Murtha, Justin Fortna2014-03-142014-03-142009-06-18etd-06262009-141905http://hdl.handle.net/10919/33762Small unmanned aerial vehicles (SUAVs) are plagued by alarmingly high failure rates. Because these systems are small and built at lower cost than full-scale aircraft, high quality components and redundant systems are often eschewed to keep production costs low. This thesis proposes a process to ``design in'' reliability in a cost-effective way. Fault Tree Analysis is used to evaluate a system's (un)reliability and Dempster-Shafer Theory (Evidence Theory) is used to deal with imprecise failure data. Three unique sensitivity analyses highlight the most cost-effective improvement for the system by either spending money to research a component and reduce uncertainty, swap a component for a higher quality alternative, or add redundancy to an existing component. A MATLAB$^{\circledR}$ toolbox has been developed to assist in practical design applications. Finally, a case study illustrates the proposed methods by improving the reliability of a new SUAV design: Virginia Tech's SPAARO UAV.In CopyrightFault Tree AnalysisReliabilitySPAARODrone aircraftDempster-Shafer TheoryEvidence TheoryThesishttp://scholar.lib.vt.edu/theses/available/etd-06262009-141905/