Multipath clutter rejection for digital radio mondiale-based HF passive bistatic radar with OFDM waveform

In digital radio mondiale (DRM)-based high frequency (HF) passive bistatic radar, target echoes need to be detected against the direct-path wave and multipath echoes. A novel approach is proposed to reject the direct-path wave and multipath echoes. The signal is projected into a subspace orthogonal to the clutter subspace carrier by carrier, exploiting the fact that the direct-path wave and multipath echoes at the same carrier in orthogonal frequency division multiplexing (OFDM) waveform are totally correlated. Simulation and experimental results following the theory analysis verify the performance of the new approach.