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Indoor and Outdoor Sensor Networks for Positioning and Localization

A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Sensor Networks".

Deadline for manuscript submissions: closed (30 November 2023) | Viewed by 21427

Special Issue Editors


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Guest Editor
Department of Electrical and Information Engineering, University of Cassino and Southern Lazio, 03043 Cassino, Italy
Interests: sensor networks and distributed measurement systems; characterization of components and electrical systems; noninvasive tests in industrial fields; characterization of sensor networks for IoT and Industry 4.0; measurements methods for telecommunication devices and systems
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Guest Editor
Department of Electrical and Information Engineering, University of Cassino and Southern Lazio, Cassino, Italy
Interests: eddy current testing; nondestructive methods; thickness measurement

Special Issue Information

Dear Colleagues,

Sensor networks represent an important and attractive framework for scientific interests. Numerous research aspects have been the object of study, including the challenges of the node-position estimation within the network. Localization is an important and challenging task of sensor networks; the aim is to reliably estimate the position of nodes in different application scenarios, such as event detection, classification, object tracking, and home assistance.

Sensor networks can be set up outdoors and indoors; however, often due to the constraints on cost, energy consumption, and accessibility of the environments, the well-established satellite positioning systems cannot be used. In such cases, the identification of technologies and algorithms able to provide the position of the nodes with accuracy compatible with the specific application is fundamental.

In this context, it is our pleasure to announce this Special Issue on "Indoor and Outdoor Sensor Networks for Positioning and Localization". This Special Issue is focused on all aspects related to localization for performance improvement in any application scenario. It includes the proposition of methodologies, development of algorithms and setups, sensor characterization, and data fusion from different technologies. Original contributions on the mentioned topics are welcome.

Prof. Dr. Luigi Ferrigno
Dr. Filippo Milano
Guest Editors

Manuscript Submission Information

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Keywords

  • localization
  • sensor networks
  • positioning systems
  • sensors
  • positioning algorithm
  • tracking
  • navigation
  • sensor fusion

Published Papers (14 papers)

