• Title/Summary/Keyword: CFAR Detector

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Performance analysis of CFAR detectors based on order statistics for nonhomogeneous background (비균일 환경에서 표적 검파를 위한 순서계통에 근거한 일정오경보율 검파기의 성능 해석)

  • 한동석
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.7
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    • pp.1550-1558
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    • 1997
  • In this paper, we first propose a modified OS CFAR detector called the order statistics cell averaging(OSCA) CFAR detector and anlyze its performance for a Rayleigh target in homogeneous backgrounds, clutter edges, and satistics smallest of(OSSO) CFAR detectors for a Rayleigh target to nonhomogeneous environments. Computer simulation results show that the OSCA CFAR detector has superior performance to OS, OSGO, and OSSO CFAR detectors in homogeneous and multiple target environments. And the proposed detector shows its robustness for fast detection because it requires falf the processing time of the OS CFAR detector.

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Analysis of the Generalized Order Statistics Constant False Alarm Rate Detector

  • Kim, Chang-Joo;Lee, Hwang-Soo
    • ETRI Journal
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    • v.16 no.1
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    • pp.17-34
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    • 1994
  • In this paper, we present an architecture of the constant false alarm rate (CFAR) detector called the generalized order statistics (GOS) CFAR detector, which covers various order statistics (OS) and cell-averaging (CA) CFAR detectors as special cases. For the proposed GOS CFAR detector, we obtain unified formulas for the false alarm and detection probabilities. By properly choosing coefficients of the GOS CFAR detector, one can utilize any combination of ordered samples to estimate the background noise level. Thus, if we use a reference window of size N, we can realize $(2^N-1)$ kinds of CFAR processors and obtain their performances from the unified formulas. Some examples are the CA, the OS, the censored mean level, and the trimmed mean CFAR detectors. As an application of the GOS CFAR detector to multiple target detection, we propose an algorithm called the adaptive mean level detector, which censors adaptively the interfering target returns in a reference window.

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A New Formula to Predict the Exact Detection Probability of a Generalized Order Statistics CFAR Detector for a Correlated Rayleigh Target

  • Kim, Chang-Joo
    • ETRI Journal
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    • v.16 no.2
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    • pp.15-25
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    • 1994
  • In this paper we present a new formula which can predict the exact detection probability of a generalized order statistics (GOS) constant false alarm rate (DFAR) detector for a partially correlated Rayleigh target model (0 < $ \rho$< 1) in a closed form, where $\rho$ is the correlation coefficient between returned pulses. By simply substituting a set of specific coefficient into the derived formula, one can obtain the detection probability of any kind of CFAR detector. Detectors may include the order statistics CFAR detector, the censored mean level detector, and the trimmed mean CFAR detector, but are not necessarily restricted to them. The numerical result for the first order Markov correlation model as applied to some of the detectors shows that as $\rho$ increases from zero to one, higher signal-to-noise ratio is required to achieve the same detection probability.

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Maximum a posteriori CFAR for weibull clutter (Weibull clutter 에 대한 최대사후확률 일정오경보수신기)

  • Yu, Kung-T.;Seo, Jin-H.
    • Proceedings of the KIEE Conference
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    • 1995.11a
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    • pp.146-148
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    • 1995
  • A CFAR algorithm for weibull clutter is discussed. The Maximum a posteriori(MAP) estimator for two parameters(skewness and scale) of the weibull clutter is proposed, assuming the probability density function of skewness parameter is known. And proposed MAP estimator is compared with the Maximum likelihood(ML) estimator. Using this MAP estimator, we can design CFAR detector which is shown to have smaller CFAR loss than ML CFAR detector by the statistical simulation method.

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Performance Analysis of the Clutter Map CFAR Detector with Noncoherent Integration

  • Kim, Chang-Joo;Lee, Hyuck-Jae
    • ETRI Journal
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    • v.15 no.2
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    • pp.1-9
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    • 1993
  • Nitzberg has analyzed the detection performance of the clutter map constant false alarm rate (CFAR) detector using single pulse. In this paper, we extend the detection analysis to the clutter map CFAR detector that employs M-pulse noncoherent integration. Detection and false alarm probabilities for Swerling target models are derived. The analytical results show that the larger the number of integrated pulses M, the higher the detection probability. On the other hand, the analytical results for Swerling target models show that the detection performance of the completely decorrelated target signal is better than that of the completely correlated target.

