Abstract:Interference statistic characteristics are analyzed in ship-based passive synthetic Impulse and Aperture Radar (SIAR). After estimating covariance matrix at range bin interested using data from some positive and all negative frequency bins with cosine weights, eigen-decomposition is applied to interested data for co-channel interference suppression provided that its power is stronger than target echoes. Meanwhile, improved suppression approach to nonstationary interference from multipath propagation is proposed by forming adaptive STAP in fast-time domain and maintaining slow-time statistical properties of the first order sea clutter output approximately unperturbed by filter fluctuation. Analysis and suppression approach are verified by real data.