A New RSSI-based Centroid Localization Algorithm by Use of Virtual Reference Tags

A good design of node location is critical for efficient and effective wireless communications. This paper presents an improved algorithm, in order to solve the low localization accuracy caused by traditional centroid algorithm. The improved algorithm combined with VIRE system and traditional centroid algorithm. The VIRE algorithm is introduced and the signal propagation model is utilized to construct virtual reference tags in the location area. Simulation shows that this further developed algorithm has further improved the accuracy of positioning up to 35.12% compared to the traditional centroid algorithm. It is concluded that this algorithm can further improve the locating accuracy in comparison with the original centroid algorithm

Near field phased array DOA and range estimation of UHF RFID tags

This paper presents a near field localization system based on a phased array for UHF RFID tags. To estimate angle and range the system uses a two-dimensional MUSIC algorithm. A four channel phased array is used to experimentally verify the estimation of angle and range for an EPC gen2 tag. The system is calibrated for phase offsets introduced by hardware as simulations show the sensitivity to these offsets. Experiments with this calibrated receiver array give inaccurate ranging estimates. A solution is to calibrate the system for every angle, allowing meaningful range estimates. Experiments in a different environment show a reduced result, indicating the need for extensive calibration

Research on port AGV composite positioning based on UWB/RFID

In recent years, ports in various countries have successively carried out research and application of fully automated terminal. The terminal adopts the "Double car shore bridge + AGV + ARMG" automation process, which is the most widely used and relatively mature fully automated solution. At present, the AGV navigation of the terminal is based on RFID magnetic nail positioning and the accuracy is good. However, nowadays UWB technology has become the most popular technology in ranging and positioning. The research in this work is based on UWB/RFID composite positioning, which is mainly used for the specific localization tasks in the port and it can accurately locate the position of the AGV. This MSc work studies the UWB positioning system first and then researches the traditional 3D positioning algorithm. Importance contribution expressed by 3D TOA localization algorithm. For RFID system, this connection between the reader and the carrier is designed, and the reference tag is buried. At last, data-based on RFID localization algorithm in scene analysis method is adopted for positioning. Secondly, the basis of the composite positioning system is data fusion technology. The most widely used and mature fusion algorithm is the Kalman filter algorithm and Particle filter. Finally, the experimental analysis of UWB and RFID composite positioning system is implemented. The results indicate that UWB and RFID composite positioning system can reduce the cost of the positioning system. Higher positioning accuracy and robustness are characterizing the developed system.Nos últimos anos, portos de vários países realizaram sucessivamente pesquisas e aplicações de terminais totalmente automatizados. O terminal adota o processo de automação "Double car shore bridge + AGV + ARMG", que é a solução totalmente automatizada mais amplamente utilizada e relativamente madura. Atualmente, a navegação AGV do terminal é baseada no posicionamento da etiqueta RFID e a precisão é boa. No entanto, hoje em dia, a tecnologia UWB tornou-se na tecnologia mais popular relativamente ao alcance e posicionamento. A pesquisa neste trabalho é baseada no posicionamento composto por UWB / RFID, usado principalmente para tarefas de localização específicas nos portos, podendo desta forma localizar-se com precisão a posição do AGV. Este projeto de mestrado estuda em primeiro lugar o sistema de posicionamento UWB, e depois um algoritmo tradicional de posicionamento 3D. A contribuição da importância expressa pelo algoritmo de posicionamento “time of arrival” (TOA) 3D foi proposta. Para o sistema de posicionamento RFID, a conexão entre o leitor e a transportadora é projetada e a etiqueta de referência é ocultada. Por fim, o algoritmo de “k-nearest neighbor” baseado numa base de dados e no método de análise de cena é adotado para realizar o posicionamento. Em segundo lugar, a base do sistema de posicionamento composto é a tecnologia de fusão de dados. O algoritmo de fusão mais amplamente utilizado e maduro é o algoritmo de filtro Kalman e o filtro de partículas. Finalmente, é realizada a análise experimental do sistema de posicionamento composto UWB e RFID. Os resultados experimentais mostram que o sistema de posicionamento composto UWB e RFID pode reduzir o custo do sistema de posicionamento. O sistema desenvolvido é caracterizado por uma maior precisão de posicionamento e robustez

