Link Budget Maximization for a Mobile-Band Subsurface Wireless Sensor in Challenging Water Utility Environments

A subsurface chamber transceiver system and associated propagation channel link budget considerations for an underground wireless sensor system (UWSS) are presented: the application was a sewerage system for a water utility company. The UWSS operates over the GSM850/900, GSM1800/1900, and Universal Mobile Telecommunications System (UMTS) bands in order to operate with the standard public mobile phone system. A novel antenna was developed to minimize path loss from the underground location: a folded loop type, which is small enough to fit conveniently inside a utility manhole access chamber while giving adequate signal strength to link to mobile base stations from such a challenging environment. The electromagnetic performance was simulated and measured in both free space and in a real manhole chamber. An experimental test bed was created to determine the return loss and received signal strength with different transceiver positions below the manhole chamber access cover. Both numerical and experimental results suggested an optimum position of the unit inside the manhole, combining easy access for maintenance with viable received signal strength. This confirmed that the characteristics were adequate for incorporation in a transceiver designed to communicate with mobile base stations from underground. A field trial confirmed the successful operation of the system under severe conditions

Remote Sensing

This dual conception of remote sensing brought us to the idea of preparing two different books; in addition to the first book which displays recent advances in remote sensing applications, this book is devoted to new techniques for data processing, sensors and platforms. We do not intend this book to cover all aspects of remote sensing techniques and platforms, since it would be an impossible task for a single volume. Instead, we have collected a number of high-quality, original and representative contributions in those areas

Design and Modelling of Passive UHF RFID Tags for Energy Efficient Liquid Level Detection Applications. A study of various techniques in the design, modelling, optimisation and deployment of RFID reader and passive UHF RFID tags to achieve effective performance for liquid sensing applications

Sewer and oil pipeline spillage issues have become major causes of pollution in urban and rural areas usually caused by blockages in the water storage and drainage system, and oil spillage of underground oil pipelines. An effective way of avoiding this problem will be by deploying some mechanism to monitor these installations at each point in time and reporting unusual liquid activity to the relevant authorities for prompt action to avoid a flooding or spillage occurrence. This research work presents a low cost energy efficient liquid level monitoring technique using Radio Frequency Identification Technology. Passive UHF RFID tags have been designed, modelled and optimized. A simple rectangular tag, the P-shaped tag and S-shaped tag with UHF band frequency of operation (850-950 MHz) has been designed and modelled. Detailed parametric analysis of the rectangular tag is made and the optimised design results analysed and presented in HFSS and Matlab. The optimised rectangular tag designs are then deployed as level sensors in a gully pot. Identical tags were deployed to detect 4 distinct levels in alternate positions and a few inches in seperation distance within the gully pot height (Low, Mid, High and Ultra high). The radiation characteristic of tag sensors in deployment as modelled on HFSS is observed to show consistent performance with application requirements. An in-manhole chamber antenna for an underground communication system is analysed, designed, deployed and measured. The antenna covers dual-band impedance bandwidths (i.e. 824 to 960 MHz, and 1710 to 2170 MHz). The results show that the antenna prototype exhibits sufficient impedance bandwidth, suitable radiation characteristics, and adequate gains for the required underground wireless sensor applications. Finally, a Linearly Shifted Quadrifilar Helical Antenna (LSQHA) designed using Genetic Algorithm optimisation technique for adoption as an RFID reader antenna is proposed and investigated. The new antenna confirms coverage of the RFID bandwidth 860-960 MHz with acceptable power gain of 13.1 dBi.Petroleum Technology Development Fund (PTDF) and National Space Research and Development Agency (NASRDA)

Ambient RF energy harvesting and efficient DC-load inductive power transfer

This thesis analyses in detail the technology required for wireless power transfer via radio frequency (RF) ambient energy harvesting and an inductive power transfer system (IPT). Radio frequency harvesting circuits have been demonstrated for more than fifty years, but only a few have been able to harvest energy from freely available ambient (i.e. non-dedicated) RF sources. To explore the potential for ambient RF energy harvesting, a city-wide RF spectral survey was undertaken in London. Using the results from this survey, various harvesters were designed to cover four frequency bands from the largest RF contributors within the ultra-high frequency (0.3 to 3 GHz) part of the frequency spectrum. Prototypes were designed, fabricated and tested for each band and proved that approximately half of the London Underground stations were found to be suitable locations for harvesting ambient RF energy using the prototypes. Inductive Power Transfer systems for transmitting tens to hundreds of watts have been reported for almost a decade. Most of the work has concentrated on the optimization of the link efficiency and have not taken into account the efficiency of the driver and rectifier. Class-E amplifiers and rectifiers have been identified as ideal drivers for IPT applications, but their power handling capability at tens of MHz has been a crucial limiting factor, since the load and inductor characteristics are set by the requirements of the resonant inductive system. The frequency limitation of the driver restricts the unloaded Q-factor of the coils and thus the link efficiency. The system presented in this work alleviates the use of heavy and expensive field-shaping techniques by presenting an efficient IPT system capable of transmitting energy with high dc-to-load efficiencies at 6 MHz across a distance of 30 cm.Open Acces

Enhancing In-Situ Structural Health Monitoring through RF Energy-Powered Sensor Nodes and Mobile Platform

