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Investigation of ionospheric effects on SAR Interferometry (InSAR): A case study of Hong Kong / Wu Zhu in Advances in space research, vol 58 n° 4 (August 2016)
[article]
Titre : Investigation of ionospheric effects on SAR Interferometry (InSAR): A case study of Hong Kong Type de document : Article/Communication Auteurs : Wu Zhu, Auteur ; Xiao-Li Ding, Auteur ; Hyung-Sup Jung, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 564 - 576 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] bande L
[Termes IGN] coordonnées GPS
[Termes IGN] Hong-Kong
[Termes IGN] image ALOS-PALSAR
[Termes IGN] interféromètrie par radar à antenne synthétique
[Termes IGN] perturbation ionosphérique
[Termes IGN] teneur totale en électronsRésumé : (auteur) Synthetic Aperture Radar Interferometry (InSAR) has demonstrated its potential for high-density spatial mapping of ground displacement associated with earthquakes, volcanoes, and other geologic processes. However, this technique may be affected by the ionosphere, which can result in the distortions of Synthetic Aperture Radar (SAR) images, phases, and polarization. Moreover, ionospheric effect has become and is becoming further significant with the increasing interest in low-frequency SAR systems, limiting the further development of InSAR technique. Although some research has been carried out, thorough analysis of ionospheric influence on true SAR imagery is still limited. Based on this background, this study performs a thorough investigation of ionospheric effect on InSAR through processing L-band ALOS-1/PALSAR-1 images and dual-frequency Global Positioning System (GPS) data over Hong Kong, where the phenomenon of ionospheric irregularities often occurs. The result shows that the small-scale ionospheric irregularities can cause the azimuth pixel shifts and phase advance errors on interferograms. Meanwhile, it is found that these two effects result in the stripe-shaped features in InSAR images. The direction of the stripe-shaped effects keep approximately constant in space for our InSAR dataset. Moreover, the GPS-derived rate of total electron content change index (ROTI), an index to reflect the level of ionospheric disturbances, may be a useful indicator for predicting the ionospheric effect for SAR images. This finding can help us evaluate the quality of SAR images when considering the ionospheric effect. Numéro de notice : A2016-591 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2016.05.004 En ligne : http://dx.doi.org/10.1016/j.asr.2016.05.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81747
in Advances in space research > vol 58 n° 4 (August 2016) . - pp 564 - 576[article]GBAS ionospheric threat model assessment for category I operation in the Korean region / Minchan Kim in GPS solutions, vol 19 n° 3 (July 2015)
[article]
Titre : GBAS ionospheric threat model assessment for category I operation in the Korean region Type de document : Article/Communication Auteurs : Minchan Kim, Auteur ; Yunjung Choi, Auteur ; Hyang-Sig Jun, Auteur ; Jiyun Lee, Auteur Année de publication : 2015 Article en page(s) : pp 443 - 456 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] Corée du sud
[Termes IGN] gradient ionosphèrique
[Termes IGN] perturbation ionosphérique
[Termes IGN] système d'extension au solRésumé : (auteur) During extreme ionospheric storms, anomalous ionospheric gradients can become high enough to affect Global Navigation Satellite Systems (GNSS) Ground-Based Augmentation Systems (GBAS) and to threaten the safety of GBAS users. An ionospheric anomaly threat model for the Conterminous United States (CONUS) was developed based on extreme ionospheric gradients observed in CONUS during the last solar maximum period (2000–2004). However, in order to understand and mitigate ionosphere threats occurring in different geographical regions, ionospheric anomaly threat models have to be established for the relevant regions. To allow the certification of a GBAS ground facility in South Korea, a Korean ionospheric anomaly threat model must be determined. We describe the method of data analysis that was used to estimate ionospheric spatial gradients. Estimates of anomalous gradients in the Korean region were used to define and build an ionospheric anomaly threat model for this region. All gradient estimates obtained using Korean GNSS reference network data for potential ionospheric storm dates from 2000 to 2004 were included in this threat space. The maximum spatial gradient within this threat space is 160 mm of delay per km of user separation, which falls well within the bounds of the current ionospheric threat model for CONUS. We also provide a detailed examination of the two largest ionospheric spatial gradient events observed in this study, which occurred on November 10, 2004, and November 6, 2001, respectively. Numéro de notice : A2015-463 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-014-0404-6 En ligne : https://doi.org/10.1007/s10291-014-0404-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77144
in GPS solutions > vol 19 n° 3 (July 2015) . - pp 443 - 456[article]Wuhan ionospheric oblique-incidence sounding system and its new application in localization of ionospheric irregularities / Shu-Zhu Shi in IEEE Transactions on geoscience and remote sensing, vol 53 n° 4 (April 2015)
