Access profile

There are a wide range of degrees that qualify students for admission to the doctoral programme in Aerospace Science and Technology. The applicants considered most suitable for admission are those who have completed a master's degree in Aerospace Science and Technology, or a master's degree related to the scientific field of the programme. Master’s degrees in aeronautical engineering or in the area of space physics are considered particularly suitable.

University graduates who have significant research experience or a specialisation in one of the scientific fields of the programme and a basic knowledge of aspects of air navigation may also be considered for admission. (Students who do not possess this knowledge can be oriented so that they complete the minimum number of bridging courses necessary to acquire it.)

In addition to this academic background, it is considered important that applicants have certain personal characteristics – namely, an interest in the research projects carried out within the framework of the programme; critical and analytical skills; initiative and perseverance; the ability to work in a team; and the ability to communicate effectively, both orally and in writing. Foreign non-Spanish speaking students must have an advanced level of English that enables them to conduct research work, participate in presentations, follow courses, and write their doctoral thesis and associated reports in correct English.

Output profile

Doctoral candidates who complete a doctoral degree will have acquired the following competencies, which are needed to carry out quality research (Royal Decree 99/2011, of 28 January, which regulates official doctoral studies):

a) A systematic understanding of the field of study and a mastery of the research skills and methods related to the field.
b) An ability to conceive, design or create, put into practice and adopt a substantial process of research or creation.
c) An ability to contribute to pushing back the frontiers of knowledge through original research.
d) A capacity for critical analysis and an ability to assess and summarise new and complex ideas.
e) An ability to communicate with the academic and scientific community and with society in general as regards their fields of knowledge in the manner and languages that are typical of the international scientific community to which they belong.
f) An ability to foster scientific, technological, social, artistic and cultural progress in academic and professional contexts within a knowledge-based society.

The award of a doctoral degree must equip the graduate for work in a variety of settings, especially those requiring creativity and innovation. Doctoral graduates must have at least acquired the personal skills needed to:

a) Develop in contexts in which there is little specific information.
b) Find the key questions that must be answered to solve a complex problem.
c) Design, create, develop and undertake original, innovative projects in their field.
d) Work as part of a team and independently in an international or multidisciplinary context.
e) Integrate knowledge, deal with complexity and make judgements with limited information.
f) Offer criticism on and intellectually defend solutions.

Finally, with respect to competencies, doctoral students must:
a) have acquired advanced knowledge at the frontier of their discipline and demonstrated, in the context of internationally recognised scientific research, a deep, detailed and well-grounded understanding of theoretical and practical issues and scientific methodology in one or more research fields;
b) have made an original and significant contribution to scientific research in their field of expertise that has been recognised as such by the international scientific community;
c) have demonstrated that they are capable of designing a research project that serves as a framework for carrying out a critical analysis and assessment of imprecise situations, in which they are able to apply their contributions, expertise and working method to synthesise new and complex ideas that yield a deeper knowledge of the research context in which they work;
d) have developed sufficient autonomy to set up, manage and lead innovative research teams and projects and scientific collaborations (both national and international) within their subject area, in multidisciplinary contexts and, where appropriate, with a substantial element of knowledge transfer;
e) have demonstrated that they are able to carry out their research activity in a socially responsible manner and with scientific integrity;
f) have demonstrated, within their specific scientific context, that they are able to make cultural, social or technological advances and promote innovation in all areas within a knowledge-based society;
g) have demonstrated that they are able to participate in scientific discussions at the international level in their field of expertise and disseminate the results of their research activity to audiences of all kinds.

Number of places

10

Duration of studies and dedication regime

Duration
The maximum period of study for full-time doctoral studies is three years, counted from the date of admission to the programme to the date of submission of the doctoral thesis. The academic committee of the doctoral programme may authorise a doctoral candidate to pursue doctoral studies on a part-time basis. In this case, the maximum period of study is five years, counting from the date of admission to the programme to the date of submission of the doctoral thesis. For calculating these periods, the date of admission is considered to be the date of the first enrolment for tutorials, and the date of submission the moment in which the Doctoral School officially deposits the doctoral thesis.

For full-time doctoral candidates, the minimum period of study is two years, counted from the date of an applicant's admission to the programme until the date on which the doctoral thesis is deposited; for part-time doctoral candidates it is four years. When there are justified grounds for doing so, and the thesis supervisor and academic tutor have given their authorisation, doctoral candidates may request that the academic committee of their doctoral programme exempt them from the minimum period of study requirement.

The calculation of periods of study will not include periods of absence due to illness, pregnancy or any other reason provided for in the regulations in force. Students who find themselves in any of these circumstances must notify the academic committee of the doctoral programme, which, where appropriate, must inform the Doctoral School. Doctoral candidates may also temporarily withdraw from the programme for up to one year, and this period may be extended for an additional year. Doctoral candidates who wish to interrupt their studies must submit a justified request to the academic committee of the doctoral programme, which will decide whether or not to approve the request. Each programme will establish conditions for readmission to doctoral studies.

Extension
If full-time doctoral candidates have not applied to deposit their thesis by the end of the three-year period of study, the academic committee of the programme may authorise an extension of up to one year. In exceptional circumstances, a further one-year extension may be granted, subject to the conditions established by the corresponding doctoral programme. In the case of part-time doctoral candidates, an extension of two years may be authorised. In both cases, in exceptional circumstances a further one-year extension may be granted by the Doctoral School's Standing Committee, upon the submission of a reasoned application by the academic committee of the doctoral programme.

Dismissal from the doctoral programme
A doctoral candidate may be dismissed from a doctoral programme for the following reasons:

• The doctoral candidate submitting a justified application to withdraw from the programme.
• The maximum period of study and of extensions thereof ending.
• The doctoral candidate not having enrolled every academic year (unless he or she has been authorised to temporarily withdraw).
• The doctoral candidate failing two consecutive assessments.
• The doctoral candidate having disciplinary proceedings filed against him or her that rule that he or she must be dismissed from the UPC.

Dismissal from the programme implies that doctoral candidates cannot continue studying at the UPC and the closing of their academic record. This notwithstanding, they may apply to the academic committee of the programme for readmission and the committee must reevaluate them in accordance with the criteria established in the regulations.

Organization

• Pons Prats, Jordi

• Pons Prats, Jordi
• Rojas Gregorio, Jose Ignacio
• Rovira Garcia, Adrià

• Department of Physics (PROMOTORA)
• Department of Civil and Environmental Engineering
• Department of Computer Architecture
• Department of Electronic Engineering
• Department of Materials Science and Metallurgy
• Department of Mathematics
• Department of Mechanical Engineering
• Department of Signal Theory and Communications
• Department of Strength of Materials and Structural Engineering

Access profile

There are a wide range of degrees that qualify students for admission to the doctoral programme in Aerospace Science and Technology. The applicants considered most suitable for admission are those who have completed a master's degree in Aerospace Science and Technology, or a master's degree related to the scientific field of the programme. Master’s degrees in aeronautical engineering or in the area of space physics are considered particularly suitable.

University graduates who have significant research experience or a specialisation in one of the scientific fields of the programme and a basic knowledge of aspects of air navigation may also be considered for admission. (Students who do not possess this knowledge can be oriented so that they complete the minimum number of bridging courses necessary to acquire it.)

