Moving Target Detection Using Passive Bistatic Radars in Presence of Interfering Target and I/Q Imbalances

This paper addresses moving target detection in the presence of an Interfering Target (IT) using Passive Bistatic Radar (PBR) systems affected by hardware mismatches. We focus on In-phase/Quadrature-phase Imbalances (IQIs) common in Direct-Conversion Receivers (DCRs), where IT echoes mask the Main Target (MT). When unmitigated, both effects significantly degrade detection performance. Unlike existing approaches, we assume unknown noise power and unknown target Doppler Shifts (DSs), further increasing the detection challenge. We develop a new signal model for this scenario, formulate a Binary Composite Hypothesis Testing (BCHT) problem, and derive a closed-form asymptotically optimal Generalized Likelihood Ratio Test (GLRT) detector using the Neyman-Pearson criterion. To improve computational efficiency, we exploit Fast Fourier Transform (FFT) symmetry properties and employ batch data processing, substantially reducing computational complexity and execution time. We also analyze the impact of amplitude and phase mismatches on the PBR signal model. Theoretical analysis and simulations demonstrate improved detection probability and enhanced robustness to IQI compared with state-of-the-art methods.