The thesis traces the history of missile aerodynamic prediction methods and defines the aerodynamic requirements for the subsonic free-flight projectiles configurations under consideration. Different types of trajectory model are described with the aerodynamic input requirement being analysed. Methods of generating the required aerodynamic data for the trajectory models are discussed emphasising the aerodynamic models capabilities, weaknesses and ease of use. The method of masses aerodynamic prediction method is defined, highlighting the adaptations to the method that were carried out to generate the aerodynamic stability data required for subsequent projectile trajectory analysis. An assessment of the sensitivity and accuracy of the simulated data is carried out using experimental flight trial data on different projectile configurations. Finally, using the simulation models developed in previous chapters, a parametric analysis is carried out on different projectile configurations to optimise the trajectory performance.

Today, the air transport industry has become an essential element of global society by its great contributions to the wide exchanges of cultures/people and to the rapid growth in the world economy. However, on the other hand, the adverse impacts on the environment caused by air transport, such as air pollution, noise and climate change, are drawing, increasingly, growing public concern. In order to address the steady growth in air-travel demand in the next decades through an environmentally-friendly way and realise the ACARE 2020 environmental goals, The Clean Sky programme has been launched by European Union over the period 2008 – 2013. The project research, described in this thesis and sponsored by the Clean Sky programme, aims at evaluating the feasibility of reducing the environmental impact of commercial aviation through the introduction of changes in the aircraft operational rules and procedures, as well as the application of the new-generation propfan (open rotor) engine, based on flight trajectory multidisciplinary optimisation and analysis of commercial aircraft. In order to accomplish the above research objectives, a complete methodology to achieve and realise optimum flight trajectories has been initially proposed. Then, 12 component-level models which function as simulating different disciplines, such as aircraft performance, engine performance, engine gaseous emission, and flight noise, have been developed or selected/adopted. Further, nine system-level integration and optimisation models were built. These system-level models simulate flights from Amsterdam Schiphol airport in the Netherlands to Munich airport in Germany flown by different types of aircraft through different flight phases with different optimisation objectives. Finally, detailed investigations into the flight trajectory optimisations were performed, extensive optimisation results were achieved and corresponding description, analysis and comparisons were provided. The main contributions of this work to knowledge broadly comprise the following: 1) the further development regarding the methodology of flight trajectory multidisciplinary optimisation; 2) previous work on aircraft trajectory optimisation has often considered fixed objectives over the complete flight trajectory. This research focused on representative flight phases of a flight mission with different optimisation objectives, namely, noise impact and fuel burn during the departure phase; fuel burn and flight time during en route phase; and noise impact and NOx emission during the arrival phase; 3) this research has extended the current flight trajectory optimisations to turboprop and propfan equipped aircraft. As a result, a relative complete 2D flight trajectory multidisciplinary optimisation spectrum, spanned by primary commercial aircraft types, primary flight phases and primary optimisation objectives of interest, has been built. Although encouraging progress have been achieved, this project research, as with any other research activity, is also only ‘on the way’ rather than coming to the ‘end’ point. There are still many aspects which can be improved further and there is still much new research and exploration which can be investigated further. All these have also been suggested in this thesis.

