Pub Date : 2026-01-28DOI: 10.1109/LSENS.2026.3658427
Gang Zhao;Liwen Chen;Liangpeng Gao;Xiaochun Cheng
To address the challenges of degraded positioning accuracy, drift, or complete failure in environments where satellite signals are obstructed (e.g., basements, tunnels, canyons, forests, mountainous regions, and urban high-rise buildings), this letter proposes a navigation and positioning algorithm for complex terrains by integrating pseudolites with time difference of arrival and trilateration techniques. First, to enhance the antiinterference capability and positioning accuracy of low-cost satellite receivers in conventional integrated navigation systems, we improve robustness and precision through the fusion of global navigation satellite system (GNSS) and inertial measurement unit (IMU) data. At the front-end processing stage, the algorithm calculates the relative positions and time differences between multiple pseudolites and receivers while integrating absolute position data derived from trilateration for state estimation, thereby providing accurate initial pose initialization for the back-end module. Subsequently, the back end employs an extended Kalman filter to fuse data from wheel odometry, GNSS, and IMU, optimizing the algorithm's accuracy and global consistency. Finally, the proposed algorithm is validated in high-dynamic motion scenarios and a comprehensive campus environment. Experimental results demonstrate that, compared to mainstream GNSS/IMU fusion methods and LiDAR-based simultaneous localization and mapping algorithms, the proposed algorithm achieves superior positioning accuracy (with a root-mean-square error reduction of 58%–72% in occluded scenarios) and exhibits enhanced robustness in aggressive motion conditions.
{"title":"A Pseudolite-Aided Navigation and Positioning Method for Complex Terrain Environments","authors":"Gang Zhao;Liwen Chen;Liangpeng Gao;Xiaochun Cheng","doi":"10.1109/LSENS.2026.3658427","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3658427","url":null,"abstract":"To address the challenges of degraded positioning accuracy, drift, or complete failure in environments where satellite signals are obstructed (e.g., basements, tunnels, canyons, forests, mountainous regions, and urban high-rise buildings), this letter proposes a navigation and positioning algorithm for complex terrains by integrating pseudolites with time difference of arrival and trilateration techniques. First, to enhance the antiinterference capability and positioning accuracy of low-cost satellite receivers in conventional integrated navigation systems, we improve robustness and precision through the fusion of global navigation satellite system (GNSS) and inertial measurement unit (IMU) data. At the front-end processing stage, the algorithm calculates the relative positions and time differences between multiple pseudolites and receivers while integrating absolute position data derived from trilateration for state estimation, thereby providing accurate initial pose initialization for the back-end module. Subsequently, the back end employs an extended Kalman filter to fuse data from wheel odometry, GNSS, and IMU, optimizing the algorithm's accuracy and global consistency. Finally, the proposed algorithm is validated in high-dynamic motion scenarios and a comprehensive campus environment. Experimental results demonstrate that, compared to mainstream GNSS/IMU fusion methods and LiDAR-based simultaneous localization and mapping algorithms, the proposed algorithm achieves superior positioning accuracy (with a root-mean-square error reduction of 58%–72% in occluded scenarios) and exhibits enhanced robustness in aggressive motion conditions.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 3","pages":"1-4"},"PeriodicalIF":2.2,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15DOI: 10.1109/LSENS.2026.3654361
R. C. Ajay Krishna;Banibrata Mukherjee
In this work, a robust and improved loosely coupled (LC) Global Navigation Satellite System (GNSS)- Inertial Navigation System (INS) integration scheme incorporating three important features, such as dynamic inertial measurement unit (IMU) calibration, Mahalanobis distance-based outlier rejection (MDOR) mechanism, and innovation-based adaptive estimation (IAE) technique, is presented for reliable and accurate navigation. Unscented Kalman filter (UKF)-based dynamic calibration of IMU is adapted here because it accurately transmits statistical distributions without linearization, which is better at managing nonlinear INS dynamics than the extended Kalman filter. Further, MDOR mechanism is proposed to identify and exclude erroneous GNSS measurements before the filter update, whereas, IAE technique is proposed to dynamically tune the filter’s noise covariance. A hardware setup is developed using a GNSS receiver, IMU sensor, and microcontroller to capture data for real vehicular trajectories. The proposed framework has been implemented in MATLAB and further experimentally demonstrated with real trajectory data. The navigation accuracy of the proposed method exhibits upto 75% improvement with respect to conventional LC integration. The contribution lies on careful integration and validation of dual-layer architecture with interlayer feedback mechanism and nested-architecture for known UKF-based IMU calibration. The proposed framework can provide a precise navigation solution to improve resilience even in partial GNSS challenging areas.
