Applying auxiliary array to suppress mainlobe interference for ground-based radar

When ground-based radar is applied to the detection of long-range targets, the interference around the target is located primarily in the radar mainlobe, such that the radar detection capabilities are significantly degraded. Conventional methods of interference suppression mainly focus on sidelobe interference suppression. In the presence of mainlobe interference, sidelobe interference suppression methods will distort and offset the mainlobe peak, so that mainlobe interference could not be effectively suppressed. However, there is currently no suitable mainlobe interference suppression method. In this letter, based on a large aperture auxiliary array, a technique of mainlobe interference suppression is proposed for ground-based radar. The geometry of auxiliary array with uniform array spacing is designed based on conventional sidelobe interference cancellation theory at first. Then, two adaptive beamforming methods for mainlobe interference suppression are presented based on the rules of minimum mean square error (MMSE) and maximum signal-to- interference-plus-noise ratio (MSINR). Since sparse large aperture auxiliary array with uniform array spacing results in high grating lobes, the array spacing is redesigned based on a modified genetic algorithm to reduce the grating lobes. The effectiveness of proposed methods is illustrated by simulations.