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Synthetic Aperture Radar Target Detection Using Multi-Cell Averaging CFAR Scheme (다중 셀 평균 기반 CFAR 검출을 이용한 SAR 영상 표적 탐지 기법)

  • Song, Woo-Young;Rho, Soo-Hyun;Jung, Chul-Ho;Kwag, Young-Kil
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.2
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    • pp.164-169
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    • 2010
  • Since the range and Doppler resolution of the synthetic aperture radar(SAR) image becomes very high, the target detection accuracy can be significantly increased, but the computational burden is also increased. The conventional single-cell based CFAR detector performs the target detection on every single cell basis, thus it causes the serious increment of the computational load. In this paper, the improved two-step MCA-CFAR detector is proposed for the improvement of the target detection as well as the reduction of computational load: the first step is to use the MCA-CFAR, and the second step is to use the single-cell based CFAR detection in the expected target area for final decision. The performance of the proposed algorithm is compared with the conventional single-cell based CFAR and MCA-CFAR on SAR images.

Closely Spaced Target Detection using Intensity Sorting-based Context Awareness

  • Kim, Sungho;Won, Jin-Ju
    • Journal of Electrical Engineering and Technology
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    • v.11 no.6
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    • pp.1839-1845
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    • 2016
  • Detecting remote targets is important to active protection system (APS) or infrared search and track (IRST) applications. In normal situation, the well-known constant false alarm rate (CFAR) detector works properly. However, decoys in APS or closely spaced targets in IRST degrade the detection capability by increasing background noise level in the CFAR detector. This paper presents a context aware CFAR detector by the intensity sorting and selection of background region to reduce the effect of neighboring targets that lead to incorrect estimation of background statistics. The existence of neighboring targets can be recognized by intensity sorting where neighboring targets usually show highest ranks. The proposed background statistics (mean, standard deviation) estimation method from median local pixels can be aware of the background context and reduce the effects of the neighboring targets, which increase the signal-to-clutter ratio. The experimental results on the synthetic APS sequence, real adjacent target sequence, and remote pedestrian sequence validated that the proposed method produced an enhanced detection rate with the same false alarm rate compared with the hysteresis-CFAR (H-CFAR) detection.

Excision GO-CFAR Detectors (Excision GO-CFAR 검출기)

  • 한용인;김태정
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.29B no.1
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    • pp.50-57
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    • 1992
  • This paper proposes and analyzes a new CFAR(Constant False Alarm Rate) detector called the EXGO(Excision Greatest Of)-CFAR. This is the combination of the EXCA(Excision Cell Averaging)-CFAR that shows a good performance under the influence of interferences and the GO(Greatest Of)-CFAR that fights well with clutter edges. For the performance analysis, the formulas for the detection probability and the false alarm probability are derived and computed, and the results are compared with other existing CFAR detectors. Our analysis shows that the proposed EXGO-CFAR considerably improves the false-alarm-rate performance of the EXCA-CFAR at clutter edges while maintaining the high detection probability performance of the EXCA-CFAR in the homogeneous and/or interference noise environment.

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Performance Improvement of a Variability-index CFAR Detector for Heterogeneous Environment (비균질 환경에 강인한 검출기를 위한 변동 지수 CFAR의 성능 향상)

  • Shin, Jong-Woo;Kim, Wan-Jin;Do, Dae-Won;Lee, Dong-Hun;Kim, Hyoung-Nam
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.3
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    • pp.37-46
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    • 2012
  • In RADAR and SONAR detection systems, noise environment can be classified into homogeneous and heterogeneous environment. Especially heterogeneous environments are modelled as target masking and clutter edge. Since the variability-index (VI) CFAR, a composed CFAR algorithm, dynamically selects one of the mean-level algorithms based on the VI and the MR (mean ratio) test, it is robust to various environments. However, the VI CFAR still suffers from lowered detection probabilities in heterogeneous environments. To overcome these problems, we propose an improved VI CFAR processor where TM (trimmed mean) CFAR and a sub-windowing technique are introduced to minimize the degradation of the detection probabilities appeared in heterogeneous environments. Computer simulation results show that the proposed method has the better performance in terms of detection probability and false alarm probability compared to the VI CFAR and single CFAR algorithms.

An Improvement in Detection Performance of Logarithmic Receiver (대수수신계통의 탐색특성개선)

  • 윤현보;장태무;조광래
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.9 no.1
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    • pp.45-48
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    • 1984
  • A serious degradation of blocking of the detection performance in a cell aeraging-logarithmic detector/constant false alarm rate(CA-LOG/CFAR) is known to be caused by the presence of a large interfering noise in the set of sample mean. A technique consisting of the logarithmic circuit and inverter has been proposed to alleviate this problem, by modifying the conventional CA-LOG/CFAR receiver. The detection performance of the proposed technique is linearly improbed over the normal output level and the blocking characteristics of the CA-LOG/CFAR can be changed to finite output level.

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