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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.
21

Localization algorithms for indoor UAVs

Barac, Daniel January 2011 (has links)
The increased market for navigation, localization and mapping system has encouraged the research to dig deeper into these new and challenging areas. The remarkable development of computer soft- and hardware have also opened up many new doors. Things which more or less where impossible ten years ago are now reality. The possibilities of using a mathematical approach to compensate for the need of expensive sensors has been one of the main objectives in this thesis. Here you will find the basic principles of localization of indoor UAVs using particle filter (PF) and Octomaps, but also the procedures of implementing 2D scanmatching algorithms and quaternions. The performance of the algorithms is evaluated using a high precision motion capture system. The UAV which forms the basis for this thesis is equipped with a 2D laser and an inertial measurement unit (IMU). The results show that it is possible to perform localization in 2D with centimetre precision only by using information from a laser and a predefined Octomap.
22

Radiobaserad positionering för UAV'er

Jakobsson, David, Jansson Stenroos, Erik January 2013 (has links)
Navigering med UAV:er kräver att farkostens och eventuellt ett måls position går att mäta ut under flygtillfället. I det allra flesta fall önskas en så hög noggrannhet som möjligt på positionen. DECCA är ett pensionerat system som var konstruerat för att läsa av fasförändringar mellan multiplar av en grundfrekvens. Systemet hade analoga mätare som gav utslag på förändringen av fasen och positionen kunde mätas ut på speciella kartor med inteferenslinjer som motsvarade en viss fasskillnad. GPS ger idag en precision ner på ett par meter, men med optimeringstekniker DGPS går det att komma ner i centimeternoggrannhet. Förutsättningen är att UAV:en befinner sig i ett geografiskt område med en minimal propagering på GPS-signalen. GPS är ett system som används idag och som fortfarande utvecklas. Fokus har lagts på att beskriva hur GPS går till väga för att få en hög precision på positioneringen och med de svårigheter som uppkommer med de långa avstånden mellan mottagaren och satelliten. En kort beskrivning över DECCA-systemets svagheter och styrkor ges, samt en kort sammanställning över hur DECCA och GPS skulle prestera i ett system med sändande antenner utplacerade över ett mindre geografisk område. / UAV navigation requires that the position of the vehicle and perhaps the destination to be measured, in flight. The reliability of close accuracy are in most case crucial for a positioning system. DECCA was constructed to measure the phase differences between several broadcasting frequencies, where all origin from one same fundamental frequency and broadcast as multiples of the source frequency. The system had analog meters which indicated the phase differences and with different interference lines corresponding to a certain phase different printed on a map, one could denote a rough position for the receiver. Today’s GPS grants accuracy within a few meter, but with technology as DGPS the precision can extend to a few centimetres. The condition for the precise position is where the GPS-signal are exposed for minimal propagation effects. Thus, the crucial is the receiver’s geographic location. Today GPS is active and used by numerous user around the world, but it is constant under development and improvement. The focal point has been to describe how GPS gets a good accuracy and the difficulties with the long distances between receiver and satellite. A short description over the weakness and strengths in DECCA has been made. And one short compilation over how well DECCA and GPS would perform in a system with multiple broadcast antennas, placed over a limited geographic area.
23

The UAV logger as a potential alternative for timber transportation in the Canadian boreal forest

Wychreschuk, Alena 14 August 2012 (has links)
The Canadian boreal forest has substantial natural resources located in remote isolated areas that are of economic interest. Requirements of the log extraction operation are to minimize impact on the ecosystem and its inhabitants. Transportation is one of the largest direct costs of forestry operations and many potential harvest areas are left untouched because of the high costs to build and maintain logging roads and water crossings. Alternatives to the traditional surface transportation system could benefit the industry, the residents and the ecosystem. The economics of a Lighter-Than-Air UAV Logger concept for log transportation is compared to the current truck and road build option using a cost comparison model and three harvest area case studies. At the engineered price estimate of $4.1 million, the results suggest that the UAV Logger is an uneconomic transportation alternative in the boreal forest at current product prices and supply availability. Conditions that favour the UAV Logger as a competitive economic alternative include small harvest volumes and high road build costs.
24

The UAV logger as a potential alternative for timber transportation in the Canadian boreal forest

