A5027301362- Indoor and Outdoor Localization Technologies
- RFID technology advancements
- Underwater Vehicles and Communication Systems
- Energy Harvesting in Wireless Networks
- Robotics and Sensor-Based Localization
- Antenna Design and Analysis
- Planetary Science and Exploration
- Inertial Sensor and Navigation
- Soil Moisture and Remote Sensing
- Geophysical Methods and Applications
- Geophysical and Geoelectrical Methods
- Astro and Planetary Science
- Bluetooth and Wireless Communication Technologies
- Acoustic Wave Resonator Technologies
- Wireless Body Area Networks
- Wireless Power Transfer Systems
- Microwave and Dielectric Measurement Techniques
- Radio Wave Propagation Studies
- Advanced Antenna and Metasurface Technologies
- Magnetic Field Sensors Techniques
- Space Science and Extraterrestrial Life
- Electromagnetic Scattering and Analysis
- Microwave Imaging and Scattering Analysis
- Experimental and Theoretical Physics Studies
- Underwater Acoustics Research
Jet Propulsion Laboratory
2014-2024
California Institute of Technology
2013-2018
North Carolina State University
2014
Carnegie Mellon University
2010-2013
Walt Disney (United States)
2011
The University of Texas at Arlington
2007-2009
This paper provides an introductory survey on the various systems that exploit magnetic fields for positioning. Such find applications in those scenarios, both indoors and outdoors, where global navigation satellite are not available or fail to provide information with needed accuracy. While main idea of using electromagnetic position dates back past century, new application-led research this topic has emerged recent years. Results have expanded application range positioning technologies...
Measurements of the magnetoquasistatic fields generated from a magnetic dipole (an electrically small current loop) located above Earth are presented and compared to calculations using complex image theory. With horizontal (i.e., surface normal parallel Earth) emitting loop at height <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">h</i> copolarized receiving xmlns:xlink="http://www.w3.org/1999/xlink">z</i> ≥ 0, coupling between dipoles was...
Traditional wireless position-location systems, operating using propagating waves, suffer reduced performance in non-line-of-sight (NLoS) applications. systems that use quasistatic fields have instead been limited to short ranges, progressive direction-finding applications, require RF fingerprinting, or do not provide complete immunity dielectric obstacles (use of electric fields). These limitations impose severe restrictions applications such as tracking an American football during game...
In this paper, the use of hollow metal heating, ventilating, and air-conditioning (HVAC) ducts as a potential communication channel between passive ultrahigh-frequency (UHF) radio-frequency identification (RFID) readers tags is studied. HVAC behave electromagnetic waveguides with much lower signal attenuation compared to free-space propagation. This low-loss environment allows one greatly increase range UHF RFID systems build, for example, long sensor network spanning an entire...
Measurements of the reflected magnetoquasistatic fields at terminals a fixed generating resonant magnetic dipole (an electrically small resonating current loop) due to mobile coupled is presented. Using copolarized transmit-receive and loop, with co-aligned loop surface normals, coupling was measured for distances up 2.19 m along direction normals include strongly resonance region. Inverting theoretical expressions estimate distance from field values resulted in an average rms error 0.61...
This article discusses the implementation of a 2-D pseudospectral time-domain (PSTD) full-wave simulator for solving large-scale low-frequency (e.g., HF) electromagnetic (EM) scattering problems with application radar sounding planetary subsurfaces. Compared to other computational EM algorithms, PSTD solver is both memory-efficient and accurate applications. New domain designs are developed efficiently simulate half-space media normal oblique incidence from arbitrary wave sources. As...
We present the magnetoquasistatic (MQS) coupling theory between a mobile transmitting device located within building (indoor) and fixed receiving outside (outdoor), with assumption that can be approximated as homogeneous conducting body for penetration few skin-depths into building, due to long-wavelength MQS field. The permits decoupled sensing of range orientation when multiaxis devices are used. validate in an industrial demonstrate ranging average error 0.42 m.
In this paper we extend the theory of Radio Frequency (RF) propagation as it relates to within metal circular pipes. This work is motivated by a need understand operation UHF IDentification (RFID) systems when tags are placed These pipes shown be similar tube waveguides which hollow. We derive Bessel function that used identify constants, different transverse electric and magnetic modes, cut-off frequencies multimode attenuation. parameters operating limitations passive RFID in hollow A...
This paper describes the environmental effects and performance analysis of 2.45 GHz Surface Acoustic Wave (SAW) based RFID systems. Piezoelectric materials their underlying principles are reviewed to describe nature SAWs. A is conducted measure readability read range for individual tags, compared multiple tags in a field environment. On other hand, temperature, humidity, altitude vibration on operability system described. Finally, conclusion drawn with regards SAW-based
In this paper we extend the theory of radio frequency (RF) propagation within helical and toroidal metal pipes. This work is motivated by need to understand operation UHF identification (RFID) systems when tags are placed The field components inside a pipe derived obtain attenuation constants different transverse electric magnetic modes. cutoff frequencies, angle deployment used identify operating limitations passive RFID in hollow model then simplified describe case pipe. extends existing...
