A Coastal Clutter and Its Azimuth Ambiguity Suppression Method for SAR Images

Abstract

In Synthetic Aperture Radar (SAR) images, azimuth ambiguity is an important factor affecting image quality. Azimuth Doppler spectrum is theoretically an infinite spectrum that is not limited by bandwidth. Due to azimuth sampling, the spectrum part larger than the pulse repetition frequency is folded into a pulse repetition frequency (PRF), so it is difficult to find a solution to remove it completely using traditional methods. Especially in ocean images, the azimuth ambiguity caused by strongly scattered land, island or ship targets will affect the detection of sea targets. Aiming at the problem of loss of azimuth resolution and missing alarm caused by the coverage of target information on the sea surface while suppressing azimuth ambiguity, this paper proposes a coastal clutter and its azimuth ambiguity suppression method for SAR Images, which using SAR sensors to re-navigate the same area to obtain multi-temporal SAR images. At the same time, according to the dynamic characteristics of the sea surface, spatial frequency domain filtering and ideal filter methods are combined to complete the removal of near-coast ground clutter and azimuth ambiguity.