Suppression of Azimuth Ambiguity for the Detection of Ships on the Ocean by Wide-Swath Synthetic Aperture Radar

This study proposes the suppression of the azimuth ambiguity with high azimuth resolution and signal-to-noise ratio in an image captured at a low pulse repetition frequency for the detection of ships on the ocean with wide swath by spaceborne synthetic aperture radar (SAR). The proposed scheme can reduce the azimuth ambiguity by processing the two images divided in the Doppler frequency region, which selects pixels with smaller values between the two images and derives their gains. After evaluating the proposed scheme, we discovered that azimuth ambiguity can be suppressed, and the expected swath of the observed image is equivalent to five times that of the conventional SAR image. The proposed scheme improved the signal-to-azimuth ambiguity power ratio by 27.7 dB.