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Débris spatiaux, l’inquiétante prolifération / Laurent Polidori in Géomètre, n° 2199 (février 2022)
[article]
Titre : Débris spatiaux, l’inquiétante prolifération Type de document : Article/Communication Auteurs : Laurent Polidori, Auteur Année de publication : 2022 Article en page(s) : pp 16 - 16 Langues : Français (fre) Descripteur : [Vedettes matières IGN] Technologies spatiales
[Termes IGN] débris spatial
[Termes IGN] orbite
[Termes IGN] prévention des risques
[Termes IGN] risque technologique
[Termes IGN] satellite artificiel
[Termes IGN] satellite nettoyeurRésumé : (Auteur) Les collisions accidentelles et les destructions volontaires de satellites augmentent dangereu?sement le nombre de petits objets qui traînent dans l’espace... Pouvons?nous ralentir cette réaction en chaîne ? Numéro de notice : A2022-220 Affiliation des auteurs : non IGN Nature : Article nature-HAL : ArtSansCL DOI : sans Date de publication en ligne : 01/02/2022 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100047
in Géomètre > n° 2199 (février 2022) . - pp 16 - 16[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 063-2022021 RAB Revue Centre de documentation En réserve L003 Disponible On-orbit BDS signals and transmit antenna gain analysis for a geostationary satellite / Meng Wang in Advances in space research, vol 69 n° 7 (April 2022)
[article]
Titre : On-orbit BDS signals and transmit antenna gain analysis for a geostationary satellite Type de document : Article/Communication Auteurs : Meng Wang, Auteur ; Tao Shan, Auteur ; Lei Liu, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 2711 - 2723 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales
[Termes IGN] affaiblissement de la précision
[Termes IGN] orbite géostationnaire
[Termes IGN] orbite terrestre
[Termes IGN] orbitographie
[Termes IGN] récepteur BeiDou
[Termes IGN] satellite géostationnaire
[Termes IGN] signal BeiDouRésumé : (auteur) A Beidou navigation satellite system (BDS) receiver with high sensitivity is embarked in a geostationary orbit (GEO) spacecraft to demonstrate characteristics of BDS signals tracked. This receiver can be compatible with the regional (BDS-2) and global (BDS-3) systems, which have three orbit types: medium Earth orbit (MEO), inclined geostationary orbit (IGSO), and GEO. The on-orbit BDS signal characteristics, including observations quantity, availability, position dilution of precision (PDOP), and carrier-to-noise ratio (C/N0), are presented according to in-flight data. The observations and distribution of C/N0 with respect to nadir angles were analyzed. The average number of the BDS satellites tracked is 4.4, and the average PDOP is 12.0. PDOP improves when the BDS GEO and IGSO observations are involved. The maximum value of C/N0 of the BDS-3 MEO satellites is approximately 49 dB-Hz, which is roughly 2 dB higher than that of the BDS-2 MEO satellites. Most of the C/N0 of the BDS-3 MEO satellite at nadir angles beyond 26° is in the range of 27–34 dB-Hz. We reconstruct the transmit antenna gain for all observed BDS satellites using C/N0 measurements. Moreover, we investigate the main and side lobe characteristics of the BDS satellites in terms of different orbit types and satellite manufacturers. The side lobe signals of the BDS-3 MEO generally have 20–30 dB lower gain than the peak main lobe gain. The side lobe signal performance of the BDS-2 MEO is evidently better than that of the BDS-3 MEO. We give side lobe characteristics analysis of the BDS-3 MEO satellites from two different manufacturers based on the transmit antenna gain reconstructed. Numéro de notice : A2022-230 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1016/j.asr.2022.01.022 Date de publication en ligne : 25/01/2022 En ligne : https://doi.org/10.1016/j.asr.2022.01.022 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100107
in Advances in space research > vol 69 n° 7 (April 2022) . - pp 2711 - 2723[article]Broadcast ephemerides for LEO augmentation satellites based on nonsingular elements / Lingdong Meng in GPS solutions, vol 25 n° 4 (October 2021)
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Titre : Broadcast ephemerides for LEO augmentation satellites based on nonsingular elements Type de document : Article/Communication Auteurs : Lingdong Meng, Auteur ; Junping Chen, Auteur ; Jiexian Wang, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : n° 129 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales
[Termes IGN] élément orbital
[Termes IGN] éphémérides de satellite
[Termes IGN] modèle d'orbite
[Termes IGN] mouvement Képlerien
[Termes IGN] orbite basse
