Doa Resolution Enhancement of Coherent Signals Via Spatial Averaging of Virtually Expanded Arrays

Abstract

The virtual expansion method of the array aperture was suggested in order to improve the direction-of-arrival (DOA) resolution of coherent signals. But the virtual expansion of a single array has an inherent limit to improve the DOA resolution capability due to spurious peaks at the spatial spectrum. To overcome the limit of this method, the spatial spectrum averaging method of the virtually expanded arrays is proposed. From the simulation results for coherent signals impinging on an uniform circular array, the perfect DOA resolution capability of 100% is achieved at the SNR of more than −5 dB by the Deterministic Maximum Likelihood (DML) algorithm including the proposed method. Meanwhile, the DOA resolution capability of the standard DML algorithm is less than 11% at the SNR of more than −5 dB.