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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Numerical Vortex Approach To Aerodynamic Modeling of SUAV/VTOL Aircraft

Hunsaker, Douglas F. 02 January 2007 (has links) (PDF)
A combined wing and propeller model is presented as a low-cost approach to preliminary modeling of slipstream effects on a finite wing. The wing aerodynamic model employs a numerical lifting-line method utilizing the 3D vortex lifting law along with known 2D airfoil data to predict the lift distribution across a wing for a prescribed upstream flowfield. The propeller/slipstream model uses blade element theory combined with momentum conservation equations. This model is expected to be of significant importance in the design of tail-sitter vertical take-off and landing (VTOL) aircraft, where the propeller slipstream is the primary source of air flow past the wings in some flight conditions. The algorithm is presented, and results compared with published experimental data.
2

A Surveillance System to Create and Distribute Geo-Referenced Mosaics Using SUAV Video

Andersen, Evan D. 14 June 2008 (has links)
Small Unmanned Aerial Vehicles (SUAVs) are an attractive choice for many surveillance tasks. However, video from an SUAV can be difficult to use in its raw form. In addition, the limitations inherent in the SUAV platform inhibit the distribution of video to remote users. To solve the problems with using SUAV video, we propose a system to automatically create geo-referenced mosiacs of video frames. We also present three novel techniques we have developed to improve ortho-rectification and geo-location accuracy of the mosaics. The most successful of these techniques is able to reduce geo-location error by a factor of 15 with minimal computational overhead. The proposed system overcomes communications limitations by transmitting the mosaics to a central server where there they can easily be accessed by remote users via the Internet. Using flight test results, we show that the proposed mosaicking system achieves real-time performance and produces high-quality and accurately geo-referenced imagery.
3

Militär nytta på stridsteknisk nivå : SUAV-system och CUAS / Military utility on the technical level : Small UAVs and CUAS

Janurberg, William January 2019 (has links)
Detta självständiga arbete undersöker stridstekniska obemannade luftfarkostsystem (SUAV) och potentiella tekniska system som är motverkande mot obemannade luftfarkoster (CUAS). Nyttjandet av stridstekniska obemannade luftfarkostsystem har ökat kraftigt och har observerats i både Syrien och Ukraina. I den ryska armén har de sett framgångsrik användning i samverkan med befintliga artillerisystem. Syftet med detta självständiga arbete är att analysera och förstå de effekter som tekniken har på militära operationer. I detta arbete används det militärtekniska konceptet ’militär nytta’ Andersson m.fl. (2015) i kombination med Johnsonkriteriet som används för att beräkna räckvidden på infraröda sensorer. Tillsammans med användningen av systemanalys och scenariobaserade metoder, har stridstekniska obemannade luftfarkostsystem och tekniska system som är motverkande mot obemannade luftfarkoster värderats med konceptet militär nytta. Slutsatserna från detta arbete visar att stridstekniska obemannade luftfarkostsystem har en god militär nytta då de används mot en motoriserad skyttebataljon (militär aktör), i förberedelsefasen av en fördröjningsstrid (kontext). Vid värderingen av de två tekniska systemalternativen som motverkar obemannade luftfarkoster; eldvapensystem och robotsystem, har bärbara luftvärnsrobotsystem bedömts ha en bättre militär nytta än automatkanonsystem på grund av dess möjliga användning i avsuttna operationer. / This independent project studies Small Unmanned Aerial Vehicles and potential Counter Unmanned Aerial Systems. The usage of Small Unmanned Aerial Systems has grown rapidly and has seen use in warfare in both Syria and Ukraine. In the Russian armed forces, they have seen successful use when used in combination with legacy artillery systems. The purpose of this independent project is to analyse and understand the effects that technology has on military operations. In this project, a military-technology concept called ‘military utility’ Andersson et al. (2015) is used in combination with the Johnson criteria which is used to calculate infrared sensor range. Together with the use of systems analysis and scenario-based methods, Small Unmanned Aerial Vehicles and two identified Counter Unmanned Aerial System alternatives have been assessed with the military utility concept. The conclusions of this independent project show that Small Unmanned Aerial Vehicles have a good degree of military utility when used against a motorized infantry battalion (military actor), in the preparatory phase of a delay operation (context). When assessing the two Counter Unmanned Aerial System alternatives; gun-based systems and missile air defence systems, man-portable air-defence systems have, because of their possible use in dismounted operations, been considered to have a greater military utility in comparison to autocannon systems.

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