• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.39 no.4
• /
• pp.347-357
• /
• 2003

This paper describes on the suppression of sea clutter on marine radar display using a cell-averaging CFAR(constant false alarm rate) technique, and on the analysis of radar echo signal data in relation to the estimation of ARPA functions and the detection of the shadow effect in clutter returns. The echo signal was measured using a X -band radar, that is located on the Pukyong National University, with a horizontal beamwidth of $$3.9^{\circ}$$, a vertical beamwidth of $20^{\circ}$, pulsewidth of $0.8 {\mu}s$ and a transmitted peak power of 4 ㎾ The suppression performance of sea clutter was investigated for the probability of false alarm between $l0-^0.25;and; 10^-1.0$. Also the performance of cell averaging CFAR was compared with that of ideal fixed threshold. The motion vectors and trajectory of ships was extracted and the shadow effect in clutter returns was analyzed. The results obtained are summarized as follows；1. The ARPA plotting results and motion vectors for acquired targets extracted by analyzing the echo signal data were displayed on the PC based radar system and the continuous trajectory of ships was tracked in real time. 2. To suppress the sea clutter under noisy environment, a cell averaging CFAR processor having total CFAR window of 47 samples(20+20 reference cells, 3+3 guard cells and the cell under test) was designed. On a particular data set acquired at Suyong Man, Busan, Korea, when the probability of false alarm applied to the designed cell averaging CFAR processor was 10$^{-0}$.75/ the suppression performance of radar clutter was significantly improved. The results obtained suggest that the designed cell averaging CFAR processor was very effective in uniform clutter environments. 3. It is concluded that the cell averaging CF AR may be able to give a considerable improvement in suppression performance of uniform sea clutter compared to the ideal fixed threshold. 4. The effective height of target, that was estimated by analyzing the shadow effect in clutter returns for a number of range bins behind the target as seen from the radar antenna, was approximately 1.2 m and the information for this height can be used to extract the shape parameter of tracked target..

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.11a
• /
• pp.41-43
• /
• 2022

항행선박에 위치정보를 제공하기 위하여 관내 유인등대 및 주요 항로상에 레이더 비콘 14기를 설치·운영 중이나, 대부분의 선박에서 전자해도와 AIS를 이용하고 다른 표지와 기능이 중복되어 레이더 비콘 운영에 대한 개선방안을 마련하였다..

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.48 no.6
• /
• pp.124-132
• /
• 2011

In a modern electronic warfare, radar signal environments become more denser and complex. Therefor the capability of reliable signal analysis techniques is required for ES(Electronic warfare Support) system to identify and analysis individual emitter signals from received signals. In this paper, we propose the new signal grouping algorithm to ensure the reliable signal analysis and to reduce the cost of the signal processing steps in the ES. The proposed grouping algorithm uses KDE(Kernel Density Estimator) and its CDF(Cumulative Distribution Function) to compose windows considering the statistical distribution characteristics based on the radar frequency modulation type. Simulation results show the good performance of the proposed technique in the signal grouping.

• Electronics and Telecommunications Trends
• /
• v.15 no.5 s.65
• /
• pp.86-93
• /
• 2000

지하 탐사용 레이더를 이용하여 지하에 매설된 구조물의 위치를 파악하고 그에 따른 근사 이미지의 추출 방법을 제안하였다. 기본원리는 구조물에 의해 산란되어 수신 안테나로 유입되는 펄스신호의 지연시간과 크기를 측정하는 데 있으며, 측정의 실용성을 위하여 레이더 탐색경로에 따른 수신신호의 절대치 적분 방법을 사용하였다. 일반적으로 지하매질은 침투 주파수에 따라서 다양한 분산 및 손실 특성을 나타내는데, 이러한 매질 특성은 다항 Debye 모델을 이용하여 기술되었다. 3차원 전파(電波) 전파(傳播)를 위한 시뮬레이션에는 FDTD(Finite Difference Time Domain) 방법을 사용하였다.

