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Full-Text Articles in Engineering
Absolute Positioning Using The Earth's Magnetic Anomaly Field, Aaron J. Canciani
Absolute Positioning Using The Earth's Magnetic Anomaly Field, Aaron J. Canciani
Theses and Dissertations
Achieving worldwide alternatives to GPS is a challenging engineering problem. Current GPS alternatives often suffer from limitations such as where and when the systems can operate. Navigation using the Earth's magnetic anomaly field, which is globally available at all times, shows promise to overcome many of these limitations. We present a navigation filter which uses the Earth's magnetic anomaly field as a navigation signal to aid an inertial navigation system (INS) in an aircraft. The filter utilizes highly-accurate optically pumped cesium (OPC) magnetometers to make scalar measurements of the Earth's magnetic field and compare them to a map using a …
Physical Layer Defenses Against Primary User Emulation Attacks, Joan A. Betances
Physical Layer Defenses Against Primary User Emulation Attacks, Joan A. Betances
Theses and Dissertations
Cognitive Radio (CR) is a promising technology that works by detecting unused parts of the spectrum and automatically reconfiguring the communication system's parameters in order to operate in the available communication channels while minimizing interference. CR enables efficient use of the Radio Frequency (RF) spectrum by generating waveforms that can coexist with existing users in licensed spectrum bands. Spectrum sensing is one of the most important components of CR systems because it provides awareness of its operating environment, as well as detecting the presence of primary (licensed) users of the spectrum.
Utilization Of A Geodesic Sphere And Quadcopter As Two-Way Field Probe For Electro-Magnetic Field Measurements In An Indoor Radar Cross Section Range, Nathan Lett
Theses and Dissertations
Radar Cross Section (RCS) measurements rely heavily on multiple assumptions. Uncertainty in the final measurement is determined based on these assumptions. One source in particular is the non-homogeneous nature of the transmission path between radar test equipment and a target under test. The following research extends prior research. This thesis intends to provide a unique two-way field probe solution for measuring Electro-magnetic (EM) fluctuations in a test volume. In this thesis, the design, development, and demonstration of a geodesic sphere encased quadcopter two-way probe is explained. The Parrot® Bebop Drone quadcopter was used with a 2v frequency divided geodesic sphere …
Characterization Of Quad-Copter Positioning Systems And The Effect Of Pose Uncertainties On Field Probe Measurements, James C. Dossett
Characterization Of Quad-Copter Positioning Systems And The Effect Of Pose Uncertainties On Field Probe Measurements, James C. Dossett
Theses and Dissertations
When measuring the Radar Cross Section (RCS) of a test object, many uncertainties must be accounted for, such as the non-homogeneous nature of the medium between the radar test equipment and the platform under test. There are a variety of other error sources, including clutter and Radio Frequency Interference (RFI), motivating the development of techniques to measure and model the uncertainties in RCS measurements. The following research, in unison with prior and current efforts, intends to reduce the impact of these uncertainties by utilizing a unique two-way field probe in the form of a geodesic sphere encompassing a commercial quad-copter …
An Openeaagles Framework Extension For Hardware-In-The-Loop Swarm Simulation, Derek B. Worth
An Openeaagles Framework Extension For Hardware-In-The-Loop Swarm Simulation, Derek B. Worth
Theses and Dissertations
Unmanned Aerial Vehicle (UAV) swarm applications, algorithms, and control strategies have experienced steady growth and development over the past 15 years. Yet, to this day, most swarm development efforts have gone untested and thus unimplemented. Cost of aircraft systems, government imposed airspace restrictions, and the lack of adequate modeling and simulation tools are some of the major inhibitors to successful swarm implementation. This thesis examines how the OpenEaagles simulation framework can be extended to bridge this gap. This research aims to utilize Hardware-in-the-Loop (HIL) simulation to provide developers a functional capability to develop and test the behaviors of scalable and …
Integrity Determination For Image Rendering Vision Navigation, Sean M. Calhoun
Integrity Determination For Image Rendering Vision Navigation, Sean M. Calhoun
Theses and Dissertations
This research addresses the lack of quantitative integrity approaches for vision navigation, relying on the use of image or image rendering techniques. The ability to provide quantifiable integrity is a critical aspect for utilization of vision systems as a viable means of precision navigation. This research describes the development of two unique approaches for determining uncertainty and integrity for a vision based, precision, relative navigation system, and is based on the concept of using a single camera vision system, such as an electro-optical (EO) or infrared imaging (IR) sensor, to monitor for unacceptably large and potentially unsafe relative navigation errors. …
Interference Suppression Using Knowledge-Aided Subarray Pattern Synthesis, David A. New
Interference Suppression Using Knowledge-Aided Subarray Pattern Synthesis, David A. New
Theses and Dissertations
Most phased array systems subarray many antenna elements into far fewer digitized channels. While having more degrees of freedom (DOF) yields better performance, adding channels to create more digital DOF increases system cost and data throughput requirements. A subarray itself constitutes a phased array with as many DOF as it has antenna element weights. Typically, only one degree of freedom is used to steer the maximum gain direction of the subarray pattern. For typical antenna geometries a single subarray will provide many more spatial DOF than there are digitized channels. The inherent DOF of the subarrays could be used to …
Comparison Of Methods For Radio Position Of Non-Emitting Dismounts, Collin J. Seanor
Comparison Of Methods For Radio Position Of Non-Emitting Dismounts, Collin J. Seanor
Theses and Dissertations
Radio Tomographic Imaging (RTI) is a form of Device Free Passive Localization (DFPL) that utilizes the Received Signal Strength (RSS) values from a collection of wireless transceivers to produce an image in order to localize a subject within a Wireless Sensor Network (WSN). Radio Mapping is another form of DFPL that can utilize the same RSS values from a WSN to localize a subject by comparing recent values to a set of calibration data. RTI and Radio Mapping have never been directly compared to one another as a means of localization within a WSN. The goal of this research is …
Multihop Rendezvous Algorithm For Frequency Hopping Cognitive Radio Networks, John A. Pavlik
Multihop Rendezvous Algorithm For Frequency Hopping Cognitive Radio Networks, John A. Pavlik
Theses and Dissertations
Cognitive radios allow the possibility of increasing utilization of the wireless spectrum, but because of their dynamic access nature require new techniques for establishing and joining networks, these are known as rendezvous. Existing rendezvous algorithms assume that rendezvous can be completed in a single round or hop of time. However, cognitive radio networks utilizing frequency hopping that is too fast for synchronization packets to be exchanged in a single hop require a rendezvous algorithm that supports multiple hop rendezvous. We propose the Multiple Hop (MH) rendezvous algorithm based on a pre-shared sequence of random numbers, bounded timing differences, and similar …