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Analysis of a possible future degradation in the DORIS geodetic results related to changes in the satellite constellation / Pascal Willis in Advances in space research, vol 39 n° 10 (May 2007)
[article]
Titre : Analysis of a possible future degradation in the DORIS geodetic results related to changes in the satellite constellation Type de document : Article/Communication Auteurs : Pascal Willis , Auteur Année de publication : 2007 Article en page(s) : pp 1582 - 1588 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] données DORIS
[Termes IGN] DORIS
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] rotation de la Terre
[Termes IGN] secteur spatial
[Termes IGN] simulation numériqueRésumé : (auteur) Recently, several improvements were made in the DORIS data processing at the IGN/JPL (Institut Geographique National, France; Jet Propulsion Laboratory, California Institute of Technology, USA) analysis center: use of GRACE-derived gravity fields, data preprocessing and station discontinuity detection, etc. This allowed enhanced performances for ground station geodetic positioning (typically 10 mm using a week of data), as well as for polar motion (0.5–1.0 mass for daily determination). However, since the loss in 2004 of the DORIS receiver on the TOPEX/Poseidon mission, only four satellites (SPOT-2, SPOT-4, SPOT-5, and ENVISAT) are currently equipped with DORIS receivers. Furthermore, most of them are aging and some have already far exceeded their expected lifetime. The goal of this paper is to analyze how the geodetic performances could be degraded in the future if one or more of these satellites would unfortunately be lost, and to envisage which satellites are currently the most critical in the DORIS geodetic performances. We have reanalyzed 1 year of recent DORIS data (2005), processing all possible combinations of satellite constellation sub-sets. We then compared these results (station coordinates and polar motion) with those obtained in regular data processing when using DORIS data from all four available satellites in 2005. We demonstrate the importance of the SPOT-5 data, equipped with a new type of on-board DORIS receiver. The study also shows some possible weaknesses in our current ENVISAT orbit computations. Fortunately, new DORIS satellites are also expected in the near future (Jason-2, CRYOSAT-2 and AltiKa), which could improve current DORIS-derived geodetic results due to their specific type of orbit (different from the SPOT sun-synchronous orbits) and also to enhanced on-board receivers. Numéro de notice : A2007-659 Affiliation des auteurs : IGN (1940-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2006.11.018 Date de publication en ligne : 09/06/2007 En ligne : https://doi.org/10.1016/j.asr.2006.11.018 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102695
in Advances in space research > vol 39 n° 10 (May 2007) . - pp 1582 - 1588[article]Galileo signal experimentation / M. Hollreiser in GPS world, vol 18 n° 5 (May 2007)
[article]
Titre : Galileo signal experimentation Type de document : Article/Communication Auteurs : M. Hollreiser, Auteur ; M. Crisci, Auteur ; Jean-Marie Sleewaegen, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 44 - 50 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] GIOVE (satellite)
[Termes IGN] interférence
[Termes IGN] signal Galileo
[Termes IGN] test de performance
[Termes IGN] trajet multipleRésumé : (Editeur) The GIOVE-A satellite, transmitting the full set of modulations envisaged for Galileo (except MBOC), presents the first opportunity to assess performance of the future signals in real-life conditions, under interference and multipath. Signal, receiver, and sensor-station experimentation demonstrate that all Galileo signals perform significantly better than GPS-C/A with regard to noise and multipath performance. Copyright Questex Media Group Inc Numéro de notice : A2007-222 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28585
in GPS world > vol 18 n° 5 (May 2007) . - pp 44 - 50[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-07051 RAB Revue Centre de documentation En réserve L003 Disponible Meet GIOVE-A: Galileo's first test satellite / E. Rooney in GPS world, vol 18 n° 5 (May 2007)
[article]
Titre : Meet GIOVE-A: Galileo's first test satellite Type de document : Article/Communication Auteurs : E. Rooney, Auteur ; M. Unwin, Auteur ; A. Bradford, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 36 - 42 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Satellites artificiels
[Termes IGN] antenne GPS
[Termes IGN] charge utile
[Termes IGN] constellation Galileo
[Termes IGN] GIOVE (satellite)
[Termes IGN] plateforme
[Termes IGN] réflecteur
[Termes IGN] test de performanceRésumé : (Editeur) Similarly to GPS spacecraft, Galileo satellites must operate in a very harsh environment, more than 20,000 kilometers above the Earth, and through the intense Van Alien electron belt. The first Galileo demonstrator satellite draws from experience designing small satellites in a much lower orbit. GIOVE-A required greater power and changes to methods for communicating with the satellite, controlling the attitude, and regulating the temperature. This article presents the design, manufacture, launch, and commissioning of GIOVE-A. Copyright Questex Media Group Inc Numéro de notice : A2007-221 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28584
in GPS world > vol 18 n° 5 (May 2007) . - pp 36 - 42[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-07051 RAB Revue Centre de documentation En réserve L003 Disponible Time for GIOVE-A: the onboard rubidium clock experiment / J. Hahn in GPS world, vol 18 n° 5 (May 2007)
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Titre : Time for GIOVE-A: the onboard rubidium clock experiment Type de document : Article/Communication Auteurs : J. Hahn, Auteur ; D. Navarro-Reyes, Auteur ; F. Gonzalez, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 64 - 69 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Satellites artificiels
[Termes IGN] GIOVE (satellite)
[Termes IGN] horloge atomique
[Termes IGN] temps universel
