Simple and Effective GNSS Spatial Processing Using a Low-Cost Compact Antenna Array

A compact planar four-element antenna array that can be used to improve the robustness and accuracy in applications of satellite-based navigation systems that require simple, low-cost, lightweight, and efficient antenna solutions is proposed in this article.By introducing an orthonormal transformation in the digital signal processing stage, it is possible to simplify the effect of the distorted in situ antenna radiation patterns obtaining an equivalent almost ideal phased array response. The actual prototype designed under this concept is a 14 cm x 14 cm single-layer microstrip antenna array for the GNSS L1/E1-bands that achieves a good total antenna efficiency without employing any additional matching/decoupling stage. Promising results obtained through numerical simulations and on-field experiments showing effective direction of arrival estimations and mitigation of radio frequency interferences with simple spatial processing algorithms applied after the proposed signal transformation are presented.