{"title":"Novel GNSS-INS Integration Scheme With UKF-Based Dynamic IMU Calibration and Dual-layer Design for Reliable Navigation","authors":"R. C. Ajay Krishna;Banibrata Mukherjee","doi":"10.1109/LSENS.2026.3654361","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3654361","url":null,"abstract":"In this work, a robust and improved loosely coupled (LC) Global Navigation Satellite System (GNSS)- Inertial Navigation System (INS) integration scheme incorporating three important features, such as dynamic inertial measurement unit (IMU) calibration, Mahalanobis distance-based outlier rejection (MDOR) mechanism, and innovation-based adaptive estimation (IAE) technique, is presented for reliable and accurate navigation. Unscented Kalman filter (UKF)-based dynamic calibration of IMU is adapted here because it accurately transmits statistical distributions without linearization, which is better at managing nonlinear INS dynamics than the extended Kalman filter. Further, MDOR mechanism is proposed to identify and exclude erroneous GNSS measurements before the filter update, whereas, IAE technique is proposed to dynamically tune the filter’s noise covariance. A hardware setup is developed using a GNSS receiver, IMU sensor, and microcontroller to capture data for real vehicular trajectories. The proposed framework has been implemented in MATLAB and further experimentally demonstrated with real trajectory data. The navigation accuracy of the proposed method exhibits upto 75% improvement with respect to conventional LC integration. The contribution lies on careful integration and validation of dual-layer architecture with interlayer feedback mechanism and nested-architecture for known UKF-based IMU calibration. The proposed framework can provide a precise navigation solution to improve resilience even in partial GNSS challenging areas.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 2","pages":"1-4"},"PeriodicalIF":2.2,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-15DOI: 10.1109/LSENS.2026.3654225
Da Xu;Zhenghao Lu;Zheng Shi;Xiaopeng Yu
A CMOS temperature sensor targeting automotive and industrial applications is presented. The sensor integrates a BJT-based sensing frontend with a second-order $Sigma Delta$ ADC. To address the accumulation of common-mode error in the integrator under low supply voltages, which can lead to large input common-mode deviations that reduce the integrator amplifier gain and degrade the ADC SNR, a novel sampling scheme is proposed. By means of a carefully designed sampling sequence, the proposed scheme maintains the amplifier input common-mode voltage within a small and predictable range, thereby stabilizing the amplifier gain and preventing SNR degradation. In addition, the sampling scheme reduces the number of ADC input branches, which effectively minimizes leakage current. To further enhance the measurement accuracy, a finite BJT current-gain compensation resistor and a bitstream-controlled dynamic element matching (BSC-DEM) technique are employed in the sensing frontend. Fabricated in a 180 nm CMOS process, the prototype achieves an inaccuracy of $pm$1.0 °C (3$sigma$) from −50 °C to 150 °C. The sensor consumes 6.3 μA from a 1.8 V supply at room temperature, achieves a resolution of 0.018 °C, and occupies an active area of 0.1 mm$^{2}$.
