Improved windowing functions for Y-shape Synthetic Aperture Imaging Radiometers. - Université Pierre et Marie Curie Accéder directement au contenu
Communication Dans Un Congrès Année : 2002

Improved windowing functions for Y-shape Synthetic Aperture Imaging Radiometers.

Résumé

The SMOS (Soil Moisture and Ocean Salinity) space mission is an ESA (European Space Agency) project using a Synthetic Aperture Imaging Radiometer (SAIR) operating in the L-band for global monitoring of surface soil moisture (SSM) and sea surface salinity (SSS). The Y-shape of the selected synthetic antenna leads to a limited frequency domain where the Fourier transform of the brightness temperature of a scene is measured: a star-shape experimental frequency coverage. The resulting truncation causes Gibbs oscillations to appear in the reconstructed brightness temperature maps. The windowing principle is to reduce Fourier components near zero at the boundaries of the experimental frequency domain in order to reduce the sharp frequency cut-off. Previous works have used windowing functions to reduce Fourier components near zero at the boundaries of the star-shape experimental frequency coverage. However, these functions depend only on a radial parameter. As a consequence, sharp frequency cut-off still remains near the troughs of the star where the Fourier components may not be damped down to zero. The aim of the present work is to reduce the remaining oscillations by adding an angular parameter to the radial one in order to properly take into account the shape of the frequency coverage. Various factors of merit (full-width at half maximum, highest sidelobe level, beam efficiency...) are computed for characterizing the spatial properties of the Fourier transform of more than 20 windowing functions depending on both radial and angular parameters. They are compared to those obtained with functions depending only on the radial parameter.
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Dates et versions

hal-00005175 , version 1 (06-06-2005)

Identifiants

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Bruno Picard, Gérard Caudal, Eric Anterrieu, Philippe Waldteufel. Improved windowing functions for Y-shape Synthetic Aperture Imaging Radiometers.. IEEE International Geoscience and Remote Sensing Symposium, 2002. IGARSS '02. , Jun 2002, Tronto, Canada. pp.2756-2758, ⟨10.1109/IGARSS.2002.1026765⟩. ⟨hal-00005175⟩
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