Evaluation of Clutter Suppression in CP-OFDM Based Passive Radar

In recent years, digital broadcasting signals, like Digital Audio/Video Broadcast (DAB/DVB), have received increasing attention in passive radar system. Most of these digital broadcasting signals use orthogonal frequency division multiplex (OFDM) modulation with cyclic prefix (CP-OFDM). Benefitting from the distinctive characteristics of the CP-OFDM signal, several efficient methods have been proposed to handle the high clutter problem in the CP-OFDM based passive radar. These methods are all operated in the subcarrier domain. In this paper, an evaluation of the inner relationship and suppression performance of these subcarrier-domain methods are presented, along with the discussion of their Doppler response and computational complexity. The mathematical derivations demonstrate that two of the methods have almost the equivalent suppression mechanism and their suppression performance depends on the modulation scheme of the illuminators of opportunity (IOs). Besides, these methods can achieve comparable suppression performance to that of the temporal method but have lower computational and memory complexity. Numerical experiments on simulated and real data as well validate the evaluation results.