1,721,096 research outputs found
UAV-based 3D localization of passive UHF-RFID tags empowering outdoor stock management
No full textThe management of stocks in outdoor warehouses and shipyards is not a trivial task, and UHF-RFID technology represents an attractive candidate to face it. This paper presents the application of a fast 3D Synthetic Aperture Radar (SAR) method sped up through Particle Swarm optimization (PSO) for localizing goods tagged with passive UHF-RFID tags by exploiting a remotely piloted Unmanned Aerial Vehicle (UAV). The UAV carries reader and antenna and can freely move in the three directions of the space, by forming synthetic arrays with a large aperture length along the three spatial directions. The UAV trajectory is measured through a differential GPS system. Performance is validated through an experimental analysis which demonstrates the feasibility of the proposed system
A Survey on Indoor Vehicle Localization through RFID Technology
No full textThis paper presents a state-of-the-art analysis on the methods suitable for vehicle indoor localization and exploiting the RFID (Radio Frequency IDentification) technology. The survey describes three main categories of vehicle localization systems: (i) solutions exploiting only the RFID technology, (ii) sensor-fusion techniques combining data from RFID systems and proprioceptive sensors, and (iii) sensor-fusion techniques combing RFID data with those of other exteroceptive sensors in addition to the RFID system itself. For each method, implementation and methodological details are discussed, by highlighting the applied RFID technology, namely passive HF-RFID, passive UHF-RFID, or any other RFID system. Also, the employed RFID parameters, i.e., tag EPC, RSSI or backscattered phase, are discussed. The survey focuses on the achievable localization performance, also accounting for infrastructure-deployment costs together with complexity and maintenance overhead. Positioning, tracking, navigation and simultaneous localization and mapping (SLAM) issues are here considered. The analysis highlights pros and cons of each method, together with the main challenges and perspectives of RFID-based solutions for vehicle localization
Exploiting Near-Field Antenna Detuning in Collision Avoidance Systems for RFID-equipped Robots
No full textThis paper presents a collision avoidance system for mobile robots equipped with UHF-RFID (Ultra-High Frequency-Radio Frequency IDentification) readers. The proposed system requires the presence of RFID tags with self-tuning chips to recognize the tag antenna mismatch caused by the near-field interaction with the robot-installed antenna. The self-tuning tags are provided with a capacitors network used to re-tune the antenna in presence of mismatches. The network configuration is transmitted to the reader through modulated backscattering. The onboard computing intelligence can use this information to recognize a hazardous situation, stop the robot, and calculate a new safe route. The system is implemented and tested in a real environment where a statistical analysis with a large dataset is conducted to provide an optimized and reliable low-cost system
Compact Dual-Band Circularly Polarized Stacked Patch Antenna for Microwave-Radio-Frequency Identification Multiple-Input-Multiple-Output Application
No full textA compact, low-profile, two-port dual-band circularly polarized (CP) stacked patch antenna for radio-frequency identification (RFID) multiple-input-multiple-output (MIMO) readers is proposed, which employs the shared-aperture technique. The proposed antenna adopts a 1.524 mm thickness Rogers Ro4350b substrate with relative permittivity of 3.48. Two pairs of isolated ports are working at two microwave- (MW-) RFID bands (2.4-2.485 GHz and 5.725-5.875 GHz) with high port isolation of 25 dB and 30 dB, respectively. A shared metal slot layer is designed to separate two feeding structures of the lower band and upper band for port isolation enhancement as well as saving space. Corner-truncated square slot and patch configurations have been designed to obtain CP modes. In the lower and upper MW-RFID bands, the relative impedance bandwidths are 12.2% and 5.7%, and the maximum realized gains are higher than 7.3 dBic. Moreover, two-element configurations have been combined for an RFID MIMO system that occupies a dimension of 119 mm × 119 mm × 12.9 mm. The MIMO antenna performance of envelope correlation coefficient (ECC) is lower than 0.03, and diversity gain is close to 10 dB
Compact Dual Circularly Polarized Patch Antenna with High Ports Isolation for MIMO WLAN Application
