Ao longo das últimas décadas, o paradigma de sistemas críticos em segurança vem sofrendo transformações como forma de se adequar às novas necessidades demandadas, tais como redução de custos e aumento da produtividade. No Sistema de Gerenciamento de Tráfego Aéreo, esta transformação é preconizada pelo paradigma CNS/ATM (Communication, Navigation, Surveillance / Air Traffic Management), baseado no uso de novas tecnologias digitais, sobretudo satélites, aplicadas à comunicação, à vigilância, à navegação e ao gerenciamento do tráfego aéreo. O CNS/ATM visa reduzir as restrições do atual paradigma de tráfego aéreo como forma de atender sua crescente demanda, mantendo (ou melhorando) os atuais níveis de segurança. Porém, esta mudança de paradigma traz consigo novos desafios e necessidades, sobretudo, quanto à forma de se avaliar os sistemas resultantes. Em face destes novos desafios e problemas enfrentados, este trabalho propôs um método de avaliação de risco, constituído pela união dos métodos \"absoluto\" e \"relativo\" preconizados pela Organização da Aviação Civil Internacional (OACI), pelo emprego do formalismo das redes de Petri Fluidas e Estocásticas (RPFE) na modelagem dos sistemas, e pela comparação entre os valores de métricas de segurança estimados para o sistema avaliado e para um sistema legado. Este método foi aplicado para avaliar a segurança na mudança do atual paradigma de vigilância aérea, baseado em equipamentos Radar, para o paradigma de Vigilância Dependente Automática por Radiodifusão (ADS-B). Como conclusões, o método proposto mostrou-se promissor para avaliar a segurança de sistemas baseados nos atuais paradigmas de sistema críticos em segurança, especialmente o CNS/ATM, onde o formalismo das RPFE proporcionou modelar suas principais características, e a simulação por eventos discretos permitiu estimar as métricas desejadas. Além disso, a ADS-B mostrou-se uma aplicação viável para a vigilância no Sistema de Controle de Tráfego Aéreo, sendo capaz de reduzir o nível de exposição das aeronaves a eventos de perda de separação e, assim, melhorar os níveis de segurança do tráfego aéreo. / In last decades, the safety critical systems paradigm has changing to adapt itself to new necessities, such as costs reduction and productivity demand growth. In the Air Traffic System, those changes are ruled by CNS/ATM paradigm (Communication, Navigation, Surveillance / Air Traffic Management), based on new digital Technologies, mainly Satellites, applied to Communication, Surveillance, Navigation and Air Traffic Management. CNS/ATM intends to reduce the restrictions of current air traffic paradigm, enabling the growth of air traffic capacity without affecting current safety levels. However, this new paradigm brings together new challenges and needs, mainly related to safety assessment. In face of these new challenges, this work proposed a method of risk assessment constituted by the union of the \"absolute\" and \"relative\" assessment methods adopted by the International Civil Aviation Organization (ICAO), by modeling systems using Fluid Stochastic Petri Nets (FSPN) formalism, and by comparison between safety metrics obtained from proposed and legacy system simulations. This method was applied to assess a new concept of air traffic surveillance, named \"Automatic Dependent Surveillance - Broadcasting\" (ADS-B). As main conclusions, the proposed method was promising to assess system safety properties based on current safety critical system paradigm, especially the CNS/ATM, where FSPN formalism provided important modeling capabilities and discrete event simulation allowed estimating the desired safety metric. Besides, ADS-B has meaningfully reduced the separation losses risks and, therefore, it could be used to air traffic control surveillance system to improve capacity and/or safety levels of air traffic system.

