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EarthEnv-DEM90: A nearly-global, void-free, multi-scale smoothed, 90m digital elevation model from fused ASTER and SRTM data / Natalie Robinson in ISPRS Journal of photogrammetry and remote sensing, vol 87 (January 2014)
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Titre : EarthEnv-DEM90: A nearly-global, void-free, multi-scale smoothed, 90m digital elevation model from fused ASTER and SRTM data Type de document : Article/Communication Auteurs : Natalie Robinson, Auteur ; James Regetz, Auteur ; Robert P. Guralnick, Auteur Année de publication : 2014 Article en page(s) : pp 57 - 67 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie spatiale
[Termes IGN] filtrage du bruit
[Termes IGN] fusion de données
[Termes IGN] image Terra-ASTER
[Termes IGN] lissage de données
[Termes IGN] MNS SRTM
[Termes IGN] modèle numérique mondial de surfaceRésumé : (Auteur) A variety of DEM products are available to the public at no cost, though all are characterized by trade-offs in spatial coverage, data resolution, and quality. The absence of a high-resolution, high-quality, well-described and vetted, free, global consensus product was the impetus for the creation of a new DEM product described here, ‘EarthEnv-DEM90’. This new DEM is a compilation dataset constructed via rigorous techniques by which ASTER GDEM2 and CGIAR-CSI v4.1 products were fused into a quality-enhanced, consistent grid of elevation estimates that spans ?91% of the globe. EarthEnv-DEM90 was assembled using methods for seamlessly merging input datasets, thoroughly filling voids, and smoothing data irregularities (e.g. those caused by DEM noise) from the approximated surface. The result is a DEM product in which elevational artifacts are strongly mitigated from the input data fusion zone, substantial voids are filled in the northern-most regions of the globe, and the entire DEM exhibits reduced terrain noise. As important as the final product is a well defined methodology, along with new processing techniques and careful attention to final outputs, that extends the value and usability of the work beyond just this single product. Finally, we outline EarthEnv-DEM90 acquisition instructions and metadata availability, so that researchers can obtain this high-resolution, high-quality, nearly-global new DEM product for the study of wide-ranging global phenomena. Numéro de notice : A2014-012 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2013.11.002 En ligne : https://doi.org/10.1016/j.isprsjprs.2013.11.002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32917
in ISPRS Journal of photogrammetry and remote sensing > vol 87 (January 2014) . - pp 57 - 67[article]Réservation
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Titre : GNSS meteorology in spatially dense networks Type de document : Thèse/HDR Auteurs : Fabian Peter Hurter, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2014 Collection : Astronomisch-Geodätische Arbeiten in der Schweiz, ISSN 0025-6676 num. 91 Importance : 185 Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-37-6 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Bernese
[Termes IGN] données GNSS
[Termes IGN] météorologie
[Termes IGN] propagation du signal
[Termes IGN] retard troposphérique zénithal
[Termes IGN] signal GNSS
[Termes IGN] station GNSS
[Termes IGN] station météorologique
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] traitement du signalIndex. décimale : 30.84 Applications de géodésie spatiale à l'atmosphère Résumé : (auteur) Two basic products from GNSS meteorology have been investigated in detail: (a) the Zenith Total Delay (ZTD) and, (b) wet refractivity fields reconstructed from Zenith Wet Delays (ZWD).The thesis aims at quantifying the accuracies of GNSS-derived ZTDs and refractivities and at characterizing their temporal and spatial resolution. In a first study using operational radiosondes and Global Navigation Satellite System (GNSS) data from the Swiss meteorological station in Payerne, the following uncertainty figures are obtained: With respect to the radiosonde, the GNSS-derived ZTD has a 1–3mm dry bias. Annual systematic variations of the comparison are found to have an amplitude of 1–2 mm . Removal of most systematic effects from the GNSS minus radiosonde ZTD time series plus a thorough budget of the radiosonde uncertainties allows the derivation of the random GNSS uncertainties. In the winter half-year, the standard deviation is shown to be 2.5–3.5 mm , during the summer half-year we obtain 3.5–5.0 mm.
