[G02-2] Gravimetry

[G02-2-05] An innovative tool for marine Gravimetry: results of a survey with a cold atom gravimeter

^○Marie-Francoise Lalancette^{1, 3, 4}, Didier Rouxel^{1, 4}, Yannick Bidel², Alexandre Bresson², Nassim Zahzam², Sylvain Lucas^1,4, Cedric Blanchard², Gildas Delachienne¹ (1.Shom, Brest, France, 2.ONERA, Paris, France, 3.IUEM/LGO/UMR6538, 4.GRGS)

Measurements of marine gravimetry are usually carried out by relative shipborne gravimeter. We present the development and the tests of an absolute onboard gravimeter for marine applications that highlights a real technological breakthrough. This instrument is based on the measurement of the acceleration of a cloud of cold atoms in free fall with an atom interferometry method. This technology has already shown excellent performances for static gravimeters and compares favorably with the best classical mechanical absolute gravimeters. Here the challenges were to develop a cold atom gravimeter able to measure gravity in a mobile platform where the gravimeter is subject to accelerations and rotations. For this purpose, the sensor head has been miniaturized and placed in a gyrostabilized platform. The gravimeter has also been adapted to work with strong vibrations and accelerations which occur in a ship. We report the gravity marine survey realized by strong swell and bad weather in the bay of Biscaye during the winter 2015-2016. After laboratory tests, the prototype has been successfully tested on the French Shom N/O vessel " Beautemps-Beaupre " during two campaigns of few days and compared to the commercial spring marine gravimeter KSS32-M. We present the results and the benefit of such a technology for marine surveyors.