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

Abstract

A compact planar four-element antenna array that can be used to improve robustness and accuracy in applications of satellite-based navigation systems which require simple, low-cost, lightweight but also efficient antenna solutions is proposed. 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 \times 14 cm single layer microstrip antenna array for the GNSS L1/E1-bands that achieves 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.