In this paper, we present an experimental study on the SAR of human head in environment with a typical RFID reader system. The results predict that 2 antennas at distances 10cm from operating additively, will contribute to up maximum 2.02763 W/kg, which is above limit for safe exposure RF radiation as allowed by FCC US (1.6 W/kg).
Spaceborne radar remote sensing of the earth system is essential to study natural and man-made changes in ecosystem, water energy cycles, weather air quality, sea level, surface dynamics. A major challenge with current approaches lack broad spectrum tunability due narrow band microwave electronics, that limit systems specific science variable retrievals. This results a significant limitation studying dynamic coupled processes such as subsurface hydrology from single compact instrument, where...
This paper presents a novel Real-Time Localisation System (RTLS) based upon 2.45 GHz Surface Acoustic Wave (SAW) Radio Frequency Identification (RFID) systems. The system utilises localisation method that combines the angular rotation of RFID reader's antenna with inherent Time-of-Flight (TOF) distance measurement capabilities SAW system. design rests sound physical fundamentals electromagnetic radiation and operation. was implemented empirically evaluated. It determined to provide accurate...
A technique using magnetoquasistatic fields has been shown to enable accurate ranging in non-line-of-sight environments. Due the nonlinear field coupling equations, suffers when extended 2-D and 3-D due of range orientation errors combined with convergence solution. Using a 2-axis transmit-receive concept, theory is presented decouple orientation. The results are linear orientation-invariant range-invariant sensing. Measurements inverted decoupled equations demonstrate peak 0.2-0.4 m for up...
Recent developments in long-range magnetoquasistatic position sensing have enabled the decoupling of one-dimensional (1-D) range and orientation mobile device to be sensed. By advancing theory, we demonstrate accurate two-dimensional (2-D) using a single-anchor system through azimuthal-direction angle device. The result is 2-D positioning with mean geometrical error 0.26 m for ranges up 30 receiver system—not relying on triangulation/trilateration.
In this paper, we identify the most significant problems involving impacts of radio frequency (RF) radiation on human body. The coming pervasive healthcare environment will rely heavily upon wirelessly communicating devices to provide information visibility and communication capabilities required achieve these ambitious systems. impact continuous RF exposure must be understood ensure that first do no harm with our new environments. specific absorption rates (SAR) is a dosimetric measure has...
Two-dimensional (2-D) measurements of the magnetoquasistatic fields generated from a magnetic dipole (an electrically small current loop) located above earth are compared to calculations using complex image theory. The coupling between vertical (i.e., surface normal parallel earth) emitting loop and seven receiving loops was measured in two-dimensional x-y grid 27.43 m by m, all earth, where were outside this grid. Inverting theoretical expressions estimate position field values resulted an...
Magnetoquasistatic position tracking has been shown to be an excellent technique measure distances between emitting and receiving loop for up 50 m along a direction perpendicular the surface normal of loops. For short from (i.e., less than about ten radii) there is error in estimated distance. In this paper, we examine cause show that significant portion due simplification as simple magnetic dipole. By including more accurate expression source field, errors can significantly reduced. We...
Groundwater provides roughly 43% of the water used globally for irrigated agriculture. Understanding, predicting, and managing environmental processes that define natural capital Earth's changing groundwater is one most pressing societal challenges 21st century. To understand influence dynamics in vadose zone on terrestrial ecosystems, to estimate future sustainability resources, a regional eventually global assessment table depth required. enable observations hydrologic systems' dynamics,...
The magnetoquasistatic (MQS) field coupling theory is presented for long ranges between a transmitting device located outdoor to receiving indoor. validated based on measurements in large indoor house environment (>8000 ft2) with the far outside (>11 m from outer wall). We discuss system and demonstrate position sensing compact mobile MQS receiver house.
Remote experience and visualization in sporting events can be significantly improved by providing accurate tracking information of the players objects event. Sporting such as American football or rugby have proved difficult for camera- radio-based due to blockage line-of-sight, proximity ball groups players. Magnetoquasistatic fields been shown enable position orientation sensing these environments [1]-[3]. In this work, we introduce a magnetoquasistatic tag developed an during game-play. We...
An American football was tracked using a long-range magneto-quasistatic position and orientation measurement system. A low-weight emitter that emitted low-frequency quasistatic magnetic field embedded within an football. The weighed total of 26.5 g, which the manufacturing tolerance football, did not alter dynamics ball. Measurements person carrying along goal line are described, with description construction tracking technique demonstrated measurements distance accuracy 15 cm azimuthal...