The French EO high spatial resolution hyperspectral dual mission - an update

More than 25 years of airborne imaging spectroscopy and spaceborne sensors such as Hyperion [1] or HICO [2] have clearly demonstrated the ability of such a remote sensing technique to produce value added information regarding surface composition and physical properties for a large variety of applications [3]. Scheduled missions such as EnMAP [4], HISUI [5] or PRISMA [6] prove the increased interest of the scientific community for such a type of remote sensing data. In France, after gathering a group of Science and Defence users of imaging spectrometry data (Groupe de Synthèse Hyperspectral, GSH [7]) to establish an up-to-date review of possible applications, define instrument specifications required for accurate, quantitative retrieval of diagnostic parameters, and identify fields of application where imaging spectrometry is a major contribution, CNES (French Space Agency) decided a pre-phase A study for an hyperspectral mission concept called HYPXIM (HYPerspectral-X IMagery), the main fields of applications of which were to be vegetation, coastal and inland waters, geosciences, urban environment, atmospheric sciences, cryosphere and Defence. During this pre-phase A, the feasibility of such a platform was evaluated, based on specific studies supported by Defence and a more accurate definition of reference radiances and instrument characteristics. Results also pointed to applications where high spatial resolution was necessary and would not be covered by the other foreseen hyperspectral missions. For example, in the case of ecosystem studies, it is generally agreed that many model variables and processes are not accurately represented and that upcoming sensors with improved spatial and spectral capabilities, such as higher resolution imaging spectrometers, are needed to further improve the quality and accuracy of model variables [8, 9]. The growing interest for urban environment related applications also emphasized the need for an increased spatial resolution [10, 11]. Finally, short revisit time is an issue for security and Defense as well as crisis monitoring. Table 1 summarizes the Science and Defence mission requirements at the end of pre-phase A. Two instrument designs were proposed by the industry (EADS-Astrium and Thales Alenia Space) based on these new requirements [12]: HYPXIM-Challenging, on a micro-satellite platform, with a 15 m pixel and HYPXIM-Performance, on a mini-satellite platform, with a 8 m pixel, and possible TIR hyperspectral capabilities. Both scenarios included a PAN camera with a 1.85 m pixel. Platform agility would allow for “on-event mode” with a 3-day revisit time. CNES decided to select HYPXIM-Performance, the system providing a higher spatial resolution (pixel ≤ 8 m, [13, 14]), but without TIR capabilities, for a phase A study [15]. This phase A was to start at the beginning of 2013 but is currently stopped due to budget constraints. An important part of the activities has been focusing on getting the French community more involved through various surveys and workshops in preparation for the CNES prospective meeting, an important step for the future of the mission. During this prospective meeting, which took place last March, decision was taken to keep HYPXIM alive as a mid-term (2020-2025) mission. The attendance at the recent workshop organized by the SFPT-GH (Société Française de Photogrammétrie et Télédétection, Groupe Hyperspectral) which gathered more than 90 participants from various field of application, including the industry (see http://www.sfpt.fr/hyperspectral for more details), demonstrates the interest and support of the French scientific community for a high spatial resolution imaging spectrometry mission

Short-range wideband FMCW radar for millimetric displacement measurements

International audienceThe frequency modulated continuous wave (FMCW) radar is an alternative to the pulse radar when the distance to the target is short. Typical FMCW radar implementations have a homodyne architecture transceiver which limits the performances for short-range applications: the beat frequency can be relatively small and placed in the frequency range affected by the specific homodyne issues (DC offset, self-mixing and 1/f noise). Additionally, one classical problem of a FMCW radar is that the voltage controlled oscillator adds a certain degree of nonlinearity which can cause a dramatic resolution degradation for wideband sweeps. This paper proposes a short-range X-band FMCW radar platform which solves these two problems by using a heterodyne transceiver and a wideband nonlinearity correction algorithm based on high-order ambiguity functions and time resampling. The platform's displacement measurement capability was tested on range profiles and synthetic aperture radar (SAR) images acquired for various targets. The displacements were computed from the interferometric phase and the measurement errors were situated below 0.1 mm for metal bar targets placed at a few meters from the radar

Remote Sensing Studies of Urban Canopies: 3D Radiative Transfer Modeling

Need for better understanding and more accurate estimation of radiative fluxes in urban environments, specifically urban surface albedo and exitance, motivates development of new remote sensing and three‐dimensional (3D) radiative transfer (RT) modeling methods. The discrete anisotropic radiative transfer (DART) model, one of the most comprehensive physically based 3D models simulating Earth/atmosphere radiation interactions, was used in combination with satellite data (e.g., Landsat‐8 observations) to better parameterize the radiative budget components of cities, such as Basel in Switzerland. After presenting DART and its recent RT modeling functions, we present a methodological concept for estimating urban fluxes using any satellite image data

