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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.
31

RGBI-Bilddaten mit RPAS und FOVEON Sensoren

Gehrke, Ralf 10 August 2015 (has links)
In den letzten Jahren hat sich der Einsatz von Remotely Piloted Aerial Systems (RPAS) zur Geodatenerfassung immer mehr verbreitet. Dabei liegt das Hauptaugenmerk auf dem Einsatz von herkömmlichen Kameras mit drei Kanälen (Rot, Grün, Blau (RGB)). Mit dieser Kombination werden 3D-Daten und Orthophotomosaike erzeugt. Ein weiteres, jedoch kleineres Augenmerk liegt auf der Entwicklung von Sensoren mit mehr als drei Kanälen für Fragestellungen der Fernerkundung. Auffallend ist dabei, dass die Hersteller viel Arbeit in die radiometrische Qualität und die spektrale Auflösung der Sensoren stecken, deren geometrische Qualität ganz im Gegensatz zur herkömmlichen RGB-Kamera aber vernachlässigen. Die vorliegende Arbeit verfolgt einen anderen Ansatz: Ein bestehendes System wird unter der Berücksichtigung eines begrenzten Budgets (low-cost) und dem Erhalt der hohen geometrischen Abbildungsqualität um einen vierten Kanal im nahen Infrarot ergänzt. Anwendungsmöglichkeiten ergeben sich überall dort, wo gleichzeitig das Vorhandensein oder der Zustand von Vegetation und die Geometrie mit RPAS erfasst werden soll. Sigma Kameras mit Foveon® Sensoren sind bereits für ihre hohe Abbildungsqualität bekannt. Durch den Ausbau des Infrarot-Sperrfilters kann diese Kamera, ebenso wie fast alle Sensoren auf Silizium-Basis, für die Erfassung des Near Infrared (NIR) modifiziert werden. Mit der Kombination einer RGB- und einer NIR-Kamera zu einem Sensorkopf und einer selbst entwickelten Datenverarbeitung können Vierkanalbilddaten erzeugt werden, die die hohe Abbildungsqualität der Sigma Kamera und gleichzeitig die Zusatzinformation im NIR besitzen. Die Weiterverarbeitung in einer modernen Photogrammetriesoftware mit einem Structure from Motion (SFM)-Ansatz verspricht ein effizientes und praxisgerechtes Arbeiten. Der entwickelte Sensorkopf wird in zwei Einsatzszenarien zur Anwendung gebracht. In der Luftbildarchäologie kann der Zeitraum der Erfassung von Bodendenkmälern mit RPAS durch diesen Sensorkopf erheblich erweitert werden. Das Bodendenkmal ist sowohl im hochaufgelösten Oberflächenmodell als auch im NIR deutlicher zu erkennen als in einer herkömmlichen RGB-Aufnahme. Bei der Filterung eines Oberflächenmodells zu einem Geländemodell konnte gezeigt werden, dass die Verwendung des NIR den herkömmlichen Einsatz von neigungsbasierten Filtern sinnvoll ergänzt und zu besseren Ergebnissen führt. Durch den Rückgriff auf gebrauchte Sigma Kompaktkameras und weit verbreitete Software mit SFM-Algorithmen konnte der low-cost Ansatz voll erfüllt werden. Die radiometrische Qualität wurde untersucht und es wurde festgestellt, dass diese nicht an den Stand der Technik von speziellen und teuren Algorithmen und Sensoren heranreicht. Für die gezeigten Anwendungen ist sie jedoch als ausreichend zu bewerten.
32

Incident Response Enhancements using Streamlined UAV Mission Planning, Imaging, and Object Detection

