An effective CLEAN algorithm for interference cancellation and weak target detection in passive radar

In passive radar which exploits opportunity source as the illuminator, the presence of direct signal and clutter echoes in surveillance channel is demonstrated strongly affecting the detection performance. In this paper, based on the well-known CLEAN approach which iteratively removes strong signal and detects targets, an effective CLEAN algorithm is derived for interference cancellation. The new technique adopts the method of orthogonal subspace projection and is more robust even under the following cases: (i) The arrival time of interference signals may be fractional sampling interval after sampling; (ii) The Doppler-delay estimation of interference may be inaccuracy; (iii) The echoes from continuous scattering targets may be Dopplerdelay spread. The approach is shown to be effective through simulation results which considers digital video broadcasting satellites (DVB-S) as the illuminator.