Real-time Location System Research Articles

Measuring Sensitivity and Precision of Real-Time Location Systems (RTLS): Definition, Protocol and Demonstration for Clinical Relevance.

The ability of a Real Time Location System (RTLS) to provide correct information in a clinical environment is an important consideration in evaluating the effectiveness of the technology. While past efforts describe how well the technology performed in a lab environment, the performance of such technology has not been specifically defined or evaluated in a practice setting involving workflow and movement. Clinical environments pose complexity owing to various layouts and various movements. Further, RTL systems are not equipped to provide true negative information (where an entity is not located). Hence, this study defined sensitivity and precision in this context, and developed a simulation protocol to serve as a systematic testing framework using actors in a clinical environment. The protocol was used to measure the sensitivity and precision of an RTL system in the emergency department space of a quaternary care medical center. The overall sensitivity and precision were determined to be 84 and 93% respectively. These varied for patient rooms, staff area, hallway and other rooms.

Quantifying movement variability with fractals: From fall prediction to pharmaceutical evaluations and automated social distancing

Background: Movement speed is by definition the distance between two points divided by the time spent traversing it. Movement path tortuosity (Fractal D) describes the actual path traversed;it increases as more random turns are added. Although time is not used in its calculation because it is a spatial measure, the quantification of path tortuosity has yielded a novel means to describe path characteristics that correlate with temporal measures.= Objective: After summarizing the initial published application of Fractal D to human movement paths, its applications to numerous areas are reviewed. Method: Fractal D quantifies the degree a path deviates from a straight line, yielding an index that ranges from 1.0 (perfect straightness) to 2.0 (chaotic). Fractal D has been successfully used when subjects’ real time location systems data are the source. Results: Research is summarized relating elevated path tortuosity to cognitive deficits in young and elderly adults, the prediction of future falls, movement paths during searches of virtual spaces, evaluation of drug effects, and automatic monitoring of multiple persons moving in common spaces and social distancing. Conclusion: After its application from describing free movements of wild animals, the adaptation of Fractal D to human movement path variability has spread to several areas of study. © 2021, Gerontechnology. All Rights Reserved.

Enhanced Agility for Assembly Tasks via Self-Sufficient Mobile Working Stations

Abstract This paper introduces the standardized design and the use of self-sufficient Mobile Working Stations (MWS) for meeting upcoming requirements in providing agility for wide range assembly tasks. It describes how the physical equipment of an assembly line can be prepared for being fit for processing highly customized or even fairly new products outside the existing production portfolio in a very short time. Herein all relevant mechanical, informational and safety related aspects for a new setup have to be obtained. This includes a maximum in functionality and universality of the single MWS and the environment of the factory as a whole as well as the use of a Real Time Locating System (RTLS) for providing the always up to date positions of the MWS or other moveable elements in such an agile factory. The paper closes with an outlook to related ongoing research topics.

A Low-Cost Indoor Real-Time Locating System Based on TDOA Estimation of UWB Pulse Sequences

One of the most popular technologies adopted for indoor localization is ultrawideband impulse radio (IR-UWB). Due to its peculiar characteristics, it is able to overcome the multipath effect that severely reduces the capability of receivers (sensors) to estimate the position of transmitters (tags) in complex environments. In this article, we introduce a new low-cost real-time locating system (RTLS) that does not require time synchronization among sensors and uses a one-way communication scheme to reduce the cost and complexity of tags. The system is able to evaluate the position of a large number of tags by computing the time difference of arrival (TDOA) of UWB pulse sequences received by at least three sensors. In the presented system, the tags transmit sequences of 2-ns UWB pulses with a carrier frequency of 7.25 GHz. Each sensor processes the received sequences with a two-step correlation analysis performed first on a field-programmable gate array (FPGA) chip and successively on an on-board processor. The result of the analysis is the time of arrival (TOA) of the tag sequence at each sensor and the ID of the associated tag. The results are sent to a host PC implementing trilateration algorithm based on the TDOA computed among sensors. We will describe the characteristics of the custom hardware that has been designed for this project (tag and sensor) as well as the processing steps implemented that allowed us to achieve an optimum localization accuracy of 10 cm.