No full textThis paper proposes a design of two-ports circularly polarized stacked patch antenna with square ring slot feeding technique for multiple-input-multiple-output (MIMO) application. The antenna with a quarter-wavelength slot and chamfering patch., which radiates at 2.4 GHz., occupies an overall area of mathbf{96} *mathbf{96} *mathbf{42 mm}^{mathbf{3}}. The 7.6-dBic gain antenna prototype presents an axial ratio lower than 0.4 dB in the operating frequency band (2.4 to 2.485 GHz) as well as a port isolation higher than 27 dB. Therefore., this antenna demonstrates good port-to-port isolation., axial ratio (AR) as well as a compact dimension and is suitable to be used in systems that operate in a wireless local area network (WLAN) frequency band
Self-locating RFID robot for tag localization in retails
No full textThis paper presents a RFID-based mobile robot able of self-locating within an indoor scenario and to estimate the position of target UHF-RFID tags. To locate itself, the robot exploits a sensor-fusion method which combines data from an infrastructure of passive reference RFID tags arranged in known locations and data from rotary wheel encoders. Besides, during its motion it is able of measuring the target tag locations through a synthetic-array approach. The knowledge of the reader antenna trajectory is here achieved from the RFID-based sensor-fusion method which exhibits a localization error lower than 0.27 m for 20-m long paths in a real office environment. Then, the estimated trajectory is exploited for target tag localization with high accuracy by using the synthetic-array approach
RFID Tag Localization with UGV in Retail Applications
No full textThis paper presents the application of the phase-based SARFID technique to locate static tags through an Unmanned Grounded Vehicle (UGV) equipped with a UHF-RFID reader. The UGV is remote-controlled to move inside an indoor environment and the knowledge of its trajectory is achieved through a Simultaneous Localization And Mapping (SLAM) procedure. The bi-dimensional tag position can be estimated with a location error in the order of few centimetres if the phase samples are collected in a proper spatial interval. Differently from other localization techniques, neither reference tags (anchor tags), nor large phased array antennas are required
Investigation of Phase Offset Calibration for SAR-based RFID Localization in Harsh Environments
No full textThis paper investigates the issue of phase offset calibration in the localization of Radio Frequency Identification (RFID) tags by using Synthetic Aperture Radar (SAR) methods. Although these techniques demonstrate robustness in handling challenges like multipath interference, the phase-offset calibration represents an open issue which deserves further investigation. Indeed, it can be affected by antenna radiation pattern and polarization mismatch between reader antenna and tag. In this paper, we propose a phase-offset calibration method based on polynomial fitting and we analyse its effectiveness by using an antenna motion system implemented through a Cartesian gantry portal in indoor scenario
Mobile-robots indoor tracking and navigation: perspectives for RFID technology
No full textLocalization of mobile robots is a key task for the implementation of autonomous robotic systems. Several technolo-gies have been explored with advantages and disadvantages to perform this task. Recently, RFID technology has been taken into consideration due to its low cost and practicality, giving rise to a new line of research. By exploiting the probability of detection, the received signal strength, or the phase of the tag replies, it is possible to get vehicle location information. Obviously, RFID technology shows pros and cons, and several precautions must be taken into account for real-systems deployment. This work aims to give an overview of advantages and challenges that RFID technology has to face to be used on a large scale in mobile-robotics applications
UHF-RFID smart gate: Tag action classifier by artificial neural networks
Full text linkThe application of Artificial Neural Networks (ANNs) to discriminate tag actions in UHF-RFID gate is presented in this paper. By exploiting Received Signal Strength Indicator values acquired in a real experimental scenario, a multi-layer perceptron neural network is trained to distinguish among tags incoming, outgoing or passing the RFID gate. A 99% accuracy can be obtained in tag classification by employing only one reader antenna and independently from tag orientation and typology
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