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Research

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18 pages, 8270 KiB  
Article
An Effective GNSS/PDR Fusion Positioning Algorithm on Smartphones for Challenging Scenarios
by Jingkui Zhang, Baoguo Yu, Yuxiang Ge, Jingxiang Gao and Chuanzhen Sheng
Sensors 2024, 24(5), 1452; https://doi.org/10.3390/s24051452 - 23 Feb 2024
Cited by 1 | Viewed by 560
Abstract
The location-based smartphone service brings new development opportunities for seamless indoor/outdoor positioning. However, in complex scenarios such as cities, tunnels, overpasses, forests, etc., using only GNSS on smartphones cannot provide stable and reliable positioning results. Usually, additional sensors are needed to assist GNSS. [...] Read more.
The location-based smartphone service brings new development opportunities for seamless indoor/outdoor positioning. However, in complex scenarios such as cities, tunnels, overpasses, forests, etc., using only GNSS on smartphones cannot provide stable and reliable positioning results. Usually, additional sensors are needed to assist GNSS. This paper investigates the GNSS positioning algorithm assisted by pedestrian dead reckoning (PDR) in complex scenarios. First, we introduce a step detection algorithm based on the peak–valley of acceleration modulus, and the Weinberg model and the Mahony algorithm in PDR are used to estimate step length and heading. On this basis, we evaluated the performance of GNSS/PDR fusion positioning in an open scenario, a semiopen scenario, and a blocked scenario, respectively. Finally, we develop a GNSS/PDR real-time positioning software, called China University of Mining and Technology-POSitioning (CUMT-POS) version 1.0, on the Android 10 platform. By comparing GNSS solutions, PDR solutions, GNSS/PDR solutions, and real-time kinematic (RTK) solutions, we verify the potential auxiliary ability of PDR for GNSS positioning in complex environments, proving that multisource sensor fusion positioning significantly improves reliability and stability. Our research can help the realization of urban informatization and smart cities. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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20 pages, 1936 KiB  
Article
BLE-Based Indoor Localization: Analysis of Some Solutions for Performance Improvement
by Filippo Milano, Helbert da Rocha, Marco Laracca, Luigi Ferrigno, António Espírito Santo, José Salvado and Vincenzo Paciello
Sensors 2024, 24(2), 376; https://doi.org/10.3390/s24020376 - 08 Jan 2024
Cited by 1 | Viewed by 1237
Abstract
This paper addresses indoor localization using an anchor-based system based on Bluetooth Low Energy (BLE) 5.0 technology, adopting the Received Signal Strength Indicator (RSSI) for the distance estimation. Different solutions have been proposed in the scientific literature to improve the performance of this [...] Read more.
This paper addresses indoor localization using an anchor-based system based on Bluetooth Low Energy (BLE) 5.0 technology, adopting the Received Signal Strength Indicator (RSSI) for the distance estimation. Different solutions have been proposed in the scientific literature to improve the performance of this localization technology, but a detailed performance comparison of these solutions is still missing. The aim of this work is to make an experimental analysis combining different solutions for the performance improvement of BLE-based indoor localization, identifying the most effective one. The considered solutions involve different RSSI signals’ conditioning, the use of anchor–tag distance estimation techniques, as well as approaches for estimating the unknown tag position. An experimental campaign was executed in a complex indoor environment, characterized by the continuous presence in the movement of working staff and numerous obstacles. The exploitation of multichannel transmission using RSSI signal aggregation techniques showed the greater performance improvement of the localization system, reducing the positioning error (from 1.5 m to about 1 m). The other examined solutions have shown a lesser impact in the performance improvement with a decrease or an increase in the positioning errors, depending on the considered combination of the adopted solutions. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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24 pages, 3380 KiB  
Article
Reverberation-Robust Self-Calibration and Synchronization of Distributed Microphone Arrays by Mitigating Heteroscedasticity and Outlier Occurrence in TDoA Measurements
by Szymon Woźniak and Konrad Kowalczyk
Sensors 2024, 24(1), 114; https://doi.org/10.3390/s24010114 - 25 Dec 2023
Viewed by 662
Abstract
The network of distributed microphone arrays is usually established in an ad hoc manner; hence, network parameters such as the mutual positioning and rotation of the arrays, positions of sources, and synchronization of their recording onset times are initially unknown. In this article, [...] Read more.
The network of distributed microphone arrays is usually established in an ad hoc manner; hence, network parameters such as the mutual positioning and rotation of the arrays, positions of sources, and synchronization of their recording onset times are initially unknown. In this article, we consider the problem of passively jointly self-calibrating and synchronizing distributed arrays in reverberant rooms. We use a typical two-step approach where, initially, the relative geometry of the network is estimated using Direction of Arrival (DoA) measurements. Subsequently, the absolute scale and synchronization parameters are estimated using Time Difference of Arrival (TDoA) measurements. This article presents methods to improve the robustness and accuracy of estimation of the absolute geometric scaling and synchronization parameters in reverberant conditions, in which TDoA measurements do not follow a normal distribution; furthermore, outliers often occur. To remedy these issues, we propose a Weighted Least Squares (WLS) estimator and schema for weighting the TDoA measurements to increase the estimation accuracy from heteroscedastic TDoA measurements. In addition, we propose an iterative reweighing algorithm with a binary weight to detect and reject TDoA outliers, which exploits the residuals of the parametric model in the least absolute value minimization. A numerical evaluation shows significant improvements in the proposed method over the state of the art in terms of the relative scaling error and mean absolute value of the synchronization parameters. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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26 pages, 1079 KiB  
Article
A Data-Driven Factor Graph Model for Anchor-Based Positioning
by Ana Moragrega and Carles Fernández-Prades
Sensors 2023, 23(12), 5660; https://doi.org/10.3390/s23125660 - 17 Jun 2023
Viewed by 1132
Abstract