Today, the air transport industry has become an essential element of global society by its great contributions to the wide exchanges of cultures/people and to the rapid growth in the world economy. However, on the other hand, the adverse impacts on the environment caused by air transport, such as air pollution, noise and climate change, are drawing, increasingly, growing public concern. In order to address the steady growth in air-travel demand in the next decades through an environmentally-friendly way and realise the ACARE 2020 environmental goals, The Clean Sky programme has been launched by European Union over the period 2008 – 2013. The project research, described in this thesis and sponsored by the Clean Sky programme, aims at evaluating the feasibility of reducing the environmental impact of commercial aviation through the introduction of changes in the aircraft operational rules and procedures, as well as the application of the new-generation propfan (open rotor) engine, based on flight trajectory multidisciplinary optimisation and analysis of commercial aircraft. In order to accomplish the above research objectives, a complete methodology to achieve and realise optimum flight trajectories has been initially proposed. Then, 12 component-level models which function as simulating different disciplines, such as aircraft performance, engine performance, engine gaseous emission, and flight noise, have been developed or selected/adopted. Further, nine system-level integration and optimisation models were built. These system-level models simulate flights from Amsterdam Schiphol airport in the Netherlands to Munich airport in Germany flown by different types of aircraft through different flight phases with different optimisation objectives. Finally, detailed investigations into the flight trajectory optimisations were performed, extensive optimisation results were achieved and corresponding description, analysis and comparisons were provided. The main contributions of this work to knowledge broadly comprise the following: 1) the further development regarding the methodology of flight trajectory multidisciplinary optimisation; 2) previous work on aircraft trajectory optimisation has often considered fixed objectives over the complete flight trajectory. This research focused on representative flight phases of a flight mission with different optimisation objectives, namely, noise impact and fuel burn during the departure phase; fuel burn and flight time during en route phase; and noise impact and NOx emission during the arrival phase; 3) this research has extended the current flight trajectory optimisations to turboprop and propfan equipped aircraft. As a result, a relative complete 2D flight trajectory multidisciplinary optimisation spectrum, spanned by primary commercial aircraft types, primary flight phases and primary optimisation objectives of interest, has been built. Although encouraging progress have been achieved, this project research, as with any other research activity, is also only ‘on the way’ rather than coming to the ‘end’ point. There are still many aspects which can be improved further and there is still much new research and exploration which can be investigated further. All these have also been suggested in this thesis.

This paper studies the impacts on flight trajectories, such as lateral and vertical changes, when avoiding the formation of persistent contrails for transatlantic flights. A sophisticated Earth-System Model (EMAC) coupled with a flight routing submodel (AirTraf) and a contrail submodel (CONTRAIL) is used to optimize flight trajectories concerning the flight time and the flight distance through contrail forming regions (contrail distance). All the trajectories are calculated taking into account the effects of the actual and local meteorological parameters, e.g., wind, temperature, relative humidity, etc. A full-year simulation has been conducted based on a daily flight schedule of 103 transatlantic flights. The trade-off between the flight time and contrail distance shows a large daily variability, meaning for the same increase in flight time, the reduction in contrail distance varies from 20% to 80% depending on the daily meteorological situation. The results confirm that the overall changes in flight trajectories follow a seasonal cycle corresponding to the nature of the potential contrail coverage. In non-summer seasons, the southward and upward shifts of the trajectories are favorable to avoid the contrail formation. In summer, the northward and upward shifts are preferred. A partial mitigation strategy for up to 40% reduction in contrail distance can be achieved throughout all the seasons with a negligible increase in flight time (less than 2%), which represents a reasonable trade-off between flight time increase and contrail avoidance.