In a further study in the western part of Switzerland, wet refractivities have been derived on the basis of interpolated ZWDs from the Automatic GNSS Network for Switzerland (AGNES). The employed interpolation algorithm is termed least-squares collocation. It makes use of a deterministic function to describe the general parametric field and a correlation function describing the spatial and temporal correlations between the zenith wet delays. Corresponding wet refractivities show accuracies superior to results from tomographic reconstructions of a similar data set. Further inclusion of ground meteorological measurements of temperature and water vapour pressure im- prove the derived refractivities in the lowest 2 km of the troposphere. Radio occultations are added to the reconstruction. The data combination enables the extension of the radio occultation profiles down to the ground. It is also shown that the GNSS data largely contributes to the profile quality above the atmospheric boundary layer. Transformation of the wet refractivities to humidity values with temperature profiles from a radiometer in Payerne show accuracies of a similar order of mag nitude to those from numerical weather prediction analysis. Hence, application of the algorithm in nowcasting of rain or investigating boundary layer processes are envisaged.
The third part of the thesis investigates the results from a campaign network of 34 geodetic- grade receivers. They were deployed close to and around Zermatt (Switzerland) for one month in summer 2010. The stations were spaced at distances of a few kilometers from each other and at heights between 1600–3500 m above mean sea level. The mountainous region provides an excellent natural laboratory to investigate the influences affecting the accuracy of the ZTD. Additionally, the Alpine region is prone to small-scale fluctuations in the troposphere. Thus, the spatial and temporal variability of the ZTD has been investigated. The influences of satellite obstructions, antenna and receiver types and a number of processing strategies on the estimated ZTD are analysed and validated with measurements from radiosondes launched during the campaign. The analysis suggests that 1 hour temporal resolution should not be undercut for estimated ZTDs. A temporal resolution of 30 minutes introduces more noise without better following the tropospheric fluctuation. The horizontal variability observed in ZTDs indicates correlation scale lengths of a few kilometers. From comparison with radiosondes, the ZTD uncertainty is shown to have 4–6 mm standard deviation. Some stations show signs of systematic effects caused by multipath and low- quality antenna patterns. Through the GNSS-inherent negative correlation of height with zenith delay, both parameters are similarly affected by these systematic influences. The performance of the numerical weather prediction model COSMO-2 is characterized in terms of integrated atmospheric state. The analysis yields preliminary recommendations on the assimilation of zenith total path delays into weather models in regions of highly complex topography such as the Swiss Alps.Note de contenu : 1 Introduction
1.1 Review of GNSS meteorology
1.2 Potential synergies with other water vapour measurements . 1.3 Challenges in GNSS meteorology
1.4 Objectives and structure of the thesis
2 Theory
2.1 Refractivity and path delay in the atmosphere
2.2 Collocation with the software COMEDIE
2.3 Water vapour tomography software AWATOS2
3 Comparison of zenith path delays from GNSS and radiosonde measurements
3.1 Data description
3.2 Formal uncertainties of ZTD estimates from GNSS
3.3 Comparison of ZTDs
3.4 Influence of processing strategy on GNSS ZTDs
3.5 2nd and 3rd order ionospheric effects .
3.6 Comparison of ZWDs
3.7 Formal uncertainty of radiosonde-derived ZTDs
3.8 Derivation of random GNSS ZTD uncertainty
3.9 Correlation between GNSS heights and ZTDs
3.10 Discussion .
3.11 Conclusion .
4 Payerne profile study
4.1 Abstract
4.2 Introduction
4.3 Description of data sets
4.4 Processing
4.5 Results .
4.6 Discussion
4.7 Conclusions
5 Geodetic water vapor campaign in Zermatt
5.1 Data description and processing
5.2 Troposphere results
5.3 Conclusions
6 ConclusionsNuméro de notice : 12952 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère En ligne : http://www.sgc.ethz.ch/sgc-volumes/sgk-91.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76823 Réservation
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Titre : Improved convergence for GNSS precise point positioning Type de document : Thèse/HDR Auteurs : Simon Banville, Auteur Editeur : Fredericton [Canada] : University of New Brunswick Année de publication : 2014 Collection : Technical report num. 294 Importance : 293 p. Format : 21 x 30 cm Note générale : bibliographie
dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Geodesy and Geomatics EngineeringLangues : Anglais (eng) Descripteur : [Termes IGN] ambiguïté entière
[Termes IGN] correction ionosphérique
[Termes IGN] erreur systématique
[Termes IGN] mesurage de phase
[Termes IGN] phase GNSS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] précision centimétrique
[Termes IGN] signal GLONASS
[Termes IGN] teneur totale en électrons
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) The precise point positioning (PPP) methodology allows for cm-level positioning accuracies using a single GNSS receiver, through careful modelling of all error sources affecting the signals. Adoption of PPP in several applications is however muted due to the time required for solutions to converge or re-converge to their expected accuracy, which regularly exceeds 30 minutes for a moving receiver. In an attempt at solving the convergence issues associated with PPP, three aspects were investigated.