UWB Localization in a Smart Factory: Augmentation Methods and Experimental Assessment

The advent of the fourth industrial revolution (Industry 4.0) aims at increasing automation and efficiency in manufacturing processes by the adoption of information and communication technologies. Several of the proposed solutions rely on precise localization of material, equipment, or operators. This article investigates the employment of ultrawideband (UWB) real-time location systems (RTLS) in a factory environment and proposes an augmentation technique to mitigate the impairments that arise in such a complex scenario. A Bayesian filtering method is developed to jointly track the motion dynamics and the time-varying visibility conditions of the UWB antennas, with particle-based implementation to deal with the nonlinearity of the UWB measurements. Laboratory tests and industrial experiments are carried out to evaluate the performance of three commercial off-the-shelf UWB technologies: Decawave, Sewio, and Ubisense. The experimental data are then used to calibrate and test the developed filtering technique, showing that it is possible to significantly reduce the positioning error originating from dense multipath and NLOS effects by jointly tracking the target dynamics and visibility conditions.

UWB-Based Safety System for Autonomous Guided Vehicles Without Hardware on the Infrastructure

Automated Guided Vehicles (AGV) are unmanned transport vehicles widely used in the industrial sector to substitute manned industrial trucks and conveyors. In order to guarantee safe operation, AGVs must be equipped with a safety system to stop their movement in presence of obstacles or humans in their path. This work presents a novel safety system for AGVs that is based on Ultra Wideband (UWB) technology. Unlike previous works based on UWB Real-Time Location Systems (RTLS), the proposed safety system does not require installing hardware on the plant's infrastructure. Instead, the AGV is equipped with sensors capable of locating the tag of a person or a mobile asset. This simplifies deployment of the solution and enables its use in dynamic environments. The proposed safety system was mounted in an AGV designed by the company ASTI Mobile Robotics. Dynamic measurements showed that the proposed safety system accurately mirrors the relative movement between the AGV and tag. Furthermore, the proposed safety system employs a novel method for post-processing ranging data. Measurements showed that this method improves the accuracy of the system, resulting in a more homogeneously distributed positioning error around a room.

Antenna Delay Calibration of UWB Nodes

Impulse-radio ultra-wideband (IR-UWB) networks are gaining wide acceptance in short-to-medium range wireless sensing and positioning applications that require high accuracy. It is achieved generally via signal message exchange between ultra-wideband (UWB) transceiver nodes, where the signal propagating through their analog circuitry suffers transmitting and receiving antenna delays. Such delays, unless measured and properly corrected for, may induce an error in range estimation between UWB nodes and eventually affect the accuracy of real-time location systems (RTLSs) based on the IR-UWB. This paper presents a system to measure the antenna delays of UWB nodes. It provides comprehensive mathematical modeling, design, and implementation of the proposed antenna delay measurement system. Experimental evaluation in a line-of-sight (LOS) environment shows its effectiveness for maintaining the accuracy of the range measurement between UWB nodes by taking into consideration the antenna delays measured by the proposed system.

Movement at work: A comparison of real time location system, accelerometer and observational data from an office work environment

Office workers can spend significant periods of time being stationary whilst at work, with potentially serious health consequences. The development of effective health interventions could be aided by a greater understanding of the location and environmental context in which this stationary behaviour occurs. Real time location systems (RTLS) potentially offer the opportunity to gather this much needed information, but they have not been extensively trialled in office workplaces, nor rigorously compared against more familiar devices such as accelerometers. The aim of this paper was to determine whether an RTLS can measure and spatially locate the non-stationary and stationary behaviours of adults working in an office work environment. Data collected from a series of comparison studies undertaken in a commercial office building suggests that RTLS can measure the velocity at which people are moving and locate them, when stationary, with an accuracy of 0.668 m (SD 0.389). This opens up significant opportunities to further understand how people move within buildings, the indoor physical environmental influences on that movement, and the development of effective interventions to help people to move more whilst at work.

Conditions of Cost-Effectiveness for the Use of Real-Time Location Systems (RTLS) in Medical Facilities and the Benefits of Effective Implementation Process

The healthcare system today faces numerous challenges due to lack of visibility of resources and low utilisation, excessive rental as well as purchase of medical equipment. The article attempts to identify the possibilities of implementing a system of identification and location of assets in healthcare system institutions. This research presents market analysis in the context of available technological solutions. The implementation of real-time location system (RTLS) would enable not only tracking of equipment and inventory in medical facilities, but also increase visibility of inventory and manage the entire supply chain. Presentation of the proposed solution made it possible to assess costs, potential savings and the implementation process. This article is a starting point for a discussion on the cost-effectiveness of using RTLS in the healthcare system.