The impact of air travel on the climate, along with its increasing share in CO2 emissions have raised the demand for sustainable air travel solutions. The current aircraft technologies have seen significant improvement throughout the years. Although, the rate at which new aircraft technologies are developed can not keep up with the increased demand for air travel. Hence, a different approach to reduce the aviation’s impact on climate can be achieved by optimizing the vertical flight path in order to reduce the fuel consumption, i.e. using dynamic programming. Upon departure, an optimization of the vertical flight path is initiated and an optimal flight plan is suggested to the flight crew.  The fuel saving produced by the optimal flight plan is a potential saving that can only be fully achieved if the flight crew chose to fly according to the optimized flight path. However, restrictions from the Air Traffic Control, as well as the flight crew’s willingness to follow the optimized flight path can affect the achieved saving. Hence, a tool is developed in order to compute trip fuel consumption from post-flight data obtained from the Automatic Dependent Surveillance-Broadcast (ADS-B) surveillance technology. A method to identify the start and end positions of cruise segments is successfully implemented. Two methods of calculating the fuel are implemented and compared. The first method is based on simulating the actual flight, which uses the same performance model as for the simulation of the operational flight plan trip and optimized trip. The second method is based on utilizing the ADS-B data to obtain the aircraft speed which in return can be used as a parameter to obtain the fuel flow of the aircraft, hence the trip is not simulated. The results reveals that the simulation method produces flight trajectories that are comparable to the operational and optimized flight plans since they use the same model structure. However, using ADS-B data to obtain fuel consumption represents the actual flight trajectory more accurately.  Furthermore, an optimization algorithm based on the onboard Flight Management Computer is implemented. According to the results, the FMC optimization offers a sufficient optimization of the cruise phase, when compared to the OFP trip, however performs worse than the dynamic programming, which provides a global optimal solution. / Flygresornas inverkan på klimatet, tillsammans med dess ökande andel av CO2-utsläppen, har ökat kraven på hållbara flygplanslösningar. Den nuvarande flygplansteknologin har genomgått betydande förbättringar genom åren. Men takten för vilken ny flygplansteknik utvecklas kan inte hålla jämna steg med den ökade efterfrågan på flygresor. Däremot kan ett annat tillvägagångssätt för att minska flygets påverkan på klimatet uppnås genom att optimera den vertikala flygvägen för att minska bränsleförbrukningen, d.v.s. med hjälp av högupplösta väderdata. Vid avgång initieras en dynamisk programmering där optimering av den vertikala flygbanan och en optimal färdplan föreslås för flygbesättningen.  Bränslebesparingen som den optimala färdplanen ger är en besparingspotential som endast kan uppnås fullt ut om flygbesättningen väljer att flyga enligt den. Restriktioner från flygledningen, samt flygbesättningens vilja att följa den optimerade färdplanen kan dock påverka den uppnådda besparingen. Därav utvecklas ett verktyg för att beräkna färdens bränsleförbrukning från postflight data erhållna från Automatic Dependent Surveillance-Broadcast (ADS-B) övervakningsteknologi. En metod för att identifiera start- och slutpositionerna för kryssningssegment implementeras framgångsrikt. Två metoder för att beräkna bränslet implementeras och jämförs. Den första metoden baseras på att simulera den faktiska flygningen. Denna metod använder samma prestandamodell som för simuleringen av den operativa färdplanens resa och den optimerade resan. Den andra metoden baseras på att använda ADS-B-data för att erhålla flygplanets hastighet, som i sin tur kan användas som en parameter för att få fram flygplanets bränsleflöde vid en tidpunkt. Resultaten visar att simuleringsmetoden ger flygbanor som är rättvist jämförbara med de operativa och optimerade flygplanerna, då de använder samma modell. Men att använda ADS-B-data för att få bränsleförbrukning representerar den faktiska flygbanan mer exakt.  Dessutom implementeras en optimeringsalgoritm baserad på den inbyggda Flight Management Computer. Enligt resultaten erhåller FMC-optimeringen en tillfredsställande optimering av kryssningsfasen, jämfört med OFP-resan, men presterar sämre än den dynamiska programmeringen, vilket alltid ger en global optimal lösning.

