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Atmospheric water vapour sensing by means of differential absorption spectrometry using solar and lunar radiation / Stefan Walter Münch (2014)
Titre : Atmospheric water vapour sensing by means of differential absorption spectrometry using solar and lunar radiation Type de document : Thèse/HDR Auteurs : Stefan Walter Münch, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2014 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 92 Importance : 210 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-35-2 Note générale : bibliographie, thèse publiée
Diss., Eidgenössische Technische Hochschule ETH Zürich, Nr. 21491, 2013Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Atmosphère
[Termes IGN] correction troposphérique
[Termes IGN] détecteur à transfert de charge
[Termes IGN] pouvoir de résolution spectrale
[Termes IGN] rayonnement solaire
[Termes IGN] spectromètre
[Termes IGN] spectrométrie
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] troposphèreIndex. décimale : 47.50 Atmosphère Résumé : (auteur) Tropospheric water vapour plays a crucial role in the understanding of a variety of different atmospheric processes, ranging from local weather phenomena to global climate change. Regarding satellite geodesy, water vapour acts as disturbing factor for various measurement methods, causing path delays of radio signals and consequently leads to considerable biases in the measurement results. The spatial and temporal concentration distribution can hardly be modelled and therefore has to be determined instrumentally to correct the influence computationally. The application of the principle of “Differential Optical Absorption Spectroscopy” (DOAS) using the sun as radiation source to locally determine integrated water vapour concentrations (PW), has proven itself as a very potent methodology, with good relative and absolute accuracy, high temporal resolution and comparably low calibration efforts. It also seems especially well suited for validation purposes for independent measurement methods.
The intention of the presented project is to implement the findings from the development of earlier prototype instruments and to contemplate several further aspects related with the DOAS approach to determine atmospheric water vapour: Improved temporal coverage of the measurement method through inclusion of night time measurements with the help of moonlight, which are enabled by means of a massively increased system sensitivity to deal with the up to six orders of magnitude lower intensity of the background radiation with respect to solar measurements. Further it is to investigate, how reliable acquisitions of sun transmission spectra can be achieved, when deploying the system on moving platforms, for possible future validation measurements of satellite-borne radiometer data on satellite ground tracks on the open sea. The prototype instruments developed should particularly feature high field versatility, requiring eased transportability, resistance to weather and not least the possibility of a fully automatic measurement procedure, including instrument self-calibration.
For this purpose two identically constructed compact measurement systems were built. The instruments dispose of a custom-built telescope (heliostat principle) and an optically directly coupled spectrometer unit. The whole system is enclosed in a rugged aluminium hull, including most of the steering electronics. The motorized telescope is able to follow the moving light source fully autonomously, also with the platform moderately moving. A quasi-monochromator with an echelle grating as main dispersion element is used as spectrometer unit, allowing a compact architecture, a great spectral resolution and efficiency at the same time. Together with a back-thinned CCD detector highly resolved images of water vapour absorption lines can be obtained. The primary wavelength range lies between 789 nm and 802 nm, the reciprocal linear dispersion amounts to 7.3 pm/px at a focal length of just 400 mm. A motorized deflection mirror in the spectrometer allows the observation of adjacent spectral windows and serves for the highly precise position stabilization of the spectrum on the CCD sensor.
Test measurements with the sun and the moon as background radiation source show the extraordinarily high system light throughput and the high spectral resolving power of the apparatus. However illumination dependent interference structures on the detector (etaloning) prevent the deduction of usable transmission spectra from the measured raw data. For that reason a variety of optical measures to homogenize the radiation entering the spectrometer with respect to field and aperture are examined. As a feasible solution, with sufficient radiation distribution and a still acceptable intensity attenuation, a short quartz light guiding fibre with a hexagonal cross section has been found and implemented.
For instrumental control a software package has been developed, which autonomously handles the measurement process including the various calibration processes and the interaction of the various sensors and actuators. Additionally a variety of algorithms have been provided, helping to eliminate various defective influences in the raw data, as the correction of stray and false light portions or the elimination of interspersed beat structures in lunar spectra. Furthermore procedures which serve in spectrum processing have been supplied, as for the computation of a holistic intensity baseline or the dynamic determination of apparatus profiles. For the determination of the water vapour concentrations from the measured spectroscopic data established computational procedures could be used mostly.
Various available spectroscopic databases have been analysed regarding the suitability of the listed absorption line parameters for the deduction of reliable water vapour concentrations. Comparison between the two identically built solar spectrometers yield considerable deviations of up to 1.5 kg/m 2 in the zenith integral concentrations which are presumably ascribable to systematic influences likely caused by unrecognized stray light influence. The mean value of the stochastic deviations amounts to about 1.1 % of the slant PW concentration. The cross-comparison with an independent measurement method, in this case GPS meteorology, however also shows significant divergences and thus point to the various further systematic effects which have to be examined more closely, as e.g. the uncertainty of the published spectroscopic parameters regarding line strength and line broadening as well as the baseline determination in the measured spectra.
