Direct path and multipath cancellation in passive radars using Subband Variable Step-Size LMS algorithm

In passive radar, the transmitted signal is not designed for radar purposes and has not thumb tack self ambiguity function, so in matched filter processing, the target´s echoes can be masked by the sidelobes of the direct path and multipath components received by the receiver antenna. So cancellation is essential before matched filter processing. In some papers the use of adaptive filters for cancellation have been reported. In this paper, a Subband Variable Step-Size LMS (VSLMS) algorithm is introduced for the purpose. Simulation is carried out to verify its performance.