Link, Eric Matthew 29 June 2023 (has links)
Systems composed of simple, reliable tools are needed to facilitate adoption of Uncrewed Aerial Vehicles (UAVs) into incident response teams. Existing systems require operators to have highly skilled level of knowledge of UAV operations, including mission planning, low-level system operation, and data analysis. In this paper, a system is introduced to reduce required operator knowledge level via streamlined mission planning, in-flight object detection, and data presentation. For mission planning, two software programs are introduced that utilize geographic data to: (1) update existing missions to a constant above ground level altitude; and (2) auto-generate missions along waterways. To test system performance, a UAV platform based on the Tarot 960 was equipped with an Nvidia Jetson TX2 computing device and a FLIR GigE camera. For demonstration of on-board object detection, the You Only Look Once v8 model was trained on mock propane tanks. A Robot Operating System package was developed to manage communication between the flight controller, camera, and object detection model. Finally, software was developed to present collected data in easy to understand interactive maps containing both detected object locations and surveyed area imagery. Several flight demonstrations were conducted to validate both the performance and usability of the system. The mission planning programs accurately adjust altitude and generate missions along waterways. While in flight, the system demonstrated the capability to take images, perform object detection, and return estimated object locations with an average accuracy of 3.5 meters. The calculated object location data was successfully formatted into interactive maps, providing incident responders with a simple visualization of target locations and surrounding environment. Overall, the system presented meets the specified objectives by reducing the required operator skill level for successful deployment of UAVs into incident response scenarios. / Master of Science / Systems composed of simple, reliable tools are needed to facilitate adoption of Uncrewed Aerial Vehicles (UAVs) into incident response teams. Existing systems require operators to have a high level of knowledge of UAV operations. In this paper, a new system is introduced that reduces required operator knowledge via streamlined mission planning, in-flight object detection, and data presentation. Two mission planning computer programs are introduced that allow users to: (1) update existing missions to maintain constant above ground level altitude; and (2) to autonomously generate missions along waterways. For demonstration of in-flight object detection, a computer vision model was trained on mock propane tanks. Software for capturing images and running the computer vision model was written and deployed onto a UAV equipped with a computer and camera. For post-flight data analysis, software was written to create image mosaics of the surveyed area as well as to plot detected objects on maps. The mission planning software was shown to appropriately adjust altitude in existing missions and to generate new missions along waterways. Through several flight demonstrations, the system appropriately captured images and identified detected target locations with an average accuracy of 3.5 meters. Post-flight, the collected images were successfully combined into single-image mosaics with detected objects marked as points of interest. Overall, the system presented meets the specified objectives by reducing the required operator skill level for successful deployment of UAVs into incident response scenarios.
33

Human-UAV Collaborative Search with Concurrent Flights and Re-Tasking

Broz, Alexander Turina 29 August 2022 (has links)
This thesis discusses a system that allows an operator to use two unmanned aerial vehicles (UAVs) to search an area. Prior work accomplished this in separate survey and search missions, and this work combines those two missions into one. The user conducts a search by selecting an area to survey, and the first drone flies above it, providing up to date information about the area. Points of interest (POI) are then marked by the user and investigated by the second drone. This system assumes a static and known obstacle map, and segmenting the environment during the missions leaves potential for future work. Both drones are equipped with cameras that stream video for the user to observe. A custom graphical user interface (GUI) was created to allow for the drones to be controlled. In addition to marking a search area and POI, the user can pause the drone and delete or add new POI to change the mission mid-flight. Both drones are commanded remotely by a ground station (GCS), leaving only low-level control to the onboard computers. This ground station uses a nearest neighbor solution to the travelling salesman problem and a wavefront path planner to create a path for the low altitude drone. The software architecture is based on the Robot Operating System (ROS), and the GCS uses the MAVLink messaging protocol to communicate with the drones. In addition to the system design, this paper discusses UAV human interaction and how it is applied to this system. / Master of Science / This thesis discusses a system that allows an operator to use two drones to search an area. Prior work accomplished this in separate survey and search missions, and this work combines those two missions into one. The user conducts a search by selecting an area to survey, and the first drone flies above it, providing up to date information about the area. Points of interest (POI) are then marked by the user and investigated by the second drone. This system assumes that obstacles in the environment are static and already known. Both drones are equipped with cameras that stream video for the user to observe. A custom graphical user interface (GUI) was created to allow for the drones to be controlled. In addition to providing the initial mission for the drones, the user can also change the mission mid-flight. Both drones are commanded remotely by a separate computer, leaving only very basic control to the drones. This ground station uses a simple path planner to create a path for the low altitude drone to avoid obstacles. The software architecture is based on the Robot Operating System (ROS), and the GCS uses the MAVLink messaging protocol to communicate with the drones. In addition to the system design, this UAV human interaction and how it is applied to this system.
34

