DOA and Polarization Estimation Based on Sparse COLD Array

Direction of arrival (DOA) ambiguity influences the performance of array signal processing. To address this problem, a DOA and polarization estimation method is proposed in this paper. Based on sparse uniform concentric semi-circular array consisting of concentred orthogonal loop and dipole pairs, the actual array steering vector can be transformed into a virtual one without additional computation. By applying dot division and dot product operation to outer and inner circular ring array spatial steering vectors, two new spatial steering vectors of arrays whose inter-element spacing are less and much larger than half wavelength are obtained respectively, the cyclic phase ambiguity is disambiguated effectively. In the proposed algorithm, all the array elements (actual and virtual) contribute toward the derivation of both the coarse estimations and the fine estimations, thereby achieving full exploitation of the entire physical aperture, the estimation precision is herein improved.