{"title":"A Low-Power BJT-Based CMOS Temperature Sensor Using a Common-Mode Error Suppression Sampling Scheme From −50 °C to 150 °C","authors":"Da Xu;Zhenghao Lu;Zheng Shi;Xiaopeng Yu","doi":"10.1109/LSENS.2026.3654225","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3654225","url":null,"abstract":"A CMOS temperature sensor targeting automotive and industrial applications is presented. The sensor integrates a BJT-based sensing frontend with a second-order <inline-formula><tex-math>$Sigma Delta$</tex-math></inline-formula> ADC. To address the accumulation of common-mode error in the integrator under low supply voltages, which can lead to large input common-mode deviations that reduce the integrator amplifier gain and degrade the ADC SNR, a novel sampling scheme is proposed. By means of a carefully designed sampling sequence, the proposed scheme maintains the amplifier input common-mode voltage within a small and predictable range, thereby stabilizing the amplifier gain and preventing SNR degradation. In addition, the sampling scheme reduces the number of ADC input branches, which effectively minimizes leakage current. To further enhance the measurement accuracy, a finite BJT current-gain compensation resistor and a bitstream-controlled dynamic element matching (BSC-DEM) technique are employed in the sensing frontend. Fabricated in a 180 nm CMOS process, the prototype achieves an inaccuracy of <inline-formula><tex-math>$pm$</tex-math></inline-formula>1.0 °C (3<inline-formula><tex-math>$sigma$</tex-math></inline-formula>) from −50 °C to 150 °C. The sensor consumes 6.3 μA from a 1.8 V supply at room temperature, achieves a resolution of 0.018 °C, and occupies an active area of 0.1 mm<inline-formula><tex-math>$^{2}$</tex-math></inline-formula>.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 2","pages":"1-4"},"PeriodicalIF":2.2,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rise of electronic waste worldwide over the years has given birth to a new field of research of sustainable, biodegradable, green electronics, which generate minimal waste with less carbon emission. A sustainable platform for continuous sensor monitoring in wearable electronics requires a sustainable, clean, safe, and flexible energy storage solution. Research on paper electronics has seen a major flourishing in recent years, where the need of the hour is to find a sustainable energy storage solution. Recently discovered, MXene electrodes typically use H2SO4-based electrolytes, which are quite toxic and harmful. In this work, as an alternative, a novel Nafion-based gel electrolyte has been developed, operating within the same potential window as H2SO4 (0.6 V). This screen-printed, biocompatible microsupercapacitor (MSC) on paper substrates has an outstanding capacitance of 121 mF cm−2 at a voltage scan rate of 1 mV s−1, with only a single pass of screen printing. This strategy provides stable, inexpensive, environment-friendly, scalable, and flexible on-chip MSCs, paving the way for a next-generation energy storage platform for wearable electronics.
{"title":"Toward Green Electronics: Screen-Printed MXene-Based Microsupercapacitors on Paper Substrate with Nafion-Based Gel Electrolyte","authors":"Sushree Sangita Priyadarsini;Aditi Ghosh;Subho Dasgupta","doi":"10.1109/LSENS.2026.3652104","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3652104","url":null,"abstract":"The rise of electronic waste worldwide over the years has given birth to a new field of research of sustainable, biodegradable, green electronics, which generate minimal waste with less carbon emission. A sustainable platform for continuous sensor monitoring in wearable electronics requires a sustainable, clean, safe, and flexible energy storage solution. Research on paper electronics has seen a major flourishing in recent years, where the need of the hour is to find a sustainable energy storage solution. Recently discovered, MXene electrodes typically use H<sub>2</sub>SO<sub>4</sub>-based electrolytes, which are quite toxic and harmful. In this work, as an alternative, a novel Nafion-based gel electrolyte has been developed, operating within the same potential window as H<sub>2</sub>SO<sub>4</sub> (0.6 V). This screen-printed, biocompatible microsupercapacitor (MSC) on paper substrates has an outstanding capacitance of 121 mF cm<sup>−2</sup> at a voltage scan rate of 1 mV s<sup>−1</sup>, with only a single pass of screen printing. This strategy provides stable, inexpensive, environment-friendly, scalable, and flexible on-chip MSCs, paving the way for a next-generation energy storage platform for wearable electronics.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 3","pages":"1-4"},"PeriodicalIF":2.2,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1109/LSENS.2026.3652667
Apinan Aurasopon;J. Jittakort;Sanya Kuankid
This letter presents a simple and accurate interface circuit for three-wire resistive sensors based on a noninverting amplifier and a two-phase ratiometric measurement technique. The circuit is excited by a single positive reference voltage, while an analog switch alternates two current paths to produce distinct steady-state output levels corresponding to different lead-wire configurations. Digital averaging of these steady-state output levels enables effective compensation of lead-wire resistance, op-amp offset, and switch on-resistance effects, with averaging performed digitally after direct ADC sampling. Experimental results demonstrate excellent linearity over the 490–3026 Ω range, corresponding to approximately −130 °C to 525 °C for a Pt1000 sensor, with a maximum relative error of 0.22% and nonlinearity below 0.16% FSS. These results confirm the circuit’s accuracy, simplicity, and suitability for compact, low-power resistive sensor instrumentation.