This work presents a data-driven factor graph (FG) model designed to perform anchor-based positioning. The system makes use of the FG to compute the target position, given the distance measurements to the anchor node that know its own position.The aim was to design [...] Read more.
This work presents a data-driven factor graph (FG) model designed to perform anchor-based positioning. The system makes use of the FG to compute the target position, given the distance measurements to the anchor node that know its own position.The aim was to design a hybrid structure (that involves data and modeling approaches) to address positioning models from a Bayesian point of view, customizing them for each technology and scenario. The weighted geometric dilution of precision (WGDOP) metric, which measures the effect on the positioning solution of distance error to the corresponding anchor node and network geometry of the anchor nodes, was taken into account. The presented algorithms were tested with simulated data and also with real-life data collected from IEEE 802.15.4-compliant sensor network nodes with a physical layer based on ultra-wide band (UWB) technology, in scenarios with one target node, three and four anchor nodes, and a time-of-arrival-based range technique. The results showed that the presented algorithm based on the FG technique provided better positioning results than the least squares-based algorithms and even UWB-based commercial systems in various scenarios, with different setups in terms of geometries and propagation conditions. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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26 pages, 4764 KiB  
Article
MA-RTI: Design and Evaluation of a Real-World Multipath-Assisted Device-Free Localization System
by Marco Cimdins, Sven Ole Schmidt, Fabian John, Manfred Constapel and Horst Hellbrück
Sensors 2023, 23(4), 2199; https://doi.org/10.3390/s23042199 - 15 Feb 2023
Cited by 5 | Viewed by 1434
Abstract
Device-free localization (DFL) systems exploit changes in the radio frequency channel by measuring, for example, the channel impulse response (CIR), to detect and localize obstacles within a target area. However, due to a lack of well-defined interfaces, missing modularization, as well as complex [...] Read more.
Device-free localization (DFL) systems exploit changes in the radio frequency channel by measuring, for example, the channel impulse response (CIR), to detect and localize obstacles within a target area. However, due to a lack of well-defined interfaces, missing modularization, as well as complex system configuration, it is difficult to deploy DFL systems outside of laboratory setups. This paper focused on the system view and the challenges that come with setting up a DFL system in an indoor environment. We propose MA-RTI, a modular DFL system that is easy to set up, and which utilizes a multipath-assisted (MA) radio-tomographic imaging (RTI) algorithm. To achieve a modular DFL system, we proposed and implemented an architectural model for DFL systems. For minimizing the configuration overhead, we applied a 3D spatial model, that helps in placing the sensors and calculating the required calibration parameters. Therefore, we configured the system solely with idle measurements and a 3D spatial model. We deployed such a DFL system and evaluated it in a real-world office environment with four sensor nodes. The radio technology was ultra-wideband (UWB) and the corresponding signal measurements were CIRs. The DFL system operated with CIRs that provided a sub-nanosecond time-domain resolution. After pre-processing, the update rate was approximately 46 Hz and it provided a localization accuracy of 1.0 m in 50% of all cases and 1.8 m in 80% of all cases. MA fingerprinting approaches lead to higher localization accuracy, but require a labor-intensive training phase. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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16 pages, 2742 KiB  
Article
Magnetic-Field-Based Indoor Positioning Using Temporal Convolutional Networks
by Guanglie Ouyang, Karim Abed-Meraim and Zuokun Ouyang
Sensors 2023, 23(3), 1514; https://doi.org/10.3390/s23031514 - 30 Jan 2023
Cited by 3 | Viewed by 2166
Abstract
Traditional magnetic-field positioning methods collect magnetic-field information from each spatial point to construct a magnetic-field fingerprint database. During the positioning phase, real-time magnetic-field measurements are matched to a magnetic-field map to predict the user’s location. However, this approach requires a significant amount of [...] Read more.
Traditional magnetic-field positioning methods collect magnetic-field information from each spatial point to construct a magnetic-field fingerprint database. During the positioning phase, real-time magnetic-field measurements are matched to a magnetic-field map to predict the user’s location. However, this approach requires a significant amount of time to traverse the entire magnetic-field fingerprint database and does not effectively leverage the magnetic-field sequence’s unique patterns to improve the accuracy and robustness of the positioning system. In recent years, the application of deep learning for the indoor positioning of magnetic fields has grown rapidly, especially by using the magnetic-field sequence as a time series and a trained long short-term memory (LSTM) model to predict the position, directly avoiding the time-consuming matching process. However, the training of LSTM is time-consuming, and the degradation problem occurs as the stack of layers increases. This article proposes a temporal convolutional network (TCN)-based magnetic-field positioning system that extracts magnetic-field sequence features by preprocessing them with coordinate transformation, smoothing filtering, and first-order differencing. The proposed method is seamlessly applicable to heterogeneous smartphones. The trained TCN models are compared with the LSTM and gated recurrent unit (GRU) models, showing the high accuracy and robustness of the proposed algorithm. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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17 pages, 444 KiB  
Article
Majorization-Minimization Method for Elliptic Localization in the Absence of Transmitter Position
by Liehu Wu and Yanbin Zou
Sensors 2023, 23(1), 373; https://doi.org/10.3390/s23010373 - 29 Dec 2022
Cited by 1 | Viewed by 1133
Abstract
This paper investigates the problem of elliptic localization in the absence of transmitter position. An efficient iterative method is developed to jointly evaluate the target and transmitter positions. Using the measurement information from the indirect paths reflected from the target and the direct [...] Read more.