In addition to this academic background, it is considered important that applicants have certain personal characteristics – namely, an interest in the research projects carried out within the framework of the programme; critical and analytical skills; initiative and perseverance; the ability to work in a team; and the ability to communicate effectively, both orally and in writing. Foreign non-Spanish speaking students must have an advanced level of English that enables them to conduct research work, participate in presentations, follow courses, and write their doctoral thesis and associated reports in correct English.

Access requirements

Applicants must hold a Spanish bachelor’s degree or equivalent and a Spanish master’s degree or equivalent, provided they have completed a minimum of 300 ECTS credits on the two degrees (Royal Decree 43/2015, of 2 February)

In addition, the following may apply:

• Holders of an official degree awarded by a university in Spain or any other country in the European Higher Education Area, pursuant to the provisions of Article 16 of Royal Decree 1393/2007, of 29 October, which establishes official university course regulations, who have completed a minimum of 300 ECTS credits on official university degrees, of which at least 60 must be at the master's degree level.
• Holders of an official Spanish bachelor’s degree comprising at least 300 credits, as provided for by EU regulations. Holder of degrees of this kind must complete bridging courses unless the curriculum of the bachelor’s degree in question included research training credits equivalent in value to those which would be earned on a master's degree.
• Holders of an official university qualification who, having passed the entrance examination for specialised medical training, have completed at least two years of a training course leading to an official degree in a health-sciences specialisation.
• Holders of a degree issued under a foreign education system. In these cases, homologation is not required, but the UPC must verify that the degree certifies a level of training equivalent to an official Spanish master's degree and qualifies the holder for admission to doctoral studies in the country where it was issued. Admission on this basis does not imply homologation of the foreign degree or its recognition for any purpose other than admission to doctoral studies.
• Holders of a Spanish doctoral qualification issued under previous university regulations.

Note 1: Doctoral studies entrance regulations for holders of an undergraduate degree awarded before the introduction of the EHEA (CG 47/02 2014)

Note 2: Governing Council Decision 64/2014, which approves the procedure and criteria for assessing the fulfilment of academic admission requirements for doctoral studies by holders of non-homologated foreign degrees (CG 25/03 2014)

Admission criteria and merits assessment

• Academic record (weighting: 50%)
• Motivation (weighting: 30-40%)
• Knowledge of languages (weighting: 10-20%). For applicants who do not speak Spanish, a good level of English is essential (a prerequisite) and will not be considered an additional merit.

Other points that are not requirements but will be taken into consideration in the context of the weighted requirements listed above:
• Research experience.
• Personal contact by e-mail or in face-to-face interviews.
• Grants or scholarships from the applicant’s country of origin (for foreign students).
• Whether or not the student will work exclusively on preparing their thesis.

Training complements

The academic committee for the programme may require that doctoral students pass specific bridging courses. In such cases, the committee will keep track of the bridging courses completed and establish appropriate criteria to limit their duration.

Bridging courses will provide research training. In no case may doctoral students be required to enrol for 60 or more ECTS credits. (The academic regulations for doctoral courses state that bridging courses may also provide cross-disciplinary training, but it is anticipated that this point will be changed so that bridging courses are associated only with research training credits, particularly in the case of students admitted to a doctoral programme with a bachelor’s degree that carries 300 ECTS credits.)

Taking into account the doctoral student activity report, the academic committee for the programme may propose measures that complement those specified in the regulations and which result in doctoral students who do not meet the specified requirements being excluded from the programme.

Students admitted to the programme will be required to take bridging courses on general subjects related to air navigation if their academic background does not include studies in this area. This knowledge is the bedrock of the programme. It is therefore absolutely essential that all graduates of the programme have this general and specific knowledge. An example of this would be students whose thesis focuses on a topic related to aircraft (e.g. materials used in avionics or subsystems), for whom a partial knowledge would be sufficient. This partial knowledge should be complemented by other more general knowledge of the fundamentals of aeronautics.

Exceptional students admitted with a notable background in research, and those who have not completed a master's degree in aeronautics (or a similar degree) but hold an entrance qualification that is closely aligned with the content of the programme, may be exempted from this requirement provided that their thesis is clearly focused on a topic in the field of aeronautics or aerospace science and technology (on the understanding that in the course of producing such a thesis they will acquire the minimum knowledge of general content required.)

Enrolment period for new doctoral students

Students enrolling in the doctoral programme for the first time must do so by the deadline specified in the admission decision.
Unless otherwise expressly indicated, enrolments corresponding to admission decisions issued from the second half of April on must be completed within the ordinary enrolment period for the current academic year.

More information at the registration section for new doctoral students

Enrolment period

Ordinary period for second and successive enrolments: first half of October.

More information at the general registration section

Procedure for the preparation and defense of the research plan

Doctoral candidates must submit a research plan, which will be included in their doctoral student activity report, before the end of the first year. The plan may be improved over the course of the doctoral degree. It must be endorsed by the tutor and the supervisor, and it must include the method that is to be followed and the aims of the research.

At least one of these annual assessments will include a public presentation and defence of the research plan and work done before a committee composed of three doctoral degree holders, which will be conducted in the manner determined by each academic committee. The examination committee awards a Pass or Fail mark. A Pass mark is a prerequisite for continuing on the doctoral programme. Doctoral candidates awarded a Fail mark must submit a new research plan for assessment by the academic committee of the doctoral programme within six months.

The committee assesses the research plan every year, in addition to all of the other activities in the doctoral student activity report. Doctoral candidates who are awarded two consecutive Fail marks for the research plan will be obliged to definitely withdraw from the programme.

If they change the subject of their thesis, they must submit a new research plan.

Formation activities

• Activity: Tutorial.

Hours: 288

Type: compulsory

• Activity: Publications.

Hours: 300

Type: optional

• Activity: Mobility

Hours: 480

Type: optional

• Activity: Assessment based on doctoral student activity report (DAD) and research plan.

Hours: 4

Type: compulsory

• Activity: Training in information skills

Hours: 1.5

Type: optional

• Activity: Research methodology

Hours: 12.

Type: optional

• Activity: Innovation and creativity

Hours: 8

Type: optional

• Activity: Language and communication skills

Hours: 18

Type: optional

• Activity: Courses and seminars

Hours: 50

Type: optional

• Activity: Workshops

Hours: 50

Type: optional

Procedure for assignment of tutor and thesis director

The academic committee of the doctoral programme assigns a thesis supervisor to each doctoral candidate when they are admitted or enrol for the first time, taking account of the thesis supervision commitment referred to in the admission decision.

The thesis supervisor will ensure that training activities carried out by the doctoral candidate are coherent and suitable, and that the topic of the candidate’s doctoral thesis will have an impact and make a novel contribution to knowledge in the relevant field. The thesis supervisor will also guide the doctoral candidate in planning the thesis and, if necessary, tailoring it to any other projects or activities undertaken. The thesis supervisor will generally be a UPC professor or researcher who holds a doctoral degree and has documented research experience. This includes PhD-holding staff at associated schools (as determined by the Governing Council) and UPC-affiliated research institutes (in accordance with corresponding collaboration and affiliation agreements). When thesis supervisors are UPC staff members, they also act as the doctoral candidate’s tutor.