The impact of air travel on the climate, along with its increasing share in CO2 emissions haveraised the demand for sustainable air travel solutions. The current aircraft technologies haveseen significant improvement throughout the years. Although, the rate at which new aircrafttechnologies are developed can not keep up with the increased demand for air travel. Hence, adifferent approach to reduce the aviation’s impact on climate can be achieved by optimizing thevertical flight path in order to reduce the fuel consumption, i.e. using dynamic programming.Upon departure, an optimization of the vertical flight path is initiated and an optimal flight planis suggested to the flight crew. The fuel saving produced by the optimal flight plan is a potential saving that can only be fullyachieved if the flight crew chose to fly according to the optimized flight path. However, restrictionsfrom the Air Traffic Control, as well as the flight crew’s willingness to follow theoptimized flight path can affect the achieved saving. Hence, a tool is developed in order tocompute trip fuel consumption from post-flight data obtained from the Automatic DependentSurveillance-Broadcast (ADS-B) surveillance technology. A method to identify the start andend positions of cruise segments is successfully implemented. Two methods of calculating thefuel are implemented and compared. The first method is based on simulating the actual flight,which uses the same performance model as for the simulation of the operational flight plantrip and optimized trip. The second method is based on utilizing the ADS-B data to obtain theaircraft speed which in return can be used as a parameter to obtain the fuel flow of the aircraft,hence the trip is not simulated. The results reveals that the simulation method produces flighttrajectories that are comparable to the operational and optimized flight plans since they use thesame model structure. However, using ADS-B data to obtain fuel consumption represents theactual flight trajectory more accurately. Furthermore, an optimization algorithm based on the on-board Flight Management Computeris implemented. According to the results, the FMC optimization offers a sufficient optimizationof the cruise phase, when compared to the OFP trip, however performs worse than the dynamicprogramming, which provides a global optimal solution / Flygresornas inverkan på klimatet, tillsammans med dess ökande andel av CO2-utsläppen, harökat kraven på hållbara flygplanslösningar. Den nuvarande flygplansteknologin har genomgåttbetydande förbättringar genom åren. Men takten för vilken ny flygplansteknik utvecklas kaninte hålla jämna steg med den ökade efterfrågan på flygresor. Däremot kan ett annat tillvägagångssättför att minska flygets påverkan på klimatet uppnås genom att optimera den vertikalaflygvägen för att minska bränsleförbrukningen, d.v.s. med hjälp av högupplösta väderdata. Vidavgång initieras en dynamisk programmering där optimering av den vertikala flygbanan och enoptimal färdplan föreslås för flygbesättningen. Bränslebesparingen som den optimala färdplanen ger är en besparingspotential som endast kanuppnås fullt ut om flygbesättningen väljer att flyga enligt den. Restriktioner från flygledningen,samt flygbesättningens vilja att följa den optimerade färdplanen kan dock påverka denuppnådda besparingen. Därav utvecklas ett verktyg för att beräkna färdens bränsleförbrukningfrån post-flight data erhållna från Automatic Dependent Surveillance-Broadcast (ADS-B) övervakningsteknologi.En metod för att identifiera start- och slutpositionerna för kryssningssegmentimplementeras framgångsrikt. Två metoder för att beräkna bränslet implementeras ochjämförs. Den första metoden baseras på att simulera den faktiska flygningen. Denna metodanvänder samma prestandamodell som för simuleringen av den operativa färdplanens resa ochden optimerade resan. Den andra metoden baseras på att använda ADS-B-data för att erhållaflygplanets hastighet, som i sin tur kan användas som en parameter för att få fram flygplanetsbränsleflöde vid en tidpunkt. Resultaten visar att simuleringsmetoden ger flygbanor somär rättvist jämförbara med de operativa och optimerade flygplanerna, då de använder sammamodell. Men att använda ADS-B-data för att få bränsleförbrukning representerar den faktiskaflygbanan mer exakt. Dessutom implementeras en optimeringsalgoritm baserad på den inbyggda Flight ManagementComputer. Enligt resultaten erhåller FMC-optimeringen en tillfredsställande optimering avkryssningsfasen, jämfört med OFP-resan, men presterar sämre än den dynamiska programmeringen,vilket alltid ger en global optimal lösning.

