“That’s it, the cloud has passed, look on the screen. This luminous point is Kochab, one of the stars of Ursa Minor. » It is nearly 4 p.m. on Wednesday June 21, the sun dazzles the tarmac at Le Bourget airport (Seine-Saint-Denis). However, despite this intense luminosity, the impassive operator continues his demonstration on the stand of Sodern, the world leader in star finders. “Now I’m going to point the viewfinder to a clearer corner of the sky, and you’re going to see Dubhe and Merak, which are part of the constellation Ursa Major. » And indeed, two small shiny dots appear, each on a different screen.
If it is sometimes possible to see the Moon in broad daylight and the Evening Star in the late afternoon, nothing like this for the other stars before dark. Until now at least, since at the International Air and Space Show at Le Bourget, this subsidiary of ArianeGroup presented equipment, barely larger than a shoebox, allowing them to be spotted that they are invisible to the naked eye.
A stunning experience under a blue sky. The company has thus, in a few months, adapted to terrestrial use the technology it masters in space. It allows satellites equipped with it to locate themselves by aiming at the stars, and to correct their trajectory if necessary. Two landmarks are necessary and the inertial unit, coupled to the viewfinder, then extrapolates the position.
Non-jammable system
On Earth, this geolocation will allow users to be autonomous and sure of their situation because the system “is non-jammable and non-decoyable, unlike satellite positioning systems, such as GPS”, explains Vincent Dedieu, Deputy Managing Director. The war in Ukraine has also shown the vulnerability of radio navigation signals which could be manipulated, providing false data to ships approaching the coast or causing drones to lose control.
A constraint however for this innovation, the need for a clear sky, the clouds preventing the location of the stars. Hence the idea of testing it first on planes because they fly above the cloud layer. But also to install it on boats, sailing slowly because, once their course is fixed, the drift is low and a readjustment every day, even every two days, is enough.
“In a way, we return to the sextant”, raises Mr. Dedieu. If celestial navigation is increasingly watched in the United States, “I don’t know of any projects similar to ours at the moment”, he adds. The demonstration initially interested the military, but Sodern’s objective is to achieve commercialization in two or three years. And also, until then, to continue research to finally break through the clouds.