The Impact of Nurse Experience and Sequential Organ Failure Assessment on Nurses’ Workflow in an Intensive Care Unit

The purpose of this study is to understand the impact of Nurse Experience (NE) and Sequential Organ Failure Assessment (SOFA) on nurses’ workflow and process time in an Intensive Care Unit (ICU). In this study, a combination of data from the time-motion study observations, ICU nurses’ Real-Time Location System (RTLS), and the Real-Time Measurement System (RTMS) data were used to develop multiple Hierarchical Task Analysis (HTA) charts. HTA chart helped us to identify the ICU nurses’ workflow patterns. The results showed that ICU nurses spent over 47% of their time on performing primary care (in-room activities) and 25% on out-of-room activities. Furthermore, NE levels and SOFA scores had significant impacts on the average process time of nurse handoff, in-room Electronic Medical Record (EMR) charting, and the workflow patterns of out-of-room activities and out-of-room EMR usage. The outcomes of this study will provide a detailed workflow of ICU nurses and might help nurse managers to conduct a better strategy for improving ICU nurse’s workflow.

An Automated Real-Time Localization System in Highway and Tunnel Using UWB DL-TDoA Technology

There exists an electromagnetic shielding effect on radio signals in a tunnel, which results in no satellite positioning signal in the tunnel scenario. Moreover, because vehicles always drive at a high speed on the highway, the real-time localization system (RTLS) has a bottleneck in a highway scenario. Thus, the navigation and positioning service in tunnel and highway is an important technology difficulty in the construction of a smart transportation system. In this paper, a new technology combined downlink time difference of arrival (DL-TDoA) is proposed to realize precise and automated RTLS in tunnel and highway scenarios. The DL-TDoA inherits ultra-wideband (UWB) technology to measure the time difference of radio signal propagation between the location tag and four different location base stations, to obtain the distance differences between the location tag and four groups of location base stations. The proposed solution achieves a higher positioning efficiency and positioning capacity to achieve dynamic RTLS. The DL-TDoA technology based on UWB has several advantages in precise positioning and navigation, such as positioning accuracy, security, anti-interference, and power consumption. In the final experiments on both static and dynamic tests, DL-TDoA represents high accuracy and the mean errors of 11.96 cm, 37.11 cm, 50.06 cm, and 87.03 cm in the scenarios of static tests and 30 km/h, 60 km/h, and 80 km/h in dynamic tests, respectively, which satisfy the requirements of RTLS.

An Accurate and Real-Time Commercial Indoor Localization System in LTE Networks

In this paper, a commercial high-accuracy, low-cost and real-time indoor building-level localization system is proposed, which is applicable for locating the Minimization of Drive-Tests (MDT) data in the long-term-evolution (LTE) cellular communication network system. The system utilizes MDT data containing Global Navigation Satellite Systems (GNSS) information which is easy to collect and low cost to assist indoor localization, instead of using indoor drive test (DT) data which needs high manual collection and maintenance costs. In order to compensate for the loss of location accuracy, this paper innovatively divide the online process into two phases: indoor and outdoor (IO) identification phase and indoor localization phase. A real-time and precise GMM-based unsupervised algorithm is applied to identifying if the non-GNSS MDT data is in indoor environment in IO identification phase. Then, a multi-class classification algorithm based on Bayesian classifier is used to locate indoor MDT data to the specific building. The results of experiments conducted in an in-service LTE network using more than 100 LTE base stations demonstrate that the proposed technique yields a IO identification accuracy of 90% and an indoor location accuracy of 49.3m(@67%) respectively, which provides at least 30.2% enhancement in location accuracy compared to traditional technology without DT fingerprint database. This proposed indoor localization technique is applicable in network optimization and Operation and Maintenance (O&M) to assist communication service providers to reduce their operating expense (OPEX) by locating those MDT data without GNSS information.