{"title":"A Simple Noninverting Amplifier for Three-Wire Resistive Sensors Using a Single-Supply Ratiometric Measurement","authors":"Apinan Aurasopon;J. Jittakort;Sanya Kuankid","doi":"10.1109/LSENS.2026.3652667","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3652667","url":null,"abstract":"This letter presents a simple and accurate interface circuit for three-wire resistive sensors based on a noninverting amplifier and a two-phase ratiometric measurement technique. The circuit is excited by a single positive reference voltage, while an analog switch alternates two current paths to produce distinct steady-state output levels corresponding to different lead-wire configurations. Digital averaging of these steady-state output levels enables effective compensation of lead-wire resistance, op-amp offset, and switch <sc>on</small>-resistance effects, with averaging performed digitally after direct ADC sampling. Experimental results demonstrate excellent linearity over the 490–3026 Ω range, corresponding to approximately −130 °C to 525 °C for a Pt1000 sensor, with a maximum relative error of 0.22% and nonlinearity below 0.16% FSS. These results confirm the circuit’s accuracy, simplicity, and suitability for compact, low-power resistive sensor instrumentation.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 2","pages":"1-4"},"PeriodicalIF":2.2,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1109/LSENS.2026.3651304
Ruijie Liu;Zhiqi Ming;Engang Tian;Hongtian Chen
This letter focuses on the fault detection (FD) problems for a class of nonlinear dynamic systems, particularly in scenarios where conventional methods are prone to failure. Specifically, when a Takagi–Sugeno (T-S) fuzzy model is utilized for system approximation, the residual signal generated exhibits complex nonzero dynamics even under healthy operating conditions, which leads to poor FD performance of traditional residual-based methods. To address this problem, this letter proposes an integrated method that combines a T-S fuzzy soft-sensor with an autoencoder. The method first utilizes the fuzzy soft-sensor to generate residuals, and then the autoencoder is employed to learn the residual patterns under normal operation states. Ultimately, the FD is achieved by monitoring the reconstruction error of the autoencoder, which is quantified as the squared prediction error statistic. The final case study on a ship propulsion system validates the feasibility and superiority of the proposed FD method in detecting both actuator and sensor faults.
{"title":"Integrated Fault Detection Using Fuzzy Soft-Sensor and Autoencoder Techniques for Nonlinear Dynamic Systems","authors":"Ruijie Liu;Zhiqi Ming;Engang Tian;Hongtian Chen","doi":"10.1109/LSENS.2026.3651304","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3651304","url":null,"abstract":"This letter focuses on the fault detection (FD) problems for a class of nonlinear dynamic systems, particularly in scenarios where conventional methods are prone to failure. Specifically, when a Takagi–Sugeno (T-S) fuzzy model is utilized for system approximation, the residual signal generated exhibits complex nonzero dynamics even under healthy operating conditions, which leads to poor FD performance of traditional residual-based methods. To address this problem, this letter proposes an integrated method that combines a T-S fuzzy soft-sensor with an autoencoder. The method first utilizes the fuzzy soft-sensor to generate residuals, and then the autoencoder is employed to learn the residual patterns under normal operation states. Ultimately, the FD is achieved by monitoring the reconstruction error of the autoencoder, which is quantified as the squared prediction error statistic. The final case study on a ship propulsion system validates the feasibility and superiority of the proposed FD method in detecting both actuator and sensor faults.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 3","pages":"1-4"},"PeriodicalIF":2.2,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1109/LSENS.2026.3651328
Ahsan Ali;Subha Dharmapalan Puthankattil
Alzheimer’s disease (AD) is a degenerative disorder of the brain that affects elderly individuals, leading to cognitive decline and memory loss. Mild cognitive impairment (MCI) is a transition stage between normal cognition (NC) and AD. Early detection of MCI is crucial since it allows for timely intervention to delay AD progression. The onset of AD is associated with tissue alterations in the fornix, a white matter region of the brain responsible for cognition, learning, memory consolidation, and attention. In this study, fornix morphometrics in MCI and AD are characterized using structural magnetic resonance (sMR) brain images and pseudo-Zernike moment (PZM) features. For this study, a publicly available database is used. Initially, a standard pipeline is used to preprocess the sMR brain images, followed by segmentation of the fornix structure using the level set without reinitialization (LSWR) algorithm. Subsequently, 64 PZMs are computed from the fornix region. Statistical tests, such as the Kolmogorov–Smirnov test, student’s t-test, Wilcoxon–Mann–Whitney test, and one-way analysis of variance are employed to identify significant features, and machine learning algorithms also performed for binary classification. The outcomes revealed that the LSWR algorithm segmented the fornix structure at an accuracy of 99%. The PZM features exhibited statistical significance (p < 0.05) in distinguishing MCI and AD, emphasizing their effectiveness in capturing fornix shape variations. The proposed approach employed in this study emphasizes the clinical relevance in differentiating MCI from NC and AD subjects.
