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Ramirez, J. 2015 (Feb). PoCoLoCo, Positioning through Cooperating Loquacious Communications. Technical University of Catalonia (UPC), Castelldefels, Catalonia (Spain). Advisor(s): Cristina Barrado, P.R.
Keywords: UAV, UAS, Navigation, Surveillance, CNS convergence
Abstract: Aerial Transportation system is based in a legacy infrastructure that supports its different functionality separately. There is a tendency to simplify the infrastructure, increasing its efficiency, technical and monetary. UAS are perceived by the general public as simplified versions of the conventional aviation because they have not any human flight crew on board. In fact, they have a flight crew, but this flight crew is placed on ground adding some complications to the system (e.g: Command & Control link). Conventional aviation perceives UAS as a source of problems, mainly because they have no human flight crew on board capable of creating the situational awareness of the UAS. This lack of situational awareness compromises as well the rest of airspace users safety. This PhD explores the capability of UAS to contribute to the situational awareness of both the own aircraft (generating navigation data) as to the situational awareness of the rest of airspace users (generating surveillance data). The contribution to the situational awareness of both the own aircraft (navigation data) as well as the rest of airspace users (surveillance) is simulated assuming UAS communications based on TDMA and at the communication rates described in the literature. The simulation scenario has been kept simple with a low communication rate and a low number of UAS flying in the simulated area. The results of navigation are in line with the RNP1. The results in surveillance are in line with the 3NM separation but with a refresh rate much higher. Then, with this proposal, UAS could be considered as contributors to the situational awareness instead as the problem that destroys the situational awareness.
BibTeX:
      @phdthesis{PhD_ramirez_15_UAV-CNS,
      author = {Jorge Ramirez},
      title = {PoCoLoCo, Positioning through Cooperating Loquacious Communications},
      school = {Technical University of Catalonia (UPC)},
      year = {2015},
      month = {Feb},
      address = {Castelldefels, Catalonia (Spain)},
      url = {http://www.tdx.cat/handle/10803/286787}
      }
  
Delgado, L. 2013 (Apr). Cruise speed reduction for air traffic flow management. Technical University of Catalonia (UPC), Castelldefels, Catalonia (Spain). Advisor(s): Prats, X.
Keywords: ATFM, speed reduction, Ground Delay programs
Abstract: Nowadays, many air transport infrastructures suffer from congestion. This situation is worsened by a continuous increase in traffic, and, traffic density due to hub and spoke systems. Weather is one of the main causes which leads to punctual capacity reduction. To mitigate these imbal- ances, air traffic flow management (ATFM) initiatives are usually undertaken, ground delay at the origin airport being one of the main ones used. By assigning delay on ground at the departure airport, the arrival traffic is spread out and the arrivals are metered at the congested infrastruc- ture. However, forecasting when these capacity drops will be solved is usually a difficult task. This leads to unnecessarily long regulations, and therefore to the realisation of unnecessary delay and an underuse of the capacity of the infrastructures.
The implementation of precise four dimension trajectories, envisaged in the near future, presents new opportunities for dealing with these capacity demand imbalances. In this context, a promising technique is the use of speed variation during the cruise. Generally, it is considered that flying slower than the maximum range speed (MRC) is neither efficient nor desirable. In this dissertation a new approach is presented. When airlines plan their flights, they consider the cost of time along with the cost of fuel. It is therefore common practice to select speeds that are faster than MRC. Thus, it is possible to fly slower than MRC while maintaining fuel consumption as initially planned. This airborne delay can be considered at a pre-tactical phase to divide the as- signed air traffic flow management delay between ground and airborne delay. With this strategy, the delay is absorbed gradually during the flight using the same fuel as initially planned, but with the advantage that, if the regulation is cancelled before planned, the flights which are already airborne are in a better position to recover part of their assigned delay.
This dissertation focuses on the study of this concept. Firstly, a study of the trade-off exist- ing between fuel consumption and flight time, when modifying the nominal cruise speed, is pre- sented. Secondly, the airborne delay that can be realised without incurring extra fuel consumption is defined and assessed in the absence and presence of wind. The influence of selecting a different flight level than initially planned, and the use of extra fuel consumption to obtain higher delay are also considered and analysed. Results show that for short and mid-range flights around 5 mi- nutes of airborne delay can be realised, while for longer flights this value increases up to around 25 minutes. The flight level is identified as one of the main parameters which affect the amount of airborne delay realisable.
Then, the application of the suggested cruise speed reduction on realistic ATFM initiatives, and, in particular, on ground delay programs (GDP) in the United States, is presented. In order to obtain significant results, the GDPs implemented in North American airspace during 2006 are analysed. Scenarios for San Francisco International, Newark Liberty International and Chicago O’Hare International are studied in detail, as these airports were the ones where the most GDPs were implemented in 2006. In addition, due to their location, they present different traffic be- haviours. In order to consider the traffic, Federal Aviation Administration data and the aerody- namics and fuel consumption characteristic form Airbus are used.
Finally, the use of a radius of exemption in the GPDs and the use of ration policies different from the operative ration-by-schedule, are also analysed. To conclude, a brief discussion of the impact of this speed reduction strategy on the air traffic management is presented.
BibTeX:
      @phdthesis{PhD_delgado_13_cruise,
      author = {Luis Delgado},
      title = {Cruise speed reduction for air traffic flow management},
      school = {Technical University of Catalonia (UPC)},
      year = {2013},
      month = {Apr},
      address = {Castelldefels, Catalonia (Spain)},
      url = {http://www.tdx.cat}
      }
  