Despite the considerable sensitivity losses with respect to the originally planned design due to beam homogenization, the methodology has been successfully applied to lunar measurements, albeit with reduced accuracy as stated in stochastic appraisals and with considerably lower temporal resolution.
The project presented here confirms and clarifies the possibilities of the application of DOAS for ground- based remote sensing of integral water vapour concentrations, but also gives clear indication on the different systematic biases which have to be examined more closely, e.g. regarding the accuracy of the spectroscopic parameters (both, for line strength and line broadening), as well as the determination procedure of the baseline in the measured spectra. This work also points out the chances as well as the serious difficulties which arise from the design, construction and deployment of highly integrated DOAS spectrometers of high performance. Regarding the application of various optical components and detectors for the development of similar instruments valuable insights have been gathered.Numéro de notice : 14913 Affiliation des auteurs : non IGN Autre URL associée : URL ETH Zurich Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD : Sciences : ETH Zurich : 2013 DOI : 10.3929/ethz-a-010006561 En ligne : http://e-collection.library.ethz.ch/view/eth:7591 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76813 Réservation
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Titre : Blind tropospheric model for Austria Type de document : Mémoire Auteurs : Paoline Prevost, Auteur Editeur : Champs-sur-Marne : Ecole nationale des sciences géographiques ENSG Année de publication : 2014 Importance : 36 p. Format : 21 x 30 cm Note générale : bibliographie
Rapport de projet pluridisciplinaire, cycle Ingénieur 2e annéeLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] Autriche
[Termes IGN] correction troposphérique
[Termes IGN] données météorologiques
[Termes IGN] international GPS service for geodynamics
[Termes IGN] modèle numérique
[Termes IGN] propagation troposphérique
[Termes IGN] retard troposphérique
[Termes IGN] signal GNSS
[Termes IGN] station GNSS
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] traitement de données GNSS
[Termes IGN] traitement du signalIndex. décimale : PROJET Mémoires : Rapports de projet - stage des ingénieurs de 2e année Résumé : (auteur) Lors de la traversée de l’atmosphère, les signaux GNSS sont retardés. Ces retards peuvent être séparés en deux parties : la partie humide et l’autre dite hydrostatique (Saastamoinen, 1972). Ces délais peuvent être très importants, c’est pourquoi il est très important de savoir les modéliser. Pour cela, des modèles de correction troposphérique peuvent être utilisés. Le but de ce stage est de développer un modèle régional numérique de correction troposphérique pour l’Autriche. Une grille d’une très bonne résolution était nécessaire à cause des nombreuses régions montagneuses que comporte l’Autriche. Après avoir traité les données météorologiques pour les rendre utilisables dans nos calculs, les paramètres nécessaires aux calculs des deux parties du retard troposphérique ont été calculés comme suggéré dans (Nafisi, 2012) et (Pain, 2013). Puis, le délai total a été comparé pour trois stations IGS avec GPT2w, un modèle numérique mondial des corrections troposphériques également développé par l’université technologique de Vienne. Note de contenu : Introduction
1 Context
1.1 Technical definitions
1.1.1 Blind model
1.1.2 Zenith delay
1.2 The existing
1.3 Objectives
2 Method
2.1 Preparation of the data
2.1.1 Presentation of the data
2.1.2 Treatment of the data
2.2 Calculation of the parameters
2.2.1 Define the useful parameters
2.2.2 Harmonic decomposition – Least square calculation
3 Results
3.1 Internal validation
3.1.1 Pressure
3.1.2 Water vapor decrease factor
3.1.3 Hydrostatic mapping function coefficient
3.1.4 Temperature lapse rate
3.2 External validation
ConclusionNuméro de notice : 22178 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Mémoire de projet pluridisciplinaire Organisme de stage : Université Technique de Vienne Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74681 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 Real-time precise point positioning regional augmentation for large GPS reference networks / Xinging Li in GPS solutions, vol 18 n° 1 (january 2014)
[article]
Titre : Real-time precise point positioning regional augmentation for large GPS reference networks Type de document : Article/Communication Auteurs : Xinging Li, Auteur ; Maorong Ge, Auteur ; Jan Douša, Auteur Année de publication : 2014 Article en page(s) : pp 61 - 71 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] ambiguïté entière
[Termes IGN] correction atmosphérique
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] positionnement ponctuel précis
