• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.298-303
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• 2011

최근 한반도의 잇따른 북한의 Jamming(교란신호)으로 인해 무선통신 기반 산업에 피해사례가 늘고 있다. 이에 국토해양부(위성항법중앙사무소)에서 운영중인 위성항법보정시스템(이하 "DGPS") 데이터 분석하였다. 그 결과 2010년도 발생한 재밍과 달리 2011년도에는 DGPS 기준국/감시국에서는 감지가 되지 않은 것으로 분석 되었으나, 피해 현황을 조사하여 이를 토대로 범국가적 대책방안(항행 백업시스템 개발, 유관기관과의 정보공유를 통한 감지 통합시스템 구축) 및 DGPS 운영 효율성 확보방안(감시국 신설, 실시간 감시프로그램 강화 등)에 대하여 제안하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.10
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• pp.1073-1078
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• 2014

In this paper, an effective repeat-back jamming (RBJ) mitigation scheme known assuccessive repeat-back jamming cancellation (SRC) is proposed for the utilization of the successive interference cancellation (SIC) algorithm which is used to mitigate the near-far effect and the multiple-access interference for code division multiple-access communication systems. The proposed scheme uses a combined pseudo-random noise (C-PRN) signal from the estimated major parameters of RBJ signals. To evaluate the performance of the proposed scheme, the root mean squared (RMS) code tracking errors are shown according to the standard deviation of the parameter estimation errors of an RBJ signal, and using the well-known major parameters estimation schemes with a C-PRN signal through Monte-Carlo simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.11
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• pp.977-983
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• 2016

This paper proposes a novel code-tracking scheme to track the fine code synchronization for BOC (pn,n)-modulated global navigation satellite system signals in a repeat-back jamming environment. The correlation function of BOC (pn,n)-modulated signals has several peaks. The correlation function in the advanced offset region remains almost unchanged due to the repeat-back signals being received later than a line-of-sight signal in the same multipath signal receiving case. Additionally, the combined pseudo-random noise signal can be treated as repeat-back jamming signals, like multipath signals. In this paper, we propose a novel code-tracking scheme utilizing the advantages of using a combined pseudo-random noise signal in the advanced offset region and verify its performance through simulation.

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.499-506
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• 2015

Global navigation satellite systems (GNSS) is operating widely in civil and military area. GNSS signals, however, can be easily interfered because its signal is vulnerable to jamming. Thus, a sort of backup or alternative system is needed in order that the navigation performance is assured to a certain degree in case of GNSS jamming. In order to suggest a series of backup or alternative system of regional navigation, in this paper, we introduced a high altitude long endurance unmanned aerial vehicle (HALE UAV) with pseudolites using inverted GPS and transceiver system. We simulated the positioning error of the regional navigation system using HALE UAV with inverted GPS or transceivers concepts. We estimated the position error of HALE UAV calculate user position errors based on the position error of HALE UAV and general pseudorange error.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.299-302
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• 2010

GPS를 이용하여 고정밀도의 위치정보를 얻기 위해서는 가시위성의 기하학적 배치가 매우 중요한 요소로 작용되며 이 척도가 DOP라고 불리는 계수이다. 본 논문에서는 향후 많은 항법위성이 생길 경우 통합방식에 의해 원하는 위성을 선택함으로서 고의적인 재밍에 대한 대책 및 위치정보의 정밀도 향상 측면에서 매우 유용할 것으로 판단되어 첫 단계로 GPS 와 GLONASS의 통합 시스템 구축시 정밀도의 근간을 이루는 DOP 향상에 대하여 연구하였다. 데이터 분석결과 단독 GPS 사용시 보다 통합 GNSS 시스템이 0.3 ~ 0.8 정도의 우수한 GDOP 정보를 얻을 수 있었다. 따라서 이는 GDOP 뿐만이 아니라 결과적으로 고정밀도의 위치정보를 얻을 수 있음을 확인하였다.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.2 s.17
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• pp.48-56
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• 2004

This paper presents the GPS receiver's inherent interference effectiveness based on the receiver's internal processing gain. This research is to verify the weakness of the GPS satellite signals and evaluate the receiver's vulnerability in an interference situation. The experiment for the narrow band interference effectiveness for the L1 C/A code GPS receiver has been performed by using the Spirent GSS4765 jamming simulator. After analyzing the experimental result, it is compared with the calculated J/S value of the two different L1 C/A code GPS receivers. By the above result, the narrowband jamming effectiveness of the each jamming source and the jamming margin for the each receiver are to be analyzed in detail. Finally, we could utilize the result to analyze the jamming effectiveness on the GNSS receiver.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.9
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• pp.792-797
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• 2013

This paper has derived the conversion loss according to the synchronized condition between the transmitted and locally generated spreading signals for the civil global positioning system (GPS) receiver in the heavy wideband Gaussian noise environments. From this, the outputs of the 2-bit nonuniform quantizer, which has the minimum conversion loss, is set to ${\pm}1$ and ${\pm}2$, while the quantization step size is approximated to the jamming-to-signal power ratio.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.77-80
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• 2019

GPS 항법 시스템은 재밍(jamming)에 취약한 것으로 알려져 있다. 실제로 2010년부터 북한은 서해상과 수도권에 GPS 전파교란 공격을 감행, 운행 중이던 선박과 항공기의 네비게이션 등에 다수의 장애현상을 유발시켰다. 이것에 대한 대안으로 eLoran(enhanced Long Range Navigation)이 GPS 항법 시스템을 보완할 수 있다고 알려져 있다. 이에 따라 해양수산부(MOF)는 기존 포항·광주 로란-C 송신국에 UTC(Coordinated Universal Time) 기반의 시각동기시스템 구축하여 지상파 eLoran 시스템으로 활용하기 위한 eLoran 사업을 진행하고 있다. 본 논문에서는 기존 포항·광주 로란-C 송신국에 UTC(Coordinated Universal Time) 기반의 시각동기시스템을 구축하기 위한 요구 사항을 살펴보고, 이 요구 사항에 따른 포항·광주 로란-C 시각동기시스템의 구축 결과에 대해 기술하였다.

• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.121-126
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• 2014

ETRI(Electronics and Telecommunication Research Institute) has joined National GNSS Research Center program of Defense Acquisition Program Administration and Agency for Defense Development in 2010. The research subject is technology for MSAR(Military Search and Rescue) system configuration. In this project, we analyses the ways in order to improve the accuracy, reliability, availability for MSAR system from M&S(Modeling and Simulation). The MSAR System M&S Software can be used for performance analysis of new elements, such as ground elements and satellite elements without any hardware development. In this paper, after introduction of the architecture design and functional scope of the simulator, the performance analysis result for MSAR M&S software is presented.

• Journal of Satellite, Information and Communications
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• v.8 no.2
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• pp.29-35
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• 2013

In this paper, we investigate the type and detection methode of spoofing attack, and then analyze the performance of spoofing detection algorithm in GPS L1 signal through the simulation. Generally spoofer is different from the jammer, because the receiver can be operated and not. In case of spoofing the GPS receiver is hard to recognize the spoofing attack and can be operated normally without stopping because the spoofing signal is the mimic GPS signal. To evaluate the performance of spoofing detection algorithm, both the software based spoofing and GPS signal generator and the software based GPS receiver are implemented. In paper, we can check that spoofing signal can affect to the DLL and PLL tracking loop because code delay and doppler frequency of spoofing. The spoofing detection algorithm has been implemented using the pseudorange, signal strength and navigation solution of GPS receiver and proposed algorithm can effectively detect the spoofing signal.