Mapping a Forest: Utilizing an Unmanned Aerial Vehicle to Track Phenology

Hogue, Jonathon D. 19 June 2018 (has links)
No description available.
35

Cellular-connected UAV in Next-Generation Wireless Networks

Cherif, Nesrine 01 November 2022 (has links)
Unmanned aerial vehicle (UAV) technology has gained a great interest in communication systems due to its ability to host a cellular base station (BS) and thus act as an aerial BS (UAV-BS). The inheritance of mobility in the airspace makes the deployment of UAV-BSs flexible and agile aiming to mainly complement the terrestrial network, extend its coverage, and serve as a capacity injector in high-throughput demand scenarios. Besides, a UAV can also act as an aerial user (UAV-UE) for various use cases, such as aerial data collection and cargo delivery. Such UAV-UE missions need reliable cellular communication links in order to safely operate in beyond visual line-of-sight (BVLoS). Since terrestrial networks were not primarily designed to serve aerial users, due to their down-tilted BS antennas, re-coursing solely to these networks for aerial users’ cellular connectivity might not be a viable approach as a long-term solution. Alternatively, deploying UAV-BSs in this context can substantially improve both aerial and terrestrial users coverage and capacity. One of the challenging issues is how to characterize the UAV-UE performance in integrated aerial/terrestrial networks, called vertical heterogeneous networks (VHetNets). First, we thoroughly study the aerial user’s performance in terms of coverage probability in a VHetNets setup. Under a more realistic system model, we revisit the coverage and throughput performances of an aerial user in VHetNets, considering LoS and non-LoS (NLoS) transmissions and under different spectrum sharing policies among separate aerial and terrestrial networks. Some insights have been concluded on the integration of aerial BSs and UAV-UEs with the existing terrestrial network. Specifically, optimal positioning of UAV-BSs for maximized aerial users coverage was investigated for various aerial users distribution and spectrum allocations. Moreover, visioning that UAV technology will revolutionize the cargo delivery industry, we proposed a new concept of 3D aerial highways, which designs coordinated routes for a massive number of UAVs used mainly for delivery purposes. In this context, multiple network technologies were proposed and discussed to guarantee the cellular connectivity of cargo-UAVs in 3D aerial highways. For the particular case of connectivity supported by terrestrial cellular networks, an optimal energy-efficient and low-handoff trajectory planning for a cargo-UAV mission was proposed, with respect to disconnectivity constraints. Consequently, associated design guidelines and recommendations have been drawn. Leveraging reinforcement learning (RL) tools, we proposed a novel algorithm for path planning and cell association for the cargo-UAV that maximizes its cellular service reliability and minimizes the handoff events. Finally, we introduced a new paradigm, intermittently tethered UAV (iTUAV), as a trade-off between mobility and energy availability for providing cellular connectivity in temporary events.
36

Short range reconnaissance unmanned aerial vehicle / S.J. Kersop.

Kersop, Stefanus Jacobus January 2009 (has links)
Unmanned aerial vehicles (UAVs) have been used increasingly over the past few years. Special Forces of various countries utilise these systems successfully in war zones such as Afghanistan. The biggest advantage is rapid information gathering without endangering human lives. The South African National Defence Force (SANDF) also identified the need for local short range aerial reconnaissance and information gathering. A detailed literature survey identified various international players involved in the development of small hand-launch UAV systems. Unfortunately, these overseas systems are too expensive for the SANDF. A new system had to be developed locally to comply with the unique requirements, and budget, of the SANDF. The survey of existing systems provided valuable input to the detailed user requirement statement (URS) for the new South African development. The next step was to build a prototype using off-the-shelf components. Although this aircraft flew and produced good video images, it turned out to be unreliable. The prototype UAV was then replaced with a standard type model aircraft, purchased from Micropilot. Some modifications were needed to ensure better compliance with the URS. Laboratory and field tests proved that the aircraft can be applied for aerial images, within range of 10 km from the ground control station (GCS). The major limitation is that it can only fly for 40 minutes. Furthermore, the airframe is not robust, needing repairs after only 15 flights. Although the system has shortcomings, it has already been used successfully. It is expected that improved battery technologies and sturdier light-weight materials will further help to improve the system beyond user specifications. / Thesis (MIng (Electrical Engineering))--North-West University, Potchefstroom Campus, 2010.
37

