• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.717-722
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• 2007

Inverse synthetic aperture radar(ISAR) images represent two-dimensional(2-D) spatial distribution of electromagnetic scattering phenomenology against a target. Hence, they are usually used in the areas of automatic target recognition (ATR) or non-cooperative target recognition(NCTR), identifying a target using radar in a long distance. This paper makes use of Korea Miniature Synthetic Aperture Radar(KOMSAR) to generate ISAR images of a real and maneuvering aircraft. The data obtained from KOMSAR are processed to eliminate phase errors due to motion of a target, with the use of entropy-based ISAR autofocusing technique. Results show that we can successfully obtain ISAR images of a real aircraft, and the success of experiments implies that a significant step toward ATR using radar has been established.

• Journal of Korea Ship Safrty Technology Authority
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• v.14
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• pp.30-43
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• 2004

국내 소형 어선은, 목선이 80% 이상, FRP선이 20%내외, 강선이 1% 이내를 차지하고 있다. 소형 목선과 FRP선은 크기가 작고 구성물질이 레이더 전자파를 반사키는 강도가 약하므로 중. 대형 선박에서 탐지하지 못하여 충돌에 의한 해난사고가 가장 큰 비율로 발생하고 있다.<중략>

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.12
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• pp.1190-1197
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• 2013

AESA(Active Electronically Scanned Array radar) radar is able to instantaneously and adaptively position and control the beam, and such adaptive beam pointing of AESA radar enables to remarkably improve the multi-mission capability. For this reason, radar resource management(RRM) becomes new challenging issue. RRM is a technique efficiently allocating finite resources, such as energy and time to each task in an optimal and intelligent way. This paper deals with a design of radar resource management algorithms and simulator implemented main algorithms for development of airborne AESA radar. In addition, evaluation results show that developed radar system satisfies a main requirement about simultaneous multiple target tracking and detection by adopting proposed algorithms.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.4
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• pp.467-475
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• 2014

In this paper, we introduce a sparse recovery algorithm applied to a radar signal model, based on the compressive sensing(CS), for the formulation of the radar signatures, such as high-resolution range profile(HRRP) and ISAR(Inverse Synthetic Aperture Radar) image. When there exits missing data in observed RCS data samples, we cannot obtain correct high-resolution radar signatures with the traditional IDFT(Inverse Discrete Fourier Transform) method. However, high-resolution radar signatures using the sparse recovery algorithm can be successfully recovered in the presence of data missing and qualities of the recovered radar signatures are nearly comparable to those of radar signatures using a complete RCS data without missing data. Therefore, the results show that the sparse recovery algorithm rather than the DFT method can be suitably applied for the reconstruction of high-resolution radar signatures, although we collect incomplete RCS data due to unwanted interferences or jamming signals.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.506-513
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• 2021

The durability and safety of reinforced concrete structures significantly depend on the reinforcement conditions, concrete cover thickness, cracks, and concrete strength. There are two ways to accurately determine the information on reinforcing bars embedded in concrete - the local destructive method and the non-destructive rebar detection test. In general, the non-destructive rebar detection tests, such as the electromagnetic wave radar method, electromagnetic induction method, and radiation method, are adopted to avoid damage to the structural elements. The moisture content and temperature of concrete affect the dielectric constant, which is the electrical property of concrete, and cause interference in the non-destructive rebar detection test results. Therefore, in this study, the effects of the electromagnetic wave radar method and electromagnetic induction method have been analyzed according to the temperature and surface moisture content of concrete. Due to the technological advancement and development of equipment, the average error rate was less than 5% in the specimens at 24℃, irrespective of their operating principles. Among the tested methods, the electromagnetic induction method showed very high accuracy. The electromagnetic wave radar method indicated a relatively small error rate in the dry state than in the wet state, and exhibited a relatively high error rate at high temperatures. It was confirmed that the error could be reduced by applying the electromagnetic wave radar method when the temperature of the probe was low and in a dry state, and by using the electromagnetic induction method when the probe was in a wet state or at a high temperature.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.1
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• pp.52-59
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• 2009

In modern radars, dynamic range requirements far severed due to high CNR(Clutter-to-Noise Ratio) environment operation scenario. ADC spurious signal restricted the required dynamic range. In this paper, receiver gain of active phased array radar dependent on ADC nonlinear characteristic was analyzed. Within limited scope of ADC SFDR which blocks required system dynamic range, ADC dynamic range reaches trade-off with ADC SNR loss. Comparing antenna stage output noise voltage to that of ADC input, receiver gain was mathematically analyzed. Finally the whole contents were explained from the application example.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.9
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• pp.828-836
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• 2015

In this paper, the assessment technique for track accuracy in the phased array radar is proposed. It is assumed that ${\alpha}-{\beta}$ tracking filter to track the target is established in the phased array radar. In order to assess the track accuracy strictly, we should use the real target position data acquired from the special instrument, ACMI(Air Combat Maneuvering Instrument) pod or DGPS(Differential Global Positioning System). However, this method leads to increase the experiment cost and test time. We derive the relationship between the residuals of tracking filter and the standard deviations of range and angle tracking errors which are assigned as track assessment index. The theory of sample variance is introduced in this assessment because track accuracy has to be calculated with many residual samples.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.4
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• pp.448-458
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• 2013

In this paper, we present the performance and the experimental results of the adaptive beamformer in the radar system with the planar active array. The study of the adaptive beamformer has already been performed in several literatures, but it is difficult to find the results or examples those are implemented in the actual radar system. Here we employ the adaptive beamformer to the practical radar system with subarray architecture. The performance of beamformer will be demonstrated by modeling and simulation and finally the far-field experimental results.

• 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.18 no.5
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• pp.1243-1248
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• 2014

In General, LPI radar's detection probability by ES equipments is lower than that of conventional pulsed radar because of very low transmitting power and high antenna gain etc. LPI radar is a kind of RF stealth technique such as RCS reduction design. Therefore the ultimate goal of LPI radar is detection probability reduction by opponent. If one of the two, RCS value or LPI radar performance is not sufficient, own platform will be found first by opponent. In this paper, some considerations are suggested for detection probability reduction.