A Direct-Path Interference Resistant Passive Detector

Passive radar, which detects and tracks targets of interest by using noncooperative illuminators of opportunity (IOs), has become popular since qualified IO sources are widely accessible nowadays. This letter examines the target detection problem for a passive multistatic radar, where the receivers are contaminated by nonnegligible noise and direct-path interference (DPI). The signal transmitted from the IO is treated as a deterministic but unknown process. A generalized likelihood ratio test approach is proposed, where the H
₁
estimation problem is solved using an iterative method. A clairvoyant matched filtering detector, which assumes the knowledge of the IO waveform, is provided as well to benchmark performance. Simulation results are presented to show the effectiveness of the proposed detector in the presence of DPI.