PhD holders who do not meet these criteria (as a result of their contractual relationship or the nature of the institution to which they are attached) must be approved by the UPC Doctoral School's Standing Committee in order to participate in a doctoral programme as researchers with documented research experience.

The academic committee of the doctoral programme may approve the appointment of a PhD-holding expert who is not a UPC staff member as a candidate’s thesis supervisor. In such cases, the prior authorisation of the UPC Doctoral School's Standing Committee is required. A UPC staff member who holds a doctoral degree and has documented research experience must also be proposed to act as a co-supervisor, or as the doctoral candidate’s tutor if one has not been assigned.

A thesis supervisor may step down from this role if there are justified reasons (recognised as valid by the committee) for doing so. If this occurs, the academic committee of the doctoral programme will assign the doctoral candidate a new thesis supervisor.

Provided there are justified reasons for doing so, and after hearing any relevant input from the doctoral candidate, the academic committee of the doctoral programme may assign a new thesis supervisor at any time during the period of doctoral study.

If there are academic reasons for doing so (an interdisciplinary topic, joint or international programmes, etc.) and the academic committee of the programme gives its approval, an additional thesis supervisor may be assigned. Supervisors and co-supervisors have the same responsibilities and academic recognition.

The maximum number of supervisors of a doctoral thesis is two: a supervisor and a co-supervisor.

For theses carried out under a cotutelle agreement or as part of an Industrial Doctorate, if necessary and if the agreement foresees it this maximum number of supervisors may not apply. This notwithstanding, the maximum number of supervisors belonging to the UPC is two.

More information at the PhD theses section

Permanence

The academic committee of the programme may authorise an extension of up to one year for full-time doctoral candidates who have not applied to deposit their thesis by the end of the three-year period of study, in the terms outlined in the Academic Regulations for Doctoral Studies of the Universitat Politècnica de Catalunya. In the case of part-time candidates, an extension of two years may be authorised. In both cases, in exceptional circumstances a further one-year extension may be granted by the Doctoral School's Standing Committee, upon the submission of a reasoned application by the academic committee of the doctoral programme.

A doctoral candidate may be dismissed from a doctoral programme for the following reasons:

• The doctoral candidate submitting a justified application to withdraw from the programme.
• The maximum period of study and of extensions thereof ending.
• The doctoral candidate not having enrolled every academic year (unless he or she has been authorised to temporarily withdraw).
• The doctoral candidate failing two consecutive assessments.
• The doctoral candidate having disciplinary proceedings filed against him or her that rule that he or she must be dismissed from the UPC.

Dismissal from the programme implies that doctoral candidates cannot continue studying at the UPC and the closing of their academic record. This notwithstanding, they may apply to the academic committee of the programme for readmission and the committee must reevaluate them in accordance with the criteria established in the regulations.

International Mention

The doctoral degree certificate may include International Doctorate mention. In this case, the doctoral candidate must meet the following requirements:

a) During the period of study leading to the award of the doctoral degree, the doctoral candidate must have spent at least three months at a respected higher education institution or research centre outside Spain to complete courses or do research work. The stays and activities carried out must be endorsed by the thesis supervisor and authorised by the academic committee of the programme. The candidate must provide a certifying document issued by the person responsible for the research group of the body or bodies where the stay or activity was completed. This information will be added to the doctoral student’s activity report.
b) Part of the thesis (at least the summary and conclusions) must be written and presented in one of the languages commonly used for science communication in the relevant field of knowledge, which must not be an official language of Spain. This rule does not apply to stays and reports in Spanish or to experts from Spanish-speaking countries.
c) At least two PhD-holding experts belonging to a higher education institution or research centre outside Spain must have issued officially certified reports on the thesis.
d) The thesis examination committee must have included at least one PhD-holding expert from a higher education or research institution outside Spain who was not responsible for the candidate’s stay abroad (point a) above).
e) The thesis defence must have taken place on UPC premises or, in the case of joint programmes, at the location specified in the collaboration agreement.

List of authorized thesis for defense

Last update: 11/12/2023 05:45:35.

List of lodged theses

Last update: 11/12/2023 05:30:23.

List of defended theses by year

• ALONSO ALONSO, MARIA TERESA: Galileo broadcast ephemeris and clock errors, and observed fault probabilities for ARAIM
  
  Author: ALONSO ALONSO, MARIA TERESA
  Thesis link: http://hdl.handle.net/10803/689431
  Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Normal
  Reading date: 31/03/2023
  Thesis director: SANZ SUBIRANA, JAIME | ROVIRA GARCIA, ADRIÀ
  

  Committee:
       PRESIDENT: ORUS PEREZ, RAUL
       SECRETARI: ARAGON ANGEL, MARIA ANGELES
       VOCAL NO PRESENCIAL: TA, TUNG HAI
  Thesis abstract: The characterization of Clock and Ephemeris error of the Global Navigation Satellite Systems is a key element to validate the assumptions for the integrity analysis of GNSS Safety of Life (SoL) applications. Specifically, the performance metrics of SoL applications require the characterization of the nominal User Range Errors (UREs) as well as the knowledge of the probability of a satellite, Psat or a constellation fault, Pconst, i.e. when one or more satellites are not in the nominal mode. We will focus on Advanced Autonomous Integrity Monitoring (ARAIM). The present dissertation carries-out an end-to-end characterization and analysis of Galileo and GPS satellites for ARAIM. It involves two main targets. First, the characterization of Galileo and GPS broadcast ephemeris and clock errors, to determine the fault probabilities Psat and Pconst, and the determination on an upper bound of the nominal satellite ranging accuracy (sURA). Second, using these experimental results, to assess the performance of the ARAIM at user level. With regard to the first goal, the main contribution has been the extension of the algorithms already developed for GPS satellites to the Galileo constellation. This is not a straightforward task, as it requires to consider the particular features of Galileo data. This characterization involved the development and implementation of complex algorithms to consolidate broadcast navigation files from a huge set of individual receivers, and using these consolidated files, to develop automatic monitors to assess the nominal behaviour of the GNSS satellites and detect anomalous events. The methodology has been applied to more than 5 years of Galileo data (since Galileo Open Service was declared on 15 December 2016) and more than 10 years of GPS data. Thanks to this analysis the satellite orbit and clock faults have been identified, the probability of failure established and sURA determined.The Not-to-Exceed (NTE) thresholds from Galileo commitments have been used to identify the satellite faults and to estimate the observed probabilities Psat and Pconst. Using the NTE = 39.78 m, when excluding the first six-month period of Galileo IS OS, the analysis over the last five-year window shows very promising results. Only two satellite faults have been found. These two faults over this five-year period result in a fault probability Psat=3.0 × 10-6/sat, which is far below the 1 × 10-5/sat commitment.Regarding to te second goal, the main contribution of this thesis has been the assessment of the global performance of the H-ARAIM based in the experimental results of previous characterization of Psat, Pconst and sURA. The approach involves multi-constellation (Galileo and GPS) and single constellation (Galileo alone or GPS alone). The metric for H-ARAIM examinations the 99.5th percentile of availability for the Required Navigation Performance (RNP) with lateral accuracy of 0.1 (RNP-0.1). The results show almost 100% global coverage for all analysed configurations, except with single-frequency Galileo with E1 or E5, or Galileo plus GPS with E5 and L5. This is when the basic-constellation, with 24 satellites per constellation, or the optimistic constellation with 27 satellites, are used. With a degraded-constellation (23 satellites), RNP-0.1 is only achieved with multi-constellation and dual frequency [Galileo E1/E5 plus GPS L1/L5]. The dissertation also includes a sensitivity analysis of ARAIM algorithm as a function of the Integrity Support Message (ISM).
  