[Termes IGN] test de performanceRésumé : (Editeur) Apart from the ability to launch satellites, what was the single greatest technological development which has made global navigation satellite systems possible? Time's up (that should give you a hint). It is the atomic clock. GNSS receivers work by accurately timing how long it takes signals to travel from the satellites' antennas to the receiver's antenna and converting the time delays to ranges using the speed of light. Each delay is essentially the difference between the time a particular signal transition was received, as measured with the receiver's clock, and the time that same transition left a satellite, as measured with the satellite's clock. The delays must be measured very accurately since a timing error of just 10 nanoseconds is equivalent to a ranging error of about 3 meters. One of the clocks must be a highly stable reference clock. The demands on the timekeeping ability of the other clock is much less since its timing error can be estimated from measurements. The only practical approach for a GNSS is to place reference clocks in the satellites, permitting receivers to operate with a low-cost clock whose error is estimated along with the receiver's coordinates from the simultaneous measurements made on four or more satellites. Only atomic clocks have the required accuracy and stability to be used as reference clocks. Scientists have developed three basic kinds of atomic clock, each based on a different element ; cesium, rubidium, and hydrogen. The GPS Block II and IIA satellites each carried four clocks: two cesium and two rubidium whereas the Block IIR and IIR-M satellites each carry three rubidium clocks. GLONASS satellites carry three cesium clocks. The European Galileo system will also use redundant atomic clocks onboard its satellites. One candidate clock for the future Galileo satellites is the European Rubidium Atomic Frequency Standard. Two of these clocks are flying onboard the GIOVE-A test satellite which was launched on December 28, 2005. In this month's column, the GIOVE clock experiment team discusses the tests which have been conducted to assess the performance of the satellite's active clock and their future plans for onboard clock assessment including the passive hydrogen maser to be flown on GIOVE-B. Copyright Questex Media Group Inc Numéro de notice : A2007-223 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28586
in GPS world > vol 18 n° 5 (May 2007) . - pp 64 - 69[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-07051 RAB Revue Centre de documentation En réserve L003 Disponible Developments in South & East Asia: Space image acquisition for geospatial intelligence / Gordon Petrie in Geoinformatics, vol 10 n° 3 (01/04/2007)
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Titre : Developments in South & East Asia: Space image acquisition for geospatial intelligence Type de document : Article/Communication Auteurs : Gordon Petrie, Auteur Année de publication : 2007 Article en page(s) : pp 38 - 45 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] acquisition d'images
[Termes IGN] ALOS
[Termes IGN] CARTOSAT
[Termes IGN] CBERS
[Termes IGN] Chine
[Termes IGN] Corée du sud
[Termes IGN] image satellite
[Termes IGN] Inde
[Termes IGN] Japon
[Termes IGN] KOMPSAT
[Termes IGN] Malaisie
[Termes IGN] Panchromatic Remote Sensing Instrument for Stereo Mapping
[Termes IGN] ROCSAT
[Termes IGN] Taïwan
[Termes IGN] Thaïlande
[Termes IGN] THEOS
[Termes IGN] Tsinghua (microsatellite)Résumé : (Auteur) By far the biggest source of the data needed for geospatial intelligence purposes comes from the high resolution imagery acquired from spaceborne and airborne platforms. In the specific context of South and East Asia, where there are numerous concerns about national security and threats from neighbours, the primary source for this type of intelligence is spaceborne imagery. Indeed the defence and security agencies in the larger countries in this part of Asia have all been large consumers of the high-resolution space imagery provided, by commercial suppliers such as GeoEye, DigitalGlobe, SPOT Image and ImageSat International. However, recently, nearly all of these Asian countries have either acquired or they are creating their own national capabilities to acquire this type of imagery to overcome the actual or potential restrictions and the delays that occur with the supply of space imagery from sources out with their control. The situation has already been discussed in a preliminary manner in an article published in Geolnformatics by the present writer three years ago (in the March 2004 issue) as part of his world wide survey of high-resolution imaging from space. This new article will concentrate on the many new developments that have taken place in the region since then. Copyright GeoInformatics Numéro de notice : A2007-197 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28560
in Geoinformatics > vol 10 n° 3 (01/04/2007) . - pp 38 - 45[article]GNSS : Update, Giove-B Bom Bursts / Huibert-Jan Lekkerkerk in Geoinformatics, vol 10 n° 3 (01/04/2007)PermalinkThailand Earth Observation System: mission and products / M. Kaewmanee in Revue Française de Photogrammétrie et de Télédétection, n° 185 (Mars 2007)PermalinkUtiliser GLONASS, une gageure ? / Valerio Baiocchi in Géomatique expert, n° 55 (01/03/2007)PermalinkPROBA proves the technology: PROBA-1 passes 5 years in orbit / F. Teston in ESA bulletin, n° 129 (February 2007)PermalinkReaping the rewards: coordinating Europe's Earth observation ground system / E. Forcada in ESA bulletin, n° 129 (February 2007)Permalink50 ans d'aventure spatiale / Centre national d'études spatiales (2007)PermalinkAriane, une épopée européenne / W. Huon (2007)PermalinkLes débuts de la recherche spatiale française au temps des fusées-sondes / H. Moulin (2007)PermalinkICESat altimetry data product verification at White Sands Space Harbor / L.A. Magruder in IEEE Transactions on geoscience and remote sensing, vol 45 n° 1 (January 2007)PermalinkModelling and prediction of GPS availability with digital photogrammetry and LiDAR / Georges E. Taylor in International journal of geographical information science IJGIS, vol 21 n° 1-2 (january 2007)Permalink