Null widening method for conformal array based on covariance matrix enhancement

Conformal arrays are widely used in various aircrafts since they do not affect the aerodynamic performance of the carriers. When conformal arrays are used to suppress fast‐moving interference, it is possible that the weight mismatches the data of measurement due to the perturbation of the interference location. Traditional null widening methods are based on linear or planar arrays and cannot be applied to conformal arrays directly. Therefore, a null widening method used for conformal arrays is proposed in this article. In the method, the spatial spectrum of the signal is first calculated, and then the convolution of spatial spectrum in the interference region and 2‐D window function is calculated to enhance the spatial spectrum. Next, the enhanced covariance matrix is calculated based on the convolution results. Finally, the sample matrix inversion (SMI) method is used to calculate the weight. This method can be used for common conformal arrays and can form two‐dimensional nulls in space. Based on the numeral simulation results, it is verified that the proposed method can form widened nulls and improve the robustness of interference suppression effectively.