La comunidad científica ha mostrado gran interés por estudiar los fenómenos que ocurren sobre la superficie de la tierra, específicamente los que suceden en la atmósfera, los océanos, o la superficie del suelo, y que afectan el clima o modifican la superficie de la tierra. Para poder analizar y predecir estos fenómenos, se monitorizan parámetros que se relacionan de manera directa o indirecta con procesos biofísicos y geofísicos. Es en este punto donde la teledetección entra en juego, puesto que es la técnica que permite medir tales parámetros de forma remota sin necesidad de entrar en contacto directo con un objeto o una superficie. En particular, la teledetección por microondas permite la detección de energía electromagnética casi bajo cualquier condición climática y a cualquier hora del día, debido a que a esta longitud de onda la energía electromagnética puede penetrar a través de las nubes, polvo, neblina y lluvia, y es menos susceptible a la dispersión atmosférica, que afecta en gran medida a las señales ópticas. Actualmente existen varios sistemas de teledetección por microondas que se han embarcado en satélites, para monitorizar parámetros biofísicos y geofísicos sobre la superficie de la tierra de manera global. También se han desarrollado estos sistemas para ser transportados en plataformas aéreas tripuladas para realizar estudios a nivel local o regional, donde se desea obtener información de una zona en particular en tiempos relativamente cortos. Sin embargo, ambas plataformas representan, entre otras cosas, un alto coste, no solo económico sino de infraestructura, equipo, grupos de trabajo, permisos de operación, y varios requerimientos más. El creciente desarrollo de los sistemas aéreos no tripulados (Unmanned Aerial Vehicle, UAV), ha hecho posible su uso para transportar sensores de teledetección. Los sistemas UAV presentan las mismas ventajas que los sistemas aéreos tripulados, pero además añaden otras ventajas adicionales. Por ejemplo, pueden ser operados durante varias horas de forma autónoma, el coste de explotación y desarrollo puede ser menor que el de un avión tripulado si se emplea un UAV de bajas prestaciones. Por tal motivo en este trabajo se propone el uso de un aeromodelo de control por radio como plataforma UAV para monitorizar diversos parámetros geofísicos y biofísicos de la tierra mediante sensores activos y pasivos de teledetección por microondas. Para realizar las medidas de teledetección pasiva se ha desarrollado el sensor denominado Airborne RadIometEr at L-Band (ARIEL) que es un radiómetro Dicke de bajo peso y pequeñas dimensiones, y que trabaja en Banda L (≈1.4 GHz). En la presenta memoria se muestra el diseño del sensor, las características principales de funcionamiento, y las técnicas de procesamiento de datos. Posteriormente se presentan las campañas de medida realizadas en zonas de cultivo, suelo descubierto, y zonas costeras. En tales campañas se han conseguido generar mapas de temperatura de brillo y de humedad de suelo. Con el fin de llevar a cabo medidas de teledetección activa se ha desarrollado el sistema denominado AiR Based REmote Sensing ARBRES, que consta de dos sensores radar de apertura sintética SAR diseñados a dos frecuencias diferentes, uno en Banda C (≈ 5.3 GHz) y otro en Banda X (≈ 9.65 GHz). Ambos radares son de onda continua FMCW, además son de bajo peso, bajo consumo de potencia y de pequeñas dimensiones. Ambos sensores tienen la capacidad de realizar medidas de interferometría SAR. En esta memoria se muestran las características de funcionamiento del sistema, así como algunos algoritmos de focalización de imágenes SAR, y una técnica para compensar los movimientos de la plataforma de vuelo. Finalmente se presentan medidas en campo para obtener imágenes de reflectividad de un escenario, y se muestran también los resultados para medidas realizadas en configuración de interferometría de simple pasada, la cual está relacionada con la topografía del terreno.