Short range reconnaissance unmanned aerial vehicle / S.J. Kersop.

Kersop, Stefanus Jacobus January 2009 (has links)
Unmanned aerial vehicles (UAVs) have been used increasingly over the past few years. Special Forces of various countries utilise these systems successfully in war zones such as Afghanistan. The biggest advantage is rapid information gathering without endangering human lives. The South African National Defence Force (SANDF) also identified the need for local short range aerial reconnaissance and information gathering. A detailed literature survey identified various international players involved in the development of small hand-launch UAV systems. Unfortunately, these overseas systems are too expensive for the SANDF. A new system had to be developed locally to comply with the unique requirements, and budget, of the SANDF. The survey of existing systems provided valuable input to the detailed user requirement statement (URS) for the new South African development. The next step was to build a prototype using off-the-shelf components. Although this aircraft flew and produced good video images, it turned out to be unreliable. The prototype UAV was then replaced with a standard type model aircraft, purchased from Micropilot. Some modifications were needed to ensure better compliance with the URS. Laboratory and field tests proved that the aircraft can be applied for aerial images, within range of 10 km from the ground control station (GCS). The major limitation is that it can only fly for 40 minutes. Furthermore, the airframe is not robust, needing repairs after only 15 flights. Although the system has shortcomings, it has already been used successfully. It is expected that improved battery technologies and sturdier light-weight materials will further help to improve the system beyond user specifications. / Thesis (MIng (Electrical Engineering))--North-West University, Potchefstroom Campus, 2010.
38

Video syntezátor / Video Synthesizer

Richtr, Pavel Unknown Date (has links)
Generating a video signal for ATtiny85 , authoring software worldwide for video game console ATARI2600 on the theme of UAV attacks and their media image - a reinterpretation of using "low res" generated video.
39

Review of Present Systems and Costs of Conceptual Designs of UAV:s for Humanitarian Relief Missions.

