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Reflected blessings : position estimation using non-line-of-sight GPS signals / Yuting Ng in GPS world, vol 28 n° 3 (March 2017)
[article]
Titre : Reflected blessings : position estimation using non-line-of-sight GPS signals Type de document : Article/Communication Auteurs : Yuting Ng, Auteur ; Grace Xingxin Gao, Auteur Année de publication : 2017 Article en page(s) : pp 42 - 47 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal
[Termes IGN] estimation de position
[Termes IGN] signal GPS
[Termes IGN] trajet multipleRésumé : (Auteur) Building obstructions and reflections present serious challenges to GPS receivers operating in urban environments. In such environments, buildings may obstruct GPS signals, leading to reduced GPS signal availability. In addition, buildings may reflect GPS signals, resulting in reception of nonline- of-sight (NLOS) signals. NLOS GPS signals are delayed versions of the line-of-sight (LOS) signals. As such, they lead to pseudorange errors, resulting in positioning errors. Conventional approaches treat NLOS GPS signals as unwanted interference to be rejected or mitigated. Numéro de notice : A2017-291 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85326
in GPS world > vol 28 n° 3 (March 2017) . - pp 42 - 47[article]Study of the effects on GPS coordinate time series caused by higher-order ionospheric corrections calculated using the DIPOLE model / Liansheng Deng in Geodesy and Geodynamics, vol 8 n° 2 (March 2017)
[article]
Titre : Study of the effects on GPS coordinate time series caused by higher-order ionospheric corrections calculated using the DIPOLE model Type de document : Article/Communication Auteurs : Liansheng Deng, Auteur ; Weiping Jiang, Auteur ; Hua Chen, Auteur ; Zhaohan Zhu, Auteur ; Wen Zhao, Auteur Année de publication : 2017 Article en page(s) : pp 111 - 119 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] amplitude
[Termes IGN] bruit blanc
[Termes IGN] bruit rose
[Termes IGN] champ géomagnétique
[Termes IGN] correction ionosphérique
[Termes IGN] GAMIT
[Termes IGN] GLOBK
[Termes IGN] série temporelle
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) As one of the main error sources in high-precision Global Positioning System (GPS) data processing, higher-order ionospheric (HOI) delays cause significant effects on coordinate time series that cannot be ignored in analyses of long time series. Typically two geomagnetic models, DIPOLE model and International Geomagnetic Reference Field (IGRF) model, are used for calculating HOI corrections. This paper investigates the effects of HOI correction caused by the DIPOLE model on coordinate time series. GPS data from 104 globally distributed International GNSS Service (IGS) stations spanning from January, 1999 to December, 2003 were reprocessed following up-to-date processing strategies utilizing GAMIT and GLOBK software. Two coordinate time series solutions before and after applying HOI corrections using the DIPOLE model were derived for studying the effects in terms of seasonal variations and noise amplitudes. The results show that after applying the HOI corrections calculated with DIPOLE, the noise amplitudes of the coordinate time series increased, especially in the north and east directions, and the increased amplitudes of the flicker noise were larger than those of the white noise. Furthermore, spurious periodic signals that were probably introduced by the HOI corrections from the DIPOLE model were also found. Moreover, an apparent increase was confirmed for the power spectra of most of the stations, especially in the north direction, and the amplitudes of both the annual and semi-annual signals also increased in the north and east directions. It can be inferred that the quality of the external data sources such as the geomagnetic model might be the key factors that lead to the above results. The results also suggest that we should be very careful when the DIPOLE model is used for HOI corrections. Numéro de notice : A2017-235 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1016/j.geog.2017.01.004 En ligne : https://doi.org/10.1016/j.geog.2017.01.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85167
in Geodesy and Geodynamics > vol 8 n° 2 (March 2017) . - pp 111 - 119[article]Adaptive spectral–spatial compression of hyperspectral image with sparse representation / Wei Fu in IEEE Transactions on geoscience and remote sensing, vol 55 n° 2 (February 2017)
[article]
Titre : Adaptive spectral–spatial compression of hyperspectral image with sparse representation Type de document : Article/Communication Auteurs : Wei Fu, Auteur ; Shutao Li, Auteur ; Leyuan Fang, Auteur ; Jon Atli Benediktsson, Auteur Année de publication : 2017 Article en page(s) : pp 671 - 682 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] codage
[Termes IGN] compression d'image
[Termes IGN] image hyperspectrale
[Termes IGN] pixel
[Termes IGN] représentation parcimonieuse
