Cumulant-Based Biquaternion Approach to Direction Finding of Wideband Signals

A direction-of-arrival (DOA) estimator is presented for statistically independent non-Gaussian and non-circular wideband signals in the presence of Gaussian noise (possibly spatially colored). With joint exploitation of non-Gaussianity and non-circularity of incident signals, enhanced aperture extension is achieved. The incorporation of the aligned biquaternion adjoint subspace augmentation and the aligned virtual array synthesis within the biquaternion framework, using both the standard and the complementary fourth-order cumulant matrices, enables wideband underdetermined DOA estimation: handling more signals than the number of sensors. The efficacy of the presented method has been demonstrated using simulated data.