Central Direction-of-Arrival Estimation of Coherently Distributed Sources for Antenna Arrays With Gain-Phase Errors

In radar and communication systems, coherently distributed (CD) sources are widespread due to multipath effects; however, online direction-of-arrival (DOA) estimation for CD sources has not been thoroughly investigated in consideration of array errors. In this letter, a central DOA estimator in the presence of gain-phase error is proposed. A new spatial spectrum function is constructed using the coupling relationship between the phase error and the central DOA obtained by blind signal separation. Subsequently, the spectrum ridge is removed to improve the angular resolution. The proposed noniterative algorithm requires neither prior error information for CD sources nor the prior angular distribution of CD sources and is not sensitive to the degree of gain-phase errors. Simulation results are given to demonstrate the superiority of the proposed algorithm over other algorithms.