Numéro : 2778 - Year : 2022
MARIS STELLA project: a stellar receiver to fix ship’s position
Loïc BARBOT - Aix-Marseille Université – CNRS - CNES – LAM (Marseille) et École Nationale Supérieure Maritime (ENSM) ( Marseille)
Marc FERRARI, Kjetil DOHLEN - Aix-Marseille Université – CNRS - CNES – LAM (Marseille)
Johan MONTEL - Centre National d’Études Spatiales, Toulouse
Yannick ROEHLLI - Centre de données Astrophysiques de Marseille (CeSAM, LAM (Marseille)
Jean-Luc GACH - Aix-Marseille Université – CNRS - CNES – LAM (Marseille) et First Light Imaging (Meyreuil)
William THUILLOT - Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE), Observatoire de Paris
Astronomical navigation has been used until the 90s by civil aviation but is still studied in merchant or naval academies as a method to fix the position of a ship. Considered as an emergency technic, it is implemented by an observer measuring with the sextant the angle between the horizon line and a celestial body. After calculations and plots, the position is obtained with an accuracy of several nautical miles.
Star tracking is used on satellites to measure their orientation in space in order to turn their solar panels towards the sun or their cameras and antennas towards the earth. This requires to identify several stars in the same field of view or in the fields of several star-trackers.
Furthermore, from the Earth's surface, we can observe the motion of a satellite on the celestial background like the hand of a clock on its graduated dial. Thus, a fast satellite shall allow a measure of universal time with better accuracy.
To be reliable, a stellar positioning system must have an accuracy comparable to satellite positioning, should operate day and night, even at low altitude where the atmosphere is dense in aerosols. If the position of the stars and the algorithms are well mastered, the detection of stars by daylight remains a challenge.
French projects exploit the performance of silicon cameras to achieve an accuracy of a few meters but require significant resources to stabilize and process images, because the brightness of stars remains low compared to the sky background, that scatters sunlight.
The MARIS STELLA project, led by École Nationale Supérieure Maritime and Laboratoire d'Astrophysique de Marseille, explores the potential of infrared cameras. The stars thus detectable are more numerous but this technology has not yet reached its full maturity: the performances are improving over time.
After a presentation of the current results, future tests will be described in light of the emerging possibilities around low-altitude star tracking and the context of other technologies.
Advanced search
Year