Transient interference excision and spectrum reconstruction with partial samples for over-the-horizon radar

For target detection with sparsely sampled over-the-horizon radar (OTHR) signal, there are two major hassles puzzling its clutter and target Doppler spectrum reconstruction. On one hand, the OTHR signal is usually contaminated by transient interferences, which usually leads to a significant signal loss in its excision with conventional methods. On the other hand, the sparse OTHR signal will introduce serious grating-lobes in conventional Doppler analysis methods and thus degrade the performance of target detection. In this study, an integrate clutter and target spectrum reconstruction method for sparse OTHR signal are proposed. The proposed method contains two aspects. First, based on the sparse basis representation, a transient interference excision method is developed, which uses time-frequency modulated rectangle window basis to represent the OTHR signal in a sparse way to identify transient interferences. The second aspect lies in that, based on the compressive sensing, a spectrum reconstruction method is proposed to obtain the integrate clutter and target spectrum with sparse samples. By solving the Doppler sparsity constrained optimisation with greedy algorithms, the complete Doppler spectrum is recovered effectively for target detection. The performance of the authors proposal is validated by both simulation and real-measured data sets.