RFID-based Positioning System in Complex Environments

For effective identification of objects, Radio Frequency Identification (RFID) is  used in miscellaneous activities. In recent times, RFID is also used for positioning purposes. We show a scenario of wireless propagation  in free space observed by  up to  eight antennas with different polarization located in different positions. In this way, the polarization and diagram radiation of the antennas will play  a  significant role  in  producing  electromagnetic  field  in  the  region.   In  the second  case,  the  effects  of  disturbances  in  form  of  metallic  boxes  are  studied. The determination of the position is carried out by fingerprinting procedure

Position Tracking for Passive UHF RFID Tags with the Aid of a Scanned Array

Thanks to the proliferation of radio frequency identification systems (RFID), applications have emerged concerning positioning techniques for inexpensive passive RFID tags. The most accurate approaches for tracking the tag's position, deliver precision in the order of 20 cm over a range of a few meters and require moving parts in a predefined pattern (mechanical antenna steering), which limits their application. Herein, we introduce an RFID tag positioning system that utilizes an active electronically-steered array, based on the principles of modern radar systems. We thoroughly examine and present the main attributes of the system with the aid of an finite element method simulation model and investigate the system performance with far-field tests. The demonstrated positioning precision of 1.5, which translates to under 1 cm laterally for a range of a few meters can be helpful in applications like mobile robot localization and the automated handling of packaged goods.DF

HF RFID tag location using magneto-inductive waves

Location of passive RFID tags in the HF regime presents significant problems, because of the absence of radiating fields at the low frequencies involved. Here we present a solution for one-dimensional localization based on magneto-inductive (MI) waves. Passive tags are interrogated using a travelling wave antenna based on a MI waveguide, a magnetically coupled array of L−C resonators supporting travelling waves. Load modulation signals generated by the tag during its unique identifier response are coupled into the waveguide and travel to either end with low group velocity. Signal timings are measured by cross-correlation, and the tag position is estimated to the nearest resonant loop from the difference in their arrival times. Correlation detection is demonstrated using a system model, and theoretical predictions are confirmed using an experimental system containing eleven transformer-coupled resonators operating at 13.56 MHz frequency. Accurate localization is obtained up to the tag reading limit using <1W RF power

Improving Position Estimation on RFID Tag floor Localization Using RFID Reader Transmission Power Control

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Integration of passive RFID location tracking for real-time visualization in building information models (BIM)

Navigation through large and unfamiliar facilities with labyrinths of corridors and rooms is difficult and often results in a person being lost. Additionally, locating a specific utility within a facility is often a tough task. The hypothesis tested in this research is that integrating real-time automated sensing technology and a Building Information Model will provide real time visualization that can assist in localization and navigation of a facility. The scope of this research is facility maintenance management during the Operation and Maintenance (O&M) phase of a facility. The thesis demonstrates how the integration of passive Radio Frequency Identification (RFID) tracking technology and Building Information Modeling (BIM) can assist in facilities maintenance management. The objectives of this research included 1) developing a framework that utilizes the integration of commercially-available RFID and a BIM model; 2) evaluating the framework for real-time resource location tracking within an indoor environment; and 3) developing an algorithm for real-time localization and visualization in a BIM model. A prototype application has been developed that simultaneously connects the RFID readers, a database, and a BIM model. The goal of this system is to have a real-time localization accuracy of 3 meters at 95% confidence. Testing was conducted in laboratory conditions, and the results show that the system error was within the 3 meters goal.M.S

Multi-Sensor Methods for Mobile Radar Motion Capture and Compensation.

Ph.D. Thesis. University of Hawaiʻi at Mānoa 2017

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