First, signal tracking interruptions are typically associated with integer discontinuities in carrier-phase measurements, often referred to as a cycle slips. A refined method for detecting and correcting cycle slips was thus developed, in which all error sources affecting the observations are either modelled or estimated. Application of this technique allows for instantaneous cycle-slip correction, meaning that continuous PPP solutions can be obtained even in the presence of short losses of lock on satellites.
Second, external information on the ionosphere allows for reduced convergence times, but consistency must be observed in the functional model. A new technique, termed integer levelling, was thus developed to generate ionospheric delay corrections compatible with PPP based on the decoupled-clock model. Depending on the inter-station distances in the network providing ionospheric corrections, instantaneous cm-level accuracies can be obtained in PPP.
Third, processing of GLONASS signals is more problematic than GPS due to frequency division multiple access, leading to inter-frequency carrier-phase and code biases. A novel approach for the estimation of such biases was then proposed and facilitates processing of mixed receiver types. It also allows for undifferenced GLONASS ambiguity resolution based on a heterogeneous network of stations, the first demonstration of such an approach, and therefore has the potential to further reduce PPP convergence times.
This research also emphasized potential benefits of integer-levelled observations for improved ionosphere monitoring. The main justifications for adopting this approach are: a reduction in the determination of slant total electron content errors, a simplification in the GLONASS processing strategy, its applicability in real time, and the generation of satellite biases required for the use of ionospheric constraints in PPP with ambiguity resolution.Note de contenu : CH. 1 INTRODUCTION
1.1 Background
1.2 Objectives, Methodology, and Contributions
1.3 Dissertation Outline
CH. 2 IMPROVING REAL-TIME KINEMATIC PPP WITH INSTANTANEOUS CYCLE-SLIP CORRECTION
2.1 Introduction
2.2 Time-Differenced Functional Model
2.3 Time-Differenced Adjustment Process
2.4 Cycle-Slip Correction Procedure
2.5 PPP Solution Update
2.6 Processing Results
2.7 Further Discussions
2.8 Summary, Conclusions, and Future Work
CH. 3 MITIGATING THE IMPACTS OF IONOSPHERIC CYCLE SLIPS ON GNSS OBSERVATIONS
3.1 Introduction
3.2 Cycle-Slip Detection and Estimation
3.3 Integer Least-Squares Theory
3.4 Stochastic Analysis
3.5 Experimental Results
3.6 Conclusion
CH. 4 MONITORING THE IONOSPHERE USING INTEGER-LEVELLED GPS MEASUREMENTS
4.1 Introduction
4.2 Standard Levelling Procedure
4.3 Integer-Levelling Procedure
4.4 Slant TEC Evaluation
4.5 VTEC Evaluation
4.6 Conclusion
CH. 5 GLOBAL AND REGIONAL IONOSPHERIC CORRECTIONS FOR FASTER PPP CONVERGENCE
5.1 Introduction
5.2 The Decoupled-Clock Model (DCM)
5.3 The Extended Decoupled-Clock Model (EDCM)
5.4 Integer Levelling
5.5 Analyzing the Accuracy of Slant Ionospheric Corrections
5.6 PPP with Global Ionospheric Corrections
5.7 Regional Ionospheric Corrections for PPP with Ambiguity Resolution
5.8 Conclusion
CH. 6 GLONASS AMBIGUITY RESOLUTION OF MIXED RECEIVER TYPES WITHOUT EXTERNAL CALIBRATION
6.1 Introduction
6.2 Defining Minimum Constraints
6.3 Datum Transformation
6.4 Estimation of GLONASS Inter-frequency Code Biases
6.5 Proof of Concept
6.6 Conclusion
CH. 7 CONCEPTS FOR UNDIFFERENCED GLONASS AMBIGUITY RESOLUTION
7.1 Introduction
7.2 Estimating Inter-Frequency Biases
7.3 Ambiguity Resolution in the Presence of Biases
7.4 Application of Concepts
7.5 Characteristics of IFCBs
7.6 Melbourne-Wübbena Satellite Biases
7.7 Conclusion
CH. 8 CONCLUSION
8.1 Summary
8.2 Recommendations
8.3 Putting it All TogetherNuméro de notice : 14916 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD : Geodesy and Geomatics Engineering : University of New Brunswick : 2014 En ligne : http://www2.unb.ca/gge/Pubs/TR294.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76904
Titre : Land applications of radar remote sensing Type de document : Monographie Auteurs : Damien Closson, Éditeur scientifique ; Francesco Holecz, Éditeur scientifique ; Paolo Pasquali, Éditeur scientifique ; et al., Auteur Editeur : London [UK] : IntechOpen Année de publication : 2014 Importance : 320 p. Format : 19 x 27 cm ISBN/ISSN/EAN : 978-953-51-4233-1 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] carte forestière
