Cramér-Rao Bound for Wideband DOA Estimation with Uncorrelated Sources

In this paper, the closed-form Cramér-Rao bound (CRB) is derived for direction-of-arrival (DOA) estimation under the unconditional model assumption (UMA) for uncorrelated wideband sources. The existence of the CRB is proved based on the rank condition of the introduced augmented co-array manifold (ACM) matrix. The resolution capacity is then investigated and it is found that the number of resolvable sources for the wideband model can exceed the limitation in the narrowband case without requirement of any special array structure.