Wychreschuk, Alena 14 August 2012 (has links)
The Canadian boreal forest has substantial natural resources located in remote isolated areas that are of economic interest. Requirements of the log extraction operation are to minimize impact on the ecosystem and its inhabitants. Transportation is one of the largest direct costs of forestry operations and many potential harvest areas are left untouched because of the high costs to build and maintain logging roads and water crossings. Alternatives to the traditional surface transportation system could benefit the industry, the residents and the ecosystem. The economics of a Lighter-Than-Air UAV Logger concept for log transportation is compared to the current truck and road build option using a cost comparison model and three harvest area case studies. At the engineered price estimate of $4.1 million, the results suggest that the UAV Logger is an uneconomic transportation alternative in the boreal forest at current product prices and supply availability. Conditions that favour the UAV Logger as a competitive economic alternative include small harvest volumes and high road build costs.
25

Autonomous Vertical Recovery of Fixed Wing Unmanned Aerial Vehicles

Smouter, Trevor 17 April 2013 (has links)
As unmanned aerial vehicles (UAVs) prevail in commercial and first responder applications, the need for safer and more consistent recovery methods is growing. Standard aircraft landing manoeuvres are only possible with a suitable runway which is often unavailable outside of military applications. Alternative recovery approaches can be either contained within the aircraft, ie. parachute or be setup on the ground ie. net landing. By integrating the recovery system into the vehicle, the flight preparation can be streamlined due to the fact that setting up recovering devices is no longer required. The goal of this thesis is to investigate the application of an autonomous vertical landing capability for fixed wing UAVs using articulated motors to enter vertical flight. Using an experimental UAV design, the dynamics of the problem were investigated using recorded flight data. Implementing a decoupled control approach, the aircraft was stabilized to maintain a horizontal hover. Through the characterized plant model that defines the vertical descent behaviour, a control topology was developed and tested in simulation using an optimal control approach. The developed controller was tested on the experimental UAV to verify the vertical landing performance. It was determined that this approach was well suited to autonomous vertical recovery of a fixed wing UAV. In employing this approach to UAV recovery, operators can easily operate in theatres where space for conventional landing does not exist.
26

CCUAV : Cloud Center for Unmanned Aerial Vehicle

Tell, Fredrik January 2018 (has links)
Projektets syfte är att bryta kopplingen mellan en specifik användare och drönare. Målet med projektet är att flera användare ska kunna hantera flera drönare från en central. En länk mellan en internetbaserad plattform vid namn Thingworx och en drönare med en inbyggd styrenhet, som kallas Pixhawk, sammankopplas med mikrodatorn Raspberry Pi 3. Sjöräddningssällskapet i Sverige önskar ett interface där flera av deras drönare med den inbyggda styrenheten kan hanteras och se dess position och videoström. PDSVisions mål är att skapa en demonstrator i en nyutvecklad plattform som förenklar uppkoppling med enheter med hjälp av ett begrepp som kallas IoT (Internet of Things). Resultat har resulterat i en prototyp av Sjöräddningssällskapets drönare ämnad att kontrolleras via den internetbaserade plattformen Thingworx. Drönaren startar, lyfter från marken och flyger en planerad rutt utan pilot. Slutsatsen visade att projektet kunde genomföras samt att det är möjligt att kommunicera med drönare via Thingworx
27

Business plan (model lean canvas) / Podnikatelský plán vybrané firmy (model lean canvas)

Strupplová, Lucie January 2014 (has links)
The well arranged and instructivee business plan is the basic part of every business project.. Currently is very often used the lean canvas model of the business plan. This model shows us very istructively all the factors influencing the project realisation. The dissertation is divided into the two basic parts. In the thoretical were compared the essential forms of the business plan with their differences. The practical part consists of creating the lean canvas model for the progressive company using the UAV and the MAIA application, monitoring the flight of the UAV. The economic data were analyzed and the structured scheme of the project, with the prediction was realized. The lean canvas model was very useful and optimal for this company and it´s project.
28

Exploratory Study of Unmanned Aerial Vehicles for Building Inspections: A Roofing Inspection Case Study