[article]
Titre : Wuhan ionospheric oblique-incidence sounding system and its new application in localization of ionospheric irregularities Type de document : Article/Communication Auteurs : Shu-Zhu Shi, Auteur ; Gang Chen, Auteur ; Guo-Bin Yang, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 2185 - 2194 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] écho radar
[Termes IGN] forme d'onde
[Termes IGN] ionosphère
[Termes IGN] perturbation ionosphérique
[Termes IGN] positionnement différentiel
[Termes IGN] sonde spatialeRésumé : (Auteur) In this paper, a novel oblique-incidence ionosonde (Wuhan Ionospheric Oblique-Incidence Sounding System) and its new application in the localization of the ionospheric irregularities are presented. Due to the usage of the binary-phase-coded waveform, a large signal processing gain, a high Doppler and range resolution, and a large unambiguous detection range can be achieved in this ionosonde. This ionosonde also adopts the peripheral component interconnect extensions for instruments (PXI) bus technology and is designed as a small-sized PXI-based system. Furthermore, a high-performance oven-controlled crystal oscillator that is disciplined by the Global Positioning System is used to achieve a good time and frequency synchronization. With multichannel digital receiver and multiple receiving sites, this ionosonde can be applied in the localization of the ionospheric irregularities. The details of the system configuration, the ambiguity function of the sounding waveforms, the signal processing algorithm, and the time and frequency synchronization method are described. The experimental results show that the virtual height along with the ground position of the ionospheric field-aligned irregularities can be preliminarily localized with this ionosonde. Numéro de notice : A2015-176 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2014.2357443 Date de publication en ligne : 26/09/2014 En ligne : https://doi.org/10.1109/TGRS.2014.2357443 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=75895
in IEEE Transactions on geoscience and remote sensing > vol 53 n° 4 (April 2015) . - pp 2185 - 2194[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-2015041 RAB Revue Centre de documentation En réserve L003 Disponible Climatological study of ionospheric irregularities over the European mid-latitude sector with GPS / Gilles Wautelet in Journal of geodesy, vol 88 n° 3 (March 2014)
[article]
Titre : Climatological study of ionospheric irregularities over the European mid-latitude sector with GPS Type de document : Article/Communication Auteurs : Gilles Wautelet, Auteur ; René Warnant, Auteur Année de publication : 2014 Article en page(s) : pp 223 - 240 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] analyse diachronique
[Termes IGN] Belgique
[Termes IGN] données GPS
[Termes IGN] Europe (géographie politique)
[Termes IGN] perturbation ionosphérique
[Termes IGN] teneur totale en électrons
[Termes IGN] variation
[Termes IGN] variation temporelleRésumé : (Auteur) High-frequency variability of the ionosphere, or irregularities, constitutes the main threat for real-time precise positioning techniques based on Global Navigation Satellite Systems (GNSS) measurements. Indeed, during periods of enhanced ionospheric variability, GNSS users in the field—who cannot verify the integrity of their measurements—will experience positioning errors that can reach several decimeters, while the nominal accuracy of the technique is cm-level. In the frame of this paper, a climatological analysis of irregularities over the European mid-latitude region is presented. Based on a 10 years GPS dataset over Belgium, the work analyzes the occurrence rate (as a function of the solar cycle, season and local time) as well as the amplitude of ionospheric irregularities observed at a single GPS station. The study covers irregularities either due to space weather events (solar origin) or of terrestrial origin. If space weather irregularities are responsible for the largest effects in terms of ionospheric error, their occurrence rate highly depends on solar activity. Indeed, the occurrence rate of ionospheric irregularities is about 9 % during solar maximum, whereas it drops to about 0 % during medium or low solar activity periods. Medium-scale ionospheric disturbances (MSTIDs) occurring during daytime in autumn/winter are the most recurrent pattern of the time series, with yearly proportions slightly varying with the solar cycle and an amplitude of about 10 % of the TEC background. Another recurrent irregularity type, though less frequent than MSTIDs, is the noise-like variability in TEC observed during summer nighttime, under quiet geomagnetic conditions. These summer nighttime irregularities exhibit amplitudes ranging between 8 and 15 % of the TEC background. Numéro de notice : A2014-133 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0678-4 Date de publication en ligne : 11/12/2013 En ligne : https://doi.org/10.1007/s00190-013-0678-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33038