Historicamente, os sistemas de tráfego aéreo incorporaram níveis de automação nas atividades de controle do espaço aéreo com o intuito de atender à crescente demanda por serviços aéreos e de melhorar os níveis de segurança nos procedimentos de voo. Com o crescimento expressivo previsto para os próximos anos, devido ao aumento nos números de voos e de usuários, as opções tradicionais de expansão da malha aérea e / ou construção de novos aeroportos se tornaram onerosas economicamente, tornando necessária a adoção de alternativas, tais como as técnicas / procedimentos para pousos em pistas paralelas, como forma de aproveitar parte da atual infraestrutura aeroportuária existente, sem a necessidade de enormes aportes financeiros. Para avaliar a viabilidade de projetos de pousos simultâneos em pistas paralelas, um dos fatores importantes a serem analisados é o da avaliação do risco de colisão entre aeronaves associado durante esses procedimentos. Nesse cenário, este trabalho de pesquisa propõe uma extensão no modelo de avaliação de segurança de Ogata para procedimentos de pouso em pistas paralelas, considerando que o modelo original tem o objetivo de medir o nível de risco associado somente para operações de pouso convencionais em pistas paralelas. A extensão deste modelo ocorre no sentido de também permitir a simulação em outros cenários distintos de pouso, o que torna possível tanto a realização de comparativos entre técnicas / procedimentos utilizadas em operações de pouso em pistas paralelas, quanto a avaliação do nível de risco associado. Este modelo estendido de segurança utiliza o método de Monte Carlo, da mesma forma que o original, em que um número elevado de simulações de cenários possíveis de pousos em pistas paralelas é avaliado. Com os resultados obtidos, é analisado o impacto da variação da distância entre as pistas na segurança de pousos em pistas paralelas. / Historically, air traffic control systems have incorporated some levels of automation to manage procedures of airspace control in order to meet the growing demand for air transportation services and to improve levels of safety in flight procedures. With significant growth expected in the coming years due to an increase in numbers of flights and passengers, the traditional options of expanding the air traffic network and / or construction of new airports have become economically burdensome, requiring the adoption of alternatives such as techniques / procedures for landings on parallel runways as a way of taking advantage of part of the current airport infrastructure, without requiring enormous financial contributions. To assess the feasibility of projects of landing in parallel runways, one of the important factors to be analyzed is the evaluation of the risk of collision between aircraft, associated to these procedures. In this scenario, this research proposes to extend the Ogata safety assessment model in procedures for landing on parallel runways, whereas the original model aims to measure the level of risk associated only with conventional landing operations in parallel runways. The extension of this model occurs in order to allow the simulation of different landing scenarios, which makes possible both the conduct of comparative techniques / procedures used in landing operations on parallel runways, such as the risk level assessment. This model uses the Monte Carlo simulation, the same as the original model, in which a large number of simulations of possible scenarios for landings on parallel runways are evaluated. With these results, it studies the impact of the change of distance between lanes on the safety of aircraft landing on parallel runways.

Nos últimos anos, os países desenvolvidos vêm dedicando crescentes esforços para integrar o Veículo Aéreo Não Tripulado (VANT) no espaço aéreo controlado, visando sua utilização para fins civis. Embora este tema ainda não tenha consenso quanto aos critérios a serem adotados, é de comum acordo na comunidade que, no mínimo, devam ser mantidos os atuais níveis de segurança (\"Safety\") praticados pela aviação civil mundial. Neste cenário, a convivência entre aeronaves comerciais, com cada vez mais passageiros e aeronaves não tripuladas, traz sérias preocupações com relação à capacidade que o sistema atual de navegação, controle, vigilância e de Gerenciamento de Tráfego Aéreo tem para lidar com situações de perigo decorrentes da aproximação entre estas duas categorias de aeronaves. Neste contexto, esta tese propõe uma modelagem de um VANT, tendo-se como ponto de partida os conceitos de robô móvel, cujo modelo de inteligência é fundamentado em Inteligência Artificial Distribuída (IAD), implementável segundo o paradigma de Sistemas Multi-Agentes (SMA) e que leve em consideração os principais requisitos de \"Safety\" exigidos pelo \"Communication Navigation System/Air Traffic Management\" (CNS/ATM), de modo a permitir a futura inserção destas aeronaves no espaço aéreo controlado. / During the last years, developed countries are conducting efforts to integrate Unmanned Aircraft Vehicles (UAVs) to the controlled airspace, aiming at their civilian use. So far, there has been no common consensus on the criteria to be adopted by the community that should, at least, keep the minimum safety levels international aviation has already attained. In this scenario, commercial aircrafts - with more and more passengers - and UAVs will share the same space. There will be a lot of concern related to the actual navigation, control and surveillance system capacity as well as to the air traffic control management ability to handle potentially dangerous situations due to the approximation between aircrafts of these two categories. Based on this scenario, this thesis proposes an UAV modeling having as starting point the mobile robot concept, of which the intelligence model based on Distributed Artificial Intelligence, can be implemented by using the Multi Agent Systems paradigm. This paradigm should take the main safety requirements as an obligation, as defined by the Communication Navigation System/Air Traffic Management (CNS/ATM), as a way of handling the future insertion of UAVs into the controlled airspace.

