Robust Automotive Satellite Navigation Achieved with Distributed Groups of Sub-arrays

Abstract

Ambiguous direction-of-arrival estimation is a key problem for uniformly distributed antenna arrays with inter-element spacing exceeding half of the carrier wavelength. The primary reason behind such ambiguity are the grating lobes generated in the radiation patterns due to insufficient spatial sampling. An L-shaped orthogonal arrangement of radiating elements in distributed sub-arrays is an approach that removes grating lobes and consequent ambiguity to a great extent. The reduction of footprint area by distributing the elements across a car also makes it a suitable approach for conformal integration into automotive exterior parts. In order to realize the feasibility of its application in passenger cars, we investigate and evaluate this concept through measurements and digital array signal processing. This paper presents a comparison of L-shaped antenna element arrangements for different spacings between two sub-arrays, as well as a verification of the concept when mounted on a passenger car. For each scenario, the radiation patterns are analyzed and the robustness of the system against a static interferer is verified.