Design and Experimental Evaluation of a Bluetooth 5.1 Antenna Array for Angle-of-Arrival Estimation

TL;DR

This paper presents the design and experimental testing of a Bluetooth 5.1 antenna array for accurate angle-of-arrival estimation to improve real-time IoT asset localization in environments where GPS is ineffective.

Contribution

It introduces a circular BLE 5.1 antenna array and evaluates its phase data quality for AoA estimation in controlled and real-world settings.

Findings

Phase data quality is high in anechoic chamber

Real-world environment tests show reliable AoA estimation

BLE 5.1 array enables low-cost asset localization

Abstract

On the of the applications in the realm of the Internet-of-Things (IoT) is real-time localization of assets in specific application environments where satellite based global positioning is unviable. Numerous approaches for localization relying on wireless sensor mesh systems have been evaluated, but the recent Bluetooth Low Energy (BLE) 5.1 direction finding features based on Angle-of-Arrival (AoA) promise a low-cost solution for this application. In this paper, we present an implementation of a BLE 5.1 based circular antenna array, and perform two experimental evaluations over the quality of the retrieved data sampled from the array. Specifically, we retrieve samples of the phase value of the Constant Tone Extension which enables the direction finding functionalities through calculation of phase differences between antenna pairs. We evaluate the quality of the sampled phase data in an anechoic chamber, and in a real-world environment using a setup composed of four BLE beacons.