A GNSS Interference Detection Method Based on Multiple Ground Stations

김선영,강창호,양정환,박찬국,주정민,허문범 사단법인 항법시스템학회 2012 Journal of Positioning, Navigation, and Timing Vol.1 No.1

For a GNSS receiver’s robustness against RFI and the high accuracy of navigation solution in GNSS, interference source detection and mitigation are needed. In this paper, an adaptive lattice IIR notch filter is employed to track single-tone continuous wave and swept continuous wave interference signals, and an interference detection method is proposed. Furthermore, this paper presents interference source characterization algorithm using multiple ground stations’ interference detection results. The measurement of the signal powers from each ground station is used to build weighting factors to estimate the type of the interference. The performance of interference detection algorithm is simulated for scenarios of GPS signal in the presence of single-tone continuous wave interference and swept continuous wave interference.

A GNSS Interference Detection Method Based on Multiple Ground Stations

Kim, Sun Young,Kang, Chang Ho,Yang, Jeong Hwan,Park, Chan Gook,Joo, Jung Min,Heo, Moon Beom The Institute of Positioning 2012 Journal of Positioning, Navigation, and Timing Vol.1 No.1

For a GNSS receiver's robustness against RFI and the high accuracy of navigation solution in GNSS, interference source detection and mitigation are needed. In this paper, an adaptive lattice IIR notch filter is employed to track single-tone continuous wave and swept continuous wave interference signals, and an interference detection method is proposed. Furthermore, this paper presents interference source characterization algorithm using multiple ground stations' interference detection results. The measurement of the signal powers from each ground station is used to build weighting factors to estimate the type of the interference. The performance of interference detection algorithm is simulated for scenarios of GPS signal in the presence of single-tone continuous wave interference and swept continuous wave interference.

Low-Complexity MIMO Detection Algorithm with Adaptive Interference Mitigation in DL MU-MIMO Systems with Quantization Error

Park, Jangyong,Kim, Minjoon,Kim, Hyunsub,Jung, Yunho,Kim, Jaeseok The Korea Institute of Information and Commucation 2016 Journal of communications and networks Vol.18 No.2

In this paper, we propose a low complexity multiple-input multiple-output (MIMO) detection algorithm with adaptive interference mitigation in downlink multiuser MIMO (DL MU-MIMO) systems with quantization error of the channel state information (CSI) feedback. In DL MU-MIMO systems using the imperfect precoding matrix caused by quantization error of the CSI feedback, the station receives the desired signal as well as the residual interference signal. Therefore, a complexMIMO detection algorithm with interference mitigation is required for mitigating the residual interference. To reduce the computational complexity, we propose a MIMO detection algorithm with adaptive interference mitigation. The proposed algorithm adaptively mitigates the residual interference by using the maximum likelihood detection (MLD) error criterion (MEC). We derive a theoretical MEC by using the MLD error condition and a practical MEC by approximating the theoretical MEC. In conclusion, the proposed algorithm adaptively performs interference mitigation when satisfying the practical MEC. Simulation results show that the proposed algorithm reduces the computational complexity and has the same performance, compared to the generalized sphere decoder, which always performs interference mitigation.

Low-Complexity MIMO Detection Algorithm with Adaptive Interference Mitigation in DL MU-MIMO Systems with Quantization Error

박장용,김민준,김현섭,정윤호,김재석 한국통신학회 2016 Journal of communications and networks Vol.18 No.2

In this paper, we propose a low complexity multipleinputmultiple-output (MIMO) detection algorithm with adaptiveinterference mitigation in downlink multiuser MIMO (DL MUMIMO)systems with quantization error of the channel state information(CSI) feedback. In DL MU-MIMO systems using theimperfect precoding matrix caused by quantization error of theCSI feedback, the station receives the desired signal as well as theresidual interference signal. Therefore, a complexMIMO detectionalgorithm with interference mitigation is required for mitigatingthe residual interference. To reduce the computational complexity,we propose a MIMO detection algorithm with adaptive interferencemitigation. The proposed algorithm adaptively mitigates theresidual interference by using the maximum likelihood detection(MLD) error criterion (MEC). We derive a theoretical MEC byusing the MLD error condition and a practical MEC by approximatingthe theoretical MEC. In conclusion, the proposed algorithmadaptively performs interference mitigation when satisfyingthe practical MEC. Simulation results show that the proposed algorithmreduces the computational complexity and has the sameperformance, compared to the generalized sphere decoder, whichalways performs interference mitigation.