High-Accuracy and Real-Time Indoor Positioning System Based on Visible Light Communication and Mobile Robot

For mobile robots and location-based services, precise and real-time positioning is one of the most basic capability, and low-cost positioning solutions are increasingly in demand and have broad market potential. In this paper, we innovatively design a high-accuracy and real-time indoor localization system based on visible light positioning (VLP) and mobile robot. First of all, we design smart LED lamps with VLC and Bluetooth control functions for positioning. The design of LED lamps includes hardware design and Bluetooth control. Furthermore, founded on the loose coupling characteristics of ROS (Robot Operator System), we design a VLP-based robot system with VLP information transmitted by designed LED, dynamic tracking algorithm of high robustness, LED-ID recognition algorithm, and triple-light positioning algorithm. We implemented the VLP-based robot positioning system on ROS in an office equipped with the designed LED lamps, which can realize cm-level positioning accuracy of 3.231 cm and support the moving speed up to 20 km/h approximately. This paper pushes forward the development of VLP application in indoor robots, showing the great potential of VLP for indoor robot positioning.

Technical feasibility analysis on applying ultra-wide band technology in construction progress monitoring

The Architecture, Engineering & Construction (AEC) industry has increasing demand for a more efficient and effective construction progress monitoring approach, to replace the time-consuming, error-prone and labor-intensive manual approach. Indoor positioning technology has been considered a suitable choice to meet this demand by its adaptability to the harsh and dynamic environment of the construction site. With the continuous progress of construction, the site environment is also constantly changing, Real Time Location System (RTLS) based on indoor positioning technology has a promising potential by its cost-effective advantages under this situation. In this research, Ultra-wide band (UWB) technology was adopted to develop a construction progress monitoring approach due to its stronger anti-interference ability, shorter delay and higher positioning accuracy among indoor positioning technologies. To investigate the technical feasibility of applying UWB to collect raw location data of core workforce, equipment and materials involved in different construction activities, construction activities were divided into three categories based on the characteristics of UWB technology. On and off-construction site tests were conducted to evaluate the technical feasibility in five criteria. The results of all tests proved the proposed approach has certain implementation value and under the premise of appropriate design and setting of infrastructures.

Integration of real-time locating systems into digital twins

Cyber-physical model-based solutions should rely on digital twins in which simulations are integrated with real-time sensory and manufacturing data. This paper highlights the benefits of information fusion with real-time locating systems (RTLS) and demonstrates how position and acceleration data can be utilised for the simulation-based analysis of product-specific activity times. The proposed digital twin is continuously capable to predict the production status and provide information for monitoring of production performance thanks to the real time connections of the RTLS and adaptive simulation models. The presented industrial case study demonstrates how the resulted Simulation 4.0 concept supports the analysis of human resource effectiveness (HRE) in an assembly process.

A Real Time Localization System for Vehicles Using Terrain-Based Time Series Subsequence Matching

Global Navigation Satellite Systems (GNSSs) are commonly used for positioning vehicles in open areas. Yet a GNSS frequently encounters loss of lock in urban areas. This paper presents a new real-time localization system using measurements from vehicle odometer data and data from an onboard inertial measurement unit (IMU), in the case of lacking GNSS information. A Dead Reckoning model integrates odometer data, IMU angular and velocity data to estimate the rough position of the vehicle. We then use an R-Tree structured reference road map of pitch data to boost spatial search efficiency. An optimized time series subsequence matching method matches the measured pitch data and the stored pitch data in reference road map for more accurate position estimation. The two estimated positions are fused using an extended Kalman filter model for final localization. The proposed localization system was tested for computational complexity with a median runtime of 12 ms, and for positioning accuracy with a median position error of 0.3 m.

Real time location systems: Is it big brother or a big opportunity for professional practice?

Purpose: Real Time Location Systems (RTLS) is an emerging health care technology with the potential to capture data that can be used to improve professional practice and patient outcomes. However, there is a paucity of literature in this area to guide health professionals and leaders in both the implementation and use of RTLS data. To address this gap in the literature, this qualitative study was designed to explore how staff perceive and experience RTLS, and how health care providers anticipate using RTLS data for professional practice and clinical decision making.Results: Interviews and focus groups were conducted with 31 health care professionals who work in a community hospital in Canada. There was variation between the participants in terms of the experience of being monitored, the intensity of emotions related to RTLS and being monitored, the degree to which RTLS influenced clinical decision making and reflection, and the perceptions of usefulness of RTLS data for professional practice. Three key themes emerged from the data: (1) the experience of being monitored, (2) anticipating using the data and (3) claiming the data for professional practice.Conclusions: Supports are vital to the successful adoption of RTLS and to enable health care professionals to claim and use RTLS data for professional practice and clinical decision making. During the implementation and use of RTLS data, it is crucial to recognize that RTLS data only represent the time spent in a location, and not the professional or knowledge-based practice of health professionals. Further research is required to understand the leadership strategies to guide the use of RTLS data.