[Termes IGN] réseau géodésique localRésumé : (auteur) An increasing number of GNSS reference stations are installed around the world to provide real-time precise positioning services. In most of the current services, a full network solution is required for the precise determination of biases. Such a network solution is time consuming and difficult to achieve for very large regions such as Europe or China. Therefore, we developed a multi-layer processing scheme for precise point positioning (PPP) regional augmentation to avoid processing large networks. Furthermore, we use L1 and L2 raw observations and estimate atmospheric delays, which were properly constrained to the atmospheric corrections derived from the reference stations. Therefore, inaccurate representation of atmospheric delays due to temporal and/or spatial atmospheric fluctuations in the processing can be compensated. The proposed scheme of PPP regional augmentation was implemented into the operational real-time PPP service system at GFZ for validation. The real-time orbit and clock corrections, the uncalibrated phase delays, and regional augmentation corrections are generated by this system. The augmentation corrections from the regional network are investigated and the positioning performance in terms of positioning accuracy and time for fixed solution is demonstrated in real-time. Our results indicate that a reliable fixing is possible after 5 s on average. The positioning accuracy is about 12, 10, and 25 mm in east, north, and vertical direction, respectively. Numéro de notice : A2014-664 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-013-0310-3 En ligne : https://doi.org/10.1007/s10291-013-0310-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77824
in GPS solutions > vol 18 n° 1 (january 2014) . - pp 61 - 71[article]Temperature and emissivity separation from Thermal Airborne Hyperspectral Imager (TASI) data / Yang Hang in Photogrammetric Engineering & Remote Sensing, PERS, vol 79 n° 12 (December 2013)
[article]
Titre : Temperature and emissivity separation from Thermal Airborne Hyperspectral Imager (TASI) data Type de document : Article/Communication Auteurs : Yang Hang, Auteur ; Zhang Lifu, Auteur ; Gao Yingqian, Auteur ; et al., Auteur Année de publication : 2013 Article en page(s) : pp 1099 - 1107 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] Chine
[Termes IGN] correction atmosphérique
[Termes IGN] emissivité
[Termes IGN] étalonnage radiométrique
[Termes IGN] image hyperspectrale
[Termes IGN] image TASI
[Termes IGN] radiance
[Termes IGN] température au solRésumé : (Auteur) The Thermal Airborne Hyperspectral Imager (TASI) acquires 32 bands to provide continuous spectral coverage in the wavelength range of 8 to 11.5um. The instrument was used during a field campaign in the City of Shijiazhuang, Hebei Province, China, in 2010. Land surface temperature and emissivity were measured near simultaneous with the airborne campaign for calibration and validation of the instrument. Radiance calibration was performed band-by-band using calibration coefficients, and atmospheric correction was performed using data from in situ measurements and the MODTRAN model. Surface temperature and emissivity separation were determined using the ASTER temperature-emissivity separation (ASTER_TES) and iterative spectral smooth temperature and emissivity separation (ISSTES) methods. The ASTER_TES method resulted in satisfactory agreement with ground data, with root mean square error (RMSE) values of 2.2 K for temperature and 0.0460 for broad-emissivity. The ISSTES method provided better ground validation results, with a RMSE for temperature of 1.8 K and a RMSE for broad-emissivity of 0.0394. The emissivity shapes acquired by the two methods were very similar. The results have relevance to studies of global climate change, environmental monitoring, classification, feature mining, and target recognition. Numéro de notice : A2013-688 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.79.12.1099 En ligne : https://doi.org/10.14358/PERS.79.12.1099 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32824
in Photogrammetric Engineering & Remote Sensing, PERS > vol 79 n° 12 (December 2013) . - pp 1099 - 1107[article]Description de la campagne aéroportée UMBRA : étude de l'impact anthropique sur les écosystèmes urnbains et naturels avec des images THR multispectrales et hyperspectrales / Karine R.M. Adeline in Revue Française de Photogrammétrie et de Télédétection, n° 202 (Avril 2013)PermalinkDORIS and GPS monitoring of the Gavdos calibration site in Crete / Pascal Willis in Advances in space research, vol 51 n° 8 (April 2013)PermalinkSpectral compatibility of the NDVI across VIIRS, MODIS, and AVHRR: An analysis of atmospheric effects using EO-1 Hyperion / Tomoaki Miura in IEEE Transactions on geoscience and remote sensing, vol 51 n° 3 Tome 1 (March 2013)PermalinkPermalinkÉtude comparative des précisions d’approximation de l’ITRF et application à la redéfinition des systèmes géodésiques utilisés au sein du groupe Total / Simon Olivé (2013)PermalinkMaterial reflectance retrieval in urban tree shadows with physics-based empirical atmospheric correction / Karine R.M. Adeline (2013)PermalinkPermalinkPermalinkTopographic corrections of satellite data for regional monitoring / S. Goslee in Photogrammetric Engineering & Remote Sensing, PERS, vol 78 n° 9 (September 2012)PermalinkOutils de prétraitements des images optiques Kalideos / Bruno Lafrance in Revue Française de Photogrammétrie et de Télédétection, n° 197 (Juin 2012)Permalink