AUTOMATION OF NETWORK MICRO SEGMENTATION

Network Micro Segmentation is the ability to transmit data securely between systems over a network. Systems in a network uses advanced encryption technology and provides a mechanism for creating cryptographically enforced virtual networks based on the user’s login credentials. Network Micro Segmentation is used to share the information between the selected users and protecting the sensitive data from hackers by allowing the data to be visible only to the selected users. Network Micro segmentation secures the data in motion and controls the sharing of information within or across the network by employing an innovative cloaking technique. The Automation of Network Micro Segmentation Environment is used to configure the network and systems automatically. The market value of network security reaches $15.5 billion by 2019

Mass changes of alpine glaciers at the eastern margin of the Northern and Southern Patagonian Icefields between 2000 and 2012

Despite renewed efforts to better understand glacier change and recognize glacier change trends in the Andes, relatively large areas in the Andes of Argentina and Chile are still not investigated. In this study, we report on glacier elevation and mass changes in the outer region of the Northern and Southern Patagonian Icefields in the Southern Patagonian Andes. A newly-compiled Landsat ETM+ derived glacier inventory (consisting of 2253 glaciers and ∼1314 ± 66 km2 of ice area) and differencing of the SRTM and SPOT5 DEMs were used to derive glacier-specific elevation changes over the 2000?12 period. The investigated glaciers showed a volume change of −0.71 ± 0.55 km3 a−1, yielding a surface lowering of 0.52 ± 0.35 m a−1 on average and an overall mass loss of 0.46 ± 0.37 m w.e. a−1. Highly variable individual glacier responses were observed and interestingly, they were less negative than previously reported for the neighboring Patagonian Icefields.Fil: Falaschi, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Bolch, Tobias. Universitat Zurich; SuizaFil: Rastern, Phillip. Universitat Zurich; SuizaFil: Lenzano, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lenzano, Luis Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lo Vecchio Repetto, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Moragues, Silvana Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin

Mass changes of alpine glaciers at the eastern margin of the Northern and Southern Patagonian Icefields between 2000 and 2012

Despite renewed efforts to better understand glacier change and recognize glacier change trends in the Andes, relatively large areas in the Andes of Argentina and Chile are still not investigated. In this study, we report on glacier elevation and mass changes in the outer region of the Northern and Southern Patagonian Icefields in the Southern Patagonian Andes. A newly-compiled Landsat ETM+ derived glacier inventory (consisting of 2253 glaciers and ∼1314 ± 66 km2 of ice area) and differencing of the SRTM and SPOT5 DEMs were used to derive glacier-specific elevation changes over the 2000-12 period. The investigated glaciers showed a volume change of -0.71 ± 0.55 km3 a-1, yielding a surface lowering of 0.52 ± 0.35 m a-1 on average and an overall mass loss of 0.46 ± 0.37 m w.e. a-1. Highly variable individual glacier responses were observed and interestingly, they were less negative than previously reported for the neighboring Patagonian Icefields.Publisher PDFPeer reviewe

Polarimetric Synthetic Aperture Radar (SAR) Application for Geological Mapping and Resource Exploration in the Canadian Arctic

The role of remote sensing in geological mapping has been rapidly growing by providing predictive maps in advance of field surveys. Remote predictive maps with broad spatial coverage have been produced for northern Canada and the Canadian Arctic which are typically very difficult to access. Multi and hyperspectral airborne and spaceborne sensors are widely used for geological mapping as spectral characteristics are able to constrain the minerals and rocks that are present in a target region. Rock surfaces in the Canadian Arctic are altered by extensive glacial activity and freeze-thaw weathering, and form different surface roughnesses depending on rock type. Different physical surface properties, such as surface roughness and soil moisture, can be revealed by distinct radar backscattering signatures at different polarizations. This thesis aims to provide a multidisciplinary approach for remote predictive mapping that integrates the lithological and physical surface properties of target rocks. This work investigates the physical surface properties of geological units in the Tunnunik and Haughton impact structures in the Canadian Arctic characterized by polarimetric synthetic aperture radar (SAR). It relates the radar scattering mechanisms of target surfaces to their lithological compositions from multispectral analysis for remote predictive geological mapping in the Canadian Arctic. This work quantitatively estimates the surface roughness relative to the transmitted radar wavelength and volumetric soil moisture by radar scattering model inversion. The SAR polarization signatures of different geological units were also characterized, which showed a significant correlation with their surface roughness. This work presents a modified radar scattering model for weathered rock surfaces. More broadly, it presents an integrative remote predictive mapping algorithm by combining multispectral and polarimetric SAR parameters

A review of current and potential applications of remote sensing to study the water status of horticultural crops