A LOW-DELAY AND ROBUST SOLUTION FOR RAPID MOVEMENT DETECTION USING UWB

Abstract. The increasing applications for location-based services (LBS) and real-time location system (RTLS) promote the development of indoor positioning and navigation technology. However, the positioning methods based on traditional Radio Frequency (RF) signals are difficult to improve the accuracy and sensitivity for rapid movement detection with a low latency parameter. In order to solve those problems, this paper adopted ultra-wideband (UWB) chips as the wireless communication technology and designed a method of rapid movement detection with low delay. The method consists of a topology of combined two way ranging (C-TWR), a schedule of time division multiple access (TDMA), an non-light-of-sight (NLOS) handling mechanism and an adaptive extended Kalman filter (A-EKF). To examine the low delay performance, accuracy and robustness of the system, a specific electro-displacement actuator with programmable speed is applied to provide precise ground truth for real speed and distance, and a system test platform consisting of four anchors and four tags provides information of specific situation. The results show that the system can locate the rapid moving pedestrian with a maximal speed of approximately 5 m s−1 in real-time with a positioning accuracy of less than 0.5 m. There are profound implications for further studies in the range of human wearable tags.

Attendance Tracking using RFID and IoT

Technologies played an important role in developing the way of living life in terms of making it more easer and flexible than the past. One of the technologies in prominence is RFID which stands for “Radio-Frequency Identification”. RFID uses electromagnetic fields to transfer data that can automate identity and track using tags. This technology has been widely used in IT Asset Tracking, Logistics, Real Time Location Systems, Library systems and many more including Attendance Management in schools and colleges. Internet of Things (IoT) is considered as a technology that monitors the status of physical objects, capture meaningful data and communicate them through internet to software applications. The advancement in 4G and 5G technologies have accelerated the use of IoT and for instance with RFID wearable devices in collecting data wirelessly and sending them to software applications for better decision making. This project proposes a smart Attendance Tracking system using RFID and IoT for tracking attendance of students in classrooms. The project proposes to eradicate the time consuming, insecure and inefficient way of attendance tracking by calling names or signing on paper. A common way of attendance tracking with RFID is with the biometric system. However, this project proposes a protype using RFID and IoT with cloud-based applications that reduces IT support, decreases costs and builds intelligence to RFID tags. The prototype experiments with Ultra High Frequency RFID cards in association with Arduino Raspberry Pi microcontrollers and Microsoft Azure for cloud-based app and data storage. The software recognizes the student through the information on the UHF RFID smart card for recording attendance. Besides sending SMS or email to stakeholders confirming their presence in the class the prototype also uses built-in intelligence that informs about class timings, venue and cautioning late arrivals. The data obtained wirelessly from RFID cards can be analysed and provide the organization with information related measuring attendance at sessions, demographic visibility, engagement metrics, duration spent in seminars or events and understand interests and preferences. The project accentuates the role of RFID and IoT in enhancing the smart attendance system.

Patient Flow Analysis Using Real-Time Locating System Data: A Case Study in an Outpatient Oncology Center.

Electronic health records (EHRs) have been mainly used to analyze bottlenecks in care processes of outpatient oncology clinics. However, EHR data lead to some limitations in understanding patient flow because they are manually entered and not updated in real time. Data generated from a real-time location system (RTLS) can supplement EHR data. This study aims to demonstrate how RTLS data combined with EHR data can be used to evaluate potential interventions to improve patient flow in an outpatient cancer center. EHR and RTLS data obtained from a large cancer center in central Virginia were analyzed to estimate process times and determine the various patient paths patients follow during their visit for infusion. Using the input data, we developed a discrete-event simulation (DES) model and assessed 5 what-if scenarios involving changes in staff scheduling and care processes. Raw RTLS data including > 3.5 million observations were preprocessed to remove noise and extract meaningful information. The DES results showed that new nursing schedules for the infusion center and improved pharmacy processes have positive impacts on reducing patient waiting times by approximately 20% and overall length of stay by approximately 3.4% to 4.6%, compared with the current system. Combining EHR and RTLS data, we were able to capture dynamic aspects of patient flow more realistically. DES models that represent a complex system based on accurate input data can help decision making on determining operational changes to improve patient flow.