매설 배관의 타공사 손상 조기 검출에 대한 실험적 검증

이선호,박춘수,윤동진 한국비파괴검사학회 2023 한국비파괴검사학회지 Vol.43 No.3

Damage to buried pipelines caused by third-party interference can lead to explosions, environmental pollution, ground settlement as well as economic losses. To prevent such damages, early detection technologies are required for identifying third-party interference that could affect these pipelines. Accordingly, vibration-based monitoring techniques have been extensively researched, and source localization based on the time difference of arrival have gained attention due to their effectiveness. This study aims to detect third-party interference to buried pipelines at an early stage to prevent pipeline damage. The accelerometers were attached to in-service waterwork pipelines with a diameter of 2,200 mm, a total length of 255 m, and an installation depth of 3 m to detect signals of third-party interference. The optimal frequency band for calculating the source location was determined by the results of frequency analysis. Our empirical research yielded the early detection of third-party interference in the tested pipeline, which in good agreement with the excavation position. 타공사에 의한 매설 배관 파손 사고는 대량을 누출로 인한 폭발, 환경오염, 지반 침하 그리고 경제적 손실을 초래한다. 이러한 피해를 예방하기 위해서는 타공사에 의한 배관 파손 징후를 조기에 검출 가능한 기술이 필요한 실정이다. 진동 신호를 이용한 매설 배관의 모니터링 기술은 오랫동안 많은 연구가 진행되어왔으며, 파동의 도달 시간차에 기반한 손상 위치 표정 기법이 효과적인 것으로 주목 받아 왔다. 본 연구에서는 배관이 매설된 지반 위에서 수행하는 타공사를 조기에 검출하여 배관 파손을 예방하고자 한다. 관경 2,200 mm, 총 연장 255 m 그리고 매설 심도 3 m로 구성된 실제 운용중인 용수공급관로에 진동 가속도계를 부착하여 타공사 신호를 검출하였다. 특히, 손상 위치표정을 위해 주파수 분석을 통하여 최적 주파수 대역을 선정하였다. 이를 통해 실험적으로 타공사 조기 검출이 가능함을 검증하였으며, 실제 굴착 위치와 잘 일치함을 확인하였다.

GNSS spoofing detection: Theoretical analysis and performance of the Ratio Test metric in open sky

Jie Huang,Letizia Lo Presti,Beatrice Motella,Marco Pini 한국통신학회 2016 ICT Express Vol.2 No.1

Nowadays more and more applications rely on the information provided by Global Navigation Satellite Systems (GNSSs), but the vulnerability of GNSS signals to interference, jamming and spoofing is a growing concern. Among all the possible sources of intentional interference, spoofing is extremely deceptive and sinister. In fact, the victim receiver may not be able to warn the user and discern between authentic and false signals. For this reason, a receiver featuring spoofing detection capabilities might become a need in many cases. Different types of spoofing detection algorithms have been presented in recent literature. One of the first, referred to as Ratio Metric, allows for the monitoring of possible distortions in the signal correlation. The effectiveness of the Ratio Test has been widely discussed and demonstrated, while in this paper we analyze its performance, proposing a mathematical model that is used to assess the false alarm and detection probabilities.