Present day air traffc control is reaching its operational limits and accommodating future traffic growth will be a challenging task for air traffic service providers and airline operators. Free Flight is a proposed transition from a highly-structured and centrally-controlled air traffic system to a self-optimized and highly-distributed system. In Free Flight, pilots will have the flexibility of real-time trajectory planning and dynamic route optimization given airspace constraints (traffic, weather etc.). A variety of advanced air traffc management (ATM) concepts are proposed as enabling technologies for the realization of Free Flight. Since these concepts can be exposed to unforeseen and challenging scenarios in Free Flight, they need to be validated and evaluated in order to implement the most effective systems in the field. Evaluation of advanced ATM concepts is a challenging task due to the limitations in the existing scenario generation methodologies and limited availability of a common platform (air traffic simulator) where diverse ATM concepts can be modeled and evaluated. Their rigorous evaluation on safety metrics, in a variety of complex scenarios, can provide an insight into their performance, which can help improve upon them while developing new ones. In this thesis, I propose a non-propriety, non-commercial air traffic simulation system, with a novel representation of airspace, which can prototype advanced ATM concepts such as conflict detection and resolution, airborne weather avoidance and cockpit display of traffic information. I then propose a novel evolutionary computation methodology to algorithmically generate a massive number of conflict scenarios of increasing complexity in order to evaluate conflict detection algorithms. I illustrate the methodology in detail by quantitative evaluation of three conflict detection algorithms, from the literature, on safety metrics. I then propose the use of data mining techniques for the discovery of interesting relationships, that may exist implicitly, in the algorithm's performance data. The data mining techniques formulate the conflict characteristics, which may lead to algorithm failure, using if-then rules. Using the rule sets for each algorithm, I propose an ensemble of conflict detection algorithms which uses a switch mechanism to direct the subsequent conflict probes to an algorithm which is less vulnerable to failure in a given conflict scenario. The objective is to form a predictive model for algorithm's vulnerability which can then be included in an ensemble that can minimize the overall vulnerability of the system. In summary, the contributions of this thesis are: 1. A non-propriety, non-commercial air traffic simulation system with a novel representation of airspace for efficient modeling of advanced ATM concepts. 2. An Ant-based dynamic weather avoidance algorithm for traffic-constrained enroute airspace. 3. A novel representation of 4D air traffic scenario that allows the use of an evolutionary computation methodology to evolve complex conflict scenarios for the evaluation of conflict detection algorithms. 4. An evaluation framework where scenario generation, scenario evaluation and scenario evolution processes can be carried out in an integrated manner for rigorous evaluation of advanced ATM concepts. 5. A methodology for forming an intelligent ensemble of conflict detection algorithms by data mining the scenario space.

As air traffic congestion grows, air traffic flow management (ATFM) is becoming a great concern. ATFM deals with air traffic and the efficient utilization of the airport and airspace. Air traffic efficiency is heavily influenced by unanticipated factors, or uncertainties, which can come from several sources such as mechanical breakdown; however, weather is the main unavoidable cause of uncertainty. Because weather is unpredictable, it poses a critical challenge for ATFM in current airport and airspace operations. Convective weather results in congestion at airports as well as in airspace sectors. During times of congestion, the decision as how and when to send aircraft toward an airspace sector in the presence of weather is difficult. To approach this problem, we first propose a two-stage stochastic integer program by emphasizing a given single sector. By considering ground delay, cancellation, and cruise speed for each flight on the ground in the first stage, as well as air holding and diversion recourse actions for each flight in the air in the second stage, our model determines how aircraft are sent toward a sector under the uncertainty of weather. However, due to the large number of weather scenarios, the model is intractable in practice. To overcome the intractability, we suggest a rolling horizon method to solve the problem to near optimal. Lagrangian relaxation and subgradient method are used to justify the rolling horizon method. Since the rolling horizon method can be solved in real time, we can apply it to actual aircraft schedules to reduce the costs incurred on the ground as well as in airspace. We then extend our two-stage model to a multistage stochastic program, which increases the number of possible weather realizations and results a more efficient schedule in terms of costs. The rolling horizon method as well as Lagrangian relaxation and subgradient method are applied to this multistage model. An overall comparison among the previously described methodologies are presented.

