This paper proposes a novel subspace projection algorithm for impulsive interference (IMI) suppression in echo samples received by an over-the-horizon radar (OTHR). We particularly highlight the model that the frequency spectrum of IMI component is a complex cosine signal such that IMI cosine can be filtered out by subspace projection. Compared with existing algorithms, a more simple clutter suppression algorithm is used to reject the most powerful clutter components. Furthermore, this algorithm will neither estimate nor need the exact temporal position of IMI, which avoids the impact resulted from the position estimation error. Another advantage is its little impact on true target signal and no impact on the clutter. Experimental results based on data from real high frequency surface wave (HFSW) OTHR systems are also shown to verify the proposed algorithm.
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