{"title":"Evaluation of Shape Variations in Structural MR Images of Fornix in Normal, MCI, and AD Subjects Using Pseudo-Zernike Moments","authors":"Ahsan Ali;Subha Dharmapalan Puthankattil","doi":"10.1109/LSENS.2026.3651328","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3651328","url":null,"abstract":"Alzheimer’s disease (AD) is a degenerative disorder of the brain that affects elderly individuals, leading to cognitive decline and memory loss. Mild cognitive impairment (MCI) is a transition stage between normal cognition (NC) and AD. Early detection of MCI is crucial since it allows for timely intervention to delay AD progression. The onset of AD is associated with tissue alterations in the fornix, a white matter region of the brain responsible for cognition, learning, memory consolidation, and attention. In this study, fornix morphometrics in MCI and AD are characterized using structural magnetic resonance (sMR) brain images and pseudo-Zernike moment (PZM) features. For this study, a publicly available database is used. Initially, a standard pipeline is used to preprocess the sMR brain images, followed by segmentation of the fornix structure using the level set without reinitialization (LSWR) algorithm. Subsequently, 64 PZMs are computed from the fornix region. Statistical tests, such as the Kolmogorov–Smirnov test, student’s t-test, Wilcoxon–Mann–Whitney test, and one-way analysis of variance are employed to identify significant features, and machine learning algorithms also performed for binary classification. The outcomes revealed that the LSWR algorithm segmented the fornix structure at an accuracy of 99%. The PZM features exhibited statistical significance (<italic>p</i> < 0.05) in distinguishing MCI and AD, emphasizing their effectiveness in capturing fornix shape variations. The proposed approach employed in this study emphasizes the clinical relevance in differentiating MCI from NC and AD subjects.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 2","pages":"1-4"},"PeriodicalIF":2.2,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Despite its critical role in assessing physiological strain and mitigating heat- and smoke-related risks, real-time respiratory monitoring is still largely absent in wildland firefighting. This study evaluates two wearable systems for estimating respiratory rate (RR) under operational field conditions (i.e., a multistage fire suppression protocol): a face-mounted system based on a thermistor integrated into a FFP3 facemask (Mask) and a chest-worn commercial strap (Bioharness, BH) with an integrated strain sensor. RR was estimated from raw signals using frequency–domain analysis considering both 25 s and 50 s windows lengths. Pairwise comparisons were performed between RR values estimated from Mask and BH, and, respectively, between each of them and the manufacturer–generated “Summary RR” provided by the BH's onboard processor. Results underscore the influence of signal processing over sensor placement and demonstrate the feasibility of unobtrusive RR tracking using both wearable systems in dynamic, high-risk environments.
{"title":"Respiratory Rate Monitoring During Wildland Firefighting Operations: A Comparison of Face-Mounted and Chest-Mounted Wearable Sensors","authors":"Mariangela Pinnelli;Chiara Romano;Stefano Marsella;Fabio Tossut;Roberto Setola;Emiliano Schena;Carlo Massaroni","doi":"10.1109/LSENS.2026.3652005","DOIUrl":"https://doi.org/10.1109/LSENS.2026.3652005","url":null,"abstract":"Despite its critical role in assessing physiological strain and mitigating heat- and smoke-related risks, real-time respiratory monitoring is still largely absent in wildland firefighting. This study evaluates two wearable systems for estimating respiratory rate (RR) under operational field conditions (i.e., a multistage fire suppression protocol): a face-mounted system based on a thermistor integrated into a FFP3 facemask (Mask) and a chest-worn commercial strap (Bioharness, BH) with an integrated strain sensor. RR was estimated from raw signals using frequency–domain analysis considering both 25 s and 50 s windows lengths. Pairwise comparisons were performed between RR values estimated from Mask and BH, and, respectively, between each of them and the manufacturer–generated “Summary RR” provided by the BH's onboard processor. Results underscore the influence of signal processing over sensor placement and demonstrate the feasibility of unobtrusive RR tracking using both wearable systems in dynamic, high-risk environments.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 3","pages":"1-4"},"PeriodicalIF":2.2,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1109/LSENS.2025.3647719
Soham Karak;Subha Mandal;Anumoy Ghosh;Gobinda Sen
This work presents the design and execution of a triangular inexpensive microwave sensor for multiband sensing applications. The suggested sensor makes use of a triangular shape split ring resonator as radiating patch, which gives a high Q-factor. The design with footprint of 0.08 λL x 0.3λL size makes it very small and hence useful for portable applications. The sensor's substrate is chosen as a low-loss Arlon material with a dielectric constant of 2.5 and a loss tangent of 0.0013. In order to characterize various oil samples, toluene, and ethanol, the sensor provides a strong sensing characteristic at the ISM bands with a high Q value of 43.24. The highest sensitivity of 10.62% is obtained with the proposed sensor by submerging it within the sample material, hence making it very convenient for real-time monitoring in industrial, agricultural, and health care applications due to its affordability and small size, especially when it comes to guaranteeing food safety. The efficiency of the sensors is confirmed by experimental results, which also show that they have the potential to be widely used in a variety of sensing applications.
