A mainlobe interference cancelling method

The performance of adaptive digital beamformer (ADBF) will be degraded when the expected signal is mixed in the sample data and the expected signal will be cancelled. If the interference locates in the mainlobe areas, the mainbeam will be distorted with conventional ADBF for the sake of suppressing the mainlobe interference. In this paper, a modified block matrix (MBM) method is proposed. This method avoids mainlobe distortion and has better performance of interference cancelling than the direct sample matrix inversion (SMI) method. The results of simulations support the theoretical predictions. When target signal is in the sample data, the performance of ADBF will be degraded. If the interference falls into mainlobe, the mainbeam will be distorted with conventional ADBF. In this paper, a MBM method is presented which preprocesses the sample data via a block matrix so that the influence of expected signal and mainbeam jamming is diminished. The method avoids mainlobe distortion and has the better performance of interference canceling than the direct SMI method. The computer simulation verifies it.