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Full-Text Articles in Engineering Physics

Characterization And Discrimination Of Large Caliber Gun Blast And Flash Signatures, Bryan J. Steward Dec 2011

Characterization And Discrimination Of Large Caliber Gun Blast And Flash Signatures, Bryan J. Steward

Theses and Dissertations

Two hundred and one firings of three 152 mm howitzer munitions were observed to characterize firing signatures of a large caliber gun. Muzzle blast expansion was observed with high-speed (1600 Hz) optical imagery. The trajectory of the blast front was well approximated by a modified point-blast model described by constant rate of energy deposition. Visible and near-infrared (450 - 850 nm) spectra of secondary combustion were acquired at 0.75 nm spectral resolution and depict strong contaminant emissions including Li, Na, K, Cu, and Ca. The O2 (X-b) absorption band is evident in the blue wing of the potassium D lines …


Effect Of Storm Enhanced Densities On Geo-Location Accuracy Over Conus, Lindon H. Steadman Sep 2011

Effect Of Storm Enhanced Densities On Geo-Location Accuracy Over Conus, Lindon H. Steadman

Theses and Dissertations

Storm enhanced densities (SEDs) are ionospheric plasma enhancements that disrupt radio communications in the near-Earth space environment, degrading the Global Positioning System (GPS) and other key technologies. Accurate GPS/total electron content (TEC) correction maps produced by ionosphere models can mitigate degradations from SEDs. An artificial SED was created and ingested via slant TEC measurements into the Global Assimilation of Ionospheric Measurements Gauss-Markov Kalman Filter Model to determine how many ground GPS receivers are needed to produce reliable GPS/TEC correction maps over the continental United States during geomagnetic storming. It was found that 110 well-positioned GPS receivers produced the best overall …


Sensitivity Analysis Of Empirical Parameters In The Ionosphere-Plasmasphere Model, Janelle V. Jenniges Mar 2011

Sensitivity Analysis Of Empirical Parameters In The Ionosphere-Plasmasphere Model, Janelle V. Jenniges

Theses and Dissertations

A sensitivity analysis of empirical parameters used in physics-based models was completed in this study to determine their effect on electron densities and total electron content (TEC) in the ionosphere. The model used was the Ionosphere-Plasmasphere Model (IPM) developed by Utah State University. The empirical parameters studied include the O+/O collision frequency, zonal wind, secondary electron production, nighttime ExB drifts, and tidal structure. The sensitivity analysis was completed by comparing a default run of the IPM to a run with the parameter adjusted for three geophysical cases. Many of the comparisons resulted in nonlinear changes to the model …


Integration Of A Worldwide Atmospheric Based Model With A Live Virtual Constructive Simulation Environment, David B. Simmons Mar 2011

Integration Of A Worldwide Atmospheric Based Model With A Live Virtual Constructive Simulation Environment, David B. Simmons

Theses and Dissertations

Yearly DoD spends millions of dollars on Modeling and Simulation tools in order to accomplish two fundamental tasks: make better decisions and develop better skills. Simulators that are based on realistic models enable the USAF to properly train, educate, and employ military forces. LEEDR is an atmospheric model based on worldwide historic weather data that is able to predict the extinction, absorption, and scattering of radiation across a broad range of the electromagnetic spectrum. Through this study LEEDR models the propagation of 1.0642 micron laser radiation at worldwide locations and through various environmental conditions. This modeled laser transmission output, based …


Passive Ranging Of Dynamic Rocket Plumes Using Infrared And Visible Oxygen Attenuation, Robert Anthony Vincent Mar 2011

Passive Ranging Of Dynamic Rocket Plumes Using Infrared And Visible Oxygen Attenuation, Robert Anthony Vincent

Theses and Dissertations

Atmospheric oxygen absorption bands in observed spectra of boost phase missiles can be used to accurately estimate range from sensor to target. This work compares two oxygen absorption bands in the near-infrared (NIR) and visible (Vis) spectrum, centered at 762nm and 690 nm, to passively determine range. Spectra were observed from static tests of both surface-to-air missile simulators at 405m range and a full-scale solid rocket motor at 900m range. The NIR O2 band provided range estimates accurate to within 3% for both tests, while the Vis O2 band had range errors of 77% and 15 %, respectively. …