January 2020 (has links)
abstract: Unmanned Aerial Vehicles (UAVs) have become readily available for both the average consumer and professional due to decreases in price and increases in technological capabilities. This work ventured to explore the feasible use of UAV-technology in the area of roof analysis for facilities management purposes and contrast it to traditional techniques of inspection. An underlying goal of this work was two-fold. First, it was to calculate the upfront cost of investing in appropriate UAV equipment and training for a typical staff member to become proficient at doing such maintenance work in the practice of actual roof inspections on a sample set of roofs. Secondly, it was to compare the value of using this UAV method of investigation to traditional practices of inspecting roofs manually by personally viewing and walking roofs. The two methods for inspecting roofs were compared using various metrics, including time, cost, value, safety, and other relevant measurables. In addition to the study goals, this research was able to identify specific benefits and hazards for both methods of inspection through empirical trials. These points illustrate the study as Lessons Learned from the experience, which may be of interest to those Facilities Managers who are considering investing resources in UAV training and equipment for industrial purposes. Overall, this study helps to identify the utility of UAV technology in a well-established professional field in a way that has not been previously conducted in academia. / Dissertation/Thesis / Masters Thesis Construction Management 2020
29

Assessing sharks and rays in shallow coastal habitats using baited underwater video and aerial surveys in the Red Sea

Mcivor, Ashlie 05 1900 (has links)
Years of unregulated fishing activity have resulted in low abundances of elasmobranch species in the Saudi Arabian Red Sea. Coastal populations of sharks and rays in the region remain largely understudied and may be at risk from large-scale coastal development projects. Here we aim to address this pressing need for information by using fish market, unmanned aerial vehicle and baited remote underwater video surveys to quantify the abundance and diversity of sharks and rays in coastal habitats in the Saudi Arabian central Red Sea. Our analysis showed that the majority of observed individuals were batoids, specifically blue-spotted ribbontail stingrays (Taeniura lymma) and reticulate whiprays (Himantura sp.). Aerial surveys observed a catch per unit effort two orders of magnitude greater than underwater video surveys, yet did not detect any shark species. In contrast, baited camera surveys observed both lemon sharks (Negaprion acutidens) and tawny nurse sharks (Nebrius ferrugineus), but in very low quantities (one individual of each species). The combination of survey techniques revealed a higher diversity of elasmobranch presence than using either method alone, however many species of elasmobranch known to exist in the Red Sea were not detected. Our results suggest that aerial surveys are a more accurate tool for elasmobranch abundance estimates in low densities over mangrove-associated habitats. The importance of inshore habitats, particularly for batoids, calls for a deeper understanding of habitat use in order to protect these environments in the face of unregulated fishing, mangrove removal, and anticipated developments along the coastline of the Saudi Arabian Red Sea.
30

Reduction of non-contributory work of personnel using UAV methodology (Phantom 4 Pro RTK) and conventional Topography with Total Station (Leica TS 06), in road projects

Castaneda, Brandown Leon, Cordova, Edwin Huanachin, Diaz, Victor Torres, Reyes Nique, Jose 30 September 2020 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / At present, topographic surveys in road projects are very important, since it allows us to know the conditions and variable characteristics of the area to be executed. Commonly these surveys are carried out using a total station, high precision equipment, which in turn generates a lot of demand for time in the field and a greater number of personnel for a wide study area. For this reason, another alternative for obtaining terrain data is the use of the photogrammetric technique with UAV, since the objective is to increase productivity in the topographic survey. In this article, the productive development generated in the crews was analyzed using the total station survey methodology and the UAV photogrammetric technique using balance charts with the aim of obtaining the productive, contributory and non-contributory works, since the latter two they do not add value to the development of the project. This research was carried out in a rural area with a study area of 3 Ha and its classification by orography is of type 2 soil (undulated terrain), located in the Cuculí town center, Chongoyape district, Chiclayo province in the department of Lambayeque, Peru. In order to demonstrate that the UAV survey reduces non-contributory work by 47.2%, among the most outstanding activities obtained in this research are the leisure time that the staff presents in different situations of the project development, care of topographic equipment and another of the most outstanding was the use of cell phones in the field, which do not provide efficiency in the development of data collection and therefore would increase in time and cost of linear works, sanitation and projects in open places in the stage of design engineering.

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