[Termes IGN] zone homogèneRésumé : (Auteur) Sparse representation (SR) can transform spectral signatures of hyperspectral pixels into sparse coefficients with very few nonzero entries, which can efficiently be used for compression. In this paper, a spectral-spatial adaptive SR (SSASR) method is proposed for hyperspectral image (HSI) compression by taking advantage of the spectral and spatial information of HSIs. First, we construct superpixels, i.e., homogeneous regions with adaptive sizes and shapes, to describe HSIs. Since homogeneous regions usually consist of similar pixels, pixels within each superpixel will be similar and share similar spectral signatures. Then, the spectral signatures of each superpixel can be simultaneously coded in the SR model to exploit their joint sparsity. Since different superpixels generally have different performances of SR, their rate-distortion performances in the sparse coding will be different. To achieve the best possible overall rate-distortion performance, an adaptive coding scheme is introduced to adaptively assign distortions to superpixels. Finally, the obtained sparse coefficients are quantized and entropy coded and constitute the final bitstream with the coded superpixel map. The experimental results over several HSIs show that the proposed SSASR method outperforms some state-of-the-art HSI compression methods in terms of the rate-distortion and spectral fidelity performances. Numéro de notice : A2017-141 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2016.2613848 En ligne : http://dx.doi.org/10.1109/TGRS.2016.2613848 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84629
in IEEE Transactions on geoscience and remote sensing > vol 55 n° 2 (February 2017) . - pp 671 - 682[article]Assessment of second- and third-order ionospheric effects on regional networks : case study in China with longer CMONOC GPS coordinate time series / Liansheng Deng in Journal of geodesy, vol 91 n° 2 (February 2017)
[article]
Titre : Assessment of second- and third-order ionospheric effects on regional networks : case study in China with longer CMONOC GPS coordinate time series Type de document : Article/Communication Auteurs : Liansheng Deng, Auteur ; Weiping Jiang, Auteur ; Zhao Li, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 207 - 227 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] analyse diachronique
[Termes IGN] Chine
[Termes IGN] coordonnées GPS
[Termes IGN] correction ionosphérique
[Termes IGN] déformation de la croute terrestre
[Termes IGN] effet atmosphérique
[Termes IGN] propagation ionosphérique
[Termes IGN] réseau géodésique local
[Termes IGN] retard ionosphèrique
[Termes IGN] série temporelle
[Termes IGN] surcharge atmosphériqueRésumé : (Auteur) Higher-order ionospheric (HOI) delays are one of the principal technique-specific error sources in precise global positioning system analysis and have been proposed to become a standard part of precise GPS data processing. In this research, we apply HOI delay corrections to the Crustal Movement Observation Network of China’s (CMONOC) data processing (from January 2000 to December 2013) and furnish quantitative results for the effects of HOI on CMONOC coordinate time series. The results for both a regional reference frame and global reference frame are analyzed and compared to clarify the HOI effects on the CMONOC network. We find that HOI corrections can effectively reduce the semi-annual signals in the northern and vertical components. For sites with lower semi-annual amplitudes, the average decrease in magnitude can reach 30 and 10 % for the northern and vertical components, respectively. The noise amplitudes with HOI corrections and those without HOI corrections are not significantly different. Generally, the HOI effects on CMONOC networks in a global reference frame are less obvious than the results in the regional reference frame, probably because the HOI-induced errors are smaller in comparison to the higher noise levels seen when using a global reference frame. Furthermore, we investigate the combined contributions of environmental loading and HOI effects on the CMONOC stations. The largest loading effects on the vertical displacement are found in the mid- to high-latitude areas. The weighted root mean square differences between the corrected and original weekly GPS height time series of the loading model indicate that the mass loading adequately reduced the scatter on the CMONOC height time series, whereas the results in the global reference frame showed better agreements between the GPS coordinate time series and the environmental loading. When combining the effects of environmental loading and HOI corrections, the results with the HOI corrections reduced the scatter on the observed GPS height coordinates better than the height when estimated without HOI corrections, and the combined solutions in the regional reference frame indicate more preferred improvements. Therefore, regional reference frames are recommended to investigate the HOI effects on regional networks. Numéro de notice : A2017-064 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0957-y En ligne : http://dx.doi.org/10.1007/s00190-016-0957-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84278
