Mainlobe and sidelobe jamming suppression method based on distributed array radar with eigen-projection matrix processing and null constraints

The jamming in electronic warfare environment significantly degrades the performance of the radar system, especially the mainlobe jamming. The distributed array radar can suppress the mainlobe jamming by increasing the array aperture with auxiliary arrays. However, when the aperture of an auxiliary array is smaller than that of the main array, it results in residual jamming in auxiliary arrays after beamforming and affects the performance of the radar system. To tackle this issue, a mainlobe and sidelobe jamming joint suppression method with eigen-projection matrix processing (EMP) and null constraints is proposed. In the proposed method, firstly, the adaptive beamforming with EMP is performed in main and auxiliary arrays to suppress the sidelobe jamming with mainlobe maintenance. Then, the null constraints based on the Capon spectrum of main array are applied to suppress the residual jamming in auxiliary arrays. Finally, the minimum mean square error (MMSE) beamforming is utilised to cancel the mainlobe jamming. Simulation results demonstrate the jamming suppression performance of the proposed method.