这项工作提出了一种用于多波段传感应用的三角形廉价微波传感器的设计和执行。该传感器采用三角形分环谐振器作为辐射贴片，具有较高的q系数。占地0.08 λL x 0.3λL尺寸的设计使其非常小，因此适用于便携式应用。传感器的衬底选用介电常数为2.5、损耗正切为0.0013的低损耗Arlon材料。为了表征各种油样、甲苯和乙醇，该传感器在ISM波段具有很强的传感特性，Q值高达43.24。通过将该传感器浸入样品材料中，可以获得10.62%的最高灵敏度，因此由于其价格合理且体积小，因此非常方便在工业，农业和医疗保健应用中进行实时监测，特别是在保证食品安全方面。实验结果证实了传感器的效率，也表明它们具有广泛应用于各种传感应用的潜力。
{"title":"A Compact Dual-Band Antenna Sensor for Multiband Sensing Application","authors":"Soham Karak;Subha Mandal;Anumoy Ghosh;Gobinda Sen","doi":"10.1109/LSENS.2025.3647719","DOIUrl":"https://doi.org/10.1109/LSENS.2025.3647719","url":null,"abstract":"This work presents the design and execution of a triangular inexpensive microwave sensor for multiband sensing applications. The suggested sensor makes use of a triangular shape split ring resonator as radiating patch, which gives a high <italic>Q</i>-factor. The design with footprint of 0.08 λ<italic><sub>L</sub></i> x 0.3λ<italic><sub>L</sub></i> size makes it very small and hence useful for portable applications. The sensor's substrate is chosen as a low-loss Arlon material with a dielectric constant of 2.5 and a loss tangent of 0.0013. In order to characterize various oil samples, toluene, and ethanol, the sensor provides a strong sensing characteristic at the ISM bands with a high <italic>Q</i> value of 43.24. The highest sensitivity of 10.62% is obtained with the proposed sensor by submerging it within the sample material, hence making it very convenient for real-time monitoring in industrial, agricultural, and health care applications due to its affordability and small size, especially when it comes to guaranteeing food safety. The efficiency of the sensors is confirmed by experimental results, which also show that they have the potential to be widely used in a variety of sensing applications.","PeriodicalId":13014,"journal":{"name":"IEEE Sensors Letters","volume":"10 3","pages":"1-4"},"PeriodicalIF":2.2,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1109/LSENS.2026.3652134
Koustuvmoni Bharadwaj;Krishna Bharadwaj;Kalyan Kumar Das
Soil moisture value is critical to the global hydrological cycle and impacts agriculture, environmental science, urban planning, forestry, and more. Traditional methods of measuring soil moisture, though well established, are time consuming, labor intensive, requires installation and maintenance of equipment, expensive and gives low resolution outputs. This calls for the requirement of a soil moisture calculation method which is instantaneous, portable, economic and efficient. Spectroscopy has emerged as a promising solution since it can deliver valuable insights into the composition, structure, and properties of materials across diverse fields. In this study, a spectroscopic sensor was employed to analyze soil samples, and its readings were compared with soil moisture values determined through the conventional gravimetric method. By applying different regression approaches, a relationship between the sensor output and soil moisture was established, aiming to minimize errors, such as mean absolute error (MAE), mean bias error (MBE), and root mean square error (RMSE). The findings revealed that a third-order polynomial regression equation at 705 nm wavelength provided the most accurate results, with error values of MAE, MBE, and RMSE being 0.38, 0.06, and 0.5, respectively. This outcome demonstrates that combining the spectroscopic sensor with the derived equation can offer an instantaneous, noncontact method for soil moisture estimation. Compared to the lengthy and labor-intensive gravimetric process, this approach provides a rapid and practical solution for soil moisture assessment in various applications.
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