[Termes IGN] déformation de la croute terrestre
[Termes IGN] détection de changement
[Termes IGN] données polarimétriques
[Termes IGN] filtre de déchatoiement
[Termes IGN] occupation du sol
[Termes IGN] radargrammétrie
[Termes IGN] série temporelle
[Termes IGN] surveillance d'ouvrage
[Termes IGN] traitement d'image radarRésumé : (éditeur) The aim of this book is to demonstrate the use of SAR data in three application domains, i.e. land cover (Part II), topography (Part III), and land motion (Part IV). These are preceded by Part I, where an extensive and complete review on speckle and adaptive filtering is provided, essential for the understanding of SAR images. Part II is dedicated to land cover mapping. Part III is devoted to the generation of Digital Elevation Models based on radargrammetry and on a wise fusion (by considering sensor characteristic and acquisition geometry) of interferometric and photogrammetric elevation data. Part IV provides a contribution to three applications related to land motion. Note de contenu : 1- Adaptive speckle filtering in radar imagery
2- Large scale mapping of forests and land cover with synthetic aperture radar data
3- Estimation of cultivated areas using multi-temporal SAR data
4- Combining moderate-resolution time-series RS data from SAR and optical sources for rice crop characterisation: Examples from Bangladesh
5- Change detection and classification using high resolution SAR interferometry
6- High resolution radargrammetry – 3D terrain modeling
7- Fusion of interferometric SAR and photogrammetric elevation data
8- SAR data analysis in solid Earth geophysics: From science to risk management
9- Dikes stability monitoring versus sinkholes and subsidence, Dead Sea region, JordanNuméro de notice : 25939 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Recueil / ouvrage collectif DOI : 10.5772/55833 En ligne : https://doi.org/10.5772/55833 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96301 A local contrast method for small infrared target detection / C.L. Philip Chen in IEEE Transactions on geoscience and remote sensing, vol 52 n° 1 tome 2 (January 2014)
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Titre : A local contrast method for small infrared target detection Type de document : Article/Communication Auteurs : C.L. Philip Chen, Auteur ; Hong Li, Auteur ; Yantao Wei, Auteur ; Tian Xia, Auteur ; Yuan Yan Tang, Auteur Année de publication : 2014 Article en page(s) : pp 574 - 581 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] amélioration du contraste
[Termes IGN] contraste local
[Termes IGN] détection de cible
[Termes IGN] filtrage du bruit
[Termes IGN] image infrarouge
[Termes IGN] rapport signal sur bruit
[Termes IGN] seuillage d'imageRésumé : (Auteur) Robust small target detection of low signal-to-noise ratio (SNR) is very important in infrared search and track applications for self-defense or attacks. Consequently, an effective small target detection algorithm inspired by the contrast mechanism of human vision system and derived kernel model is presented in this paper. At the first stage, the local contrast map of the input image is obtained using the proposed local contrast measure which measures the dissimilarity between the current location and its neighborhoods. In this way, target signal enhancement and background clutter suppression are achieved simultaneously. At the second stage, an adaptive threshold is adopted to segment the target. The experiments on two sequences have validated the detection capability of the proposed target detection method. Experimental evaluation results show that our method is simple and effective with respect to detection accuracy. In particular, the proposed method can improve the SNR of the image significantly. Numéro de notice : A2014-041 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2013.2242477 En ligne : https://doi.org/10.1109/TGRS.2013.2242477 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32946
in IEEE Transactions on geoscience and remote sensing > vol 52 n° 1 tome 2 (January 2014) . - pp 574 - 581[article]Réservation
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