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We propose a magnetoquasistatic (MQS) field-based technology that would enable localization and communication from surface to cave exploring robots. In this article, we focus on the localization aspect of the technology. The technique requires a minimum of two nodes, of which one is mobile and can be located in the sub-surface, whereas the second is located at a fixed location above the over-burden...
Recent progress in magnetoquasistatic (MQS) positioning theory and techniques have resulted in short to long range two-dimensional (2D) positioning using a single-anchor device — a single fixed base-station device that enables 2D positioning of a mobile device, not relying on tri-angulation/lateration. These recent works demonstrate the ability to determine the position of a mobile device in 2D space...
Recent progress in magnetoquasistatic field-based techniques have enabled decoupled and linear solutions for position and orientation sensing in non-line-of-sight environments at short to long ranges above ground. By utilizing the deep-sub-wavelength regime of the MQS source, we describe a method to enable position sensing in the indoor environment. The technique enables accurate positioning of a...
Low-frequency subsurface radar observations of Mars' polar ice deposits by MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) are heavily impacted by the electron content of Mars' ionosphere, which has a peak plasma frequency close to MARSIS operating frequencies. The resulting ionospheric distortion can be represented as attenuation and bulk delay, in addition to higher-order frequency...
Recent developments have enabled single-anchor long-range two-dimensional (2D) positioning using low-frequency magnetoquasistatic fields. The approach of using a single-anchor for 2D position and orientation sensing results in significantly simplified systems and setup when compared to previous multi-anchor systems. The various advantages of single-anchor systems over multi-anchor systems include...
Measurements of the magnetoquasistatic coupling between a co-polarized vertical emitting and receiving coil, both located above earth, is compared to calculations using complex image theory and the exact integral solutions along a direction perpendicular to the surface normal axes of the loops. Inverting the theoretical expressions of the exact integral solution to estimate distance from measured...
The monostatic backscattered magnetoquasistatic field measured at the terminals of a resonant loop due to a nearby resonant loop can be modeled using coupled mode theory. Due to close proximity of the monostatic resonant loop and the nearby resonant loop, the backscattered energy is distributed over a set of two orthogonal modes of positive energy that can be described using classical coupled mode...
Magnetoquasistatic position and orientation errors due to measurement noise are quantitatively studied using theoretical field equations and added Gaussian noise.
The monostatic backscattered magnetoquasistatic field coupling measured at the terminals of a resonant coil due to strongly coupled magnetic resonance (SCMR) coupling with a nearby passive resonant coil exhibits dual orthogonal mode splitting. The difference between the center frequencies of the orthogonal modes, known as the coupled mode frequency split, is sensitive to range of the nearby passive...
The full-wave exact integral solutions of a current carrying loop immersed in a general half-space is presented. The result is an eigenfunction reflection coefficient that is perfectly symmetric with respect to the interchange of the half-space mediums, which is in contrast to the traditional form of Sommerfeld's original solution for the current loop above earth.
Remote experience and visualization in sporting events can be significantly improved by providing accurate tracking information of the players and objects in the event. Sporting events such as American football or rugby have proved difficult for camera- and radio-based tracking due to blockage of the line-of-sight, or proximity of the ball to groups of players. Magnetoquasistatic fields have been...
Position and orientation measurements have been demonstrated, recently, using low-frequency magnetoquasistatic fields and complex image theory for distances up to 50 m [1]. The key motivation for using magnetoquasistatic fields is to enable accurate estimation of an object's position and orientation when near weakly conducting dielectric obstacles, e.g., groups of people. An example application is...
In this paper we report on a magnetoquasistatic orientation sensor that uses the magnetoquasistatic coupling between an electrically small emitting loop (magnetic dipole) and seven vertical receiving loops located on a circle of radius 12.19 m to determine the orientation of an object. By inverting the theoretical expression for the coupling between the emitter and receivers and using complex image...
A sensing technique to determine the height and orientation (pitch, roll) above a conducting half-space using magnetoquasistatic fields and complex image theory is presented. The technique is based on measuring the fields due to the complex image of a magnetic dipole source at different locations. Examples for use of this sensor include applications as diverse as aerial vehicle landing, take-off and...
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