This research contributes to long-term structural health monitoring (SHM) by exploring radio frequency energy-powered sensor nodes (RF-SNs) embedded in concrete. Unlike traditional in-situ monitoring systems relying on batteries or wire-connected power sources, the RF-SN captures radio energy from a mobile radio transmitter for sensing and communication. This offers a cost-effective solution for consistent in-situ perception. To optimize the system performance across various situations, we've explored both active and passive communication methods. For the active RF-SN, we implement a specialized control circuit enabling the node to transmit data through ZigBee protocol at low incident power. For the passive RF-SN, radio energy is not only for power but also as a carrier signal, with data conveyed by modulating the amplitude of the backscattered radio wave. To address the challenge of significant attenuation of the backscattering signal in concrete, we utilize a square chirp-based modulation scheme for passive communication. This scheme allows the receiver to successfully decode the data even under a negative signal-to-noise ratio (SNR) condition. The experimental results indicate that an active RF-SN embedded in concrete at a depth of 13.5 cm can be effectively powered by a 915MHz mobile radio transmitter with an effective isotropic radiated power (EIRP) of 32.5dBm. This setup allows the RF-SN to send over 1 kilobyte of data within 10 seconds, with an additional 1.7 kilobytes every 1.6 seconds of extra charging. For the passive RF-SN buried at the same depth, continuous data transmission at a rate of 224 bps with a 3% bit error rate (BER) is achieved when the EIRP of the transmitter is 23.6 dBm

Dense and long-term monitoring of Earth surface processes with passive RFID -- a review

Billions of Radio-Frequency Identification (RFID) passive tags are produced yearly to identify goods remotely. New research and business applications are continuously arising, including recently localization and sensing to monitor earth surface processes. Indeed, passive tags can cost 10 to 100 times less than wireless sensors networks and require little maintenance, facilitating years-long monitoring with ten's to thousands of tags. This study reviews the existing and potential applications of RFID in geosciences. The most mature application today is the study of coarse sediment transport in rivers or coastal environments, using tags placed into pebbles. More recently, tag localization was used to monitor landslide displacement, with a centimetric accuracy. Sensing tags were used to detect a displacement threshold on unstable rocks, to monitor the soil moisture or temperature, and to monitor the snowpack temperature and snow water equivalent. RFID sensors, available today, could monitor other parameters, such as the vibration of structures, the tilt of unstable boulders, the strain of a material, or the salinity of water. Key challenges for using RFID monitoring more broadly in geosciences include the use of ground and aerial vehicles to collect data or localize tags, the increase in reading range and duration, the ability to use tags placed under ground, snow, water or vegetation, and the optimization of economical and environmental cost. As a pattern, passive RFID could fill a gap between wireless sensor networks and manual measurements, to collect data efficiently over large areas, during several years, at high spatial density and moderate cost.Comment: Invited paper for Earth Science Reviews. 50 pages without references. 31 figures. 8 table

Design of mobile band subsurface antenna for drainage infrastructure monitoring

This paper presents an underground subsurface wireless sensor for drainage infrastructure water level monitoring. It operates from 800 to 2170 MHz to cover the required GSM850/900, GSM1800/1900 and UMTS bands. The system consists of a wideband antenna, transceiver, data acquisition unit and an ultrasonic sensor. The proposed antenna is a 3-dimensional inverted double F antenna and has an envelope size of 90 × 63.5 × 32 mm^3 , which is acceptably small for a cramped subsurface passageway environment. The antenna design was developed using software simulation to optimise its key parameters of return loss and radiation pattern, these being evaluated both in free space and in the partially underground environment. The design developed was then realised in hardware and tested in a representative subsurface location: a utility manhole chamber. It was found that the location of the antenna in the chamber had a significant effect on its performance, but a location that was acceptable for operational purposes was found by experiment. The overall system, including a transceiver, was demonstrated to operate satisfactorily for utility monitoring purposes, including acceptable levels of path loss for communication with mobile communication base stations

Feasibility Evaluation of a Vibration-Based Leak Detection Technique for Sustainable Water Distribution Pipeline System Monitoring

Conventional water pipeline leak-detection surveys employ labor-intensive acoustic techniques, which are usually expensive and less useful for continuous monitoring of distribution pipelines. Based on a comprehensive review of literature and available commercial products, it has been recognized that despite previous studies and products attempting to address the limitations of the conventional surveys by proposing and evaluating a myriad of leak-detection techniques (LDTs), they lacked extensive validation on complex looped systems. Additionally, they offer limited compatibility with some pipe materials such as those made of plastic and may even fail to distinguish leaks from other system disturbances. A novel LDT that addresses some of these limitations is developed and evaluated in the current study using an experimental set-up that is representative of a real-world pipeline system and made of Polyvinyl Chloride (PVC) pipe. The studied LDT requires continuous monitoring of the change in the cross spectral density of surface vibration measured at discrete locations along the pipeline. This vibration-based LDT was hypothesized to be capable of not only detecting the onset of leakage, but also determining its relative severity in complex pipeline systems. Findings based on a two-phase, controlled experimental testing revealed that the proposed LDT is capable of detecting leakages and estimating their relative severities in a real-size, multi-looped pipeline system that is comprised of multiple joints, bends and pipes of multiple sizes. Furthermore, the sustainability merits of the proposed LDT for a representative application scenario are estimated. Specifically, life cycle costs and energy consumption for monitoring the large diameter pipelines in the water distribution system of the Charleston peninsula region in South Carolina are estimated by developing conceptual prototypes of the sensing, communication and computation schemes for practically employing the proposed LDT. The prototype designs are informed by the knowledge derived from the two-phase experimental testing campaign. Overall, the proposed study contributes to the body of knowledge on water pipeline leak detection, specifically to non-intrusive vibration-based monitoring, applications on plastic pipelines, and smart and sustainable network-wide continuous monitoring schemes