[Termes IGN] orbitographieRésumé : (auteur) Low earth orbit (LEO) satellite constellations have the potential to augment global navigation satellite system services. Among the ongoing tasks of LEO-based navigation, providing broadcast ephemerides that satisfy the accuracy requirement for positioning, navigation, and timing is one of the most critical prerequisites. Singularities can occur when fitting broadcast ephemeris parameters in the case of a small eccentricity or small or large inclination. We choose an improved nonsingular element set for the LEO broadcast ephemeris design. We establish suitable broadcast ephemeris models, considering the fit accuracy, number of parameters, orbital altitude, and inclination. The fit accuracy using different orbital altitudes, orbital inclinations, and eccentricities suggests that the optimal parameters are n˙, n¨, Crc3, Crs3, Cλc3, and Cλs3, together with the basic broadcast ephemeris model. After adding these six parameters, a fit accuracy of better than 10 cm can be achieved with a 20 min arc length and 500–1400 km orbital altitudes. The effects of the number of parameters, orbital altitude, inclination, and eccentricity on the fit accuracy are discussed in detail. Finally, the performance is validated with real LEO satellites to confirm the effectiveness of the proposed method. Numéro de notice : A2021-566 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-021-01162-7 Date de publication en ligne : 22/07/2021 En ligne : https://doi.org/10.1007/s10291-021-01162-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98135
in GPS solutions > vol 25 n° 4 (October 2021) . - n° 129[article]GPS satellite differential code bias estimation with current eleven low earth orbit satellites / Xingxing Li in Journal of geodesy, vol 95 n° 7 (July 2021)
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Titre : GPS satellite differential code bias estimation with current eleven low earth orbit satellites Type de document : Article/Communication Auteurs : Xingxing Li, Auteur ; Wei Zhang, Auteur ; Keke Zhang, Auteur Année de publication : 2021 Article en page(s) : n° 76 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] erreur systématique de code différentiel
[Termes IGN] orbite basse
[Termes IGN] précision de l'estimation
[Termes IGN] récepteur GPS
[Termes IGN] teneur verticale totale en électrons
[Termes IGN] trajet multipleRésumé : (auteur) Many low earth orbit (LEO) missions have been launched recently for different geoscience studying purposes such as ionosphere detecting and gravity recovering. The onboard observations from LEO satellites provide us a great opportunity to estimate the differential code bias (DCB) which is vital for precise applications of global navigation satellites system. This paper mainly focuses on the contribution of multi-LEO combination to the DCB estimation using onboard data collected by current eleven LEO satellites from day of year (DOY) 061, 2018 to DOY 120, 2018. The single-LEO solutions with different LEO and multi-LEO solutions with different LEO subsets are compared and analyzed in detail to fully exploit the potential of LEO onboard observations in the DCB estimation. We also evaluate and discuss the vertical total electron content (VTEC) results and posterior residuals to validate the estimation accuracy. Our results show that the average DCB standard deviation (STD) values are within 0.140 ns for all eleven single-LEO solutions with the best stability of 0.082 ns for Swarm-B solution. The evaluation of multi-LEO solutions indicates that with the increase in LEO satellites, the GPS DCB stability gets improved gradually. The 9-LEO solution can achieve the stability with STD value of 0.051 ns, better than that of DCB products from the German Aerospace Center (DLR) (0.055 ns) but slightly worse than that of DCB products from the Chinese Academy of Sciences (CAS) (0.048 ns). The results suggest that the GPS DCB stability based on the onboard observations of nine LEO satellites can be comparable to the ground-based solution derived from a global ground network with hundreds of stations. The LEO space-borne receiver DCB results illustrate that the inclusion of more LEO satellites can contribute to the stability improvement of receiver DCB. In addition, the VTEC estimation can benefit from the joint processing of multiple LEO observations and achieves a noticeable reduction in the percentage of negative VTEC values. Our results also reveal that the spherical symmetry ionosphere assumption might cause accuracy degradation in the DCB estimation at low latitudes. Numéro de notice : A2021-517 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-021-01536-2 Date de publication en ligne : 22/06/2021 En ligne : https://doi.org/10.1007/s00190-021-01536-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97939