• ANGELATS COMPANY, EDUARD: On hybrid positioning using non-semantic image information
  
  Author: ANGELATS COMPANY, EDUARD
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Normal
  Reading date: 04/10/2023
  Thesis director: COLOMINA FOSCH, ISMAEL
  

  Committee:
       PRESIDENT: CASAS PIEDRAFITA, JAIME OSCAR
       SECRETARI: DELGADO GARCIA, JORGE
       VOCAL NO PRESENCIAL: MARTÍNEZ SÁNCHEZ, JOAQUIN
  Thesis abstract: Hybrid or multi-sensor-based positioning has been a research topic actively investigated in the last decade. In this context, the possibility of using information extracted from imaging sensors, for positioning, is very appealing to mitigate the problems that GNSS or INS/GNSS-based trajectories have in terms of robustness and accuracy. On the other hand, different processing workflows, sensor positioning quality or system calibration errors, may also produce even in GNSS-friendly conditions, that multiple geospatial datasets are not properly co-registered. This thesis proposes the use of non-semantic information, this is, the use of a set of geometric entities or features, to improve the trajectory estimation in a multi-sensor-based approach. This thesis covers the mathematical modelling of non-semantic information, implements several hybrid-based trajectory estimation approaches that use this kind of information with the appropriate modelling, and also explores the use of non-semantic features to model the trajectory error modelling.The implementation of combined models allowing to use of observations from camera or LiDAR sensors is the first contribution of this thesis. The proposed models have enabled improved trajectory determination in both urban post-processing and airborne environments with good accuracy (cm level). The implemented INS/GNSS trajectory error models are relatively simple but proved to be efficient. The combined models have been tested, in post-processing, using a bundle adjustment approach, with real data from metric cameras and aerial laser mapping systems as well as in Terrestrial Mobile Mapping systems (TMM). The second contribution of this thesis is the characterization of trajectory errors that TMM may have in GNSS urban scenarios. The non-semantic information extracted from the images has allowed, using an integrated sensor orientation approach, to model these errors in an urban environment. This modelling opens the door to the development of new, more advanced trajectory error models that go beyond the deterministic models currently used. The determination of trajectories in real time, in GNSS unfriendly environments, is also explored in this thesis using non-semantic features. An approach has been implemented based on a tightly coupling sequential nonlinear least squares using GNSS positions, image coordinates and raw inertial measurements. The proposed approach exploits a sliding window bundle adjustment technique to use the image coordinates of tie points and the positions and attitudes derived from the last epochs to determine the position and attitude parameters of the most recent epoch. The approach has been evaluated using both real and simulated data from a mobile mapping campaign over an urban area with long GNSS outage periods, with promising results.This thesis also presents an approach to improve the determination of Remotely Piloted Aircraft Systems (RPAS) trajectories using open aerial data obtained in the framework of a national mapping project (PNOA). The development of this methodology is another contribution aiming to ensure the geospatial coherence between the orthophotos, and digital elevation models obtained with an RPAS and the orthophotos and digital models of the PNOA. The results, applied in the context of a multi-temporal and multi-sensor high-resolution archaeological documentation, show that photogrammetric products can be generated with a similar accuracy (cm level accuracy) to the ones generated with more complex approaches. Last but not least, this thesis presents a seamless indoor-outdoor positioning approach with encouraging results (meter-level accuracy) in several scenarios. This contribution opens the door for enhanced tracking of members of civil protection and emergency teams. This is an open field of research with not widely accepted /adopted solution yet.
  

• BOTH, AMBRUS: High-fidelity numerical simulations of reacting flows with tabulated chemistry
  
  Author: BOTH, AMBRUS
  Thesis link: http://hdl.handle.net/10803/689093
  Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Normal
  Reading date: 29/06/2023
  Thesis director: MIRA MARTÍNEZ, DANIEL | LEHMKUHL BARBA, ORIOL
  

  Committee:
       PRESIDENT: MOUREAU, VINCENT
       SECRETARI: VENTOSA MOLINA, JORDI
       VOCAL: GIUSTI, ANDREA
  Thesis abstract: In the transition to net-zero carbon emission technologies, turbulent combustion is expected to retain an important role in various applications. In particular, the aviation industry is projected to widely adapt the usage of biofuels and hydrogen-based fuels in the coming decades, while the regulations concerning non-CO2 pollutant emissions are becoming more stringent. This transition entails both the gradual evolution of existing burner technologies, and the exploration of revolutionary new concepts. Large-eddy simulation of these combustion systems provides valuable insight into complex dynamic phenomena, such as flame stability and pollutant formation, thus it is an increasingly more important component of the engine development process. Such high-fidelity simulation approaches need to be further developed, gaining confidence in their applicability and exploring their limitations, while keeping in mind the complexity of available high-performance computing resources. This dissertation presents the development of computational tools for the study of multiphase reacting flows, and their application on model aero-engine combustors.Specifically, the present work applies tabulated chemistry methods for combustion modeling, which allow for the representation of complex chemical phenomena while keeping the computational cost feasible. Furthermore, liquid fuel droplets are modeled in a Lagrangian manner, giving an intuitive representation of sprays. Stand-alone computational tools are created to facilitate the user friendly flamelet calculation and tabulation in a unified framework, and to increase confidence in droplet evaporation models through single droplet simulations. Meanwhile, a high-fidelity simulation method is implemented in the multi-physics simulation code: Alya, utilizing the various preexisting code elements, and exploiting the ongoing development efforts of a large team. In particular, the low-dissipation Navier-Stokes solver of Alya is extended here to variable density flows under low Mach number conditions. This Navier-Stokes solver is coupled with arbitrarily complex thermo-chemical tables in a new framework.The developed stand-alone tools are used in this work to analyze the single droplet behavior, and to explore steady and temporally evolving laminar flamelets, and their applicability to chemistry tabulation. Subsequently the new framework of Alya is validated extensively and it is used in the analysis of tabulated chemistry methods. The turbulent combustion process in model aero-engines is studied with the developed method at atmospheric pressure. The flame stabilization phenomenon is analyzed in a swirl stabilized technically premixed hydrogen burner approaching flashback conditions. This turbulent hydrogen flame is studied using a perfectly premixed assumption and considering mixture fraction stratifications as well. Subsequently, the Cambridge swirl bluff-body burner is studied under different conditions. A non-premixed gaseous methane flame and two spray flames using n-heptane and n-dodecane fuels are simulated close to the lean blow-out limit, studying the shear induced localized extinction in detail. The prediction of this finite rate chemistry effect is a challenging task for the applied tabulated chemistry methods, however valuable insight is gained on the applicability of different thermo-chemical manifolds, and on the effect of the liquid fuel behavior.Overall, the implemented low-dissipation finite element method is capable of predicting complex unsteady combustion phenomena, despite the simplicity of the tabulated chemistry methods. The work presented herein has been published in two peer reviewed journal articles and several conference contributions. The developed simulation framework enables the further study of industrially relevant combustion systems using high-performance computing resources.
  

