Direction of Arrival Estimation for Quasi-Stationary Signals using Nested Circular Array

In this paper, the problem of direction-of-arrival (DOA) estimation for quasi-stationary signals is addressed using non-uniform circular arrays called nested circular array. We use the Khatri-Rao (KR) subspace approach to obtain an increase in the degrees of freedom. Thus, the nested circular array is capable of resolving more sources than the number of sensors. We therefore perform overdetermined as well as underdetermined DOA estimation. The KR subspace approach provides a simple way to eliminate spatial noise covariance as well. Subspace based method MUSIC and l(1)-based optimization method has been extended to utilize the increase in degrees of freedom for DOA estimation in overdetermined and underdetermined cases using nested circular array. This approach can also be applied to stationary signals which is effective for overdetermined and underdetermined DOA estimation for Radar/Sonar. Simulation results validates the effectiveness of the proposed method. The performance of subspace based method MUSIC and l(1)-based optimization method is compared with the CramerRao lower bound (CRLB).