This paper investigates the problem of elliptic localization in the absence of transmitter position. An efficient iterative method is developed to jointly evaluate the target and transmitter positions. Using the measurement information from the indirect paths reflected from the target and the direct paths between the transmitter and receivers, a non-convex maximum likelihood estimation (MLE) problem is formulated. Owing to the non-convex nature of the issue, we apply the majorization–minimization (MM) principle to address the MLE problem, which iteratively minimizes a convex surrogate function instead of the original objective function. Moreover, the proposed MM method is further extended to tackle a general scenario where both multiple unknown transmitters and receiver position errors are considered. Finally, numerical simulations demonstrate that the proposed MM method outperforms the state-of-the-art methods. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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16 pages, 2838 KiB  
Article
An Improved Method Based on Bluetooth Low-Energy Fingerprinting for the Implementation of PEPS System
by Francesco Bonavolontà, Annalisa Liccardo, Rosario Schiano Lo Moriello, Enzo Caputo, Giorgio de Alteriis, Angelo Palladino and Giuseppe Vitolo
Sensors 2022, 22(24), 9615; https://doi.org/10.3390/s22249615 - 08 Dec 2022
Viewed by 1290
Abstract
In the automotive field, the introduction of keyless access systems is revolutionizing car entry techniques currently dominated by a physical key. In this context, this paper investigates the possible use of smartphones to create a PEPS (Passive Entry Passive Start) system using the [...] Read more.
In the automotive field, the introduction of keyless access systems is revolutionizing car entry techniques currently dominated by a physical key. In this context, this paper investigates the possible use of smartphones to create a PEPS (Passive Entry Passive Start) system using the BLE (Bluetooth Low-Energy) Fingerprinting technique that allows, along with a connection to a low-cost BLE micro-controllers network, determining the driver’s position, either inside or outside the vehicle. Several issues have been taken into account to assure the reliability of the proposal; in particular, (i) spatial orientation of each microcontroller-based BLE node which ensures the best performance at 180° and 90° referred to as the BLE scanner and the advertiser, respectively; (ii) data filtering techniques based on Kalman Filter; and (iii) definition of new network topology, resulting from the merger of two standard network topologies. Particular attention has been paid to the selection of the appropriate measurement method capable of assuring the most reliable positioning results by means of the adoption of only six embedded BLE devices. This way, the global accuracy of the system reaches 98.5%, while minimum and maximum accuracy values relative to the individual zones equal, respectively, to 97.3% and 99.4% have been observed, thus confirming the capability of the proposed method of recognizing whether the driver is inside or outside the vehicle. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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17 pages, 1401 KiB  
Article
Mobile Location in Wireless Sensor Networks Based on Multi Spot Measurements Model
by Chao Zheng, Wei Hu, Jiyan Huang, Pengfei Wang, Yufei Liu and Chenyu Yang
Sensors 2022, 22(23), 9559; https://doi.org/10.3390/s22239559 - 06 Dec 2022
Cited by 1 | Viewed by 1370
Abstract
The localization of sensors in wireless sensor networks has recently gained considerable attention. The existing location methods are based on a one-spot measurement model. It is difficult to further improve the positioning accuracy of existing location methods based on single-spot measurements. This paper [...] Read more.
The localization of sensors in wireless sensor networks has recently gained considerable attention. The existing location methods are based on a one-spot measurement model. It is difficult to further improve the positioning accuracy of existing location methods based on single-spot measurements. This paper proposes two location methods based on multi-spot measurements to reduce location errors. Because the multi-spot measurements model has more measurement equations than the single-spot measurements model, the proposed methods provide better performance than the traditional location methods using one-spot measurement in terms of the root mean square error (RMSE) and Cramer–Rao lower bound (CRLB). Both closed-form and iterative algorithms are proposed in this paper. The former performs suboptimally with less computational burden, whereas the latter has the highest positioning accuracy in attaining the CRLB. Moreover, a novel CRLB for the proposed multi-spot measurements model is also derived in this paper. A theoretical proof shows that the traditional CRLB in the case of single-spot measurements performs worse than the proposed CRLB in the case of multi-spot measurements. The simulation results show that the proposed methods have a lower RMSE than the traditional location methods. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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16 pages, 3778 KiB  
Article
Multi-Target PIR Indoor Localization and Tracking System with Artificial Intelligence
by Xuan-Ying Chen, Chih-Yu Wen and William A. Sethares
Sensors 2022, 22(23), 9450; https://doi.org/10.3390/s22239450 - 02 Dec 2022
Cited by 5 | Viewed by 2006
Abstract
Pyroelectric infrared (PIR) sensors are low-cost, low-power, and highly reliable sensors that have been widely used in smart environments. Indoor localization systems may be wearable or non-wearable, where the latter are also known as device-free localization systems. Since binary PIR sensors detect only [...] Read more.
Pyroelectric infrared (PIR) sensors are low-cost, low-power, and highly reliable sensors that have been widely used in smart environments. Indoor localization systems may be wearable or non-wearable, where the latter are also known as device-free localization systems. Since binary PIR sensors detect only the presence of a subject’s motion in their field of view (FOV) without other information about the actual location, information from overlapping FOVs of multiple sensors can be useful for localization. This study introduces the PIRILS (pyroelectric infrared indoor localization system), in which the sensing signal processing algorithms are augmented by deep learning algorithms that are designed based on the operational characteristics of the PIR sensor. Expanding to the detection of multiple targets, the PIRILS develops a quantized scheme that exploits the behavior of an artificial neural network (ANN) model to demonstrate localization performance in tracking multiple targets. To further improve the localization performance, the PIRILS incorporates a data augmentation strategy that enhances the training data diversity of the target’s motion. Experimental results indicate system stability, improved positioning accuracy, and expanded applicability, thus providing an improved indoor multi-target localization framework. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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19 pages, 8085 KiB  
