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This dissertation develops the visual pursuit method for air-to-air tracking and rendezvous of unmanned aircraft systems. It also shows the development of vector-field and proportional-integral methods for controlling UAS flight in formation with other aircraft. The visual pursuit method is a nonlinear guidance method that uses vision-based line of sight angles as inputs to the algorithm that produces pitch rate, bank angle and airspeed commands for the autopilot to use in aircraft control. The method is shown to be convergent about the center of the camera image frame and to be stable in the sense of Lyapunov. In the lateral direction, the guidance method is optimized to balance the pursuit heading with respect to the prevailing wind and the location of the target on the image plane to improve tracking performance in high winds and reduce bank angle effort. In both simulation and flight experimentation, visual pursuit is shown to be effective in providing flight guidance in strong winds. Visual pursuit is also shown to be effective in guiding the seeker while performing aerial docking with a towed aerial drogue. Flight trials demonstrated the ability to guide to within a few meters of the drogue. Further research developed a method to improve docking performance by artificially increasing the length of the line of sight vector at close range to the target to prevent flight control saturation. This improvement to visual pursuit was shown to be an effective method for providing guidance during aerial docking simulations. An analysis of the visual pursuit method is provided using the method of adjoints to evaluate the effects of airspeed, closing velocity, system time constant, sensor delay and target motion on docking performance. A method for predicting docking accuracy is developed and shown to be useful for predicting docking performance for small and large unmanned aircraft systems.

熱像儀，能感測可見光感測器無法取得的訊息，因此若能透過熱像儀器進行環境偵測，便能得到一般可見光感測器無法獲取的資料。本研究擬以四旋翼UAS酬載熱像儀得到局部區域高解析度之地面熱資訊以便作為地溫研究之背景資料使用。而一般地溫研究區，不易佈設控制點，因此本研究除於無人機上酬載熱像儀之外，並將搭載Trimble BD970 GNSS OEM接收模組，嘗試以少量地面控制點、以及GNSS動態後處理的方式取得取像時對應的GNSS觀測量輔助熱像定位定向。本研究中針對國立政治大學旁的指南溪實驗區與陽明山國家公園的小油坑實驗區，使用AI-RIDER YJ-1000-HC四旋翼UAS分別酬載熱像儀FLIR Tau 640和巨哥XM6，並且同時搭載Trimble BD970 GNSS OEM接收模組、以及GNSS動態後處理的方式取得取像時對應的GNSS觀測量搭配少量地面控制點輔助熱像定位定向，過程中透過三焦張量剔除自動匹配之誤匹配連結點。實驗結果顯示，兩實驗區所產製之DSM於不易變動區域精度經現有資料檢核均在±1m，而指南溪實驗區產製出地面解析度11公分的數值表面模型(Digital Surface Model, DSM)與正射熱像，且正射熱像平面精度達為47公分；小油坑實驗區產製出地面解析度14公分之DSM與正射熱像，正射熱像平面精度則為67公分，雖然DSM和正射熱像精度無法符合一般常規的測量規範，但成果仍然可以證明熱像直接產製DSM以及正射熱像之可行性，兩實驗區最後皆生成數值溫度表面模型(Digital Surface Temparature Model, DSTM)，顯示本研究所提方法之可行性，所生成之成果可供後續地溫研究使用。 / Thermal infrared images show the temperature change of sensed scenes. Therefore, thermal infrared camera can sense some important information that optical digital cameras cannot do for the environment monitoring. In this study, the Quadcopter UAS for thermal image collection applied to geothermal study will be developed. FIIR Tau 640 and Magnity Eletric XM6 thermal infrared sensor will be used in this thermal image collection system separately two test areas, Zhinan River nearby NCCU and Xiaoyoukeng, in the Yangmingshan National Park. Additionally, Trimble BD970 GNSS OEM board will be carried on the Quadcopter UAS to collect dual-frequency GNSS observations for determining the flying trajectory by Post-processed kinematic (PPK) technique to support the positioning and orientating of collected thermal images, and the trifocal tensor will be used to delete wrong matching tie images points. From the tests, the differences between produced DSM and existing DSM data are ± 1 m on uneasy change ground surface in two test areas. The resolution of produced DSM and thermal orthoimages are about 11 cm in Zhinan River, and 14cm in Xiaoyoukeng area. The accuracy of thermal orthoimages is 47cm in Zhinan River and 67cm in Xiaoyoukeng area. The accuracy of thermal orthoimages may not comply with a normal surveying standard, but it proves the possibility of DSM and orthorectifed thermal images generated from thermal images directly. Digital Surface Temparature Model (DSTM) produced in both tests can be used for volcanic geothermal monitoring in the future.