• ÇETIN, ENDER: Counter a drone via deep reinforcement learning
  
  Author: ÇETIN, ENDER
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Normal
  Reading date: 30/08/2023
  Thesis director: BARRADO MUXI, CRISTINA
  

  Committee:
       PRESIDENT: RAMOS GONZALEZ, JUAN JOSÉ
       SECRETARI: SALAMI SAN JUAN, ESTHER
       VOCAL: BRONZ, MURAT
  Thesis abstract: Unmanned aerial vehicles (UAV) also known as drones have been used for a variety of reasons such as surveillance, reconnaissance, shipping and delivery, etc. and commercial drone market growth is expected to reach remarkable levels in the near future. However, drones can accidentally or intentionally violate the air routes of major airports, flying too close to commercial aircraft or invading the privacy of someone. In order to prevent these unwanted events to happen, counter-drone technology is needed to eliminate the threats coming from drones and hopefully the drones can be integrated into the skies safely. A number of counter-drone solutions are being developed, but the cost of drone detection ground systems can also be very high, depending on the number of sensors deployed and powerful fusion algorithms. Counter-drone system supported by an artificial intelligence (AI) method can be an efficient way to fight against drones instead of human intervention. Considering the recent advances in AI, counter-drone systems with AI can also be very accurate. The time required to engage with the target can be less than other methods based on human intervention such as bringing down a malicious drone by a laser gun. Also, AI can identify and classify the target with a high precision in order to prevent a false interdiction with the targeted object. Counter-drone technology with AI will bring important advantages to the threats coming from some drones and will help the skies to become safer and more secure. AI has been used in different research areas in aerospace to create an intelligent system. Especially, a drone can be controlled by AI methods such as deep reinforcement learning (DRL) in different purposes. With the support of DRL, drones can become more intelligent and eventually they can be fully autonomous. The main objective of this PhD thesis is to develop an artificial intelligence approach based on deep reinforcement learning to counter drones that may pose a threat to safety or security. AI agents can continuously learn and adapt to new threats and countering drones with DRL has several advantages. One of the most important advantages is autonomous decision-making which enables AI agents to make autonomous decisions based on their environment and the situation. In this way, drone threats can be countered quickly and effectively, even in vulnerable environments. Additionally, AI agents can be trained in simulation, allowing for safe experimentation, testing, and validation before deployment. Firstly, DRL architecture is proposed to make drones behave autonomously inside a suburb neighborhood environment. Secondly, a state-of-the-art object detection algorithm for drone detection is also added to the counter drone solution. The construction of drone detection models involves transfer learning and training a state-of-the-art object detection algorithm. After achieving fully autonomous drone which can avoid obstacles in an environment, a deep reinforcement learning method to counter a drone in a 2D space in an environment is presented. In this way, drone can maintain its current altitude, and it can try to catch another drone without crashing any obstacle in the environment. Finally, a deep reinforcement learning model is developed to counter a drone in a challenging 3D space in an environment. The learner drone is not only moving in a 2D space but also changing altitudes to eliminate the target drone. It is important to ensure that AI agents are properly trained and validated so that they can make safe and responsible decisions. Without proper testing and validation, there is a risk that AI agents in sensitive areas such as airports or critical infrastructure might perform actions that could be dangerous or violate regulations. As a result, DRL-based counter-drone solutions can be made more practical, efficient, and secure for future use.
  

• DUAN, XUN: Impulse maneuver design for a solar sail spacecarft in the restricted three-body problem framework
  
  Author: DUAN, XUN
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Change of supervisor
  Reading date: 10/05/2023
  Thesis director: MASDEMONT SOLER, JOSEP JOAQUIM | GOMEZ MUNTANÉ, GERARD | YUE, XIAOKUI
  

  Committee:
       PRESIDENT: BAOYIN, HEXI
       SECRETARI: PAN, BINFENG
       VOCAL: XIN, NING
       VOCAL: YU, XIAOZHOU
       VOCAL: QIAO, DONG
  Thesis abstract: A solar sail is a method of spacecraft propulsion that uses only the solar radiation pressure (SRP). The main research object of this thesis is a solar sail spacecraft in the artificially created libration point orbits. It proposes a strategy to accomplish impulsive maneuvers by changing the parameters of the sail. The main new results are the following:1. Computation of artificial libration points as a function of the parameters of a solar sail (cone angle ¿, clock angle ¿, and lightness number ¿).The SRP is an additional repulsive acceleration in the CR3BP. As a result, the CR3BP equilibrium points L1, L2¿L5 are shifted from their original positions. The new points SL1, SL2¿SL5 correspond to positions in the rotating system where the gravitational, centrifugal, and SRP forces are balanced. These points can be represented as functions of the sail parameters ¿, ¿, and ¿. Determination and adjustment of the solar sail parameters, computation of impulse maneuvers and their application to heteroclinic orbit transfers between Lissajous orbits plus a sensitivity analysis of the parameters of the maneuver for orbit transfers. The dynamics of solar sail maneuvers is conceptually different from classical control maneuvers, which rely only on impulsive changes to the velocity of a spacecraft. Solar sail orbits are continuous in both position and velocity in a varying vector field, which opens up the possibility for the existence of heteroclinic connections by changing the vector field with a sail maneuver. Based on a careful analysis of the geometry of the phase space of the linearized equations of motion around the equilibrium points, the key points are the identification of the main dynamic parameters and the representation of the solutions using the action-angle variables. The basic dynamic properties of the connecting families have been identified, presenting systematic new options for mission analysis in the libration point regime.Based on the proposed method for making impulse maneuvers, this thesis has carried out extensive research: (1) By applying a single-impulse maneuver, two spacecraft can reach the same final Lissajous orbit despite starting from different initial phases. (2) A transfer strategy is proposed that uses multi-impulse maneuvers. The initial and final solar sail parameters are fixed. (3) A spacecraft can use multi-impulse maneuvers to make back-and-forth jumps between the initial and final artificial libration point orbits.2. Avoidance of forbidden zones considering impulsive maneuvers with the sail.There is a cylinder-like zone around the Sun--Earth axis where solar electromagnetic radiation is especially strong. The L1 libration point lies on this axis and is between the two bodies. The Earth half-shadow in the L2 region can also prevent a spacecraft from obtaining solar energy. Both problems can be modeled by placing a forbidden or exclusion zone in the YZ plane (around the libration point), which should not be crossed. To simplify and visualize the avoidance of forbidden zones, this thesis projects the 3D forbidden zones into the so-called effective phase plane (EPP), which has dimension 2. 3. Station-keeping of a solar sail moving along a Lissajous orbit.The designed station-keeping procedure periodically performs a maneuver to prevent the spacecraft to escape from a certain Lissajous orbit. The maneuver is computed so that it cancels out the unstable component of the state. Moreover, it is assumed that there is a random error in the execution of the maneuver. Considering the maneuvers performed every month, we show that the spacecraft can remain near the artificial libration points for at least 5 years, which demonstrates that station-keeping using sail reorientations to produce multiple impulses can be effective.
  