Article
Human-to-Human Position Estimation System Using RSSI in Outdoor Environment
by Takashi Yamamoto and Tomoyuki Yamaguchi
Sensors 2022, 22(19), 7621; https://doi.org/10.3390/s22197621 - 08 Oct 2022
Viewed by 1249
Abstract
Methods to prevent collisions between people to avoid traffic accidents are receiving significant attention. To measure the position in the non-line-of-sight (NLOS) area, which cannot be directly visually recognized, position-measuring methods use wireless-communication-type GPS and propagation characteristics of radio signals, such as received [...] Read more.
Methods to prevent collisions between people to avoid traffic accidents are receiving significant attention. To measure the position in the non-line-of-sight (NLOS) area, which cannot be directly visually recognized, position-measuring methods use wireless-communication-type GPS and propagation characteristics of radio signals, such as received signal strength indication (RSSI). However, conventional position estimation methods using RSSI require multiple receivers, which decreases the position estimation accuracy, owing to the presence of surrounding buildings. This study proposes a system to solve this challenge using a receiver and position estimation method based on RSSI MAP simulation and particle filter. Moreover, this study utilizes BLE peripheral/central functions capable of advertising as the transmitter/receiver. By using the advertising radio waves, our method provides a framework for estimating the position of unspecified transmitters. The effectiveness of the proposed system is evaluated in this study through simulations and experiments in actual environments. We obtained an error average of the distance to be 1.6 m from the simulations, which shows the precision of the proposed method. In the actual environment, the proposed method showed an error average of the distance to be 3.3 m. Furthermore, we evaluated the accuracy of the proposed method when both the transmitter and receiver are in motion, which can be considered as a moving person in the outdoor NLOS area. The result shows an error of 4.5 m. Consequently, we concluded that the accuracy was comparable when the transmitter is stationary and when it is moving. Compared with conventional path loss, the model can measure distances of 3 m to 10 m, whereas the proposed method can estimate the “position” with the same accuracy in an outdoor environment. In addition, it can be expected to be used as a collision avoidance system that confirms the presence of strangers in the NLOS area. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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13 pages, 294 KiB  
Article
Fixed Point Iteration Based Algorithm for Asynchronous TOA-Based Source Localization
by Yanbin Zou, Jingna Fan, Liehu Wu and Huaping Liu
Sensors 2022, 22(18), 6871; https://doi.org/10.3390/s22186871 - 11 Sep 2022
Cited by 8 | Viewed by 1283
Abstract
This paper investigates the problem of source localization using signal time-of-arrival (TOA) measurements in the presence of unknown start transmission time. Most state-of-art methods are based on convex relaxation technologies, which possess global solution for the relaxed optimization problem. However, computational complexity of [...] Read more.
This paper investigates the problem of source localization using signal time-of-arrival (TOA) measurements in the presence of unknown start transmission time. Most state-of-art methods are based on convex relaxation technologies, which possess global solution for the relaxed optimization problem. However, computational complexity of the convex optimization–based algorithm is usually large, and need CVX toolbox to solve it. Although the two stage weighted least squares (2SWLS) algorithm has very low computational complexity, its estimate performance is susceptible to sensor geometry and threshold phenomenon. A new algorithm that is directly derived from maximum likelihood estimator (MLE) is developed. The newly proposed algorithm is named as fixed point iteration (FPI); it only involves simple calculations, such as addition, multiplication, division, and square-root. Unlike state-of-the-art methods, there is no matrix inversion operation and can avoid the unstable performance incurred by singular matrix. The FPI algorithm can be easily extended to the scenario with sensor position errors. Finally, simulation results demonstrate that the proposed algorithm reaches a good balance between computational complexity and localization accuracy. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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24 pages, 4703 KiB  
Article
Exploiting Ultra-Wideband Channel Impulse Responses for Device-Free Localization
by Marco Cimdins, Sven Ole Schmidt, Peter Bartmann and Horst Hellbrück
Sensors 2022, 22(16), 6255; https://doi.org/10.3390/s22166255 - 20 Aug 2022
Cited by 7 | Viewed by 2253
Abstract
In radio-frequency (RF)-based device-free localization (DFL), the number of sensors acting as RF transmitters and receivers is crucial for accuracy and system costs. Two promising approaches for DFL have been identified in the past: radio tomographic imaging (RTI) and multi-static radar (MSR). RTI [...] Read more.
In radio-frequency (RF)-based device-free localization (DFL), the number of sensors acting as RF transmitters and receivers is crucial for accuracy and system costs. Two promising approaches for DFL have been identified in the past: radio tomographic imaging (RTI) and multi-static radar (MSR). RTI in its basic version requires many sensors for high accuracy, which increases the cost. In this paper, we show how RTI benefits from multipath propagation. By evaluating the direct and echo paths, we increase the coverage of the target area, and by utilizing UWB signals, the RTI system is less susceptible to multipath propagation. MSR maps reflections that occur within the target area to reflectors such as persons or other objects. MSR does not require that the person is located near a signal path. Both suggested methods exploit ultra-wideband (UWB) channel impulse response (CIR) measurements. CIR measurements and the modeling of multipath effects either increase the accuracy or reduce the required number of sensors for localization with RTI. We created a test setup and measure UWB CIRs at different positions with a commercially available off-the-shelf UWB radio chip, the Decawave DW1000. We compare the localization results of RTI, multipath-assisted (MA)-RTI, and MSR and investigate a combined approach. We show that RTI is improved by the analysis of multipath propagation; furthermore, MA-RTI results in a better performance compared to MSR: with 50% of all cases, the localization error is better than 0.82 m and in 80% of all cases 1.34 m. The combined approach results in the best localization result with 0.64 m in 50% of all cases. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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Review

