link-16 uses the techniques of frequency hopping and spreading code etc. In this paper, under Nakagami fading channels, we ananlyze the symbol error rates (SERs) of JTIDS/Link-16-type waveform based on both the single- and double-pulse schemes by considering the partial band noise jamming and the pulse jamming models, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.573-575
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• 2015

Positioning system using satellite GPS is used at positioning, navigation, acquisition time information and other various field and taking an important part precision guided weapon such as missile. But commercial code(C/A code) do not have ECCM. Therefore commercial code is vulnerable to various jamming techniques and noise jamming from near station can attack even the encrypted military code(P code) GPS. In this paper, GPS jamming techniques, North Korean GPS jamming cases and anti-jamming GP S technologies are surveyed and described.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.3
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• pp.382-389
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• 2013

In anti-jamming GPS receiver, adaptive signal processing techniques in which the radiation pattern of adaptive array antenna of elements may be adaptively changed used to reject interference, clutter, and jamming signals. In this paper, I describes adaptive signal processing technique using the sample matrix inversion(SMI) algorithm. This adaptive signal processing technique can be applied effectively to wideband/narrowband anti-jamming GPS receiver because it does not consider the satellite signal directions and GPS signal power level exists below the thermal noise. I also analyzed the effects of covariance matrix sample size and diagonal loading technique on the system performance of five-element circular array antenna. To attain near optimum performance, more samples required for calculation covariance matrix. Diagonal loading technique reduces the system nulling capability against low-power jamming signals, but this technique improves robustness of adaptive array antenna.