• IBÁÑEZ SEGURA, DEIMOS: Contributions to multi-purpose GNSS positioning to support multi-frequency and multi-constellation with high accuracy and integrity
  
  Author: IBÁÑEZ SEGURA, DEIMOS
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Normal
  Reading date: 23/10/2023
  Thesis director: ROVIRA GARCIA, ADRIÀ | SANZ SUBIRANA, JAIME
  

  Committee:
       PRESIDENT: GARCIA FERNANDEZ, MIQUEL
       SECRETARI: ARAGON ANGEL, MARIA ANGELES
       VOCAL: LOPEZ MARTINEZ, MANUEL
  Thesis abstract: Global Navigation Satellite System (GNSS) have revolutionized location and timing technologies due to their low cost and wide availability. Initially, GNSS was limited to the american Global Positioning System (GPS) and the Russian GLObal NAvigation Satellite System (GLONASS). However, in recent years, new GNSS systems such as European Global Navigation Satellite System (Galileo), the Chinese BeiDou Navigation Satellite System (BDS), the Japanese Quasi-Zenith Satellite System (QZSS), and Indian Regional Navigation Satellite System (IRNSS) have been deployed. These systems offer multiple frequencies and signals, which have rendered the current processing of dual-frequency single-constellation GNSS data obsolete.To address this issue, the Research group of Astronomy and Geomatics (gAGE) in Technical University of Catalonia (UPC) developed the GNSS-Lab Tool suite (gLAB) reference tool. Initially, gLAB was designed to support GPS only under a contract with the European Space Agency (ESA) and was later upgraded to become a reference tool for scientific studies. gLAB has demonstrated its research capabilities under ESA and European Union Agency for the Space Programme (EUSPA) contracts.The gLAB tool has had a great impact on the GNSS community across the globe, with 222,526 downloads from 147 different countries, which demonstrates the demand for a tool with these capabilities. The positioning algorithms originally coded in gLAB, Standard Point Positioning (SPP) and Precise Point Positioning (PPP), are upgraded to work with all new signals. In addition, advanced algorithms have been implemented, including uncombined PPP, Fast Precise Point Positioning (Fast-PPP), and Satellite-Based Augmentation System (SBAS) Dual Frequency Multi Constellation (DFMC). These additional capabilities required optimizing the code and implementing multi-threading to reduce processing times.The research carried out in this PhD has made several significant contributions. Firstly, an evaluation of European Geostationary Navigation Overlay System (EGNOS), initially developed for civil aviation, was carried out for its application for maritime purposes, proving that EGNOS is valid for this use, with even improved continuity figures. In addition, a methodology for the daily evaluation of the EGNOS Signal In Space (SIS) has been developed and implemented in a Global Monitoring System (GMS) based on gLAB.Secondly, the impact of ionospheric activity and its correct modelling on navigation, especially in SBAS systems, has been analysed. In this area, the importance of having a global index, the Along Arc TEC Rate (AATR), to measure ionospheric activity has been shown and its correlation with the degradation of the quality of service of EGNOS has been analysed.Thirdly, the effect of positioning anomalies (both in the SIS and in the receiver) has been studied, proposing methodologies for their detection based on pseudorange residuals or by combining several signals. In any of these methods, a high degree of data pre-processing is required, for which gLAB is a very suitable tool.Fourthly, a method for measurement management in gLAB has been developed. It comprises complex algorithmics that allows any combination of observables (single, dual, triple, or quadruple combinations) on a per-satellite basis, as well as to provide either manual or automatic measurement selection (and extend it for cycle-slip detectors).In conclusion, the present PhD has paved the way to modern GNSS data processing beyond the state of the art.
  

• MAS PUJOL, SERGI: Deep learning techniques for demand-capacity balancing
  
  Author: MAS PUJOL, SERGI
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Normal
  Reading date: 12/05/2023
  Thesis director: SALAMI SAN JUAN, ESTHER | PASTOR LLORENS, ENRIC
  

  Committee:
       PRESIDENT: PIERA EROLES, MIGUEL ANGEL
       SECRETARI: PRATS MENENDEZ, XAVIER
       VOCAL: DALMAU CODINA, RAMON
  Thesis abstract: Nowadays Air Navigation Service Providers (ANSPs) have to handle and accommodate a continuously increasing traffic demand in a scenario that is expected to be more time-efficient and cost-efficient. Meeting the demand with the available airspace capacity is one of the most challenging problems faced by Air Traffic Management (ATM). This collaborative Demand-Capacity Balancing process often ends up enforcing Air Traffic Flow Management (ATFM) regulations when capacity cannot be adjusted. The arrival traffic is spread out by assigning delays on the ground at the departure airport, and the arrivals are metered at the congested infrastructure. However, deciding whether and when regulations are needed is time-consuming and relies heavily on human knowledge. This leads to suboptimal and unnecessarily long regulation and, therefore, to the realization of unnecessary delay and underuse of the capacity.Over the years, many researchers have investigated new techniques to estimate better the complexity of a given Air Traffic Control (ATC) sector -- Traffic Volume (TV) -- or how to quantify the workload of the Air Traffic Controllers (ATCOs) to identify required ATFM regulations. Moreover, because of the huge impact of ATFM delays in the network, a wide variety of previous work can be found trying to optimize, improve, minimize, or predict the evolution of delays. The literature shows three main trends: proposals without any Artificial Intelligence (AI), using supervised Machine Learning or Reinforcement Learning (RL) techniques. However, there is a lack of work directly focusing on the identification of required ATFM regulations and their characteristics, and the proposed methods to smooth demand-capacity imbalances suffer from scalability issues.The main objective of this PhD thesis is to investigate the usage of AI techniques to identify and smooth DCB problems leading to ATFM regulations during the pre-tactical phase. That is when there is no available information from the Network Manager (NM) about required regulations and when levels of uncertainty are much higher. Different sets of frameworks are studied and developed, considering the needs and policies of different stakeholders. First, it is studied the identification of ATFM regulations at the TV level, using supervised techniques and developing a framework that aims to be used by the NM. The two most frequent regulations reasons are analyzed over two of the most congested European Civil Aviation Conference (ECAC) regions. Results reveal that the proposed architecture can identify almost all the regulations during the summer, which is probably the most congested season. Second, RL techniques are investigated to solve the previously identified ATFM regulation, focusing on scalability due to the usage of images. Finally, airlines are the stakeholders affected by ATFM regulations; thus, the potential benefits of identifying ATFM regulations at the flight level are also analyzed. Promising results show it is possible to predict ATFM characteristics using supervised techniques. Moreover, the models are integrated into a framework to assess the impact and severity of issued regulations to anticipate possible reactionary delays for specific aircraft frames.Overall, results prove it is possible to accurately predict ATFM regulations, the characteristics of such regulations, and automatize the smoothing process required to solve DCB issues. There are some factors to be considered that may limit the benefits of the proposed solutions, starting with data availability issues in some experiments. However, it is worth mentioning that the models have been tested under the most challenging European scenarios. Finally, deploying the proposed framework will be key to studying the benefits and impact of the proposed solution. Therefore, specific advice capabilities are proposed for the visualization of the results taking into account uncertainty.
  

