ROBUST ADAPTIVE BEAMFORMING FOR NONCIRCULAR SIGNAL AGAINST ARRAY STEERING VECTOR MISMATCH AND INTERFERENCE NONSTATIONARITY

The performance of adaptive arrays is severely degraded if the weights are in the presence of interference nonstationarity and signal steering vector mismatch. Because of this, we proposed a new robust null broadening adaptive beamforming algorithm. The method is realized by the combination of projection transform and diagonal loading technique. We got a new sample covariance matrix through diagonal loading technique and the received data transform technique which is based on the concept of subspace projection. We applied the proposed algorithm to noncircular signals which are usually encountered in the context of radio communications. According to the theoretical analysis, the projection transform operation can improve the orthogonality between signal subspaces and noise subspaces. The proposed approach can effectively broaden the jammer nulls and strengthen the null depth. Simulation results demonstrate that the proposed algorithm can provide strong robustness against both signal steering vector mismatch and jammer motion.