Experimental Research on Pseudo Carrier-Domain Interference Suppression of FM-Based Passive Radar

Frequency modulation (FM) -based passive radar is characterized by the wide distribution of transmitters and rich signal resources. The experiment shows that the detection results of different FM signals on the same target can form a strong complementary effect, and the reasonable use of it for multi-frequency detection fusion will be able to significantly improve the system's detection stability of target. However, many signals in the FM frequency band have partial spectrum overlapping with each other, and this kind of adjacent frequency interference will greatly affect the detection performance. To address this problem, we investigate a pseudo carrier-domain processing method inspired by carrier-domain clutter suppression for OFDM signals. The method performs spatial projection at every frequency point of the surveillance FM signals, which is capable of significantly suppressing the adjacent frequency interference after adaptive clutter cancellation and enhancing the target detection performance of the interfered signals. It in turn will help to expand the selectable frequency range of the FM-based passive radar. The experimental data verifies the effectiveness of this treatment.