• MELGOSA FARRÉS, MARC: Enhanced air traffic flow and capacity management under trajectory based operations considering traffic complexity
  
  Author: MELGOSA FARRÉS, MARC
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Normal
  Reading date: 22/03/2023
  Thesis director: PRATS MENENDEZ, XAVIER | VIDOSAVLJEVIC, ANDRIJA
  

  Committee:
       PRESIDENT: RANIERI, ANDREA
       SECRETARI: XU, YAN
       VOCAL: ZERROUKI, LEÏLA
  Thesis abstract: The Air Traffic Flow and Capacity Management (ATFCM) aims at maintaining the forecast traffic demand below the estimated capacity in airports and airspace sectors. The purpose is to maintain the workload of the air traffic controllers under safe limits and avoid overloaded situations. At present, the demand and the capacity management initiatives are deployed separately. Given a forecast traffic demand, the different air navigation service providers allocate their air traffic control resources providing the airspace sectorisations. Then, the network manager addresses the remaining overloads by allocating delay using the CASA algorithm based on a ration-by-schedule principle. It should be noted that some ad-hoc flights might be re-rerouted or limited in cruise altitude in order to avoid congested airspace by submitting a new flight plan. Hence, the previously chosen sectorisations may be not optimum once the demand management initiatives are deployed. Moreover, the flexibility of the airspace users is limited since they cannot express their preferences. Furthermore, the demand and the capacity are currently measured using entry counts as proxy of the air traffic control workload, which is rather easy to measure or estimate. Yet, this metric cannot evaluate the difficulty to handle different traffic patterns inside the sectors leading to the use of capacity buffers. This PhD focuses on overcoming the limitations of the current ATFCM system outlined before by the introduction of complexity metrics (instead of entry counts) in order to measure the traffic load, the better consideration of the airspace users preferences allowing the possibility of submitting alternative trajectories to avoid congested airspace, and the holistic integration of the demand and capacity management into the same optimisation problem.First, the integration of two capacity management initiatives, i.e. Dynamic Airspace Configuration (DAC) and Flight Centric ATC (FCA), is studied proving some benefits when such integration is dynamic. Next, a new concept of operation is proposed where the airspace users have the option of submitting alternative trajectories and the network manager is the responsible for the demand management (delay allocation and choice of the used trajectory) and the capacity management (selection of the airspace sectorisation), considering a network-wide optimisation. This concept of operations is mathematically modelled with two Demand and Capacity Balancing (DCB) models addressing only demand management and three holistic DCB models where the demand and the capacity management measures are considered together in the same optimisation problem.A first model aims at choosing the best trajectory and delay allocation per flight while analysing the traffic load with entry counts at traffic volume level. It is solved in a realistic case study using the historical regulations providing a 76.84% of reduction in the arrival delay if compared to the current system.
  

• SKOROBOGATOV, GEORGY: Optimizing workspace division for multi-UAV systems
  
  Author: SKOROBOGATOV, GEORGY
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Normal
  Reading date: 27/10/2023
  Thesis director: BARRADO MUXI, CRISTINA | SALAMI SAN JUAN, ESTHER
  

  Committee:
       PRESIDENT: COLOMINA FOSCH, ISMAEL
       SECRETARI: PASTOR LLORENS, ENRIC
       VOCAL: DELAHAYE, DANIEL
  Thesis abstract: With the advance of UAV-related technology using several drones in the context of a single mission becomes more and more common. New problems and challenges appear as a result.When analyzing research works on using systems of multiple UAVs we could notice that the majority of the authors provided few details on how the path planning or workspace division was done. Out of those researchers who mentioned it, some pointed out that the planning or area partitioning was performed by hand. Other researchers presented brief ideas of algorithms with too little information to implement it. In other research works very brief lists of algorithms were given that could solve the problem. And even in those cases when the information on the algorithms was provided, the algorithms themselves did not have any freely available implementations.The purpose of this thesis is to fill the gap in the area of workspace division in order to facilitate the usage of systems consisting of multiple UAVs. In order to accomplish the aforementioned goal, in this thesis, we performed analysis of the literature on the subject of workspace decomposition between multiple robots and UAVs in particular.As it will be shown later, there are almost no research works published in this area. We implemented two state of the art algorithms and shared information on how we achieved that and what were the aspects that needed clarification or could be improved. We analyzed thoroughly the produced results, and propose improvements to the algorithm that yielded better results. And finally, we proposed, implemented, and analyzed two alternative algorithms based on the obtained experience. These algorithms outperformed the algorithm from the literature in terms of quality of the resulting partition. One algorithm solves the partition problem for convex polygons and the other one solves the partition problem for non-convex polygons. Finally, we have summarized a set of open problems that could be solved in future.
  

• TIMOTE BEJARANO, CRISTHIAN CAMILO: Contributions to real-time monitoring of the ionosphere using GNSS signals
  
  Author: TIMOTE BEJARANO, CRISTHIAN CAMILO
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Article-based thesis
  Reading date: 27/03/2023
  Thesis director: GONZÁLEZ CASADO, GUILLERMO | ESCUDERO ROYO, MIGUEL
  

  Committee:
       PRESIDENT: GARCIA FERNANDEZ, MIQUEL
       SECRETARI: ARAGON ANGEL, MARIA ANGELES
       VOCAL: NIE, WENFENG
  Thesis abstract: This document presents the collection of four manuscripts published during my Doctoral academic formation, which main goal has been the real-time implementation of tools to monitor the ionosphere using Global Navigation Satellite System (GNSS) signals. Despite the fact that there is a vast literature on ionospheric modelling, the state-of-the-art becomes narrow when referring to real-time developments, especially fulfilling precise requirements on accuracy, performance, coverage, and confidence in the generated products. The main contribution of this work to the scientific community is the deployment of ionospheric-related products to monitor in real-time the state of the ionosphere.The first and second publications targeted the implementation of a novel strategy based on a definition of a GNSS Solar Flare (SF) monitor to automatically confirm Solar Flare Effects (Sfe) in geomagnetism. In the first scientific article, it is inspected the methodology used to fine-tune (adapt) a SF monitor, working with an eleven years period of data to statistically correlate detected SF using GNSS signals with respect to SFe. The results demonstrated that the proposed GNSS Solar Flare monitor can confirm Sfe events when traditional Sfe detectors are not able to respond categorically. The second publication details the methodological approach for defining the proposed GNSS Solar Flare monitor, focusing on the theoretical formulation of the Slant Total Electron Content (STEC) obtained.The third contribution used GNSS signals to detect the presence of Medium Scale Travelling Ionospheric Disturbance (MSTID) within a network of permanent GNSS stations that provide the high-accuracy positioning service known as Network-Real-Time Kinematics (NRTK). The effects of a MSTID are characterized in terms of fluctuations in the electron density in the iono- sphere, experienced differently by each one of the GNSS stations used as reference receivers within the NRTK, and resulting in a degradation of the positioning of any user of the service. The MSTIDidx index is proposed to warn users of the presence of a MSTID, implementing a novel methodology for assessing the errors in positioning based on fixing carrier-phase ambiguities in undifferenced measurements. The adoption of the proposed MSTIDidx index proves to be efficient to reduce the errors on the user positioning by excluding measurements polluted by the MSTID effects, reaching accuracy levels within the overall network similar to the ones achieved by users located close to reference stations (and therefore, less affected by MSTID effects).The fourth publication is the core of my doctoral thesis and presents the real-time implemen- tation of a model to generate ionospheric corrections suitable to fulfill the Galileo HAS. The analyzed ionospheric correction system is based on the Fast Precise Point Positioning (FPPP) technique, in which it is highlighted the benefits of integer ambiguity resolution to obtain unambiguous carrier phase measurements as input to compute the FPPP ionospheric model. Additionally, this contribution underlines the benefit of the implemented strategy, in terms of the geometric model used by the ionospheric modelling and the dataset implemented. In terms of assessing the errors of the FPPP ionospheric corrections, the 99% of the Global Positioning System (GPS) and Galileo errors in well-sounded areas and in mid-latitude stations are below one total electron content unit, which is in line according to the required ionospheric accuracy for the Galileo HAS. Furthermore, alongside the ionospheric corrections, it is presented some additional products generated by the FPPP Central Processing Facility (CPF), produced in real-time and with accuracy levels suitable to any HAS application.
  