in Journal of geodesy > vol 91 n° 2 (February 2017) . - pp 207 - 227[article]Double take : mitigating interference with a dual-polarized antenna array in a real environment / Matteo Sgammini in GPS world, vol 28 n° 2 (February 2017)
[article]
Titre : Double take : mitigating interference with a dual-polarized antenna array in a real environment Type de document : Article/Communication Auteurs : Matteo Sgammini, Auteur ; Stefano Caizzone, Auteur ; Achim Hornbostel, Auteur ; Michael Meurer, Auteur Année de publication : 2017 Article en page(s) : pp 66 - 72 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] antenne
[Termes IGN] anti-leurrage
[Termes IGN] interférence
[Termes IGN] méthode robuste
[Termes IGN] polarisation
[Termes IGN] récepteur GPSRésumé : (Auteur) [Introduction] The rapid growth of the wireless telecommunication sector and, consequently, the high demand of spectrum assigned to the new services make the frequency spectrum very crowded and quite saturated. With the weak received signal power of GNSS signals, spurious harmonics from other systems can cause unintentional interference and, therefore, a serious problem to the reliable estimation of user position, velocity and time (PVT). Besides unintentional interference, more virulent intentionally radiated signals, called jammers, may knock out the GNSS receiver; this is especially the case when a jammer with high time-frequency dynamics (such as a chirp-like jammer) affects the GNSS signal spectrum. Whether unintentional or intentional, interference represents a serious threat to GNSS in applications ranging from safety-of-life to critical sectors like law enforcement, transportation, communication and finance. In such critical applications, it is important that the GNSS receiver provides a minimum level of reliability and robustness, even at the cost of increased price and complexity. To meet this need, some manufacturers and research institutions have been developing GNSS receivers equipped with anti-jamming capabilities. In this article, we propose a novel approach to interference mitigation. [...] Numéro de notice : A2017-289 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85324
in GPS world > vol 28 n° 2 (February 2017) . - pp 66 - 72[article]Interference localization from space: part 2 applications / Luca Canzian in Inside GNSS, vol 12 n° 1 (January - February 2017)PermalinkJoint sparse representation and multitask learning for hyperspectral target detection / Yuxiang Zhang in IEEE Transactions on geoscience and remote sensing, vol 55 n° 2 (February 2017)PermalinkPermalinkCartographie de l'occupation des sols à partir de séries temporelles d'images satellitaires à hautes résolutions : identification et traitement des données mal étiquetées / Charlotte Pelletier (2017)PermalinkPermalinkPermalinkPermalinkIonosphere probing with simultaneous GNSS radio occultations / Viet-Cuong Pham in GPS solutions, vol 21 n° 1 (January 2017)PermalinkSingle Image Super-Resolution based on Neural Networks for text and face recognition / Clément Peyrard (2017)PermalinkSpringer handbook of Global Navigation Satellite Systems / Peter J.G. Teunissen (2017)PermalinkTélédétection pour l'observation des surfaces continentales, ch. 7. Modèles numériques de terrain à partir de données lidar aéroportées / Clément Mallet (2017)PermalinkTélédétection pour l'observation des surfaces continentales, Volume 1. Observation des surfaces continentales par télédétection optique / Nicolas Baghdadi (2017)PermalinkTélédétection pour l'observation des surfaces continentales, Volume 2. Observation des surfaces continentales par télédétection micro-onde / Nicolas Baghdadi (2017)PermalinkTélédétection pour l'observation des surfaces continentales, Volume 5. Observation des surfaces continentales par télédétection 3 / Nicolas Baghdadi (2017)PermalinkUtilisation conjointe de trains d'ondes LiDAR vert et infrarouge pour la bathymétrie des eaux de très faibles profondeurs / Tristan Allouis in Revue Française de Photogrammétrie et de Télédétection, n° 213 - 214 (janvier - avril 2017)PermalinkDetermination of a terrestrial reference frame via Kalman filtering of very long baseline interferometry data / Benedikt Soja in Journal of geodesy, vol 90 n° 12 (December 2016)PermalinkDictionary learning for promoting structured sparsity in hyperspectral compressive sensing / Lei Zhang in IEEE Transactions on geoscience and remote sensing, vol 54 n° 12 (December 2016)PermalinkA drift line bias estimator: ARMA-based filter or calibration method, and its application in BDS/GPS-based attitude determination / Zhang Liang in Journal of geodesy, vol 90 n° 12 (December 2016)PermalinkEvaluation of GPS standard point positioning with various ionospheric error mitigation techniques / Sampad K. Panda in Journal of applied geodesy, vol 10 n° 4 (December 2016)PermalinkImproved ambiguity resolution for URTK with dynamic atmosphere constraints / Weiming Tang in Journal of geodesy, vol 90 n° 12 (December 2016)Permalink