This thesis investigates the crucial problem of collision avoidance for autonomous vehicles.  An anti-collision system for an unmanned aerial vehicle (UAV) is studied in particular. The purpose of this system is to make sure that the own vehicle avoids collision with other aircraft in mid-air. The sensor used to track any possible threat is for a UAV limited basically to a digital video camera. This sensor can only measure the direction to an intruding vehicle, not the range, and is therefore denoted an angle-only sensor. To estimate the position and velocity of the intruder a tracking system, based on an extended Kalman filter, is used. State estimates supplied by this system are very uncertain due to the difficulties of angle-only tracking. Probabilistic methods are therefore required for risk calculation. The risk assessment module is one of the essential parts of the collision avoidance system and has the purpose of continuously evaluating the risk for collision. To do this in a probabilistic way, it is necessary to assume a probability distribution for the tracking system output. A common approach is to assume normality, more out of habit than on actual grounds. This thesis investigates the normality assumption, and it is found that the tracking output rapidly converge towards a good normal distribution approximation. The thesis furthermore investigates the actual risk assessment module to find out how the collision risk should be determined. The traditional way to do this is to focus on a critical time point (time of closest point of approach, time of maximum collision risk etc.). A recently proposed alternative is to evaluate the risk over a horizon of time. The difference between these two concepts is evaluated. An approximate computational method for integrated risk, suitable for real-time implementations, is also validated. It is shown that the risk seen over a horizon of time is much more robust to estimation accuracy than the risk from a critical time point. The integrated risk also gives a more intuitively correct result, which makes it possible to implement the risk assessment module with a direct connection to specified aviation safety rules.

This thesis deals with the development of a Conceptual Design Tool for unmanned helicopters, so called VTOL UAVs. The goal of the Design Tool is: • Quick results • Good accuracy • Easy to use The two first points of the goal are actually more or less dependent on each other. In almost all cases a high accuracy gives a slow calculator and vice versa. In order to fulfill the goal a compromise between calculation accuracy and calculation time needs to be done. To make the Design Tool an easy to use program a graphical user interface is used. The graphical user interface allows the user to systematically work his way thru the program from a fictive mission to a complete design of a helicopter. The pre-requirements on the user have been eliminated to a minimum, but for the advanced user the possibilities to create more specific and complex helicopters are good. In order to develop a Conceptual Design Tool the entire helicopter needs to be seen as a complete system. To see the helicopter as a system all of the sub parts of a helicopter need to be studied. The sub parts will be compared against each other and some will be higher prioritized than other. The outline of this thesis is that it is possible to make a user friendly Conceptual Design Tool for VTOL UAVs. The design procedure in the Design Tool is relatively simple and the time from start to a complete concept is relatively short. It will also be shown that the calculation results have a good agreement with real world flight test data.

The market for vertical takeoff and landing unmanned aerial vehicles, VTOL UAVs, is growing rapidly. To reciprocate the demand of VTOL UAVs in offshore applications, CybAero has developed a novel concept for landing on moving objects called MALLS, Mobile Automatic Launch and Landing Station. MALLS can tilt its helipad and is supposed to align to either the horizontal plane with an operator adjusted offset or to the helicopter skids. Doing so, eliminates the gyroscopic forces otherwise induced in the rotordisc as the helicopter is forced to change attitude when the skids align to the ground during landing or when standing on a jolting boat with the rotor spun up. This master’s thesis project is an attempt to get the concept of MALLS closer to a quarter scale implementation. The main focus lies on the development of the measurement methods for achieving the references needed by MALLS, the hori- zontal plane and the plane of the helicopter skids. The control of MALLS is also discussed. The measurement methods developed have been proved by tested implementations or simulations. The theories behind them contain among other things signal filtering, Kalman filtering, sensor fusion and search algorithms. The project have led to that the MALLS prototype can align its helipad to the horizontal plane and that a method for measuring the relative attitude between the helipad and the helicopter skids have been developed. Also suggestions for future improvements are presented.

