Robust direction of arrival estimate method in FM-based passive bistatic radar with a four-element Adcock antenna array

This study examines the problem of direction of arrival (DOA) estimation in FM-based passive bistatic radar using a four-element Adcock antenna array. The authors investigate the influence of the target echo, involved in the reference signal, on the DOA estimation of the corresponding target considered. Analysis shows that, unlike the pure reference signal case, a weak target echo involved in the reference signal may not affect the detection of the corresponding target. It can often have a significant impact on the estimation of a target's DOA; thus typical DOA estimate methods degrade heavily. A robust method is proposed to cope with this problem. Simulation and experimental results demonstrate the effectiveness of the method.