매설 배관 피복 결함 탐상 정확도에 미치는 인접 정류기 및 접지 구리망 간섭의 영향

김민기,임부택,김기태,장현영,박흥배,김영식 한국부식방식학회 2020 Corrosion Science and Technology Vol.19 No.4

The external corrosion of buried piping can be controlled using both coating and cathodic protection. Severalfactors are involved in the damage and deterioration of the coating on pipes. There are many detectionmethods for coating defects on pipes and the direct current voltage gradient (DCVG) method is one ofthe most powerful methods. However, the detection reliability of DCVG can be affected by interferencessuch as stray current, metal objects connected to rectifiers, and copper grids. Therefore, this study focusedon the interference effects of rectifiers and a copper grid on the reliability of coating flaw detection. Asthe length of the interference pipe connected to the rectifier increased, the reliability decreased. In contrast,as the distance between the pipe and the copper grid increased, the reliability of the coating flaw detectionincreased. The detection results produced by the DCVG method were discussed using current and potentialsimulations for a pipe with a rectifier and copper grid interference in the soil.

RNA 형광 검출을 위한 Finger형 PIN 광다이오드의 제작 및 평가

김주환 ( Ju Hwan Kim ),오명환 ( Myung Hwan Oh ),주병권 ( Byeong Kwon Ju ) 한국센서학회 2004 센서학회지 Vol.13 No.2

This paper represents the development of high sensitivity photo-sensor for the fluorescence detection in the integrated biological analysis system. The finger-type PIN photodiodes were fabricated as the photo-sensor, and had a high sensitivity (l_(light)/l_(dark) = 8720). The interference filter consisted of TiO₂ and SiO₂ was directly deposited on the photodiodes. Deposited filter with 95.5% reflection under 532 nm and 98% transmission over 580 nm exceedingly decreased the magnitude of background signal in the detection. The PDMS micro-fluidic channels are bonded on the photodiode by O₂ plasma treatment. The detection current was proportional to two primary parameters (light intensity, concentration), and the on-chip detection system could detect fluorescence signals down to 100 nM concentration (LOD = Limit of detection of rhodamine).

Chip-Interleaved Self-Encoded Multiple Access with Iterative Detection in Fading Channels

Kim, Youn-Seok,Jang, Won-Mee,Kong, Yan,Nguyen, Lim The Korea Institute of Information and Commucation 2007 Journal of communications and networks Vol.9 No.1

We propose to apply chip interleaving and iterative detection to self-encoded multiple access (SEMA) communications. In SEMA, the spreading code is obtained from user bit information itself without using a pseudo noise code generator. The proposed scheme exploits the inherent diversity in self encoded spread spectrum signals. Chip interleaving not only increases the diversity gain, but also enhances the performance of iterative detection. We employ user-mask and interference cancellation to decouple self-encoded multiuser signals. This paper describes the proposed scheme and analyzes its performance. The analytical and simulation results show that the proposed system can achieve a 3 dB power gain and possess a diversity gain that can yield a significant performance improvement in both Rayleigh and multipath fading channels.

Self-Encoded Spread Spectrum with Iterative Detection under Pulsed-Noise Jamming

Vo Nguyen Quoc Bao 한국통신학회 2013 Journal of communications and networks Vol.15 No.3

Self-encoded spread spectrum (SESS) is a novel modulation technique that acquires its spreading code from a random information source, rather than using the traditional pseudo-random noise (PN) codes. In this paper, we present our study of the SESS system performance under pulsed-noise jamming and show that iterative detection can significantly improve the bit error rate (BER)performance. The jamming performance of the SESS with correlation detection is verified to be similar to that of the conventional direct sequence spread spectrum (DSSS) system. On the other hand,the time diversity detection of the SESS can completely mitigate the effect of jamming by exploiting the inherent temporal diversity of the SESS system. Furthermore, iterative detection with multiple iterations can not only eliminate the jamming completely but also achieve a gain of approximately 1 dB at 10−3 BER as compared with the binary phase shift keying (BPSK) system under additive white gaussian noise (AWGN) by effectively combining the correlation and time diversity detections.