Identification of NLOS and Multi-Path Conditions in UWB Localization Using Machine Learning Methods

In ultra-wideband (UWB)-based wireless ranging or distance measurement, differentiation between line-of-sight (LOS), non-line-of-sight (NLOS), and multi-path (MP) conditions is important for precise indoor localization. This is because the accuracy of the reported measured distance in UWB ranging sy...

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Main Authors: Cung Lian Sang, Bastian Steinhagen, Jonas Dominik Homburg, Michael Adams, Marc Hesse, Ulrich Rückert
Format: Article
Language:English
Published: MDPI AG 2020-06-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/10/11/3980
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author Cung Lian Sang
Bastian Steinhagen
Jonas Dominik Homburg
Michael Adams
Marc Hesse
Ulrich Rückert
author_facet Cung Lian Sang
Bastian Steinhagen
Jonas Dominik Homburg
Michael Adams
Marc Hesse
Ulrich Rückert
author_sort Cung Lian Sang
collection DOAJ
description In ultra-wideband (UWB)-based wireless ranging or distance measurement, differentiation between line-of-sight (LOS), non-line-of-sight (NLOS), and multi-path (MP) conditions is important for precise indoor localization. This is because the accuracy of the reported measured distance in UWB ranging systems is directly affected by the measurement conditions (LOS, NLOS, or MP). However, the major contributions in the literature only address the binary classification between LOS and NLOS in UWB ranging systems. The MP condition is usually ignored. In fact, the MP condition also has a significant impact on the ranging errors of the UWB compared to the direct LOS measurement results. However, the magnitudes of the error contained in MP conditions are generally lower than completely blocked NLOS scenarios. This paper addresses machine learning techniques for identification of the three mentioned classes (LOS, NLOS, and MP) in the UWB indoor localization system using an experimental dataset. The dataset was collected in different conditions in different scenarios in indoor environments. Using the collected real measurement data, we compared three machine learning (ML) classifiers, i.e., support vector machine (SVM), random forest (RF) based on an ensemble learning method, and multilayer perceptron (MLP) based on a deep artificial neural network, in terms of their performance. The results showed that applying ML methods in UWB ranging systems was effective in the identification of the above-three mentioned classes. Specifically, the overall accuracy reached up to 91.9% in the best-case scenario and 72.9% in the worst-case scenario. Regarding the F1-score, it was 0.92 in the best-case and 0.69 in the worst-case scenario. For reproducible results and further exploration, we provide the publicly accessible experimental research data discussed in this paper at PUB (Publications at Bielefeld University). The evaluations of the three classifiers are conducted using the open-source Python machine learning library scikit-learn.
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spelling doaj.art-9bdcf8fe72814260bf34aeedd970e2d12023-11-20T03:12:24ZengMDPI AGApplied Sciences2076-34172020-06-011011398010.3390/app10113980Identification of NLOS and Multi-Path Conditions in UWB Localization Using Machine Learning MethodsCung Lian Sang0Bastian Steinhagen1Jonas Dominik Homburg2Michael Adams3Marc Hesse4Ulrich Rückert5Cognitronics and Sensor Systems Group, CITEC, Bielefeld University, 33619 Bielefeld, GermanyCognitronics and Sensor Systems Group, CITEC, Bielefeld University, 33619 Bielefeld, GermanyCognitronics and Sensor Systems Group, CITEC, Bielefeld University, 33619 Bielefeld, GermanyCognitronics and Sensor Systems Group, CITEC, Bielefeld University, 33619 Bielefeld, GermanyCognitronics and Sensor Systems Group, CITEC, Bielefeld University, 33619 Bielefeld, GermanyCognitronics and Sensor Systems Group, CITEC, Bielefeld University, 33619 Bielefeld, GermanyIn ultra-wideband (UWB)-based wireless ranging or distance measurement, differentiation between line-of-sight (LOS), non-line-of-sight (NLOS), and multi-path (MP) conditions is important for precise indoor localization. This is because the accuracy of the reported measured distance in UWB ranging systems is directly affected by the measurement conditions (LOS, NLOS, or MP). However, the major contributions in the literature only address the binary classification between LOS and NLOS in UWB ranging systems. The MP condition is usually ignored. In fact, the MP condition also has a significant impact on the ranging errors of the UWB compared to the direct LOS measurement results. However, the magnitudes of the error contained in MP conditions are generally lower than completely blocked NLOS scenarios. This paper addresses machine learning techniques for identification of the three mentioned classes (LOS, NLOS, and MP) in the UWB indoor localization system using an experimental dataset. The dataset was collected in different conditions in different scenarios in indoor environments. Using the collected real measurement data, we compared three machine learning (ML) classifiers, i.e., support vector machine (SVM), random forest (RF) based on an ensemble learning method, and multilayer perceptron (MLP) based on a deep artificial neural network, in terms of their performance. The results showed that applying ML methods in UWB ranging systems was effective in the identification of the above-three mentioned classes. Specifically, the overall accuracy reached up to 91.9% in the best-case scenario and 72.9% in the worst-case scenario. Regarding the F1-score, it was 0.92 in the best-case and 0.69 in the worst-case scenario. For reproducible results and further exploration, we provide the publicly accessible experimental research data discussed in this paper at PUB (Publications at Bielefeld University). The evaluations of the three classifiers are conducted using the open-source Python machine learning library scikit-learn.https://www.mdpi.com/2076-3417/10/11/3980UWBNLOS identificationmulti-path detectionNLOS and MP discriminationmachine learningSVM
spellingShingle Cung Lian Sang
Bastian Steinhagen
Jonas Dominik Homburg
Michael Adams
Marc Hesse
Ulrich Rückert
Identification of NLOS and Multi-Path Conditions in UWB Localization Using Machine Learning Methods
Applied Sciences
UWB
NLOS identification
multi-path detection
NLOS and MP discrimination
machine learning
SVM
title Identification of NLOS and Multi-Path Conditions in UWB Localization Using Machine Learning Methods
title_full Identification of NLOS and Multi-Path Conditions in UWB Localization Using Machine Learning Methods
title_fullStr Identification of NLOS and Multi-Path Conditions in UWB Localization Using Machine Learning Methods
title_full_unstemmed Identification of NLOS and Multi-Path Conditions in UWB Localization Using Machine Learning Methods
title_short Identification of NLOS and Multi-Path Conditions in UWB Localization Using Machine Learning Methods
title_sort identification of nlos and multi path conditions in uwb localization using machine learning methods
topic UWB
NLOS identification
multi-path detection
NLOS and MP discrimination
machine learning
SVM
url https://www.mdpi.com/2076-3417/10/11/3980
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AT michaeladams identificationofnlosandmultipathconditionsinuwblocalizationusingmachinelearningmethods
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