Direct Signal Interference Mitigation By Slow-Time Frequency Correction For OFDM-Based Passive Radar

Abstract

Algorithms to suppress the direct signal in the surveillance channel are vital for passive radar systems. In systems using digital waveforms, however, target detection is already possible without such suppression algorithms and hence they have so far gotten less attention. We show that a major cause of direct signal interference in OFDM-based waveforms is a frequency offset between the transmitter and the receiver. We propose a simple and computationally efficient way of correcting this offset and demonstrate its effectiveness for both digital audio and video broadcasting (DAB and DVB-T) signals.