CFAR Target Detector in Synthetic Aperture Radar

Introduction. Constant false alarm rate (CFAR) detectors have found application in synthetic aperture radar (SAR) systems. The operating principle of a classic cell averaging detector (CA-CFAR detector) is based on comparing the decision statistics in the test resolution element with an adaptive thr...

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Main Author: A. A. Monakov
Format: Article
Language:Russian
Published: Saint Petersburg Electrotechnical University "LETI" 2024-07-01
Series:Известия высших учебных заведений России: Радиоэлектроника
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Online Access:https://re.eltech.ru/jour/article/view/889
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author A. A. Monakov
author_facet A. A. Monakov
author_sort A. A. Monakov
collection DOAJ
description Introduction. Constant false alarm rate (CFAR) detectors have found application in synthetic aperture radar (SAR) systems. The operating principle of a classic cell averaging detector (CA-CFAR detector) is based on comparing the decision statistics in the test resolution element with an adaptive threshold, which is calculated from signals in the reference cells. The decision statistic is an estimate of the signal power. Therefore, target signal detection is based on the brightness contrast of the test and reference resolution cells. Such a detector is optimal provided that the noise background is homogeneous. In cases where the background homogeneity is violated, the quality of detection deteriorates. There are several known methods for improving the quality of detection (GO-CFAR, SO-CFAR, OS-CFAR, etc.). However, the precise principle of detection by brightness contrast in such CFAR detectors remains unchanged.Aim. To synthesize a CFAR detector that uses not only the brightness contrast between the test and reference resolution cells, but also the spectral differences of the signals.Materials and methods. The proposed CFAR detector uses estimates of the algebraic moments of the power spectral density of signals in range cells, based on which three decision statistics are calculated containing information about the power, the position of the energy center, and the width of the signal spectrum. The decision about the presence of a target in the test cell is carried out according to the 2/3 rule (2 threshold overshoots out of 3 comparisons).Results. A comparison of the proposed detector with the SO-CFAR detector, performed by computer simulation, showed that, under a signal-to-clutter ratio of -6 dB and a false alarm probability of 10-4, the detection probability of the proposed detector was 0.933 versus 0.708 for the SO-CFAR detector.Conclusion. The article proposes a three-parameter CFAR detector for a synthetic aperture radar system, in which the decision on the presence of a target in the test cell is made via estimation of the first three algebraic moments of the signal spectrum. The synthesized detection algorithm can also be used when detecting moving targets in SAR.
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issn 1993-8985
2658-4794
language Russian
publishDate 2024-07-01
publisher Saint Petersburg Electrotechnical University "LETI"
record_format Article
series Известия высших учебных заведений России: Радиоэлектроника
spelling doaj-art-0b172f7765f84a20a98953f048c0bbc22025-08-20T03:39:49ZrusSaint Petersburg Electrotechnical University "LETI"Известия высших учебных заведений России: Радиоэлектроника1993-89852658-47942024-07-01273526710.32603/1993-8985-2024-27-3-52-67579CFAR Target Detector in Synthetic Aperture RadarA. A. Monakov0Institute of Radio Technique and Telecommunication Technologies, Saint Petersburg State University of Aerospace InstrumentationIntroduction. Constant false alarm rate (CFAR) detectors have found application in synthetic aperture radar (SAR) systems. The operating principle of a classic cell averaging detector (CA-CFAR detector) is based on comparing the decision statistics in the test resolution element with an adaptive threshold, which is calculated from signals in the reference cells. The decision statistic is an estimate of the signal power. Therefore, target signal detection is based on the brightness contrast of the test and reference resolution cells. Such a detector is optimal provided that the noise background is homogeneous. In cases where the background homogeneity is violated, the quality of detection deteriorates. There are several known methods for improving the quality of detection (GO-CFAR, SO-CFAR, OS-CFAR, etc.). However, the precise principle of detection by brightness contrast in such CFAR detectors remains unchanged.Aim. To synthesize a CFAR detector that uses not only the brightness contrast between the test and reference resolution cells, but also the spectral differences of the signals.Materials and methods. The proposed CFAR detector uses estimates of the algebraic moments of the power spectral density of signals in range cells, based on which three decision statistics are calculated containing information about the power, the position of the energy center, and the width of the signal spectrum. The decision about the presence of a target in the test cell is carried out according to the 2/3 rule (2 threshold overshoots out of 3 comparisons).Results. A comparison of the proposed detector with the SO-CFAR detector, performed by computer simulation, showed that, under a signal-to-clutter ratio of -6 dB and a false alarm probability of 10-4, the detection probability of the proposed detector was 0.933 versus 0.708 for the SO-CFAR detector.Conclusion. The article proposes a three-parameter CFAR detector for a synthetic aperture radar system, in which the decision on the presence of a target in the test cell is made via estimation of the first three algebraic moments of the signal spectrum. The synthesized detection algorithm can also be used when detecting moving targets in SAR.https://re.eltech.ru/jour/article/view/889cfar detectoralgebraic moments of the signal spectrumsynthetic aperture radar
spellingShingle A. A. Monakov
CFAR Target Detector in Synthetic Aperture Radar
Известия высших учебных заведений России: Радиоэлектроника
cfar detector
algebraic moments of the signal spectrum
synthetic aperture radar
title CFAR Target Detector in Synthetic Aperture Radar
title_full CFAR Target Detector in Synthetic Aperture Radar
title_fullStr CFAR Target Detector in Synthetic Aperture Radar
title_full_unstemmed CFAR Target Detector in Synthetic Aperture Radar
title_short CFAR Target Detector in Synthetic Aperture Radar
title_sort cfar target detector in synthetic aperture radar
topic cfar detector
algebraic moments of the signal spectrum
synthetic aperture radar
url https://re.eltech.ru/jour/article/view/889
work_keys_str_mv AT aamonakov cfartargetdetectorinsyntheticapertureradar