Multistatic passive detection in the presence of direct-path interference

This paper examines the target detection problem in multistatic passive radar with one non-cooperative illuminator of opportunity (IO) and multiple distributed receivers. Unlike most existing passive detectors which ignore the residual direct-path interference (DPI), we consider explicitly its effect and develop two new detectors under the conditions of known noise level and, respectively, when it is unknown. Another distinction from existing solutions is that the proposed detectors exploit the correlation of the IO waveform for passive detection. The proposed detectors are developed within the generalized likelihood ratio test (GLRT) framework, which involves non-linear estimation that is solved using the expectation-maximization algorithm. Numerical results are presented to illustrate the performance of the proposed methods and several well-known passive detectors.