The standard way for both ground and aerial vehicles to navigate is to use anInertial Navigation System, INS, containing an Inertial Measurement Unit, IMU,measuring the acceleration and angular rate, and a GPS measuring the position.The IMU provides high dynamic measurements of the acceleration and the angularrate, which the INS integrates to velocity, position and attitude, respectively.While being completely impossible to jam, the dead-reckoned estimates will driftaway, i.e., the errors are unbounded. In conjunction with a GPS, providing lowdynamic updates with bounded errors, a highly dynamic system without any driftis attained. The weakness of this system is its integrity, since the GPS is easilyjammed with simple equipment and powered only by a small standard battery.When the GPS is jammed this system falls back into the behavior of the INS withunbounded errors. To counter this integrity problem a camera can be used aseither a back up to the GPS or as its replacement. The camera provides imageswhich are then matched versus a reference, e.g., a map or an aerial photo, to getsimilar estimates as the GPS would provide. The camera can of course also bejammed by blocking the view of the camera with smoke. Bad visibility can alsooccur due to bad weather, but a camera based navigation system will definitelybe more robust than one using GPS.This thesis presents two ways to fuse the measurements from the camera and theIMU, both of them utilizing the Harris corner detector to find point correspondencesbetween the camera image and an aerial photo. The systems are evaluatedby simulated data mimicking both a low and a high accuracy IMU and a camerataking snapshots of the aerial photo. Results show that for the simulated cameraimages the implemented corner detector works fine and that the overall result iscomparable to using a GPS. / Standardsättet för både flygande och markgående fordon att navigera är att användaett tröghetsnavigeringssystem, innehållande en IMU som mäter acceleration ochvinkelhastighet, tillsammans med GPS. IMU:n tillhandahåller högfrekventa mätningarav acceleration och vinkelhastighet som integreras till hastighet, positionoch attityd. Ett sådant system är omöjligt att störa, men lider av att de dödräknadestorheterna hastighet, position och attityd, med tiden, kommer att driva ivägifrån de sanna värdena. Tillsammans med GPS, som ger lågfrekventa mätningarav positionen, erhålls ett system med god dynamik och utan drift. Svagheten i ettvvisådant system är dess integritet, då GPS enkelt kan störas med enkel och billigutrustning. För att lösa integritetsproblemet kan en kamera användas, antingensom stöd eller som ersättare till GPS. Kameran tar bilder som matchas gentemoten referens ex. en karta eller ett ortofoto. Det ger liknande mätningar som de GPSger. Ett kamerabaserat system kan visserligen också störas genom att blockerasynfältet för kameran med exempelvis rök. Dålig sikt kan också uppkomma pågrund av dåligt väder eller dimma, men ett kamerabaserat system kommer definitivtatt vara robustare än ett som använder GPS.Det här examensarbetet presenterar två sätt att fusionera mätningar från etttröghetssystem och en kamera. Gemensamt för båda är att en hörndetektor, Harriscorner detector, används för att hitta korresponderande punkter mellan kamerabildernaoch ett ortofoto. Systemen utvärderas på simulerat data. Resultatenvisar att för simulerade data så fungerar den implementerade hörndetektorn ochatt prestanda i nivå med ett GPS-baserat system uppnås.

Mapping is a central and common task in robotics research. Building an accurate map without human assistance provides several applications such as space missions, search and rescue, surveillance and can be used in dangerous areas. One application for robotic mapping is to measure changes in terrain volume. In Sweden there are over a hundred landfills that are regulated by laws that says that the growth of the landfill has to be measured at least once a year. In this thesis, a preliminary study of methods for measuring terrain volume by the use of an Unmanned Aerial Vehicle (UAV) and a Light Detection And Ranging (LIDAR) sensor is done. Different techniques are tested, including data merging strategies and regression techniques by the use of Gaussian Processes. In the absence of real flight scenario data, an industrial robot has been used fordata acquisition. The result of the experiment was successful in measuring thevolume difference between scenarios in relation to the resolution of the LIDAR. However, for more accurate volume measurements and better evaluation of the algorithms, a better LIDAR is needed. / Kartering är ett centralt och vanligt förekommande problem inom robotik. Att bygga en korrekt karta av en robots omgivning utan mänsklig hjälp har en mängd tänkbara användningsområden. Exempel på sådana är rymduppdrag, räddningsoperationer,övervakning och användning i områden som är farliga för människor. En tillämpning för robotkartering är att mäta volymökning hos terräng över tiden. I Sverige finns det över hundra soptippar, och dessa soptippar är reglerade av lagar som säger att man måste mäta soptippens volymökning minst en gång om året. I detta exjobb görs en undersökning av möjligheterna att göra dessa volymberäkningarmed hjälp av obemannade helikoptrar utrustade med en Light Detectionand Ranging (LIDAR) sensor. Olika tekniker har testats, både tekniker som slår ihop LIDAR data till en karta och regressionstekniker baserade på Gauss Processer. I avsaknad av data inspelad med riktig helikopter har ett experiment med en industri robot genomförts för att samla in data. Resultaten av volymmätningarnavar goda i förhållande till LIDAR-sensorns upplösning. För att få bättre volymmätningaroch bättre utvärderingar av de olika algoritmerna är en bättre LIDAR-sensor nödvändig.