• Proceedings of the Korean Society of Disaster Information Conference
• /
• 2022.10a
• /
• pp.341-342
• /
• 2022

본 논문에서는 실내 재난 상황에서 재실자의 위치를 판단하기 위한 Frequency Modulated Continuous Wave(FMCW) 레이더 시스템의 정확도 향상을 위한 Generative Adversarial Networks(GAN) 기반의 신호 보간법을 제안한다. 제안된 실내 위치 추정 시스템은 딥러닝 학습 생성 모델을 활용하게 되는데, 학습을 위한 데이터의 수집이 용이하지 않아 부족하게 되는 학습데이터를 GAN 기법을 통해 확보하고자한다.

• The Journal of Engineering Geology
• /
• v.27 no.3
• /
• pp.217-231
• /
• 2017

The subsidence of ground in urban area can be caused by the occurrence of the cavity and the change in ground volumetric water content. The objective of this study is the detection of abnormal area of ground in urban area where the cavity or the change in ground volumetric water content is occurred by the ground penetrating radar signal. GPR survey is carried out on the test bed with a circular buried object. From the GPR survey, the signals filtered by the bandpass filtering are measured, and the methods consisting of gain function, time zero, background removal, deconvolution and display gain are applied to the filtered signals. As a result of application of the signal processing methods, the polarity of signal corresponds with the relation of electrical impedance of the cavity and the ground in test bed. In addition, the relative permittivity calculated by GPR signal is compared with that of predicted by volumetric water content of the test bed. The relative permittivities obtained from two different methods show similar values. Therefore, the abnormal area where the change in ground volumetric water content is occurred can be detected from the results of the GPR survey in case the depth of underground utilities is known. Signal processing methods and estimation of relative permittivity performed in this study may be effectively used to detect the abnormal area of ground in urban area.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2002.10a
• /
• pp.61-62
• /
• 2002

본 연구는 전보에서 개발한 RTX에 대한 응용 연구의 하나로써 레이더 영상 신호의 수록 및 해석에 부가하여 타선의 GPS 위치정보를 수신하여 자선의 전자해도(ENC) 및 radar 화면상에서 동시에 표시함으로써 이들 두 선박의 간격을 측정할 수 있는 선간거리계, 또한, 타선의 ARPA radar가 탐지한 영상신호, 타선의 기동정보(own ship data, OSD) 및 추적표적의 정보(tracked target message, TTM) 등을 자선의 레이더나 전자해도 화면상에서 실시간으로 모니터링하는 software를 개발하고, 이들의 레이더 정보를 필요에 따라 hard disk에 수록 및 재생할 수 있는 아주 간편하면서도 범용성이 있는 레이더 정보수록 및 해석 시스템을 개발하였다. (중략)

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.24 no.7
• /
• pp.730-736
• /
• 2013

Time-domain clutter generation model for airborne pulse doppler phase-array radar is presented. Time-domain surface clutter signal is generated assuming earth of a sphere and considering geometry of a clutter patch, and generation of sub-array clutter signal is presented. The generated sub-array clutter signal can be used by simulation input signal in various radar applications of DBF(Digital Beamforming), ABF(Adaptive Beamforming), Stap(Space-Time Adaptive Processing) and etc.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.12
• /
• pp.2227-2232
• /
• 2007

In this paper, it is presented a Real FFT for the FMCW radar distance measurement with high resolution. The high distance resolution needs the measurement of the accurate beat frequency. To improve the distance resolution, zoom fft, decimation, digital low pass filter and zero padding method are used. The simulation results using the Matlab show ${\pm}5mm$ of distance resolution and the measuring range is up to 35meter.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2012.11a
• /
• pp.732-735
• /
• 2012

본 논문은 지상에서 발생하는 전자파 잡음 신호의 유입에 의해 많은 영향을 받을 수 있는 헬기 등 항공기의 레이더경보수신기(Radar Warning Receiver)에서도 레이더 펄스 신호를 탐지할 수 있는 통신전자파잡음 동적제거 기법을 제안하였다. 본 논문은 지상의 노이즈 신호를 분류하는 방법을 제시하였고, 노이즈 신호 레벨을 판단하여 효과적으로 잡음을 제거하는 알고리즘을 제안하였다.