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Gradiomètre planaire aéroporté pour l'étude de la gravité en zones littorales

Abstract : The variations of the gravitational field at a spatial resolution lower than 100 km is essential to address many geodetic and geophysical questions but still remain poorly covered. It is particularly the case in land-sea transition area where the gravity fiels is poorly covered and the quality is heterogeneous. Here we put forward airborne gravity gradiometry as a convenient way to adress these limitations and we analyze in this thesis a new airborne acceleration gradiometer : GREMLIT. First, the adaptation fo this ultra-sensitive sensor to airborne conditions is studied. To avoid saturation, the accelerations detected by the sensitive axis of the gradiometer's accelerometers must be below 10e-4m.s-2. The suggested solution consists in fixing GREMLIT on a double-gimbal controlled platform. This solution is evaluated and validated for real flight dynamic conditions. Then, we assess thanks to a numerical simulator the total error on the gravitational gradients that would have been determined during an airborne survey. The simulation includes a gyrometer's bias calibration which is fully described. We show that it is possible to reach a precision 1E/(Hz)1/2 for a spatial resolution of 2 km, after an along-track Gaussian filtering in the local reference frame. The interested of airborne gravitational gradiometry for the study of coastal currents is finally discussed. In particular, a numerical method to compute the vertical deflection from gridded gravity gradients data is presented.
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https://hal.archives-ouvertes.fr/tel-01151736
Contributor : Véronique Soullier <>
Submitted on : Wednesday, May 13, 2015 - 3:05:30 PM
Last modification on : Tuesday, March 26, 2019 - 2:24:04 PM
Document(s) archivé(s) le : Wednesday, April 19, 2017 - 11:21:35 PM

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  • HAL Id : tel-01151736, version 1

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K. Douch. Gradiomètre planaire aéroporté pour l'étude de la gravité en zones littorales. Instrumentations et Détecteurs [physics.ins-det]. UNIVERSITÉ SORBONNE PARIS CITÉ, 2015. Français. ⟨tel-01151736⟩

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