Direct path interference suppression for short-range passive bistatic synthetic aperture radar imaging based on atomic norm minimisation and Vandermonde decomposition

A novel direct path interference (DPI) suppression method is proposed for passive bistatic synthetic aperture radar (SAR) imaging applications. Conventional time-domain processing methods cannot mitigate the DPI completely and will introduce errors into the target position estimation. By exploiting the sparsity of the DPI signal and the properties of its covariance matrix, the proposed method solves these problems by accurately estimating the time delay of DPI based on the atomic minimisation algorithm and Vandermonde decomposition in the frequency domain. The amplitude of DPI is then calculated by the least squares method. Simulations and experimental results of Wireless Fidelity-based passive bistatic SAR imaging of short-range targets show that the proposed method can suppress DPI more effectively and estimate the position of the target more accurately than the classical method.