Processing over-the-horizon radar (OTHR) signals is challenging due to appearance of several very close components in the time-frequency plane, strong noise and clutter, multipath propagation, and aliasing. We propose a two-stage procedure for estimating multipath signal components from the received mixture. In the first stage, the instantaneous frequency is estimated from the time-frequency representation of the received signal. The random samples consensus algorithm is applied to the instantaneous frequency estimate to improve the robustness of the procedure against various effects in the underlying signals. In the second stage, the MUSIC algorithm is applied to the dechirped and downsampled signal. The effectiveness of the proposed approach is verified using real-life signals.
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