A5084432173- Soil Moisture and Remote Sensing
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Precipitation Measurement and Analysis
- Cryospheric studies and observations
- Radio Astronomy Observations and Technology
- Geophysics and Gravity Measurements
- Climate change and permafrost
- Arctic and Antarctic ice dynamics
- Calibration and Measurement Techniques
- Spacecraft Design and Technology
- Geophysical Methods and Applications
- Antenna Design and Optimization
- Optical measurement and interference techniques
- Adaptive optics and wavefront sensing
- Advanced Measurement and Metrology Techniques
- Spacecraft and Cryogenic Technologies
- Inertial Sensor and Navigation
- Seismic Waves and Analysis
- Space Satellite Systems and Control
- Optical Systems and Laser Technology
- Experimental and Theoretical Physics Studies
- Satellite Communication Systems
- Particle Accelerators and Free-Electron Lasers
- Seismic Imaging and Inversion Techniques
- Radiative Heat Transfer Studies
Centre d'Études Spatiales de la Biosphère
2017-2025
Institut de Recherche pour le Développement
2017-2025
Centre National de la Recherche Scientifique
2009-2025
Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
2021-2024
Centre National d'Études Spatiales
2021-2024
Université Toulouse III - Paul Sabatier
2006-2022
Université de Toulouse
2008-2021
Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique
1994-2019
Institut de Recherche en Astrophysique et Planétologie
2012-2017
Observatoire Midi-Pyrénées
1996-2014
Synthetic aperture imaging radiometers (SAIRs) are potential powerful instruments for high-resolution observation of planetary surfaces at low microwave frequencies. This paper deals with the reconstruction radiometric brightness temperature maps from SAIR interferometric measurements. It is demonstrated that corresponding inverse problem not well-posed and must, therefore, be regularized in order to provide a unique stable solution. A new approach presented by referring notion modeling...
It is now well established that synthetic aperture imaging radiometers promise to be powerful sensors for high-resolution observations of the Earth at low microwave frequencies. Within this context, European Space Agency currently developing Soil Moisture and Ocean Salinity (SMOS) mission. The Y-shaped array selected SMOS fitted with equally spaced antennae leads a natural hexagonal sampling Fourier plane. This paper deals choice apodization function applied complex visibilities. aim reduce...
The European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite has provided, for the first time, systematic passive L-band (1.4 GHz) measurements from space. This new data set, with a spatial resolution of ~40 km, allowed number outstanding results over land (soil moisture, vegetation properties, frozen soils, ...), ocean (salinity, meso-scale phenomena, river plumes, high winds, ...) cryosphere. SMOS, together NASA missions SMAP Aquarius, have demonstrated interest...
The Soil Moisture and Ocean Salinity (SMOS) satellite was launched by the European Space Agency on November 2, 2009. Its payload, i.e., Microwave Imaging Radiometer with Aperture Synthesis, which is a 2-D L-band interferometric radiometer, measures brightness temperatures (BTs) in protected 1400-1427-MHz band. Although this band preserved for passive measurements, numerous radio frequency interferences (RFIs) are clearly visible SMOS data. One method to get rid of these create synthetic...
This paper is concerned with the reconstruction of radiometric brightness temperature maps from interferometric measurements. The corresponding inverse problem often ill-posed unless a regularizing constraint introduced in order to provide unique and stable solution. Standard approaches are compared illustrated numerical simulations carried out reference Soil Moisture Ocean Salinity space mission led by European Space Agency.
Clean is a matching pursuit process which has two weak points: in situations of astrophysical interest, the "clean map" not stable corresponding object representation space, and "atoms" this (translated versions beam") are well suited for reconstructing boundaries structuring entities at related resolution level. As result, must be interrupted before best possible fit reached. How does Wipe wipe clean? First, by introducing global regularization principle based on concept resolution; second,...
Synthetic aperture imaging radiometers (SAIRs) are powerful instruments for high-resolution observation of planetary surfaces at low microwave frequencies. This paper is concerned with the reconstruction radiometric brightness temperature maps from SAIR interferometric measurements. Even in absence modeling errors and noise, a systematic error, or bias, has been observed reconstructed maps. The origin this bias analyzed an efficient solution proposed reducing it. core procedure not changed,...
Synthetic aperture imaging radiometers are powerful sensors for high-resolution observations of the Earth at low microwave frequencies. Within this context, European Space Agency is currently developing soil moisture and ocean salinity (SMOS) mission devoted to monitoring SMOS global scale from L-band spaceborne radiometric obtained with a 2-D interferometer. This paper concerned reconstruction brightness temperature maps interferometric measurements. More exactly, it extends concept...
