PhD Position Full Wave Inversion Using Data-Driven Operators for GNSS-R Data

GNSS-R is a technique to carry out Earth observation based on reflections on the ground (or sea, or ice) of signals originating from GNSS (Global Navigation Satellite System) signals. The proposed project consists of educating a new generation of experts, at doctoral level, able to bring a qualitative leap to this technology. The scientific and technological goal consists of developing such systems based on a synchronized constellation of Cubesats. An important advantage of this arrangement is the very low cost of cubesats and the possibility to increase resolution based on beamforming from the satellites. Ground truth, as well as some of the methods, will originate from near-field radar technology. This will require further research on all segments of GNSS-R technology and beyond: launching and adjustment of cubesat formations, RF synchronization, interferometry between moving platforms, calibration of RF front-ends, ground testing making use of drones, cubesat systems, on-board processing, data transfer and analysis, translation into ground truth and into predictions important for climate change studies and for optimal territory management. The project may also benefit to other technologies making use of interferometry, such as radioastronomy and phased array-based communications. It is also expected to assist industry segments making use of GNSS signals, such as precision agriculture, forestry and sea and land management.
The GLITTER Doctoral Network initiative puts this Doctoral Candidate to revolutionise the ability to retrieve information from the reflecting surface using Global Navigation Satellite Systems-based Reflectometry (GNSS-R).
The objectives of this PhD project are to develop and validate 1) algorithms to retrieve virtual reflection responses from multi-source-receiver GNSS-R data, and 2) full-wave inversion by joint model- and data-driven methods.
The first step is to compute electromagnetic wave field propagation operators from GNSS-R data recorded at multiple receivers. Formation flight nano-satellites will provide the opportunity to generate a dense virtual antenna array near the ground surface, improving the possible resolution of surface and subsurface soil moisture maps. Then, 3D full-wave inversion using redatumed GNSS-R data will be investigated to make surface and subsurface soil moisture maps. Survey design for nano-satellite formation flight and ground-based receiving antennas will allow for the ability to compute data-driven wave propagation operators . Including Bayesian methods in the inverse problem will improve the ability to select the most likely subsurface models (in joint effort with PolyChord) and the results will be calibrated with drone-borne GPR results (in joint effort with UCLouvain). The expected outcome is a validated algorithm and computer code that combines data-driven propagation operators and full-wave inversion to make surface and subsurface moisture maps.

The training programme includes engaging in advanced workshops and seminars focused on remote sensing and GNSS-R technologies and their applications in environmental monitoring and agriculture; collaborating with leading institutions to broaden academic and professional networks and spur innovation; and applying research in practical settings using the latest drone and satellite technology. Hosted by TU Delft a three months stay at Polychord, London, UK, to work with Dr. Will Handley, and six months at the Université catholique de Louvain (UCLouvain), Louvain-la-Neuve, Belgium, to work with Prof. Sébastien Lambot, this program is designed to equip the candidate with the necessary skills for high-impact research in Earth observation.

Requirements:

The successful applicant will hold a MSc degree in Physics, Geophysics, Electrical Engineering, Mathematics, or related fields. Strong numerical and programming skills for forward and inverse problems are a must. Moreover, the candidate should be a good communicator, have a broad interest and learn quickly. The candidate should also possess excellent writing and verbal communication skills in English. Finally, the candidate should be motivated, innovative thinker with a passion for Earth observation and remote sensing.
Doing a PhD at TU Delft requires English proficiency at a certain level to ensure that the candidate is able to communicate and interact well, participate in English-taught Doctoral Education courses, and write scientific articles and a final thesis. For more details please check the Graduate Schools Admission Requirements.
 
This PhD position is part of the EU PhD network GLITTER.

EU eligibility criteria for candidates:
The Doctoral Candidate (DC) may be a national of a Member State, of an Associated Country or of any Third Country.
Researchers must be doctoral candidates (no doctoral degree at the date of recruitment).
The DC must not have resided or carried out her/his main activity (work, studies, etc.) in the country of her/his host organization for more than 12 months in the 3 years immediately prior to her/his recruitment.     

Salary Benefits:

Doctoral candidates will be offered a 4-year period of employment in principle, but in the form of 2 employment contracts. An initial 1,5 year contract with an official go/no go progress assessment within 15 months. Followed by an additional contract for the remaining 2,5 years assuming everything goes well and performance requirements are met.
Salary and benefits are in accordance with the Collective Labour Agreement for Dutch Universities, increasing from € 2770 per month in the first year to € 3539 in the fourth year. As a PhD candidate you will be enrolled in the TU Delft Graduate School. The TU Delft Graduate School provides an inspiring research environment with an excellent team of supervisors, academic staff and a mentor. The Doctoral Education Programme is aimed at developing your transferable, discipline-related and research skills.
The TU Delft offers a customisable compensation package, discounts on health insurance, and a monthly work costs contribution. Flexible work schedules can be arranged.
For international applicants, TU Delft has the Coming to Delft Service. This service provides information for new international employees to help you prepare the relocation and to settle in the Netherlands. The Coming to Delft Service offers a Dual Career Programme for partners and they organise events to expand your (social) network.
Each host organisation will appoint the successful applicant under an employment contract with a very competitive salary. The fellow is expected to join their host organizations starting from September 1st, 2024 (estimated time). Additional funding for participation to courses, workshops, conferences, etc. is ensured.
All positions include a doctoral track and the successful applicant will be registered for the PhD program at the host institution. If the doctoral track requires a longer duration than 48 months, the details and financial implications will be provided by the host institution.

36 - 40 hours per week

Mekelweg 2