<p dir="ltr">The absence or limited availability of operational statistics at general aviation airports restricts airport managers and operators from assessing comprehensive operational data. The traditional manual compilation of operational statistics is labor-intensive and lacks the depth and accuracy to depict a holistic picture of a general aviation airport’s operations. This research developed a reliable and efficient approach to address the problem by providing a comprehensive and versatile flight status identification framework. </p><p dir="ltr">Leveraging the BlueSky flight simulation module, the research can generate a synthetic flight database to emulate real-world general aviation aircraft’s flight scenarios. Two neural network architectures, namely, an RNN-GAN network and a refined Seq2Seq network, were explored to examine their capability to reconstruct flight trajectories. The Seq2Seq network, which demonstrated better performance, was further employed to estimate the simulated aircraft’s different metrics, such as internal mechanical metrics and flight phase. Additionally, this research undertook an array of diverse tailored evaluation techniques to assess the efficacy of flight status predictions and conducted comparative analyses between various configurations. </p><p dir="ltr">Furthermore, the research concluded by discussing the future development of the framework, emphasizing its potential for generalization across various flight data applications and scenarios. The enhanced methodology for collecting operational statistics and the analysis tool will enable airport managers and regulators to better receive a comprehensive view of the airport’s operations, facilitating airport planning and development.</p>

A new suboptimal guidance law design approach for aerospace vehicles is proposed in this thesis, followed by an advanced control design for supersonic air-breathing engines. The guidance law is designed using the newly developed Generalized Model Predictive Static Programming (G-MPSP), which is based on the continuous time nonlinear optimal control framework. The key feature of this technique is one-time backward propagation of a small-dimensional weighting matrix dynamics, which is used to update the entire control history. This key feature, as well as the fact that it leads to a static optimization problem, lead to its computational efficiency. It has also been shown that the existing model predictive static programming (MPSP), which is based on the discrete time framework, is a special case of G-MPSP. The G-MPSP technique is further extended to incorporate ‘input inequality constraints’ in a limited sense using the penalty function philosophy. Next, this technique has been developed also further in a ‘flexible final time’ framework to converge rapidly to meet very stringent final conditions with limited number of iterations. Using the G-MPSP technique in a flexible final time and input inequality constrained formulation, a suboptimal guidance law for a solid motor propelled carrier launch vehicle is successfully designed for a hypersonic mission. This guidance law assures very stringent final conditions at the injection point at the end of the guidance phase for successful beginning of the hypersonic vehicle operation. It also ensures that the angle of attack and structural load bounds are not violated throughout the trajectory. A second-order autopilot has been incorporated in the simulation studies to mimic the effect of the inner-loops on the guidance performance. Simulation studies with perturbations in the thrust-time behaviour, drag coefficient and mass demonstrate that the proposed guidance can meet the stringent requirements of the hypersonic mission. The G-MPSP technique in a fixed final time and input inequality constrained formulation has also been used for optimal guidance of an aerospace vehicle propelled by supersonic air-breathing engine, where the resulting thrust can be manipulated by managing the fuel flow and nozzle area (which is not possible in solid motors). However, operation of supersonic air-breathing engines is quite complex as the thrust produced by the engine is a result of very complex nonlinear combustion dynamics inside the engine. Hence, to generate the desired thrust, accounting for a fairly detailed engine model, a dynamic inversion based nonlinear state feedback control design has been carried out. The objective of this controller is to ensure that the engine dynamically produces the thrust that tracks the commanded value of thrust generated from the guidance loop as closely as possible by regulating the fuel flow rate. Simultaneously, by manipulating throat area of the nozzle, it also manages the shock wave location in the intake for maximum pressure recovery with sufficient margin for robustness. To filter out the sensor and process noises and to estimate the states for making the control design operate based on output feedback, an extended Kalman filter (EKF) based state estimation design has also been carried out and the controller has been made to operate based on estimated states. Moreover, independent control designs have also been carried out for the actuators so that their response can be faster. In addition, this control design becomes more challenging to satisfy the imposed practical constraints like fuel-air ratio and peak combustion temperature limits. Simulation results clearly indicate that the proposed design is quite successful in assuring the desired performance of the air-breathing engine throughout the flight trajectory, i.e., both during the climb and cruise phases, while assuring adequate pressure margin for shock wave management.