• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.1
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• pp.81-87
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• 2015

We present an implementation result of a computer GUI-based simulator using MATLAB to verify the performance of interferometric radar altimeter(IRA) which is possible to measure the slant range altitude and the cross-track angle to the nearest point for terrain aided navigation(TAN). After a brief description of the principle of TAN and IRA, we present that the grids are divided for the modeling of the reflected signal in digital elevation map(DEM) and so the radar cross section(RCS) of each grid is calculated and the signal-noise ratio(SNR) of the reflected signal in the radar beam width. And the signal processing procedures of the IRA and the structure of the IRA simulator are shown.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2628-2635
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• 2010

This paper analyzes the detection probability of FMCW (Frequency Modulated Continuous Wave) radar based on Doppler frequency and analog-digital converter bit and designs and implements signal processing part of FMCW radar. For performance evaluation, the FMCW radar system consists of a transmitted part and a received part and uses AWGN channel. The system model is verified through analysis and simulation. Frequency offset occurs in the received part caused by the mismatching between the received signal and the reference signal. In case of Doppler frequency less than about 38KHz, performance degradation of detection does not occur in FMCW radar with 75cm resolution The analog-digital converter needs at least 6 bit in order not to degrade the detection probability. And, we design and implement digital signal processing part based on DDS chip of digital transmitted signal generator for FMCW radar.

• Journal of Navigation and Port Research
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• v.39 no.4
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• pp.307-312
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• 2015

ARPA(Automatic Radar Plotting Aid) is a device to calculate CPA(closest point of approach)/TCPA(time of CPA), true course and speed of targets by vector operation of relative courses and speeds. The purpose of this study is to develop target acquisition and tracking technology for ARPA Radar implementation. After examining the previous studies, applicable algorithms and technologies were developed to be combined and basic ARPA functions were developed as a result. As for main research contents, the sequential image processing technology such as combination of grayscale conversion, gaussian smoothing, binary image conversion and labeling was deviced to achieve a proper target acquisition, and the NNS(Nearest Neighbor Search) algorithm was appllied to identify which target came from the previous image and finally Kalman Filter was used to calculate true course and speed of targets as an analysis of target behavior. Also all technologies stated above were implemented as a SW program and installed onboard, and verified the basic ARPA functions to be operable in practical use through onboard test.

• Journal of Korea Water Resources Association
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• v.39 no.4 s.165
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• pp.347-362
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• 2006

In this study, a 2-D flood inundation model was developed to evaluate the impact of levee failure in a natural basin for flood analysis. The model was applied to analyze the inundation flow from the levee break of Gamcheon river during the typhoon Rusa on October 31 through September 1, 2002. To verify the simulated results, wide range field surveys have been performed including the collection of NGIS database, land use condition, flooded area, and flow depths. Velocity distributions and inundation depths were presented to demonstrate the robustness of the model. Model results have good agreements with the observed data in terms of flood level and flooded area. The model is able to compute maximum stage and peak discharge efficiently in channel and protected lowland. Methodology considering radar-rainfall estimation using cokriging scheme, flood-runoff and inundation analysis in this study will contribute to the establishment of the national integrated flood disaster prevention system and the river or protect lowland management system.

• Korean Journal of Remote Sensing
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• v.13 no.1
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• pp.57-73
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• 1997

This paper is related to the correction of radiometric distortions induced by topographic relief. RADARSAT SAR image data were obtained over the mountainous area near southern part of Seoul. Initially, the SAR data was geometrically corrected and registered to plane rectangular coordinates so that each pixel of the SAR image has known topographic parameters. The topographic parameters (slope and aspect) at each pixel position were calculated from the digital elevation model (DEM) data having a comparable spatial resolution with the SAR data. Local incidence angle between the incoming microwave and the surface normal to terrain slope was selected as a primary geometric factor to analyze and to correct the radiometric distortions. Using digital maps of forest stands, several fields of rather homogeneous forest stands were delineated over the SAR image. Once the effects of local incidence angle on the radar backscatter were defined, the radiometric correction was performed by an empirical fuction that was derived from the relationship between the geometric parameters and mean radar backscatter. The correction effects were examined by ground truth data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.1-6
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• 2018

This study examined the quality improvement of printed circuit boards (PCBs) in relation to the power consumption for radar. The radar examined is currently in production and being used by the military. The PCB converts 28 V DC to 5 V DC but frequently malfunctions. Therefore, cause analysis was carried out. As a result, the power consumed by a certain communication IC was very high, and the heat generated by the high power consumption caused damage to the surrounding parts. Accordingly, it was changed to an improved communication IC that meets all the radar system specifications. System tests were carried out for the changed communication IC to check the impact on the system, and environmental tests were performed, which proved that the performance required by the radar system is satisfactory. As a result of this improvement, there has been no history of failure in this PCB so far. Therefore, the quality of this PCB has been improved.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2B
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• pp.159-167
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• 2010

The purpose of this study is to get the adjusted radar rainfalls by ANN(Artificial Neural Network) method. In the case of radar rainfall, it has an advantage of spatial distribution characteristics of rainfall while point rainfall has an advantage at the point. Therefore we adjusted the radar rainfall by ANN method considering the advantages of two rainfalls of radar and point. This study constructed two ANN models of Model I and Model II for radar rainfall adjustment. We collected the three rainfall events and adjusted the radar rainfall for Anseong-cheon basin. The two events were inputted into the Modeland Model to derive the optimum parameters and the rest event was used for validation. The adjusted radar rainfalls by ANN method and the raw radar rainfall were used as the input data of ModClark model which is a semi-distributed model to simulate the runoff. As the results of the simulation, the runoff by raw radar rainfall were overestimated but the peak time and peak runoff from the adjusted rainfall by ANN were well fitted to the observed hydrograph.

