A Fully Quaternion-Valued Capon Beamformer Based on Crossed-Dipole Arrays

TL;DR

This paper introduces a fully quaternion-valued Capon beamformer for crossed-dipole arrays, enhancing performance, reducing complexity, and increasing robustness by utilizing all quaternion components for the desired signal.

Contribution

The paper develops a novel fully quaternion-valued Capon beamformer that fully exploits quaternion components, improving robustness and efficiency over existing models that discard some components.

Findings

Improved beamforming performance with quaternion signals.

Reduced computational complexity compared to previous models.

Enhanced robustness against array pointing errors.

Abstract

Quaternion models have been developed for both direction of arrival estimation and beamforming based on crossed-dipole arrays in the past. However, for almost all the models, especially for adaptive beamforming, the desired signal is still complex-valued and one example is the quaternion-Capon beamformer. However, since the complex-valued desired signal only has two components, while there are four components in a quaternion, only two components of the quaternion-valued beamformer output are used and the remaining two are simply removed. This leads to significant redundancy in its implementation. In this work, we consider a quaternion-valued desired signal and develop a full quaternion-valued Capon beamformer, which has a better performance and a much lower complexity and is shown to be more robust against array pointing errors.