Published: 17 January 2020With increasingly advanced remote sensing systems, more accurate retrievals of crop water status are being made at the individual crop level to aid in precision irrigation. This paper summarises the use of remote sensing for the estimation of water status in horticultural crops. The remote measurements of the water potential, soil moisture, evapotranspiration, canopy 3D structure, and vigour for water status estimation are presented in this comprehensive review. These parameters directly or indirectly provide estimates of crop water status, which is critically important for irrigation management in farms. The review is organised into four main sections: (i) remote sensing platforms; (ii) the remote sensor suite; (iii) techniques adopted for horticultural applications and indicators of water status; and, (iv) case studies of the use of remote sensing in horticultural crops. Finally, the authors’ view is presented with regard to future prospects and research gaps in the estimation of the crop water status for precision irrigation.Deepak Gautam and Vinay Paga

De la modélisation du rayonnement solaire à la production d'énergie : recherches sur l'optimisation de la production photovoltaïque en contexte amazonien

L’objectif des recherches décrites dans ce mémoire est de répondre aux problématiques de la filière photovoltaïque en contexte amazonien afin d’assurer le développement de cette dernière. Les actions de recherche initiées ont pour but de contribuer à l’amélioration du fonctionnement des installations photovoltaïques et à la diminution des risques associés aux projets et technologies photovoltaïques implantés dans cette région. Nous abordons dans un premier temps la question de la formalisation de modèles capables d'assurer le suivi de l'éclairement solaire en vue de réaliser le contrôle et la gestion de l'énergie produite, et pour cela nous utilisons le formalisme de la modélisation par espace d’état. Le filtre Bayésien récursif est utilisé comme méthode de résolution d'un problème à espace d'état dont les observations sont issues d'images satellites. Nous veillons au caractère générique de la méthode proposée afin qu’elle soit transposable à d’autres ressources naturelles. En vue d'améliorer le caractère prédictif du filtre bayésien nous nous intéresserons à la définition des propriétés statistiques des termes d’erreur intervenant dans des modèles mathématiques simulant l'évolution de l'état de l'éclairement solaire. Nous définissons une nouvelle méthode de sélection des densités de probabilité des termes d’erreur qui interviennent dans de nombreux modèles d'évolution, puis nous appliquons cette méthode de sélection à deux modèles d'évolution de l'éclairement solaire, ce qui nous amène à remettre en cause des aspects, pourtant réputés solides, de principes communément admis. Nous proposons la définition d'une nouvelle méthode de construction de fonctions/modèles d'observation afin d’extraire des images satellites une information pertinente sur l'état de l'éclairement solaire, en particulier nous analysons la possibilité d’utiliser une loi de probabilité jointe non-paramétrique pour formaliser un concept générique qui serait applicable à d’autres variables représentatives d’une ressource renouvelable. L’évaluation de l’efficacité et de la précision du filtre bayésien conçu avec les modèles d’évolution et d’observation que nous avons développés est assurée avec des critères statistiques tels que le Biais, le RMSE et le coefficient de corrélation.Dans un second chapitre, nous abordons la question de l’estimation du potentiel de l’éclairement solaire au sol sur la zone du continent Sud-américain qui entoure la Guyane. Compte tenu de l’étendue de la zone étudiée et de la parcimonie des stations de mesures présentes dans cette zone, nous choisissons d’utiliser un algorithme permettant d'estimer l’éclairement solaire en utilisant des images satellites. Ces travaux aboutissent à la réalisation de plusieurs cartographies du potentiel de l’éclairement solaire sur un plan horizontal (Global Horizontal Irradiance - GHI) mais aussi du potentiel d’éclairement direct (Direct Normal Irradiance - DNI) ainsi que des cartographies d’indicateurs liés à l’exploitabilité du potentiel solaire, comme la variabilité journalière ou le pourcentage d’énergie reçue au sol avant et après le midi solaire par rapport à la quantité d’énergie journalière.Dans le troisième chapitre, nous abordons le thème de la production d’énergie photovoltaïque en sites isolés en contexte amazonien, nous présentons les études menées et les résultats obtenus qui visent à l'amélioration de la productivité des systèmes photovoltaïques dans un tel contexte. Le but de ces travaux n’est pas simplement de décrire les analyses faites sur la productivité des systèmes solaires mais d’établir des recommandations à partir de cas concrets, et proposer quelques pistes claires et opérationnelles pour exploiter au mieux la ressource solaire afin de satisfaire les besoins énergétiques des populations non raccordées au réseau électrique. Enfin, en guise de conclusion, nous proposerons un état synthétique des principales avancées issues de ce parcours et nous présenterons les perspectives scientifiques et techniques qu’elles ont permis d’ouvrir