• Aerospace Engineering and Technology
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• v.11 no.2
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• pp.171-181
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• 2012

As a sub-system of an air traffic control system, SDP(Surveillance Data Processor) provides with the system tracks of aircraft using the surveillance sensor data from various air traffic surveillance sensors, such as radars. Therefore, the high accuracy of tracking results is a crucial requirement for safe flights, and verification of the required system performance of SDP is an essential step in development. Moreover, the quantitative evaluation of target tracking accuracy is important for newly developed SDP, since there are several tracking methods for Multi-Sensor Multi-Target Tracking, such as MRT(Multi Radar Tracking), inevitably required as the main function of SDP. In this study, definition of required system performances, establishment of test environment, and test results for MRT performance evaluation of SDP, which is being developed in KARI(Korea Airspace Research Institute) are presented.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.712-716
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• 2007

본 연구의 목적은 기존에 구축된 임진강 홍수예보시스템의 문제점을 분석하여 새로운 예보시스템을 구축하는 것으로, 주요 내용은 수문레이더의 활용, 유효우량 산정, 유출량 계산, 하도추적, 조위 영향 감안, 시스템 효율성 개선 등 여러 분야에서 기존 시스템의 문제를 분석하고, 이를 해결할 수 있는 새로운 시스템을 구축하는 것이다. 본 연구를 통해 새로이 구축된 임진강 홍수예보시스템은 수문학적 모형의 경우 기존의 소유역 구분을 개선하여 효율적인 홍수예보가 가능하도록 최적의 소유역을 재구성하였고, 이에 따른 소유역별 매개변수 산정, 평균 강우량 산정 등을 모두 새로이 구축하였다. 수리학적 모형의 경우에는 한강과 임진강, 서해 조위를 동시에 동역학적으로 고려할 수 있도록 시스템을 재구축하였으며, 최근의 측량단면을 이용하여 최적 조도계수를 재산정하였다. 본 연구를 통해 개선된 임진강 홍수예보시스템은 과거 홍수사상에 대한 적용을 통해서 검증되었다. 수문 레이더, 수문학적 모형, 수리학적 모형 등이 모두 전산시스템 상에서 원활하게 운영되는 것이 검증되었으며, 본 연구에서 개선된 시스템의 정확도 또한 실제 적용을 통해서 검증되었다. 따라서 본 연구에서 구축된 임진강 홍수예보 시스템을 통해 임진강 유역에 대한 홍수예보의 정확성, 효율성이 크게 향상된 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.187-187
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• 2021

최근 기후 변화로 인한 한반도의 극한 홍수 및 가뭄의 발생 빈도가 급증하고 있다. 이와 같은 이상 기후의 발생으로 연간 강수량의 편차가 더 커지면서 장래 물 부족 문제가 더욱 심화될 전망이다. 따라서 본 연구에서는 한강 유역의 수문 모형 구축을 통해 미래 물수지 변화를 정량적으로 예측함으로써 기후 변화가 한강 유역의 수문순환요소와 수자원에 미치는 영향을 분석하고 평가하였다. 레이더 강우 시계열 자료의 활용을 위하여 격자 단위로 분석이 가능한 분포형 수문 모형 VIC (Variable Infiltration Capacity)을 사용하였고 모형 구축에는 레이더 강우와 종관기상관측소의 강우 자료에 조건부 합성 기법(Conditional Merging, CM)을 적용하여 보정된 강우 자료를 사용하였다. 제공되는 VIC의 토양, 식생 변수는 공간 해상도가 너무 낮고 유역 내에서도 공간적인 변동성이 크지 않아 침투에 관련된 매개변수를 토지 피복과 연관 지어 격자마다 적정한 매개변수를 회귀 분석하여 새로 산정하였다. 먼저 보정 기간 6년(2009-2014)에 대해 보정을 하고 이후 검증 기간 6년(2014-2019)에 대해 검증을 진행하였다. 보정, 검증 기간에 대한 NSE 값은 각각 0.968, 0.569로 양호한 결과를 보여주었다. 구축된 수문 모형에 기후 변화를 고려하기 위해 GCM 기반의 CMIP6 미래기상자료를 입력해서 미래의 물 수지와 수문순환요소의 변화를 모의하였고 모의 결과, 미래 기간에는 강수의 편차가 더욱 심화되면서 가뭄이 더 빈번하게 발생하는 경향을 보였다.