The thesis analyses the legality of the use of drones in warfare based on the examination of three specific case studies. Firstly the use of armed drones in Afghanistan 2001 and 2002, then Pakistan drone strikes ongoing since 2004 and lastly the Yemen case study. A developed legal framework is used to assess the legality of the use of drones. Furthermore, it briefly touches upon the aspects of morality and ethics of the use of the unmanned aerial vehicles in combat.

<p>Civil engineering structures must provide an adequate and safe performance during their time of service, and the owners of these structures must have a reliable inspection strategy to ensure time-dependent damage does not become excessive. Visual inspection is the first step in every structural inspection; however, many elements in the majority of structures are difficult to access and require specialized personal and equipment. In an attempt to reduce the risk of the inspector and the cost of additional equipment, the use of Unmanned Aircraft Systems (UAS) has been increasing in the last years. The absence of standards and regulations regarding the use of UAS in inspection of structures has allowed the market to widely advertise Unmanned Aerial Vehicles (UAV) without protocols or qualifications that prove their effectiveness, leaving the owners of the structures to solely rely on claims of the vendors before deciding which technology suits their particular inspection needs. Focusing primarily on bridge inspection, this research aimed to address the lack of performance-based evaluation and standards for UAS, developing a validation criterion to evaluate a given UAS based on a repeatable test that resembles typical conditions in a structure. </p><p><br></p><p>Current applications of UAS in inspection of structures along with its advantages and limitations were studied to determine the current status of UAS technologies. A maximum typical rotor-tip-to-rotor-tip distance of an UAV was determined based on typical UAVs used in bridge inspection, and two main parameters were found to be relevant when flying close to structures: proximity effects in the UAV and availability of visual line of sight. Distances where proximity effects are relevant were determined based on several field inspections and flights close to structures. In addition, the use of supplementary technologies such as Global Positioning System (GPS) and Inertial Measurement Units (IMU) was studied to understand their effect during inspection. </p><p><br></p><p>Following the analysis, the author introduces the idea of a series of obstacles and elements inside an enclosed space that resemble components of bridge structures to be inspected using UAVs, allowing repeatability of the test by controlling outside parameters such as lighting condition, wind, precipitation, temperature, and GPS signal. Using distances based on proximity effects, maximum typical rotor-tip-to-rotor-tip distance, and a gallery of bridges and situations when flying close to bridge structures, a final arrangement of elements is presented as the evaluation chamber. Components inside the evaluation chamber include both “real” steel and concrete specimens as well as those intended to simulate various geometric configurations on which other features are mounted. Pictures of damages of steel and concrete elements have been placed in the internal faces of the obstacles that can be assessed either in real-time flight or in post-processing work. A detailed comparison between the objectives of this research project and the results obtained by the evaluation chamber was performed using visual evaluation and resolution charts for the images obtained, the availability of visual line of sight during the test, and the absence of GPS signal.</p><p><br></p><p>From the comparison and analysis conducted and based on satisfactory flight results as images obtained during flights, the evaluation chamber is concluded to be a repeatable and reliable tool to apply to any UAS prior to inspect bridges and other structures, and the author recommends to refrain from conducting an inspection if the UAS does not comply with the minimum requirements presented in this research work. Additionally, this research provided a clearer understanding of the general phenomenon presented when UAVs approach structures and attempts to fill the gap of knowledge regarding minimum requirements and criterion for the use of UAS technologies in inspection of structures.</p>