• WASSIE, YISMAW ABERA: Spatio-temporal quality metrics for satellite SAR interferometric data
  
  Author: WASSIE, YISMAW ABERA
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Normal
  Reading date: 24/07/2023
  Thesis director: CROSETTO, MICHELE | MONSERRAT HERNANDEZ, ORIOL
  

  Committee:
       PRESIDENT: GILI RIPOLL, JOSE ANTONIO
       SECRETARI: MRÓZ, MAREK
       VOCAL NO PRESENCIAL: RUIZ ARMENTEROS, ANTONIO MIGUEL
  Thesis abstract: The availability of RADAR images for monitoring Earth¿s surface and its changes over time prompt the development of several interferometric SAR (InSAR) algorithms and methodologies. The Multi-temporal InSAR (MT-InSAR) techniques- being the one, generally, aim at extracting the temporal evolution of displacements of targets with coherent scattering behavior from a stack of SAR acquisitions that are taken from the same area and processed relative to temporal and spatial references. On the other hand, due to the complex nature of SAR measurements, addressing all possible model parameters in a comprehensive manner is still challenging and is a source of error and misinterpretation. As a well-established spaceborne geodetic technique with various applications, the accuracy of MT-InSAR products does matter, and hence potential error sources must be mitigated. The accuracy of displacement time-series (TS) estimates, in many cases, is governed by the quality and number of exploited images, associated interferograms, and selected measurement points. Such data and derived results are heavily influenced by factors, including environmental conditions at times of measurement acquisition and the processing algorithms used. Incomplete representations of factors in modeling MT-InSAR measurements may, as well, lead to omission errors and hence an incorrect estimation and interpretation of the displacement TS. Any uncertainty in the accuracy of the MT-InSAR products compromises their reliability in sensitive applications. In line with this, tools to detect, identify, and classify interferometric measurements that are particularly impacted by phase unwrapping (PhU) errors had been developed with the aim to identify and mitigate potential errors in the data¿ ultimately improving the quality and valuing the worth of MT-InSAR measurements. These tools make use of estimated phase residuals derived from a redundant network of unwrapped interferograms to formulate threshold-based quality scores as indicators of the reliability of the measurement points, images in a TS, images, and interferograms. Multiple pairs of baseline-constrained Sentinel-1 SAR images were considered to assess the potential of the tools to automatically detect, identify, and mitigate errors in the framework of the PSIG processing chain. The techniques were applied pixel by pixel in space and time to associate reliability scores highlighting the influence of global and local PhU errors in the course of the phase estimation. Experiments had generally justified that error mitigation strategies which include the exclusion of less reliable measurements from the network had relieved the impacts of errors and improved the TS estimation. Another important aspect of the thesis is the use of the point score tool as a post-PhU pixel filtering technique. The methodology contributes by providing quantitative information on the percentage of reliable pixels immediately after the PhU step. The experiments in this regard justified that the tool adds extra dimensions to common pixel selection techniques and is responsible for mitigating limitations on PhU error correction methodologies. Using it in conjunction with existing point selection techniques further guaranteed the inclusion of reliable points in the process. The results demonstrated that the proposed techniques significantly improved the quality of InSAR data. Besides, implications for various applications that rely on MT-InSAR datasets¿ such as those used in monitoring mining areas and infrastructures and those ground deformations induced either by natural or anthropogenic phenomena, have been justified. Potential avenues for future research to further improve the qualities of interferometric products including the quantification of interferometric measurement point location uncertainties are also envisioned.
  

Last update: 11/12/2023 06:01:46.

Research groups

• (MC)2-UPC-Computational continuum mechanics
• DF-Dinamica de Fluids: formacio d'estructures i aplicacions geofisiques
• GAA-Astronomy and Astrophysics Group
• gAGE-Research Group of Astronomy and Geomatics
• GCM-Group of Characterization of Materials
• ICARUS-Intelligent Communications and Avionics for Robust Unmanned Aerial Systems
• IonSAT- Ionospheric determination and navigation based on Satellite And Terrestrial systems
• L'AIRE-Laboratory of Aeronautical and Industrial Research and Studies
• LACAN - UPC-Numerical Methods for Applied Sciences and Engineering
• MNT-Micro and Nanotechnologies Research Group
• RSLAB-Remote Sensing Lab
• SPCOM-Signal Processing and Communications Group

Teachers

• Barrado Muxi, Cristina
• Bertran Alberti, Eduard
• Bruna Escuer, Pere
• Bugeda Castelltort, Gabriel
• Camps Carmona, Adriano Jose
• Casanova Hormaechea, Ignasi
• Cela Espin, Jose M.
• Crespo Artiaga, Daniel
• Gil Pons, Pilar
• Gilabert Pinal, Pere Lluis
• Gili Ripoll, Jose Antonio
• Gonzalez Casado, Guillermo
• Gonzalez Cinca, Ricard
• Gutierrez Cabello, Jordi
• Hernandez Pajares, Manuel
• Huerta Cerezuela, Antonio
• Juan Zornoza, Jose Miguel
• Masdemont Soler, Josep Joaquim
• Mateo Garcia, Antonio
• Mellibovsky Elstein, Fernando Pablo
• Montoro Lopez, Gabriel
• Oñate Ibañez de Navarra, Eugenio
• Pineda Soler, Eloi
• Pino Gonzalez, David
• Prats Menendez, Xavier
• Robuste Anton, Robus
• Rodriguez Ferran, Antonio
• Rojas Gregorio, Jose Ignacio
• Rovira Garcia, Adrià
• Salan Ballesteros, M. Núria
• Sanz Subirana, Jaime
• Vazquez, Mariano
• Villardi de Montlaur, Adeline