A new quad-quaternion model is herein established for an electromagnetic vector-sensor array, under which a multidimensional algebra-based direction-of-arrival (DOA) estimation algorithm, termed as quad-quaternion MUSIC (QQ-MUSIC), is proposed. This method provides DOA estimation (decoupled from polarization) by exploiting the orthogonality of the newly defined

The problem of closed-form parameter estimation using a diversely polarized antenna array of arbitrary configurations is herein considered, under the coexistence of circular and strictly noncircular signals that occurred in communication/radar systems. By incorporating noncircularity difference and polarization diversity of the incident sources with augmented polarimetric manifold decoupling, the conventional polynomial rooting based polarimetric element space (PES) subspace technique is enhanced for direction of arrival, polarization, and noncircularity phase (for strictly noncircular sources) estimation. A subspace constraint based method is also presented to improve parameter estimation of the strictly noncircular sources. Simulation results are included to illustrate the performance of the proposed methods.

The problem addressed in this paper is focused on the direction-of-arrival (DOA) estimation of the circular and noncircular wideband signals. The propagator scanning scheme is applied to the array output augmented cross covariance matrix by aligning first the baseband array observation. When the scanning angle equals a true DOA of signal, the complex envelope of the corresponding signal is perfectly aligned, and then, the associated propagator can be used to fulfill subspace separation based wideband direction finding. This method involves no data focusing and eigendecomposition. The performance of the proposed method is analyzed in terms of the mean-square errors of the DOA estimates. Simulation results are included to evaluate the new technique and to verify the performance analysis.

New direction‐of‐arrival (DOA) and non‐circular phase estimation algorithms for a mixture of circular and non‐circular signals, which are applicable to arbitrary planar arrays are presented. For simplicity, the non‐circular signals referred to are assumed to be strictly non‐circular. First, the DOAs of circular and non‐circular signals are estimated based on two polynomial formulae. Then the estimated DOAs of circular signals can be used to estimate the DOAs of non‐circular signals more precisely. Furthermore, the non‐circular phases can be calculated by the estimated DOAs of non‐circular signals. Simulation results show that the proposed algorithms outperform the compared algorithm.