Ship Detection Based on Oceanic Displaced Phase Center Antenna Technique in Along-Track Interferometric SAR

Abstract

This paper proposes a new, yet powerful constant false alarm rate (CFAR) method for ship detection in along-track interferometric (ATI) synthetic aperture radar (SAR) images. First, based on the property that sea surface is not stationary, a detecting metric, named oceanic displaced phase center antenna (ODPCA), is defined, which is an extended version of the conventional displaced phase center antenna (DPCA) technique to the case of oceanic target detection. In order to implement the automatic and adaptive detection in varying sea backgrounds in practical applications, the models characterizing the statistics of the ODPCA of sea clutter are then analytically derived and developed. Next, the completed processing chain of CFAR detection based on the ODPCA metric is given. Preliminary experiments performed on the measured L- and C-band VV-polarization ATI-SAR data by NASA/JPL's AIRSAR validate that ODPCA has better capability of clutter suppression in oceanic situation and near computation efficiency than the conventional DPCA. Moreover, the generalized gamma distribution is suitable for characterizing the ODPCA statistics in spite of sea surface roughness and velocity. Therefore, the proposed CFAR method based on the ODPCA provides a promising technique for the detection of ships using ATI-SAR data.