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.

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.

Cette thèse a pour but de découvrir la faisabilité et le potentiel de la récupération d'énergie à partir de rafales atmosphériques pour les micro et mini véhicules aériens sans pilote. L'atmosphère sert de grande source d'énergie pouvant être récoltée afin d'accroître la performance des petits UAV sous la forme d'une autonomie et d'une autonomie étendues. Il est bien connu que de nombreuses espèces d'oiseaux utilisent diverses techniques de vol pour obtenir des performances de vol étonnantes. Compte tenu du fait que les véhicules susmentionnés partagent la taille et la vitesse de vol avec des dépliants naturels, cette thèse peut être considérée comme une application des techniques de vol bio-inspirées pour les véhicules construits par l’homme. Cette étude de trois ans visait à établir une dérivation théorique des équations qui décrivent la dynamique de vol d'un aéronef en présence d'un environnement en rafales. La première réalisation a été la démonstration du mécanisme de récupération d'énergie et des paramètres d'influence à travers des simulations décrivant le vol en modèle de masse ponctuelle d'aéronef avec un contrôle optimisé de l'ascenseur en présence d'un profil de vent sinusoïdal et stochastique. La réalisation suivante est liée à un système sensoriel inspiré par la biologie qui utilise des mesures de pression des ailes pour estimer l’angle d’attaque local. Ce système particulier a été utilisé dans l’estimation du champ de vent, en tant que mécanisme décisif et protection contre le décrochage. Enfin, les dernières contributions sont liées à l’expérience et aux résultats obtenus lors d’essais en vol visant à prouver l’augmentation de l’état énergétique de l’avion lors des manœuvres de récupération d’énergie. La première campagne d'essais en vol a été réalisée avec un mini-UAV disponible dans le commerce équipé de sondes à trous multiples et d'un contrôleur conçu sur mesure. Cette campagne a démontré l’augmentation de l’état d’énergie dans un fort gradient de vent horizontal. La deuxième campagne d'essais en vol a été réalisée avec une aile volante équipée d'un système de détection de pression pour l'estimation du champ de vent. Cette campagne a également impliqué des économies supplémentaires sur la consommation d'énergie électrique lors des vols de récupération d'énergie. / This thesis aims at discovering the feasibility and potential of energy-harvesting from atmospheric gusts for micro and mini unmanned aerial vehicles. The atmosphere serves as a great source of energy that can be harvested in order to increase performance of small UAVs in form of extended endurance and range. It is well known that many bird species use various flight techniques for achieving astonishing flight performances. Considering the fact that aforementioned vehicles share size and flight speed with natural flyers, this thesis can be considered as an application of bioinspired flight techniques for man made vehicles. This three-year study set out to establish a theoretical derivation of equations that describe flight dynamics of an aircraft in presence of gusty environment. The first achievement was demonstration of energy harvesting mechanism and influencing parameters through simulations that describe aircraft point mass model flight with optimized control of elevator in presence of sinusoidal and stochastic wind profile. The next achievement is related to a biologically inspired sensory system that uses wing pressure measurements for local angle of attack estimation. That particular system found purpose in wind field estimation, as decisive mechanism and stall protection. Finally, last contributions are related to experience and results gained from flight tests which aimed to prove increase in energy state of the aircraft while performing energy harvesting maneuvers. The first flight test campaign was performed with commercially available mini UAV equipped with multi-hole probes and custom designed controller. This campaign demonstrated the raise in energy state within strong horizontal wind gradient. The second flight test campaign was done with a flying wing equipped with pressure sensing system for wind field estimation. This campaign also involved additional insight savings in electrical power consumption during energy harvesting flights.

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.