Block subspace projection-based interference suppression in passive radars

Aimed at global position system (GPS) based passive radar systems, a blocking subspace projection method was presented to remove the disturbance residuals and reduce the computational cost. In both the reference and echo channels, the received signals were divided into several consecutive blocks, and processed in parallel. Firstly, the signals received in the echo channel were projected onto the orthogonal complement subspace of the disturbance subspace. Secondly, the existing criterion of the masking effect caused by the side-lobe of strong target echo was introduced. Finally, the signals were projected onto the subspace which was orthogonal to all of strong target subspace. This method has the advantages of interference suppression quality and computational simplicity in each block. The effectiveness of the algorithm was demonstrated by the simulation.