in Journal of geodesy > vol 88 n° 3 (March 2014) . - pp 223 - 240[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2014031 SL Revue Centre de documentation Revues en salle Disponible GNSS ambiguity resolution with controllable failure rate for long baseline network RTK / Bofeng Li in Journal of geodesy, vol 88 n° 2 (February 2014)
[article]
Titre : GNSS ambiguity resolution with controllable failure rate for long baseline network RTK Type de document : Article/Communication Auteurs : Bofeng Li, Auteur ; Yunzhong Shen, Auteur ; Yanming Feng, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 99 - 112 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Continuously Operating Reference Station network
[Termes IGN] filtre de Kalman
[Termes IGN] modèle ionosphérique
[Termes IGN] perturbation ionosphérique
[Termes IGN] résolution d'ambiguïté
[Termes IGN] station de référence
[Termes IGN] traitement de données GNSS
[Vedettes matières IGN] Traitement de données GNSSRésumé : (Auteur) Many large-scale GNSS CORS networks have been deployed around the world to support various commercial and scientific applications. To make use of these networks for real-time kinematic positioning services, one of the major challenges is the ambiguity resolution (AR) over long inter-station baselines in the presence of considerable atmosphere biases. Usually, the widelane ambiguities are fixed first, followed by the procedure of determination of the narrowlane ambiguity integers based on the ionosphere-free model in which the widelane integers are introduced as known quantities. This paper seeks to improve the AR performance over long baseline through efficient procedures for improved float solutions and ambiguity fixing. The contribution is threefold: (1) instead of using the ionosphere-free measurements, the absolute and/or relative ionospheric constraints are introduced in the ionosphere-constrained model to enhance the model strength, thus resulting in the better float solutions; (2) the realistic widelane ambiguity precision is estimated by capturing the multipath effects due to the observation complexity, leading to improvement of reliability of widelane AR; (3) for the narrowlane AR, the partial AR for a subset of ambiguities selected according to the successively increased elevation is applied. For fixing the scalar ambiguity, an error probability controllable rounding method is proposed. The established ionosphere-constrained model can be efficiently solved based on the sequential Kalman filter. It can be either reduced to some special models simply by adjusting the variances of ionospheric constraints, or extended with more parameters and constraints. The presented methodology is tested over seven baselines of around 100 km from USA CORS network. The results show that the new widelane AR scheme can obtain the 99.4 % successful fixing rate with 0.6 % failure rate; while the new rounding method of narrowlane AR can obtain the fix rate of 89 % with failure rate of 0.8 %. In summary, the AR reliability can be efficiently improved with rigorous controllable probability of incorrectly fixed ambiguities. Numéro de notice : A2014-138 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0670-z Date de publication en ligne : 15/11/2013 En ligne : https://doi.org/10.1007/s00190-013-0670-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33043
in Journal of geodesy > vol 88 n° 2 (February 2014) . - pp 99 - 112[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-2014021 SL Revue Centre de documentation Revues en salle Disponible Performance evaluation of USTEC product for single-frequency precise point positioning / Mahmoud Abd-El-Rahman in Geomatica, vol 67 n° 4 (December 2013)PermalinkSingle-receiver single-channel multi-frequency GNSS integrity: outliers, slips, and ionospheric disturbances / Peter J.G. Teunissen in Journal of geodesy, vol 87 n° 2 (February 2013)PermalinkIonospheric scintillations: How irregularities in electron density perturb satellite navigation systems / Satellite-based augmentation system ionospheric working group in GPS world, vol 23 n° 4 (April 2012)PermalinkThe ionosphere : effects, GPS modeling and the benefits for space geodetic techniques / Manuel Hernández-Pajares in Journal of geodesy, vol 85 n° 12 (December 2011)PermalinkHigh-precision GNSS receivers / N. Blanco-Delgado in GIM international, vol 25 n° 11 (November 2011)PermalinkGNSS and the Ionosphere: What's in Store for the Next Solar Maximum? / A. Jensen in GPS world, vol 22 n° 2 (February 2011)PermalinkIonospheric response to the geomagnetic storm on august 21, 2003 over China using GNSS-based tomographic technique / D. Wen in IEEE Transactions on geoscience and remote sensing, vol 48 n° 8 (August 2010)PermalinkStudies of the electromagnetic field variations in ELF frequency range registred by DEMETER over the Sichuan region prior to the 12 mays 2008 earthquake / J. Blecki in International Journal of Remote Sensing IJRS, vol 31 n° 13 (July /2010)PermalinkGNSS and ionospheric scintillation: how to survive the next solar maximum / P. Kintner in Inside GNSS, vol 4 n° 4 (July - August 2009)PermalinkThe wavelet method as an alternative for reducing ionospheric effects from single-frequency GPS receivers / E.M. DE Souza in Journal of geodesy, vol 81 n° 12 (December 2007)Permalink