A new peak width NLMS filtering scheme for a DVB-T based Passive Bistatic Radar

Abstract

Adaptive cancellation is the key stage in an PBR (Passive Bistatic Radar) signal processing. In order to achieve a detection with a low false alarm rate, the main role of the adaptive cancellation is the removal of the interferences from the target echoes, which can often originate from weak signals. It is well known that the conventional NLMS (Normalized Least Mean Square) and its frequency domain version, the FBLMS (Fast Bloc Least Mean Square) are inefficient when they come to the cancellation of both non-zero Doppler multipath components and strong target echoes. Although efficient in the cancellation of both cited problems inherent to the NLMS filter, its variants such as the MCNLMS (Multi Channel NLMS), the TD-SWNLMS (Two Dimensional-Sparse Weight NLMS) and the ECA (Extensive Cancellation Algorithm) yield significant computational complexity. To alleviate these difficulties, we propose to simulate a PBR based DVB-T (Digital Video Broadcasting-Terrestrial) signal model, based on a novel 1D-NLMS (One Dimensional-NLMS) filtering scheme called the PWNLMS (Peak Width NLMS). In doing this, the filter length of the proposed filter should adapt to the accumulation of the peaks width of the CAF (Cross Ambiguity Function) and a vector of step sizes whose length should be equal to the number of the peaks. In order to obtain an optimum convergence with a low complexity, the proposed filter should guarantee an effective and a smooth control of the direct signal, multiple paths and strong target echoes cancellation.