Narrow-band comb interference suppression algorithm in spaceborne synthetic aperture radar

The Spaceborne Synthetic Aperture Radar (SAR) uses electromagnetic waves to acquire remote sensing data. However, owing to the complex electromagnetic environment encountered on the Earth’s surface, it is necessary to address the challenge of anti-interference. This work focuses on the suppression of narrow-band comb interference (NCI) in practical applications. NCI manifests as a comb-like pattern in the frequency domain, and it overlaps with SAR echoes across multiple domains. Severe NCI can compromise the quality of SAR images. Conventional suppression algorithms are ineffective against NCI owing to its unique characteristics, resulting in unsatisfactory suppression performance. This paper introduces a new NCI suppression algorithm based on independent component analysis (ICA). The algorithm uses an eigen-beam to identify NCI components, which are subsequently extracted using ICA. A novel function is constructed to approximate negentropy, aligning with the characteristics of NCI. Finally, an orthogonal projection matrix is constructed using the extracted NCI samples, which effectively suppresses NCI in the raw echo data. Simulation experiments demonstrate the effectiveness and superiority of the proposed algorithm for NCI suppression.