López, J. 2011 (Mar). Service Oriented Architecture for Embedded (Avionics) Applications. Technical University of Catalonia (UPC), Castelldefels, Catalonia (Spain). Advisor(s): Pastor, E. & Barrado, C.
Keywords: unmanned aircraft systems, UAV architecture, distributed systems, avionics
Abstract: An Unmanned Aerial Vehicle (UAV) is a low-cost non-piloted airplane designed to operate in D-cube (Dangerous-Dirty-Dull) situations. Many types of UAVs exist today; however with the advent of UAV’s civil applications, the class of mini/micro UAVs is emerging as a valid option in a commercial scenario. This type of UAV shares limitations with most computer embedded systems: limited space, limited power resources, increasing computation requirements, complexity of the applications, time to market requirements, etc. These stringent requirements are highlighted in civil applications. In this case, the same platform should be able to implement a large variety of missions with little reconfiguration time and overhead if it must be economically viable. The main thesis of this research is a middleware-based architecture specially suited to operate as a flexible payload and mission controller in a UAV. The system is composed of a number of low-cost computing devices connected by a network. The functionality of the system is divided in reusable services that can be distributed over the different nodes of the network. A middleware manages the lifecycle and the communication between services, operating the global system as a Distributed Embedded System. The communication primitives are mainly publish-subscribe based, however two- way synchronous communication, i.e remote procedure calls are also available for the services. Additional efforts have been placed in some specifics of the UAV avionics domain, in special the interoperation with unreliable and high-latency point-to-point networks. The system not only comprises the hardware onboard the airframe, it can be extended to several UAVs and the ground control station. This problematic is managed by special nodes called Communication Gateways that act as transparent proxies for the services located away. A lot of research has been done in the area of avionics middleware; however it is mainly focused on the control domain and in the real-time operation of the middleware. Our proposal differs in that we address the implementation of easily adaptable and reconfigurable unmanned missions in low-cost and low-resources hardware. The proposed middleware architecture offers simplicity, adaptability, network transparency and a high-level vision that eases the development of this sort of missions.
BibTeX:
      @phdthesis{PhD_lopez_11_service,
      author = {Juan López},
      title = {Service Oriented Architecture for Embedded (Avionics) Applications},
      school = {Technical University of Catalonia (UPC)},
      year = {2011},
      month = {Mar},
      address = {Castelldefels, Catalonia (Spain)},
      url = {http://www.tesisenxarxa.net}
      }
  
Santamaria, E. 2010 (Jun). Formal Mission Specification and Execution Mechanisms for Unmanned Aircraft Systems. Technical University of Catalonia (UPC), Castelldefels, Catalonia (Spain). Advisor(s): Pastor, E. & Barrado, C.
Keywords: unmanned aircraft systems, flight plan, rnav, mission specification
Abstract: Unmanned Aerial Systems (UAS) have great potential to be used in civil applications. Many key UAS components are already in the market, but a number of limitations need to be addressed. In particular, there is a lack of mechanisms for specifying and executing complex flight plans and to coordinate flight and payload operation according to the different mission phases, which limits autonomy capibilities of current systems. Other requirements we believe are key to the success of UAS in the civil space are reconfigurability and cost-effectiveness. As a result, an affordable platform should be able to operate in different application scenarios with reduced human intervention. In this dissertation, the addition of flight plan and mission management layers on top of a commercial-off-the-shelf flight control system is proposed. By doing so, a high level of autonomy can be achieved while taking advantage of available technologies. Reconfiguration is made possible by separating flight and mission execution from its specification. Validation of the proposed approach is carried out with two example missions run in a simulation environment that show the UAS performance in a complex flight scenario and its ability to dynamically adapt to the mission needs.
BibTeX:
      @phdthesis{PhD_santamaria_10_mission,
      author = {Eduard Santamaria},
      title = {Formal Mission Specification and Execution Mechanisms for Unmanned Aircraft Systems},
      school = {Technical University of Catalonia (UPC)},
      year = {2010},
      month = {Jun},
      address = {Castelldefels, Catalonia (Spain)},
      url = {http://www.tesisenxarxa.net}
      }
  
