• Title/Summary/Keyword: IR 신호

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A Study on On-line ARC Welding Monitoring using IR and UV sensor (IR 및 UV센서를 이용한 아크 용접 품질 모니터링에 관한 연구)

  • Yun, Chung-Seop
    • Proceedings of the KWS Conference
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    • 2005.06a
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    • pp.314-316
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    • 2005
  • 이 논문에서는 아크 용접시 발생하는 IR신호와 UV호의 상호 관계를 알아보려고 레이저 용접진단에 사용되는 IR-UV 센서 모니터링 시스템을 적용하였다. 그 결과 IR신호 크기는 용접폭에 관련이 있고, 펄스 형태의 UV신호는 IR신호 증가율이 임계값을 넘으면 나타나는 것을 알 수 있다.

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Infrared Signature Analysis of the Aircraft Exhaust Plume with Radiation Database (복사 데이터베이스를 활용한 항공기 배기 플룸 IR 신호 해석)

  • Cho, Pyung Ki;Gu, Bonchan;Baek, Seung Wook;Kim, Won Cheol
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.7
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    • pp.568-575
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    • 2016
  • For the combat survivability, an infrared signature emitted from aircraft is needed to be predicted and analyzed. In this study, we studied the infrared signature from the exhaust plume from the viewpoint of Infrared(IR) detector. The Line-By-Line method using the radiation database is used for radiative property, and radiative intensity analysis is conducted along 1-D line of sight based on the radiative property. The numerical thermo-fluid field for the plume is conducted by ANSYS FLUENT, while setting the lines of sight having the different detection angle on the thermo-fluid field. We found the high IR signature on the line of sight passing through the locally high temperature region of the plume inside, and the strongest signature from the line of sight toward the nozzle surface. Based on this, it confirms the influence of the surface radiative emission on the infrared signature.

Measurement of Infrared Signature according to the Operating Condition and Location of a Small Scale Engine (축소형 제트 엔진의 구동 조건 및 측정 위치에 따른 적외선 신호 측정 연구)

  • Gu, Bonchan;Jegal, Hyunwook;Baek, Seung Wook;Choi, Seongman;Kim, Won Cheol
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.596-597
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    • 2017
  • In this study, the measurements of infrared (IR) signature were carried out using a small scale engine with the variation of the engine performance and target positions in the exhaust plume. The operating conditions of the engine were kept constant for each test, and the measured positions were sapced at refular intervals from the nozzle exit. The measured IR signature was calibrated by using a blackbody. The results of infrared signature measurements are shown in three bands for analysis of spectral characteristics. As the engine performance decreased and the distance from the nozzle exit increased, the IR signature decreased and the level of decrease varied according to the bands.

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Computational Investigation of the Effect of UAV Engine Nozzle Configuration on Infrared Signature (무인항공기 노즐 형상 변화에 따른 IR 신호 영향성 연구)

  • Kang, Dong-Woo;Kim, June-Young;Myong, Rho-Shin;Kim, Won-Cheol
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.10
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    • pp.779-787
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    • 2013
  • The effects of various nozzle configurations on infrared signature are investigated for the purpose of analysing the infrared signature level of aircraft propulsion system. A virtual subsonic aircraft is selected and then a circular convergent nozzle, which meets the mission requirements, is designed. Convergent nozzles of different configurations are designed with different geometric profiles. Using a compressible Navier-Stokes-Fourier CFD code, an analysis of thermal flow field and nozzle surface temperature distribution is conducted. From the information of plume flow field and nozzle surface temperature distribution, IR signature of plume and nozzle surface is calculated through the narrow-band model and the RadThermIR code. Finally, qualitative information for IR signature reduction is obtained through the analysis of the effects of various nozzle configurations on IR signature.

Improvement of Computational Speed for the SVD Background Clutter Signal Subtraction Algorithm in IR-UWB Radar Systems (IR-UWB Radar 시스템에서 특이값 분해를 이용한 클러터 신호 제거 알고리즘의 연산속도 향상 기법)

  • Baek, In Seok;Jung, Moon Kwun;Cho, Sung Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38C no.1
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    • pp.89-96
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    • 2013
  • This paper presents an improved clutter signal removal algorithm using Singular Value Decomposition(SVD). For indoor positioning system using IR-UWB Radar, the target signal is extracted from received signal. We use clutter signal removal algorithm using SVD for target signal extraction. Clutter signal removal algorithm using SVD has the advantage of operation but the disadvantage of high computational complexity. In this paper, we propose a method to improve computational complexity. As the experimental results, it is confirmed that the method presented in this paper improve the computational complexity of clutter removal algorithm using SVD.

