Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 64 for “"Line of Sight (LOS)"”.
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The assessment of light sources
… = 8 log₁₀g where: g = (0.785/Eᵢ)Σ(L²ω/p²) (see Glossary) Hardly any research, however, has been done on discomfort glare from small sources, so the definition of a small source was just not known. It was not known whether to define it as an effective solid angle, ros or area, As. Two hypotheses …
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Four Branch Diversity Combining and Adaptive Beamforming Measurements Using Mobile Arrays at 2.05 GHz
… combining and adaptive beamforming performance of different four element arrays for mobile (vehicular speed) and portable (pedestrian speed) terminals is investigated. The performance of four element arrays with different configurations and with different element patterns is compared using the …
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The Effect of Digital Elevation Model Resolution on Wave Propagation Predictions at 24Ghz
… (DEMs) are computer-generated representations of the earth's surface. These surfaces can be used to predicted Line-of-Sight (LOS) radio propagation. DEM resolution can affect the results of this prediction. This study examines the effect of DEM resolution on accuracy by comparing varied …
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3D Simulator for Wind Interferometer Data-Model Comparison
… empirical and first principles) do a poor job of characterizing the variability of this region. One of the main objectives of the NASA ICON mission is to measure the variability of the ionosphere and thermosphere at low-mid latitudes. The MIGHTI instrument on ICON is a Doppler Interferometer …
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Optimal maneuver guidance with sensor line of sight constraint
The problem of optimal guidance design for the low altitude, subsonic, vertical plane approach maneuver of an air vehicle constrained to maintain view of a fixed final position is studied using a nonlinear, constrained, optimal control problem formulation. Multiple, competing optimization criteria …
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Spatial Coherency Estimation with a Synthetic Array
… many mobile applications rely on the location of User Equipment (UE) with a built-in wireless receiver and complementary sensors. The performance of wireless localization algorithms depends on the existence of Line-of-Sight (LOS) propagation conditions. However, the existence of …
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Estimation of ion drift velocity vector in F region ionosphere based on incoherent scattered pulse data using machine learning technique
… work on estimating the vector drift velocities of the plasma at different altitudes in the F region of the ionosphere using machine learning techniques. The computation is based on the radar data acquired with the ALTAIR (Automatic Radar Plotting Aid (ARPA) Long-Range Tracking and …
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Free-space phase-fading MIMO: system model and capacity analysis
… in specific areas and the links are dominated by Line-of-Sight (LoS) components. Since Free-Space Phase-Fading MIMO system channel is stochastic, based on Telatar's research, its capacity is determined by singular eigenvalue distribution of the random correlation matrix corresponding to channel …
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Medium Scale Travelling Ionospheric Disturbances sensed with GNSS TEC and SuperDARN
… storm on September 7-8th, 2017. The interval of this study is in the North American region between 23UT and 3UT, during the peak of the storm, when Kp reached 9. MSTIDs during the interval were investigated by previous studies. However, the roles of electrodynamic instability processes and …
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Characterizing and Improving the Non-Collaborative and Collaborative Localization Problems
… thesis focuses on the least-squares formulation of the non-collaborative and collabo- rative position location problems. For the non-collaborative problem, characterization encompassing the number of minima and the causes thereof is provided. Based on these efforts, we propose an improvement to …
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A Coverage Area Estimation Model for Interference-Limited Non-Line-of-Sight Point-to-Multipoint Fixed Broadband Wireless Communication Systems
First-generation, line-of-sight (LOS) fixed broadband wireless access techniques have been around for several years. However, services based on this technology have been limited in scope to service areas where transceivers can communicate with their base stations, unimpeded by trees, buildings and …
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UAV Communications: Spectral Requirements, MAV and SUAV Channel Modeling, OFDM Waveform Parameters, Performance and Spectrum Management
… defined, safety being the main concern. As part of this thesis, the communication needs of UAVs as important requirement for UAV integration into the national airspace is considered. Motivated by recent prediction of UAV quantities, revealing the importance of Micro UAVs (MAV) and Small UAVs …
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Three-Dimensional, Vision-Based Proportional Navigation for UAV Collision Avoidance
<p>As the number of potential applications for Unmanned Aerial Vehicles (UAVs) keeps rising steadily, the chances that these devices will operate in close proximity to static or dynamic obstacles also increases. Therefore, collision avoidance is an important challenge to overcome for Unmanned …
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Detection, identification and localization of R/C electronic devices through their unintended emissions
"The accurate and reliable detection of unintended emissions from radio receivers has a broad range of commercial and security applications. This thesis presents detection, identification, and localization methods for multiple RC electronic devices in a realistic environment. First, a Hurst …
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Vision-Enhanced Communications: On the Benefits of NLOS/LOS Knowledge in Wireless Systems
The proliferation of Internet of Things (IoT) devices equipped with meteorological, auditory, optical, and infrared sensors has opened the door to integrating sensor-based information into existing physical layer communication system design. Many properties of the wireless channel, especially for …
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Propagation models for multiple-antenna systems : methodology, measurements and statistics
… wireless communications is towards utilization of multiple antenna systems. While techniques such as beam-forming and spatial diversity have been implemented for some time, the emergence of Multiple-Input Multiple-Output (MIMO) communications has increased commercial interest and development in …
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Analysis, Simulation, and Measurement of Micro-Vibrations in Reaction Wheels for High-Performance Imaging Missions
… and geometric fidelity. This stability is often degraded by micro-vibrations originating from reaction wheels, which are the primary attitude actuators. These vibrations, resulting from mechanical unbalance, torque ripple, and bearing imperfections, propagate through the satellite structure …
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Multipath propagation models for near line-of-sight conditions
This thesis analyzes the behaviour of a multipath channel for suburban and semi-rural areas in which line of sight (LOS) or near LOS exists between the transmitter and receiver. The objective is to characterize the broadband channel for such areas. The thesis is divided into five major parts: a …
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GNSS pre-correlation waveform feature extraction methods for multipath-afflicted signal classification
Prime goal of this research is to propose and test novel algorithms for GNSS multipath environment classification on the receiver Digital Signal Processing (DSP) stage, but at an earlier processing point than it is used usually; at the generation of the digitized samples of the RF signal. Towards …
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Dynamic Metasurface Grouping for IRS Optimization in Massive MIMO Communications
… what was once consideredthe uncontrollable part of wireless communications, the channel. These smart signal mirrors show promise to significantly improve the effective signal-to-noise-ratio (SNR) of cell-users when the line-of-sight (LOS) channel between the base station (BS) and user is blocked. …
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