Hektor, Oskar January 2018 (has links)
A study of the viabliness of a UAV for humanitarian relief missions has been done. With an aeronautical model fulfilling humanitarian logistics has then the manufacture and operational life-cycle costs as well as the present air jurisdiction. In contrast to this has also an evaluation of the empty weight conceptual estimation equation been reviewed and what conditions fairly describes the sizing of a UAV. The study finds there’s a technical possibility, economic plausibility but a need for legal development. The coefficients which are sufficient to estimate the empty weight ratio are the Home built aircrafts and powered sailplane. The study concludes what present off-the-shelf systems that might be suitable to sustain humanitarian relief missions. / Syftet med den här studien har varit att undersöka möjligheterna för att använda drönare till att leverera humanitär hjälp. Att ge humanitär hjälp innebär att man assisterar stater i att leverera nödvändiga varor och tjänster till områden där den nationella staten behöver assistans för att upprätthålla nödvändiga livsvillkor för befolkningen. Det kan vara att leverera mat och mediciner men även enklare skolmateriel eller liknande. Oftast är orsaken bakom en humanitär insats att det skett någon typ av katastrof, det kan vara både natur och mänskligt skapade katastrofer. Ett exempel på en sådan nylig kris har varit inbördeskriget som rasat i Syrien under större delen av 2010-talet. Ett problem som har dykt upp är att det är svårt att få fram rätt hjälp dit den behövs, speciellt om de civila som har behovet befinner sig i en krigszon. I ett sådant fall är det mycket riskabelt att transportera och leverera humanitär hjälp till de som behöver det. De riskerar att bli skjutna, kidnappade och kapade. Detta skapar både personliga och materiella skador. Frågan blir då om man skulle kunna leverera den hjälpen med drönare, för att minska risken för personskador men också minska effekten för hela hjälpinsatsen om en eller flera av drönare skulle förvinna. Det som komplicerar hela i logistiken är att man måste ta hänsyn till hur personer byter besittning av godsen och hur man verifierar att varje person får just rätt hjälp. Speciellt då värdet av godset i en kris kan bli asymptotiskt högt. För att testa huruvida det är möjligt att använda UAV:er för humanitär hjälp skapades en simuleringsmodell av en drönare. Eftersom det förväntades att ett uppdrag är ungefär 300 km + 300km tur-o-retur övergavs någon typ av helikopterdesign tidigt. Modellen simulerade många uppdrag som bedömdes vara relevanta för en UAV som skulle leverera humanitär hjälp. Utifrån dessa uppdrag bedömdes några av de operativa kostnader som var knutna till uppdragen. Det gäller främst tillverkningskostnader, bränslekostnader samt avgifter som behöver betalas av den som använder luftrummet. Det finns en bok som är flygplanskonstruktörens bibel (Aircraft Design). Den är skriven av Daniel P. Raymer. Han föreslår där en formel för hur man konceptuellt kan bestämma vikten av ett nytt flygplan. De befintliga planen jämfördes sedan med formeln för att undersöka om dessa också stämde på drönare. Eftersom drönare inte har piloter ombord innebär det att vissa apparater inte behöver finnas på det flygplanet, vilket kan tänkas ändra hur mycket en UAV estimeras väga jämfört med ett vanligt plan. Studien kommer fram till att det som Raymer har föreslagit verkar för det mesta vara rättvisande även när man designar UAV:er. Avslutningsvis identifieras tre olika drönare som med mer eller mindre modifiering skulle kunna användas för humanitära insatser. Dock är, som nämnt tidigare, de flesta UAV:er utvecklade för olika typer av informationssamling. Då flera av dessa apparater inte är lika nödvändiga i en humanitär-logistisk situation är det sannolikt att inköpspriset skulle vara billigare än annars. Slutsatserna är att det nu är tekniskt möjligt att använda drönare för humanitär hjälp, ekonomiskt är det möjligt om än dyrt men juridiskt är det i dagsläget inte möjligt. Juridiken och reglementet för hur avgiftssystemet och luftrummet fungerar behöver utvecklas för att på ett hållbart och säkert sätt integrera autonoma farkoster med befintlig luftfart. Beroende på hur regleringarna av luftrummet förändras, ändras även de ekonomiska förutsättningarna för att använda drönare för att utföra logistiska uppdrag.
40

Streamlining UAV Communication : Investigating and implementing an accessible communication interface between a ground control station and a companion computer

Gustafsson, Johan, Mogensen, Daniel January 2023 (has links)
In the future, the usage of UAVs (Unmanned Aerial Vehicles) will be applied in many different areas. Continued research in UAVs can benefit through its applications in disaster response, humanitarian aid, environmental monitoring, infrastructure inspection, improved transportation and delivery systems, and scientific research. By leveraging UAV technology and making the technology easier to get into, we can enhance efficiency, safety, and accessibility in various fields while addressing critical global challenges and improving the well-being of individuals and communities. The entry knowledge needed for starting development with UAVs can be high due to the complex communication needed between a ground station and the UAV. This report has the goal of lowering that entry barrier by doing an investigation of some available communication protocols, choosing a protocol and using said protocol to develop and implement an interface for communication between a ground control station and companion computer onboard an UAV. The investigation of communication protocols for UAVs indicated that the widely used Mavlink protocol is the best suited communication protocol for this implementation. The development and iterative process, carried out with the mentioned protocol and a UAV flight controller, resulted in the creation of an artifact that can serve as the desired interface.

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