Royo, P. 2010 (May). An Open Architecture for the Integration of UAS Civil Applications. Technical University of Catalonia (UPC), Castelldefels, Catalonia (Spain). Advisor(s): Pastor, E. & Barrado, C.
Keywords: unmanned aircraft systems, UAV architecture, distributed systems, avionics
Abstract: Currently, Unmanned Aircraft System (UAS) are mostly being used for military applications, but with the evolution of avionics technology, a huge market in civil applications is now emerging. However, there is a lack of hardware and software support to effectively develop these potentialities in the civil domain. No commercial solution exists today that provides the support needed for these civil missions. In addition, economic efficiency requires the same UAS to be able to operate in different application types and domains. Therefore, one of the current challenges in UAS research is to define a hardware/software UAS framework that is sufficiently flexible and reusable to be operated in a wide range of civil applications. In order to be competitive in the civil market this framework must provide fast prototyping and be low in cost. The main objective of this doctoral thesis was to design and develop a flexible and reusable hardware/software abstraction layer for a UAS distributed architecture in order to carry out different UAS civil missions. The proposed abstraction layer is called UAS Service Abstraction Layer (USAL) which allows the easy and fast design of missions and solves the reusability of the system in a cost-effective way. The existence of an open-framework avionics package specifically designed for UAS alleviates the development costs, allowing them to be redesigned for different missions by a simple parameterization. For this software abstraction layer, a distributed service oriented architecture (SOA) is used. Functional units are implemented as independent services that interact with each other using a Local Area Network (LAN). From the study of UAS civil missions and the state of the art in the design of UAS architecture, an exhaustive list of self-content services needed in almost all UAS civil missions is offered. Thus, the USAL provides a list of common services needed to develop the different civil missions identified. These services have been organized into four different categories, each containing services that cooperate in the same main objective such as Flight, Mission, Payload and Awareness. The flight category services have been designed, implemented and tested over a simulation platform called ICARUS Simulation Integrated Scenario (ISIS). ISIS provides a test environment in which the USAL components or services that have already been designed can interact with others that are being designed. It also provides an easier and safer way to test the mission application. The fact that a flying UAS or other mission equipment is not needed significantly reduces the cost of testing the USAL. Finally, a proof of concept of the USAL has been built using a remote sensing application. This proof of concept and the possible mission strategy have been tested over the ISIS platform as part of the ``Sky-Eye'' project. The aim of this project is to monitor wild land fires in the Mediterranean area, with special emphasis on the hot-spot monitoring application, and thereby to demonstrate the use and reconfiguration capability of the USAL.
BibTeX:
      @phdthesis{PhD_royo_10_architecture,
      author = {Pablo Royo},
      title = {An Open Architecture for the Integration of UAS Civil Applications},
      school = {Technical University of Catalonia (UPC)},
      year = {2010},
      month = {May},
      address = {Castelldefels, Catalonia (Spain)},
      url = {http://www.tesisenxarxa.net}
      }
  
Prats, X. 2010 (Jan). Contributions to the optimisation of aircraft noise abatement procedures. PhD. thesis in Aerospace Science and Technology: Technical University of Catalonia (UPC), Castelldefels, Catalonia (Spain). Advisor(s): Quevedo, J. & Puig, V.
Keywords: Aircraft noise abatement, aircraft trajectory optimization, multi-objective optimization, fuzzy logic
Abstract: Containing the sound generated by aircraft operations, while meeting the increasing demand for aircraft transportation, is one of the major challenges that airport authorities, air traffic service providers and aircraft operators may deal with. In the forthcoming years, new avionic systems and new Air Traffic Management concepts are expected to significantly improve the design of flight procedures, enabling the definition of optimal flight procedures regarding the noise annoyance impact. In addition, one can conceive a situation where these kinds of procedures can be designed automatically or semi-automatically by an expert system, based on optimisation techniques and approximate reasoning. This would serve as a decision making tool for airspace planners and procedure designers. In this dissertation a complete framework for computing optimal noise abatement procedures is developed. Thence, a multi-criteria optimal control problem is formulated and solved by using different multi-objective optimisation techniques. A final strategy is applied successfully to a complex and real scenario, where the East departures of runway 02 at the airport of Girona (Catalonia, Spain) are optimised.
BibTeX:
      @phdthesis{PhD_prats_10_contributions,
      author = {Xavier Prats},
      title = {Contributions to the optimisation of aircraft noise abatement procedures},
      school = {Technical University of Catalonia (UPC)},
      year = {2010},
      month = {Jan},
      address = {Castelldefels, Catalonia (Spain)},
      type = {PhD. thesis in Aerospace Science and Technology},
      url = {http://www.tesisenxarxa.net/TDX-1108110-105558/}
      }
  

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