Increased efficiency at airports is necessary to reduce delays and fuel consumption. Many of the busiest airports in the nation have at least one pair of closely spaced parallel runways (CSPRs), defined by a separation of less than 2500 ft, with one runway dedicated to arrivals and the other to departures. CSPRs experience a large decrease in capacity under instrument conditions because they can no longer operate independently. In order to mitigate this decrease in capacity and to increase efficiency, proposed herein is a departure regulator for runways so configured, along with a plan of study to investigate the effects of this regulator. The proposed departure regulator makes use of data from precision tracking systems such as ADS-B to issue automated or semi-automated departure clearances. Assuming sequential departure separations are sufficient for clearance, the regulator will automatically issue, or advise the controller to issue, the departure clearance as soon as the arrival on the adjacent runway has descended below its decision height. By issuing the departure clearance earlier, the departure regulator reduces the gap between a pair of arrivals that is required to clear a departure. By decreasing the gap, the regulator increases the number of opportunities where a departure clearance can be issued, given a particular arrival stream. A simulation models the effects of the regulator and quantifies the resulting increases in capacity. The simulation results indicate that all forms of the regulator would provide significant gains of between 14% and 23% in capacity over the current operating paradigm. The results also indicate that the capacity gains are greatest at high arrival rates. Therefore, implementation of the departure regulator could significantly decrease the congestion at many major airports during inclement weather.

Short Term Conflict Alert (STCA) is an automated warning system designed to alert air traffic controllers to possible loss of separation between aircraft. STCA systems are complex, with many parameters that must be adjusted to achieve best performance. Current procedure is to manually ‘tune’ the governing parameters in order to finely balance the trade-off between wanted alerts and nuisance alerts. We present an incremental approach to automatically optimising STCA systems, using a simple evolutionary algorithm. By dividing the parameter space into regional subsets, we investigate methods of reducing the number of evaluations required to generate the Pareto optimal Receiver Operating Characteristic (ROC) curve. Multi-archive techniques are devised and are shown to cut the necessary number of iterations by half. A method of estimating the fitness of recombined regional parameter subsets without actual evaluation on the STCA system is presented, however, convergence is shown to be severely stunted when relatively weak sources of noise are present. We describe a method of aggressively perturbing parameters outside of their known ‘safe’ ranges when complex inhibitory interactions are present that prevent an exhaustive search of permitted values. The scheme prevents the optimiser from repeating ‘mistakes’ and unnecessarily wasting evaluations. Results show that a more complete picture of the Pareto-optimal ROC curve may be obtained without increasing the number of necessary iterations. Efficacy of the new methods is discussed, with suggestions for improving efficiency. Sources of parameter interdependence and noise are explored and where possible mitigating techniques and procedures suggested. Classifier performance on training and test data is investigated and potential solutions for reducing overfitting are evaluated on a toy problem. We comment on potential uses of the ROC in characterising STCA performance, for comparison to other systems and airspaces. Many industrial systems are structured in a similar way to STCA, we hope that techniques presented will be applicable to other highly parametrised, expensive problem domains.

