Target and Ambiguity Discrimination Using Doppler Spectrum from Low PRF SAR Image

Maritime surveillance is one of the useful application of spaceborne Synthetic Aperture Radar (SAR) because of its ability to operate in all weather conditions during day and night. In this application, wide swath width is favorable. The swath width depends on Pulse Repetition Frequency (PRF). Gener...

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Bibliographic Details
Main Authors: Fujihara, Hiroaki, Katayama, Yumiko, Oishi, Noboru, Yokota, Yuya, Shibata, Masanobu, Karasawa, Akira, Matsuki, Makoto, Nakamura, Shohei
Format: Conference Proceeding
Language:English
Subjects:
ambiguity discrimination
Azimuth
Doppler effect
Low PRF
Marine vehicles
Maritime surveillance
Radar polarimetry
SAR
Ship detection
Spaceborne radar
Surveillance
Synthetic aperture radar
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Summary:Maritime surveillance is one of the useful application of spaceborne Synthetic Aperture Radar (SAR) because of its ability to operate in all weather conditions during day and night. In this application, wide swath width is favorable. The swath width depends on Pulse Repetition Frequency (PRF). Generally, high PRF is selected to avoid range/azimuth ambiguity signals in receiving beams, however low PRF must be applied to obtain wide images [1]. Thus, ambiguity appears in wide swath width images taken with low PRF. Ambiguities presents challenges for high detection rate and low false alarm rate, which are both necessary for efficient maritime surveillance.Generally, Constant False Alarm Rate (CFAR) algorithm is applied for ship detection in SAR images. However, CFAR algorithm does not work well with high ambiguity images due to an increase in false alarms. In order to discriminate real images from ambiguities, a discrimination algorithm, which utilizes the Doppler spectrum, was created. The Doppler spectrum of the real images in the range direction is different from that of ambiguities. This paper describe the detail of the discrimination algorithm and the evaluation applied to the SAR image.
ISSN:2153-7003
DOI:10.1109/IGARSS.2019.8898726