Open AccessCorrection

Correction: Che et al. Indoor Positioning System (IPS) Using Ultra-Wide Bandwidth (UWB)—For Industrial Internet of Things (IIoT). Sensors 2023, 23, 5710

Fuhu Che

¹,

Qasim Zeeshan Ahmed

^1,*

Pavlos I. Lazaridis

Pradorn Sureephong

² and

Temitope Alade

Department of Computing and Engineering, University of Huddersfield, Huddersfield HD1 3DH, UK

College of Arts, Media and Technology, Chiang Mai University, Chiang Mai 50200, Thailand

Department of Computer Science, School of Science and Technology, Nottingham Trent University, Nottingham NG11 8NS, UK

Author to whom correspondence should be addressed.

Sensors 2023, 23(20), 8360; https://doi.org/10.3390/s23208360

Submission received: 12 September 2023 / Accepted: 25 September 2023 / Published: 10 October 2023

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Text Correction

There was an error in the original publication [1]. The previous section was more on channel impulse response, while our problem concerned making a decision on the LoS or NLoS component.

A correction has been made to “5. Detection in UWB Positioning Algorithms”, “5.1. Machine Learning For UWB In NLoS”:

To improve the accuracy of UWB positioning systems, specific NLoS mitigation techniques are required for various applications. Figure 13 illustrates a block diagram of a complete UWB precise IPS, which starts by fixing the anchors for the coordinate system and locates the mobile UWB tags within the indoor environment. The collected raw data will be used by an additional processing step for NLoS detection, which is performed using an ML classification algorithm that has been pre-trained with the raw measurement data. This model is used to mitigate the NLoS effects. For NLoS classification, the ML is used to classify the LoS and NLoS by different signal features or CIR values. For NLoS error correction, the ML can be applied for predicting the error

e_{i, j}

accurately. The actual range

r_{i, j}

between the i-th anchor

(x_{i}, y_{i}, z_{i})

and the j-th tag

(x_{j}, y_{j}, z_{j})

is defined as:

r_{i, j} = \sqrt{{(x_{i} - x_{j})}^{2} + {(y_{i} - y_{j})}^{2} + {(z_{i} - z_{j})}^{2}} .

(10)

The estimated distance

d_{i, j}

in term of the coordinate of the i-th anchor and the j-th tag is determined through calculating the signal round trip time of the ToA. The positioning of the i-th anchors is known and constant; therefore, the estimated distance

d_{i, j}

in a three-dimensional scenarios is given as:

d_{i, j}^{L o S} = r_{i, j} + ϵ_{i, j},

(11)

where

ϵ_{i, j}

is the measurement error.

For NLoS conditions, the signal direct path is reflected or blocked due to the presence of obstacles; therefore, there will be further signal propagation delay, resulting in NLoS error

e_{i, j}

. The estimated distance

d_{i, j}

can be calculated as:

d_{i, j}^{N L o S} = r_{i, j} + ϵ_{i, j} + e_{i, j},

(12)

where

e_{i, j}

is the independent positive measurement bias error. Finally, the corresponding ranging error

δ_{i}

can be expressed as:

δ_{i} = \{\begin{matrix} ϵ_{i, j}, L o S, \\ ϵ_{i, j} + e_{i, j}, N L o S . \end{matrix}

(13)

The ML algorithm can now be trained to classify the LoS and the NLoS component for the UWB signal. Therefore, high-accuracy NLoS classification and accurate prediction of

e_{i, j}

is crucial for precision IPS.

With this correction, the order of some equations has been adjusted accordingly. The authors state that the scientific conclusions are unaffected. This correction was approved by the academic editor. The original publication has also been updated.

Reference

Che, F.; Ahmed, Q.Z.; Lazaridis, P.I.; Sureephong, P.; Alade, T. Indoor Positioning System (IPS) Using Ultra-Wide Bandwidth (UWB)—For Industrial Internet of Things (IIoT). Sensors 2023, 23, 5710. [Google Scholar] [CrossRef]

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© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

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MDPI and ACS Style

Che, F.; Ahmed, Q.Z.; Lazaridis, P.I.; Sureephong, P.; Alade, T. Correction: Che et al. Indoor Positioning System (IPS) Using Ultra-Wide Bandwidth (UWB)—For Industrial Internet of Things (IIoT). Sensors 2023, 23, 5710. Sensors 2023, 23, 8360. https://doi.org/10.3390/s23208360

AMA Style

Che F, Ahmed QZ, Lazaridis PI, Sureephong P, Alade T. Correction: Che et al. Indoor Positioning System (IPS) Using Ultra-Wide Bandwidth (UWB)—For Industrial Internet of Things (IIoT). Sensors 2023, 23, 5710. Sensors. 2023; 23(20):8360. https://doi.org/10.3390/s23208360

Chicago/Turabian Style

Che, Fuhu, Qasim Zeeshan Ahmed, Pavlos I. Lazaridis, Pradorn Sureephong, and Temitope Alade. 2023. "Correction: Che et al. Indoor Positioning System (IPS) Using Ultra-Wide Bandwidth (UWB)—For Industrial Internet of Things (IIoT). Sensors 2023, 23, 5710" Sensors 23, no. 20: 8360. https://doi.org/10.3390/s23208360

APA Style

Che, F., Ahmed, Q. Z., Lazaridis, P. I., Sureephong, P., & Alade, T. (2023). Correction: Che et al. Indoor Positioning System (IPS) Using Ultra-Wide Bandwidth (UWB)—For Industrial Internet of Things (IIoT). Sensors 2023, 23, 5710. Sensors, 23(20), 8360. https://doi.org/10.3390/s23208360

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Correction: Che et al. Indoor Positioning System (IPS) Using Ultra-Wide Bandwidth (UWB)—For Industrial Internet of Things (IIoT). Sensors 2023, 23, 5710

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