PhD defense of Loïc Barbot

The defense will be on Friday December 8th at 9:30am, in the amphitheater at École Nationale Supérieure Maritime (ENSM).

Subject of thesis :
MARIS STELLA project: high-precision star tracker for maritime navigation

Summary:
Astronomical navigation is surrounded by an aura of magic for ordinary people, but it is also a headache for the future sailor who has to master this ancient art: the International Maritime Organisation imposes this training on any sailor wishing to work on the bridge of a ship for long crossings. It also requires the simultaneous use of two means of positioning to guarantee the safety of the ship and her passengers in case of a malfunction: offshore, the GNSS receiver takes the first place, but there is no candidate for the second. In the open sea, dead reckoning and celestial navigation are considered as back-up methods, ranking alongside the life raft and lifejacket.
The MARIS STELLA project is studying the feasibility of a ‘star receiver’ using a camera to detect stars and an inclinometer to measure zenithal angles. The aim is to provide the ship’s position and attitudes with an accuracy of 100 m or better, day and night. This optical and inertial sensor must enable autonomous, automatic and precise navigation without the need for an internet connection or any external adjustment other than astral.
In addition to astronomy and optics, the study explores the performance of inertial sensors available in 2023, questions geophysics on the deflection of the gravimetric vertical and requires meteorology about radiative transfer. After a review of the state of the art in these sciences and the technologies currently relying on star tracking applications, the major challenge appears: detecting stars at night as well as during the day. A choice has to be made between silicon detectors for ‘visible’ light and those capable of observing in infrared.
A detailed examination of the two options led to a decision in favour of infrared, taking advantage of the recent and rapid development of these technologies. Trials were organised to explore step by step the potential and difficulties of star observed from the ground in full sunlight, a subject rarely dealt with in scientific publications. The first lessons learned from this experiment validates the relevance of the project and lead to plan other tests.

Jury members:
Isabelle RIBET, Referee & President of Jury, Directrice de recherche, Institut d’Optique Graduate School – Paris Saclay
David BETAILLE, Referee, Directeur de recherche, IFSTTAR, Université Gustave EIFFEL
Myriam ZERRAD, Examiner, Ingénieure de recherche, Institut Fresnel – Aix Marseille Université
Hervé TRINQUET, Examiner, Ingénieur Expert, D.G.A. Maîtrise de l’Information
Marc FERRARI, Supervisor, Astronome, Aix Marseille Université