Floriane Schreiber (OPLC/MIO & ONERA) will present her thesis on Monday 14 December 2020 at 10:00 a.m.

Under the supervision of Mr Charles-Antoine GUERIN, Professor, University of Toulon (France)

 

Co-supervised by Mr Sébastien ANGELLIAUME, Research Engineer, ONERA (France)

 

will submit his thesis with a view to obtaining the degree of Doctor

 

Subject: Physics

Speciality: "Remote Sensing Radar

 

on the theme

 

Estimation of oceanographic conditions by inversion of data from an uncalibrated imaging radar

Monday 14 December 2020 at 10.00 am

 

by videoconference, for which the connection link is available on request [Back to automatic line].
to the thesis supervisor charles-antoine.guerin@univ-tln.fr

 

before a jury made up of

Mr René GARELLO, University Professor, IMT - Atlantique, Rapporteur
Gabriel SORIANO, Senior Lecturer (HDR), University of Aix-Marseille - Institut Fresnel, Rapporteur
Mrs Hélène ROUSSEL, University Professor - Sorbonne University, Examiner
Marc SAILLARD, Professor at the University of Toulon - M.I.O. Examiner
Nicolas TROUVĖ, Doctor - Engineer ONERA, Examiner
Sébastien ANGELLIAUME, Research Engineer - ONERA, Thesis co-supervisor
Mr Charles-Antoine GUĖRIN, Professor at the University of Toulon - M.I.O., Thesis supervisor

Abstract

Statistical characterisation of "sea clutter" is an important problem in microwave radar remote sensing.

It is generally based on purely empirical models which are not directly interpretable in terms of sea state and are not amenable to an inversion procedure. To model the statistical distribution of backscattered intensity, we use a two-scale approach parameterised by the radar resolution cell and the mean square slope of the waves. This model allows the normalised intensity distribution to be described analytically, using a single slope parameter, and fits experimental observations perfectly when this parameter is adjusted for the different polarisation cases. However, an inconsistency in the model's adjustment variable is observed between the two polarisation channels and is explained by a poor estimate of the polarisation ratio of the radar cross sections predicted by the two-scale model.

To correct this shortcoming, we have developed an original analytical formulation of the two-scale model, which restores the correct orders of magnitude of the polarisation ratio in a simple way, independently of radar frequencies and sea states. This improved version, validated by several experimental comparisons in various configurations, provides a coherent model of the sea clutter statistics in the different polarisation channels. Finally, we have developed an inversion method for estimating a sea state from the uncalibrated intensities collected on an imaging radar. The relevance of this model is established using different data sets, including in the presence of calibration uncertainties.

 

Key words: Remote sensing, sea clutter, imaging radar

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