Computationally Efficient Transient Interference Excision Method for Skywave Over-the-Horizon Radar

The skywave over-the-horizon radar (OTHR) has attracted considerable attention for its ability of out-of-sight surveillance. However, in practice, its operational performance is severely degraded by transient interferences. Some previous works focus on time-domain methods to achieve transient interference suppression and cannot get rid of the corruption segment blanking and data interpolation. In fact, the data interpolation method is usually time-consuming and may suffer performance loss. To avoid data interpolation, some interpolation-free methods are proposed and show superior performance. However, the significant computational costs impede the application in reality. In this letter, a new method for transient interference suppression is proposed. After interference localization, a signal subspace, representing the clutter and target, is constructed by the interference-free data. Then, transient interferences are excised by solving a bicriterion optimization problem that minimizes the quadratic fitting error and the energy orthogonal to the signal subspace simultaneously. The proposed method can excise transient interferences with clutter and potential target echoes preserved at the same time; thus, data interpolation is no longer needed. The proposed method is evaluated by experimental data collected from a trial skywave OTHR, and the results verify its effectiveness.