In order to solve the problem that current clutter suppression methods are not suitable for the clutter suppression in low-altitude slow and small target detection, the method of Filter DC (Direct Current) was proposed in the paper. This method can effectively suppress the clutter by forming a narrower notch filter, while protecting the low-altitude slow and small targets from being affected. In this method, the improvement in Signal-to-Clutter-Noise ratio (SCNR) in different clutter environments was simulated, which proved the superiority of the filter. In this paper, a clutter suppression method was proposed based on noise subspace for motion clutter. Compared with the feature vector method, this method has less influence on the noise of different Doppler channels, and it is more suitable for the detection of low-altitude slow and small targets. Finally, the feasibility and effectiveness of the algorithms were proved by real unmanned aerial vehicle data.

Abstract. Because there are many kinds of clutter interference in the detection of low and slow small targets, clutter suppression is always an important issue in radar signal processing. In this paper, clutter in complex environment is first analyzed based on a large amount of measured data, In theory, the clutter suppression algorithm with narrow spectral width and broad spectrum width is effectively studied: the weighted mean filter algorithm and the noise subspace algorithm, and the improved algorithm of weighted mean filter is proposed. Secondly, Multi-channel quasi-adaptive clutter suppression filter, simple and practical, can effectively suppress clutter in complex environments, and the algorithm is implemented, verified by the measured data, and confirmed good results.