Οι πύργοι ελέγχου αεροδρομίων αποτελούν βασικό συστατικό για την ομαλή και συνεχή εξυπηρέτηση των πτήσεων πολιτικών και στρατιωτικών αεροσκαφών. Βρίσκονται εγκατεστημένοι σε κάθε αεροδρόμιο και αποτελούν το υψηλότερο κτίριο στο περιβάλλοντα χώρο, πράγμα που δικαιολογεί και τον μεγάλο αριθμό κεραυνικών πληγμάτων που μπορούν να δεχτούν. Σκοπός αυτής της διπλωματικής εργασίας είναι η μελέτη ενός συστήματος αντικεραυνικής προστασίας που βρίσκεται εγκατεστημένο σε έναν πύργο ελέγχου αεροδρομίου. Η απόδοση του συστήματος αντικεραυνικής προστασίας διαδραματίζει σημαντικό ρόλο στην αποτελεσματική λειτουργία του πύργου ελέγχου και στη γενικότερη αποτελεσματική λειτουργία του αερολιμένα. Με τη χρήση του προγράμματος εξομοίωσης αναλογικών και ψηφιακών κυκλωμάτων Orcad-Pspice, προσομοιώνεται το σύστημα αντικεραυνικής προστασίας, με βάση τον πύργο ελέγχου που του διεθνούς αερολιμένα Ελ. Βενιζέλος, μετράται το δυναμικό στη βάση του πύργου ελέγχου και τα ρεύματα στους αγωγούς καθόδου, όταν κεραυνός πλήττει το σύστημα συλλεκτήριων αγωγών. / The airport traffic control towers are a key component for the smooth and continuous service flights for both political and military aircraft. They are located at each airport and are the highest building in the surroundings, which justifies the number of lightning strikes that accepts. The purpose of this thesis is the study of a lightning protection system which is installed in an airport control tower. The efficiency of the lightning protection system constitute an important role in the effective operation of the control tower and the overall efficient operation of the airport. Using the analog and digital circuits simulation program Orcad-Pspice, the lightning protection system simulated , based on the control tower to the International airport Eleftherios Venizelos , the measured potential at the base of the control tower and the currents in the downconductors , when lightning strikes the collectors system

Ypatingų aplinkybių (nenumatytų atvejų) planai reikalingi tam, kad oro eismo paslaugos niekada nenutrūktų, oro eismas išliktų saugus ir jo valdymas būtų kuo efektyvesnis (pvz., būtų kuo didesnis oro erdvės pralaidumas). Atsitikus bet kokiai nenumatytai situacijai, pagal jos scenarijų sukuriamas veiksmų planas, kuriuo privaloma vadovautis ypatingomis aplinkybėmis. Pagrindinis tikslas kuriant NAP tai skrydžių saugos užtikrinimas. Tai yra didžiausias prioritetas šiandieninėje aviacijoje. Oro navigacijos paslaugų teikėjo ypatingų aplinkybių (nenumatytų atvejų) planai palyginus su Eurokontrolės ir ICAO rekomendacijomis neatitinka visų reikalavimų. Kai kuriose situacijose panaudoti veiksmų planai nepilnai atitinka realybę arba tiesiog yra nepakankamai aiškūs, todėl juos būtina tobulinti. Darbą sudaro keturios dalys, įvadas, analitinė – metodinė dalis, tiriamoji dalis bei išvados ir siūlymai, literatūros sąrašas. / Contingency planning is necessary so that air navigation service would never be interrupted and safe air traffic services would be provided at any time Whenever a non-standard situation occurs the contingency plan is prepared. The main purpose of contingency planning is both to prevent the services from inefficiency and to decrease the impact of a disaster by increasing safety. Safety in aviation is priority number one, so it is necessary to be ready for any possible situation which could interrupt ANSP’s work. When analyzed and compared with ICAO and EUROCONTROL recommendations ANSP‘s contingency plans do not fully meet the requirements and some changes should be implemented as quickly as possible. It is necessary to have an adequate operational plan for any unexpected situation. Structure: introduction, three parts of work: theoretical and analysis, investigation, conclusions and suggestions, a list of references.

Den här rapporten är en utredning och analys av lämpliga arbetsuppgifter och deras nödvändiga verktyg och hjälpmedel för en skiftledare, Watch Supervisor, vid ett framtida center för fjärrstyrda flygledningstorn, Remote Tower. Ett center för fjärrstyrda flygledningstorn är en centraliserad enhet med uppgiften att flygleda och kontrollera flygsäkerheten på och nära en eller flera flygplatser. Utgångspunkten för datainsamlingen har varit intervjuer med verksamma flygledare och skiftledare på LFV, Sveriges statliga verk för flygtrafiktjänst. Studiebesök har även gjorts vid olika enheter, både flygledartorn och radarkontrollcentraler, däribland Sundsvall RTC som är världens första central för fjärrstyrd flygledning godkänd att sättas i drift. Insamlad data har kompilerats och analyserats och en rekommendation presenteras i slutet av denna rapport angående arbetsuppgifter och verktyg för ovan nämnda skiftledare i ett RTC. Resultatet visar att rollen kommer ha stora likheter med befintliga skiftledarpositioner i den svenska flygledningen.