This thesis will analyze the Z-wing configuration. The Z-wing configuration is basically an airplane that has one of the wings placed at the forward section of the fuselage and the other wing placed on the other side far aft at the fuselage. This configuration creates a lot of different and unwanted forces and moments due to a differential in lift and drag between both the wings and the main objective with this thesis is to get a Z-wing to fly straight and level flight without these strange and unwanted forces and moments over it. Therefore the contribution of the wings different parameters to different moments and forces have been mapped out. Parameters such as the angle of incidence, wing span, dihedral, placement of wings etc. All the calculations done regarding the aerodynamic forces on the Z-wing have been performed in the Tornado, which is a program that runs in MATLAB and uses Vortex Lattice Method for its calculations. The outcome was that a steady level flight was possible. The configuration does have a lot of disadvantages. It will be very difficult to control in pitch, yaw and roll, although a backwards sweep of the front wing and a backwards sweep of the aft wing made roll control much better.

This thesis describes the work performed at Saab Aeronautics in Linkoping during 2011. The work was to study and develop distributed and centralized methods for analysis of the decision making in a group of unmanned aerial vehicles (UAVs). In addition to this, some simple scenarios were studied and the work was implemented in C++ as the simulator ComDec. The literature review presented in the report provides knowledge of strategies for collaborative UAVs (communication and decision making), understanding of the problems/constraints that are relevant for data links and insight into the algorithms for decision making and autonomy. This work has resulted in a theoretical analysis of suitable design for decision making in a group of interacting autonomous UAVs. Existing methods for distributed and centralized decision making are implemented and a demonstration ofthe outcome are presented in the thesis. It is further shown how various communication problems and disturbances affect the decision making process. Finally, advantages and disadvantages of the selected strategies (communication and decision making) are discussed.

Många försvarsanalytiker och luftmaktsteoretiker har sedan 1990-talet gjort gällande att teknisktavancerade så kallade UCAV farkoster, kan komma att ersätta eller komplettera många av de idagmest avancerade stridsflygplanens uppgifter. Dessa förväntningar har inte infriats. De beväpnadeUAV som nu används i pågående operationer skulle mer kunna liknas vid beväpnade propellerdrivnasegelflygplan och utvecklingen av dessa kan sägas ha varit mer pragmatisk än innovativ.Utvecklingen skulle kunna förklaras som två olika utvecklingsspår, Armed UAV och UCAV. Undersökningenvisar att det är Armed UAV:s egenskap, uthållighet som gör att den är ett så efterfrågatsystem i dagens lågintensiva konflikter. UCAV å andra sidan har visat sig vara både dyrareoch komplexare än man tidigare förutsåg, men framförallt är dess egenskaper hastighet, autonomioch signaturanpassning i dagsläget inte efterfrågade. / During the last decade of the 20th century, visionary theorists predicted that advanced UCAVswould replace or complement existing fighter aircraft of today. Those predictions have not beenfulfilled. The Armed UAVs used in today’s conflicts could almost be seen as armed sailplanes andthe development can be described as more pragmatic then innovative. The development could beexplained as two separate development tracks, Armed UAV and UCAV. The analysis shows thatArmed UAVs characteristic persistence is the driving factor in today’s low intensive conflicts. Themore glamorous UCAV on the other hand has showed to be more complex and expensive thanexpected, and especially that its characteristics: speed, autonomy and stealth are not demanded intoday’s conflicts. / Avdelning: ALB - Slutet Mag 3 C-upps. Hylla: Upps. ChP 06-08

Luftstridskrafter har spelat en betydande roll i senare tiders Peace Support Operations (PSO). Obemannade flygande system har varit en del av dessa insatser, hur kommer rollfördelningen att vara i framtiden? Syftet med uppsatsen är att undersöka och göra en bedömning avseende hur obemannade flygsystem kan utnyttjas och ha en roll i framtida Peace Suport Operations. Litteratur- och dokumentstudier, föreläsningar och intervjuer ligger som faktabakgrund för bedömningen av hur en framtida PSO kan se ut samt vilken roll obemannade flygsystem kan ha i en framtida Peace Suport Operation. Jämförelse har skett mellan bemannade och obemannade flygande system varvid fördelar och nackdelar har belysts. Resultatet av studien är att obemannade flygande system bör kunna få en betydande roll i framtida Peace Suport Operations främst avseende underrättelseinhämtning och uppgifter där vapenleverans inte är huvuduppgiften. Obemannade flygande farkoster med stridsuppgift (UCAV) har däremot betydande hinder som måste övervinnas innan dessa kan få en viktig roll i framtida PSO. Det är inte uteslutet att UCAV efter en tids utveckling kan få en viktig roll i en framtida PSO främst inom uppgifter som karaktäriseras av stor risktagning, krav på lång uthållighet eller uppträdande i ohälsosam miljö. / Avdelning: ALB - Slutet Mag 3 C-upps.Hylla: Upps. ChP 99-01