Outdoor Navigation Using Bluetooth Angle-of-Arrival Measurements

The introduction of direction finding in the Bluetooth standard enabled the use of antenna arrays for locating Bluetooth devices, using carrier phase measurements to estimate the direction from the array to a moving device. In this work, this feature is utilized for outdoor localization. We show how...

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Main Authors: Martin L. Sollie, Kristoffer Gryte, Torleiv H. Bryne, Tor Arne Johansen
Format: Article
Language:English
Published: IEEE 2022-01-01
Series:IEEE Access
Subjects:
Online Access:https://ieeexplore.ieee.org/document/9861605/
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author Martin L. Sollie
Kristoffer Gryte
Torleiv H. Bryne
Tor Arne Johansen
author_facet Martin L. Sollie
Kristoffer Gryte
Torleiv H. Bryne
Tor Arne Johansen
author_sort Martin L. Sollie
collection DOAJ
description The introduction of direction finding in the Bluetooth standard enabled the use of antenna arrays for locating Bluetooth devices, using carrier phase measurements to estimate the direction from the array to a moving device. In this work, this feature is utilized for outdoor localization. We show how using repeated measurements from all array elements, instead of only the initial single-element reference samples as often suggested, can contribute to an improved estimate of the signal’s unknown carrier frequency offset, thereby improving the direction estimation performance. To run the direction-of-arrival estimation in real-time with high angular resolution on an embedded computer we propose a pseudo-spectrum peak search strategy that combines a coarse search, where the resolution is decided based on the array’s main lobe width, with a local nonlinear optimization for estimate refinement. We consider practical aspects relating to the phase sampling configuration and demonstrate direction estimation at up to 700m range with insignificant packet loss within 500m, and without significant loss of angular precision even when the received signal is near the receiver’s signal strength sensitivity threshold. In an open outdoor environment, using a square antenna array with 12 elements, the azimuthal performance is found to be very consistent with range, with noise standard deviation typically around 1°. While the elevation is significantly affected by multipath at lower elevation angles, with visible disagreement between frequency channels, it is shown to be consistent with simulations of ground reflection multipath.
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spelling doaj.art-50654f2f52cc4cfcad330f984ae42e0e2022-12-22T03:46:42ZengIEEEIEEE Access2169-35362022-01-0110880128803310.1109/ACCESS.2022.31997729861605Outdoor Navigation Using Bluetooth Angle-of-Arrival MeasurementsMartin L. Sollie0https://orcid.org/0000-0003-0768-6298Kristoffer Gryte1https://orcid.org/0000-0002-2223-4129Torleiv H. Bryne2https://orcid.org/0000-0002-6385-5343Tor Arne Johansen3https://orcid.org/0000-0001-9440-5989Department of Engineering Cybernetics, Centre for Autonomous Marine Operations and Systems, Norwegian University of Science and Technology (NTNU), Trondheim, NorwayDepartment of Engineering Cybernetics, Centre for Autonomous Marine Operations and Systems, Norwegian University of Science and Technology (NTNU), Trondheim, NorwayDepartment of Engineering Cybernetics, Centre for Autonomous Marine Operations and Systems, Norwegian University of Science and Technology (NTNU), Trondheim, NorwayDepartment of Engineering Cybernetics, Centre for Autonomous Marine Operations and Systems, Norwegian University of Science and Technology (NTNU), Trondheim, NorwayThe introduction of direction finding in the Bluetooth standard enabled the use of antenna arrays for locating Bluetooth devices, using carrier phase measurements to estimate the direction from the array to a moving device. In this work, this feature is utilized for outdoor localization. We show how using repeated measurements from all array elements, instead of only the initial single-element reference samples as often suggested, can contribute to an improved estimate of the signal’s unknown carrier frequency offset, thereby improving the direction estimation performance. To run the direction-of-arrival estimation in real-time with high angular resolution on an embedded computer we propose a pseudo-spectrum peak search strategy that combines a coarse search, where the resolution is decided based on the array’s main lobe width, with a local nonlinear optimization for estimate refinement. We consider practical aspects relating to the phase sampling configuration and demonstrate direction estimation at up to 700m range with insignificant packet loss within 500m, and without significant loss of angular precision even when the received signal is near the receiver’s signal strength sensitivity threshold. In an open outdoor environment, using a square antenna array with 12 elements, the azimuthal performance is found to be very consistent with range, with noise standard deviation typically around 1°. While the elevation is significantly affected by multipath at lower elevation angles, with visible disagreement between frequency channels, it is shown to be consistent with simulations of ground reflection multipath.https://ieeexplore.ieee.org/document/9861605/Bluetoothdirection-of-arrival estimationradio navigationRF localizationarray signal processing
spellingShingle Martin L. Sollie
Kristoffer Gryte
Torleiv H. Bryne
Tor Arne Johansen
Outdoor Navigation Using Bluetooth Angle-of-Arrival Measurements
IEEE Access
Bluetooth
direction-of-arrival estimation
radio navigation
RF localization
array signal processing
title Outdoor Navigation Using Bluetooth Angle-of-Arrival Measurements
title_full Outdoor Navigation Using Bluetooth Angle-of-Arrival Measurements
title_fullStr Outdoor Navigation Using Bluetooth Angle-of-Arrival Measurements
title_full_unstemmed Outdoor Navigation Using Bluetooth Angle-of-Arrival Measurements
title_short Outdoor Navigation Using Bluetooth Angle-of-Arrival Measurements
title_sort outdoor navigation using bluetooth angle of arrival measurements
topic Bluetooth
direction-of-arrival estimation
radio navigation
RF localization
array signal processing
url https://ieeexplore.ieee.org/document/9861605/
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