Performance Evaluation of Time Hopping Binary PPM Impulse Radio System according to Interference Environment (간섭 환경에 따른 TH Binary PPM IR 시스템의 성능 평가)

  • Lee, Yang-Sun;Kang, Heau-Jo
    • Journal of Advanced Navigation Technology
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    • v.6 no.4
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    • pp.318-325
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    • 2002
  • In this paper, the effects of the interference environments on the performance of the time hopping(TH) binary PPM impulse radio(IR) system are presented. Based on the monocycle pulse available within the frequency of 3.1~10.6 GHz permitted for application by FCC, a PPM-modulated TH IR system simulator was designed and followed by the analysis of the monocycle pulse characteristics as well as the system performance. Particularly for the evaluation of the system performance, the multiple access interference and the narrowband system interference signals were considered as the interference signals. Since the narrowband system interference signal has very narrow bandwidth and very large amplitude compared with those of IR system, the analysis of the IR system performance was implemented by considering the interference power and band fraction ratio of the narrowband interference signal.

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Investigation of Aircraft Plume IR Signature for Various Nozzle Configurations and Atmospheric Conditions (노즐형상 및 대기조건에 따른 항공기의 플룸 IR 신호 연구)

  • Kang, Dong-Woo;Kim, In-Deok;Myong, Rho-Shin;Kim, Won-Cheol
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.1
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    • pp.10-19
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    • 2014
  • Nozzle configurations and atmospheric conditions play a significant role in the infrared signature level of aircraft propulsion system. Various convergent nozzles of an unmanned aircraft under different atmospheric conditions are considered. An analysis of thermal flow field and nozzle surface temperature distribution is conducted using a compressible CFD code. It is shown that the IR level in rear direction is considerably reduced in deformed nozzles, whereas the IR level in adjacent azimuth angles is increased in aspect ratios around 6 due to the plume spreading effect caused by high aspect ratio of nozzles. In addition, an analysis of atmospheric transmissivity for various seasons and observation distance is conducted using the LOWTRAN 7 code and subsequently plume IR signature is calculated by considering atmospheric effects. It is shown that the IR signature is reduced significantly in summer season and near the band of carbon dioxide in case of relatively close distance.

A Study on the Effect of Engine Nozzle Configuration on the Plume IR Signature (엔진 노즐 형상이 Plume 적외선 신호에 미치는 영향에 관한 연구)

  • An, Sung-Yong;Kim, Won-Cheol;Oh, Seong-Hwan
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.8
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    • pp.688-694
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    • 2012
  • A study on the effect of engine nozzle configuration on the engine plume Infra-red (IR) signature characteristics is performed. Configuration design of an engine nozzle with high aspect ratio to reduce IR signature level and a cylindrical nozzle which is typically used for conventional aircraft which does not require IR signature reduction is performed. And CFD analysis for the two nozzles is performed to compare the flowfields characteristics of the two nozzles. Finally IR signature analysis for the two nozzles is accomplished to calculate the total intensity level at mid-wave infra-red and investigate the differences of IR signature characteristics between the two nozzles.

Computational Investigation of the Effect of Various Flight Conditions on Plume Infrared Signature (항공기 비행환경에 따른 플룸 IR 신호 영향성 연구)

  • Kim, Joon-Young;Chun, Soo-Hwan;Myong, Rho-Shin;Kim, Won-Cheol
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.3
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    • pp.185-193
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    • 2013
  • The plume infrared signature effects at various flight conditions of aircraft were investigated for the purpose of reducing infrared signature level. The nozzle of a virtual subsonic unmanned combat aerial vehicle was designed through a performance analysis. Nozzle and associated plume flowfields were first analyzed using a density-based CFD code and plume IR signature was then calculated on the basis of the narrow-band model. Finally, qualitative information for the plume infrared signature characteristics was obtained through the analysis of the IR signature effects at various flight conditions.

Computation of Flowfield and Infrared Signature in Aircraft Exhaust System for IR Reduction Design (항공기 후방동체 열유동장 및 IR 신호 예측 시스템)

  • Moon, Hyuk;Yang, Young-Rok;Chun, Soo-Hwan;Choi, Seong-Man;Myong, Rho-Shin;Cho, Tae-Hwan
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.39 no.7
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    • pp.652-659
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    • 2011
  • A computational system to predict flowfield and infrared signature in aircraft exhaust system is developed. As the first step, a virtual mission profile is considered and an engine is selected through a performance analysis. Then a nozzle that meets the requirement of each mission is designed. The internal flow in the exhaustion nozzle at the maximum thrust is analyzed using a state-of-the-art CFD code. In addition, a system to combine information of the skin temperature distribution of the nozzle and after-body surface with an infrared prediction code is developed. Finally, qualitative results for the infrared signature reduction design are obtained by investigating the infrared signature level under various conditions.