• Title/Summary/Keyword: Frequency Modulated Interrupted Continuous Wave

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Spectral Analysis Method to Eliminate Spurious in FMICW HRR Millimeter-Wave Seeker (주파수 변조 단속 지속파를 이용하는 고해상도 밀리미터파 탐색기의 스퓨리어스 제거를 위한 스펙트럼 분석 기법)

  • Yang, Hee-Seong;Chun, Joo-Hwan;Song, Sung-Chan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.1
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    • pp.85-95
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    • 2012
  • In this thesis, we develop a spectral analysis scheme to eliminate the spurious peaks generated in HRR Millimeterwave Seeker based on FMICW system. In contrast to FMCW system, FMICW system generates spurious peaks in the spectrum of its IF signal, caused by the periodic discontinuity of the signal. These peaks make the accuracy of the system depend on the previously estimated range if a band pass filter is utilized to eliminate them and noise floor go to high level if random interrupted sequence is utilized and in case of using staggering process, we must transmit several waveforms to obtain overlapped information. Using the spectral analysis one of the schemes such as IAA(Iterative Adaptive Approach) and SPICE(SemiParametric Iterative Covariance-based Estimation method) which were introduced recently, the spurious peaks can be eliminated effectively. In order to utilize IAA and SPICE, since we must distinguish between reliable data and unreliable data and only use reliable data, STFT(Short Time Fourier Transform) is applied to the distinguishment process.

Sweep Nonlinearity Estimation for High Range Resolution Millimeter-Wave Seeker Using Least Squares Method (최소 자승법을 이용한 고해상도 밀리미터파 탐색기의 비선형 위상 오차의 추정)

  • Yang, Hee-Seong;Chun, Joo-Hwan;Song, Sung-Chan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.1
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    • pp.56-67
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    • 2012
  • In this thesis, to compensate the sweep nonlinearity occurring in the high resolution radar system using FMICW or FMCW, the method of the estimation of the nonlinearity is proposed. The nonlinear phase component caused by the nonlinear characteristic of the radar system is modelled as a linear combination of the sinusoidal functions consisting of various magnitudes and phases(systematic nonlinear phase error) and a random component(stochastic nonlinear phase error). From two IF signals that are measured respectively independently for two reference point targets lying in different distances which are known, a sparse linear equation is made and solved by least squares method to estimate the nonlinear phase component. The estimated component can be used for predistortion method to compensate the sweep nonlinearity.

Analysis of Effects of Phase Noise in Radar System (위상잡음이 레이더 시스템에 미치는 영향 분석)

  • Park, Jinsung
    • Journal of the Korea Institute of Military Science and Technology
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    • v.16 no.3
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    • pp.373-381
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    • 2013
  • In this paper, the effects of phase noise on the radar system were analyzed in terms of 3 point of view. The impact(s) on the compressed pulse waveform, the FMICW(Frequency Modulated Interrupted Continuous Wave) radar performance and the receiver sensitivity were investigated. From the investigation, it was indicated that the phase noise over 10 kHz offset frequency makes the side lobe level of compressed pulse worse. Also it was founded that the FMICW radar performance, especially at the noise level of range profile, is related to the phase noise. Finally, the investigation showed that the phase noise at local oscillator affects the receiver sensitivity.