in Journal of geodesy > vol 95 n° 7 (July 2021) . - n° 76[article]Gravitational field modelling near irregularly shaped bodies using spherical harmonics: a case study for the asteroid (101955) Bennu / Blažej Bucha in Journal of geodesy, vol 95 n° 5 (May 2021)
[article]
Titre : Gravitational field modelling near irregularly shaped bodies using spherical harmonics: a case study for the asteroid (101955) Bennu Type de document : Article/Communication Auteurs : Blažej Bucha, Auteur ; Fernando Sanso, Auteur Année de publication : 2021 Article en page(s) : n° 56 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] astéroïde
[Termes IGN] champ de gravitation
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] convergence
[Termes IGN] harmonique sphérique
[Termes IGN] intégrale de NewtonRésumé : (auteur) We apply three spherical-harmonic-based techniques to deliver external gravitational field models of the asteroid (101955) Bennu within its circumscribing sphere. This region is known to be peculiar for external spherical harmonic expansions, because it may lead to a divergent series. The studied approaches are (i) spectral gravity forward modelling via external spherical harmonics, (ii) the least-squares estimation from surface gravitational data using external spherical harmonics and (iii) the combination of internal and external series expansions. While the first method diverges beyond any reasonable doubts, we show that the other two methods may ensure relative accuracy from ∼10−6 to 10−8 in the vicinity of Bennu. This is possible even with the second method, despite the fact that it relies on a single series of external spherical harmonics. Our main motivation was to study conceptual differences between spherical harmonic coefficients from satellite data (analogy to the first method) and from surface gravitational data (the second method). Such coefficients are available through the popular spherical-harmonic-based models of the Earth’s gravitational field and often are combined together. We show that the coefficients from terrestrial data may lead to a divergence effect of partial sums, though excellent accuracy can be achieved when such model is used in full. Under (presently) extreme but realistic conditions, the divergence effect of partial sums may affect many near-surface geoscientific applications, such as the geoid/quasigeoid computation or residual terrain modelling. Computer codes (Fortran, MATLAB) and data produced within the study are made freely available at http://edisk.cvt.stuba.sk/~xbuchab/. Numéro de notice : A2021-347 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-021-01493-w Date de publication en ligne : 22/04/2021 En ligne : https://doi.org/10.1007/s00190-021-01493-w Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97591
in Journal of geodesy > vol 95 n° 5 (May 2021) . - n° 56[article]Pléiades Neo, 4 satellites réactifs / Laurent Polidori in Géomètre, n° 2191 (mai 2021)PermalinkUnderstanding collective human movement dynamics during large-scale events using big geosocial data analytics / Junchuan Fan in Computers, Environment and Urban Systems, vol 87 (May 2021)PermalinkInteger phase clock method with single-satellite ambiguity fixing and its application in LEO satellite orbit determination / Kai Shao in Acta Geodaetica et Cartographica Sinica, vol 50 n° 4 ([20/04/2021])PermalinkPOD of small LEO satellites based on precise real-time MADOCA and SBAS-aided PPP corrections / Amir Allahvirdi-Zadeh in GPS solutions, vol 25 n° 2 (April 2021)PermalinkSBAS-aided GPS positioning with an extended ionosphere map at the boundaries of WAAS service area / Mingyu Kim in Remote sensing, vol 13 n° 1 (January-1 2021)PermalinkReference system origin and scale realization within the future GNSS constellation “Kepler” / Susanne Glaser in Journal of geodesy, vol 94 n° 12 (December 2020)PermalinkIntegrated processing of ground- and space-based GPS observations: improving GPS satellite orbits observed with sparse ground networks / Wen Huang in Journal of geodesy, vol 94 n° 10 (October 2020)PermalinkSensor tasking for search and catalog maintenance of geosynchronous space objects / Han Cai in Acta Astronautica, vol 175 (October 2020)PermalinkOrbit and clock analysis of BDS-3 satellites using inter-satellite link observations / Xin Xie in Journal of geodesy, vol 94 n° 7 (July 2020)PermalinkGeodetic VLBI for precise orbit determination of Earth satellites: a simulation study / Grzegorz Klopotek in Journal of geodesy, vol 94 n° 6 (June 2020)Permalink