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25 pages, 3328 KiB  
Review
A Survey of Sound Source Localization and Detection Methods and Their Applications
by Gabriel Jekateryńczuk and Zbigniew Piotrowski
Sensors 2024, 24(1), 68; https://doi.org/10.3390/s24010068 - 22 Dec 2023
Viewed by 2275
Abstract
This study is a survey of sound source localization and detection methods. The study provides a detailed classification of the methods used in the fields of science mentioned above. It classifies sound source localization systems based on criteria found in the literature. Moreover, [...] Read more.
This study is a survey of sound source localization and detection methods. The study provides a detailed classification of the methods used in the fields of science mentioned above. It classifies sound source localization systems based on criteria found in the literature. Moreover, an analysis of classic methods based on the propagation model and methods based on machine learning and deep learning techniques has been carried out. Attention has been paid to providing the most detailed information on the possibility of using physical phenomena, mathematical relationships, and artificial intelligence to determine sound source localization. Additionally, the article underscores the significance of these methods within both military and civil contexts. The study culminates with a discussion of forthcoming trends in the realms of acoustic detection and localization. The primary objective of this research is to serve as a valuable resource for selecting the most suitable approach within this domain. Full article
(This article belongs to the Special Issue Indoor and Outdoor Sensor Networks for Positioning and Localization)
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