Abstract In this series of papers, we present a new approach to the problems Fourier synthesis in finite dimension (the data are complex quantities corresponding and irregular sampling transform some object function). Part I concerns principles part II their application aperture synthesis. Depending on what is emphasized, method called FIRST or WIPE: for (Fourier interpolation reconstruction via Shannon-type techniques), WIPE deconvolution (WIPE reminiscent CLEAN, well-known astronomy). The...
The Soil Moisture and Ocean Salinity (SMOS) mission is a European Space Agency project aimed to observe two important geophysical variables, i.e., soil moisture over land ocean salinity by L-band microwave imaging radiometry. This work concerned with the contamination of SMOS data radio-frequency interferences (RFIs), which degrades performance mission. In this paper, we propose an approach that detects if given snapshot contaminated, or not, RFI. based on evaluating kurtosis each set, using...
The Soil Moisture and Ocean Salinity (SMOS) space mission is currently undergoing phase-B studies at the European Space Agency. SMOS payload an L-band interferometric radiometer based on a two-dimensional aperture synthesis concept. This paper presents first images obtained by demonstrator of instrument over land surfaces Avignon test site in 1999.
In this communication we present an update on the RFI detection used in SMOS processing chain and some elements quantified impact of RFIs level 2 soil moisture products. The algorithms which included since beginning a screening mechanism to reject contaminated brightness temperatures is now stricter. New approaches at 1 processors are also emerging will be operational their next release 2014. Despite these strengthen procedures, still impacting strongly observations examples deterioration given.
The European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) has been providing the longest consistent data record of passive L-band (1.4 GHz) observations for more than ten years. SMOS, as well NASA missions SMAP Aquarius have demonstrated interest land, ocean cryosphere studies. continuity must be assured taking into account that spatial resolution (~ 40 km) SMOS is too coarse some applications. Disaggregation strategies can implemented but using airborne data, we show quality...
Synthetic aperture interferometry (SAI) is a signal processing technique that mixes the signals collected by pairs of elementary antennas to obtain high-resolution images with aid computer. This note aims at studying effects distance between synthetic interferometer and an observed scene respect size antenna array onto imaging capabilities instrument. Far-field conditions near-field ones are compared from algebraic perspective simulations conducted microwave frequencies Microwave Imaging...
The SMOS mission is a European Space Agency project aimed at global monitoring of surface Soil Moisture and Ocean Salinity from radiometric L-band observations. This work concerned with the contamination data collected by radio frequency interferences (RFI) which degrade performance mission. RFI events are evidenced on both reference radiometers measurements interferometric ones. It explained why well-known standard detection methods cannot be used. A specific method for presented...
ESA's Soil Moisture and Ocean Salinity (SMOS) mission has been in orbit for over 6 years, its Microwave Imaging Radiometer with Aperture Synthesis (MIRAS) two dimensions keeps working well. The data almost this whole period reprocessed the new fully polarimetric version (v620) of Level-1 processor which also includes refined calibration schema antenna losses. This reprocessing allowed assessment an improved performance benchmark, a better understanding observations, preparation (v700)...
The Soil Moisture and Ocean Salinity (SMOS) mission is a European Space Agency project aimed at global monitoring of surface SMOS from radiometric L-band observations. This letter concerned with the reduction systematic error (or bias) in reconstruction brightness temperature maps interferometric measurements. A recent efficient method has been proposed for reducing this error. However, residual bias still persists. new approach down to values less than 0.1 K presented here illustrated...
The Soil Moisture and Ocean Salinity (SMOS) satellite has provided, for the very first time, systematic passive L-band (1420−1427 MHz) measurements from space with a spatial resolution of ~50 Km. This contribution presents preliminary results studies conducted High Resolution (HR) follow-on mission. SMOS-HR project is currently undergoing Phase 0 study by French agency. goal to ensure continuity while increasing ~10 Km without degrading radiometric sensitivity keeping revisit time 3 days unchanged.
Digital beam forming (DBF) and synthetic aperture interferometry (SAI) are signal processing techniques that mix the signals collected by an antenna array to obtain high-resolution images with aid of a computer. This note aims at comparing these two approaches from algebraic perspective illustrations simulations conducted microwaves frequencies within frame Soil Moisture Ocean Salinity (SMOS) mission. Although using same sharing goal, there several differences deserve attention. From point...
This study concerns the fast and accurate solution of line radiation transfer problem, under non-LTE conditions. We propose evaluate an alternative iterative scheme to classical ALI-Jacobi method, more recently proposed Gauss-Seidel Successive Over-Relaxation (GS/SOR) schemes. Our is indeed based on application a preconditioned bi-conjugate gradient method (BiCG-P). Standard tests, in 1D plane parallel geometry frame two-level atom model, with monochromatic scattering, are discussed. Rates...