Waveguide antenna topologies for distributed high-frequency near-field communication and localization

High-frequency near-field communication is an inherently short-range technology. However, the total capture volume can be increased with traveling-wave antennas. Here, we report on analysis, design, and measurements of flexible waveguide antennas and discuss their performance for near-field communication and localization. The antennas comprise sections of coaxial transmission lines loaded periodically with field-generating inductive networks. Several topologies were compared to each other theoretically and the best-performing candidate was selected to fabricate antennas between 5 and 48 meters long, each containing 15 read nodes. Waveguiding properties of the antennas were measured and agreement with theory was demonstrated. Afterwards, each antenna was integrated with a custom NFC reader and shown to be capable of near-field communication with and localization of commercial off-the-shelf transponders compliant with ISO 14443 Type A protocol. The transverse detection range was 10 cm with 1 W input RF power. Both one-dimensional and quasi two-dimensional configurations were tested. The proposed antennas are flexible, scalable, have low loss, and could be used for near-field communication, identification, and tracking of distributed and mobile tags

RF-MVO: Simultaneous 3D object localization and camera trajectory recovery using RFID Devices and a 2D monocular camera

© 2018 IEEE. Most of the existing RFID-based localization systems cannot well locate RFID-tagged objects in a 3D space. Limited robot-based RFID solutions require reader antennas to be carried by a robot moving along an already-known trajectory at a constant speed. As the first attempt, this paper presents RF-MVO, which fuses battery-free RFID and monocular visual odometry to locate stationary RFID tags in a 3D space and recover an unknown trajectory of reader antennas binding with a 2D monocular camera. The proposed hybrid system exhibits three unique features. Firstly, since the trajectory of a 2D monocular camera can only be recovered up to an unknown scale factor, RF-MVO combines the relative-scale camera trajectory with depth-enabled RF phase to estimate an absolute scale factor and spatially incident angles of an RFID tag. Secondly, we propose a joint optimization algorithm consisting of coarse-to-fine angular refinement, 3D tag localization and parameter nonlinear optimization, to improve real-time performance. Thirdly, RF-MVO can determine the effect of relative tag-antenna geometry on the estimation precision, providing optimal tag positions and absolute scale factors. Our experiments show that RF-MVO can achieve 6.23cm tag localization accuracy in a 3D space and 0.0158 absolute scale factor estimation accuracy for camera trajectory recovery

Real-time localization using received signal strength

Locating and tracking assets in an indoor environment is a fundamental requirement for several applications which include for instance network enabled manufacturing. However, translating time of flight-based GPS technique for indoor solutions has proven very costly and inaccurate primarily due to the need for high resolution clocks and the non-availability of reliable line of sight condition between the transmitter and receiver. In this dissertation, localization and tracking of wireless devices using radio signal strength (RSS) measurements in an indoor environment is undertaken. This dissertation is presented in the form of five papers. The first two papers deal with localization and placement of receivers using a range-based method where the Friis transmission equation is used to relate the variation of the power with radial distance separation between the transmitter and receiver. The third paper introduces the cross correlation based localization methodology. Additionally, this paper also presents localization of passive RFID tags operating at 13.56MHz frequency or less by measuring the cross-correlation in multipath noise from the backscattered signals. The fourth paper extends the cross-correlation based localization algorithm to wireless devices operating at 2.4GHz by exploiting shadow fading cross-correlation. The final paper explores the placement of receivers in the target environment to ensure certain level of localization accuracy under cross-correlation based method. The effectiveness of our localization methodology is demonstrated experimentally by using IEEE 802.15.4 radios operating in fading noise rich environment such as an indoor mall and in a laboratory facility of Missouri University of Science and Technology. Analytical performance guarantees are also included for these methods in the dissertation --Abstract, page iv