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Design drivers and new trends for navigation message authentication schemes for GNSS systems / Gianluca Caparra in Inside GNSS, vol 11 n° 5 (September - October 2016)
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Titre : Design drivers and new trends for navigation message authentication schemes for GNSS systems Type de document : Article/Communication Auteurs : Gianluca Caparra, Auteur ; Christian Wullems, Auteur ; Silvia Ceccato, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 64 - 73 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] authentification
[Termes IGN] sécurité informatique
[Termes IGN] signal GNSSRésumé : (auteur) GNSS has become a mature technology yielding reliable position, navigation and timing solutions upon which many applications are built. Its widespread adoption has turned into an incentive for malicious actions that, by exploiting GNSS vulnerabilities, aim at either disrupting or precisely modifying the PNT computation. Authenticating the GNSS signal at both the ranging and data levels is a proper way to detect and/or mitigate such threats. This article discusses the design drivers for GNSS authentication, reviews the predominant navigation message authentication proposals for a GNSS open service, and proposes a novel scheme based on the amortization of digital signatures. Numéro de notice : A2016-964 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans En ligne : http://www.insidegnss.com/node/5101 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83614
in Inside GNSS > vol 11 n° 5 (September - October 2016) . - pp 64 - 73[article]Generating GPS satellite fractional cycle bias for ambiguity-fixed precise point positioning / Pan Li in GPS solutions, vol 20 n° 4 (October 2016)
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Titre : Generating GPS satellite fractional cycle bias for ambiguity-fixed precise point positioning Type de document : Article/Communication Auteurs : Pan Li, Auteur ; Xiaohong Zhang, Auteur ; Xiaodong Ren, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 771 - 782 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] données GRACE
[Termes IGN] erreur systématique
[Termes IGN] positionnement ponctuel précis
[Termes IGN] résolution d'ambiguïtéRésumé : (Auteur) With the development of precise point positioning (PPP), the School of Geodesy and Geomatics (SGG) at Wuhan University is now routinely producing GPS satellite fractional cycle bias (FCB) products with open access for worldwide PPP users to conduct ambiguity-fixed PPP solution. We provide a brief theoretical background of PPP and present the strategies and models to compute the FCB products. The practical realization of the two-step (wide-lane and narrow-lane) FCB estimation scheme is described in detail. With GPS measurements taken in various situations, i.e., static, dynamic, and on low earth orbit (LEO) satellites, the quality of FCB estimation and the effectiveness of PPP ambiguity resolution (AR) are evaluated. The comparison with CNES FCBs indicated that our FCBs had a good consistency with the CNES ones. For wide-lane FCB, almost all the differences of the two products were within ±0.05 cycles. For narrow-lane FCB, 87.8 % of the differences were located between ±0.05 cycles, and 97.4 % of them were located between ±0.075 cycles. The experimental results showed that, compared with conventional ambiguity-float PPP, the averaged position RMS of static PPP can be improved from (3.6, 1.4, 3.6) to (2.0, 1.0, 2.7) centimeters for ambiguity-fixed PPP. The average accuracy improvement in the east, north, and up components reached 44.4, 28.6, and 25.0 %, respectively. A kinematic, ambiguity-fixed PPP test with observation of 80 min achieved a position accuracy of better than 5 cm at the one-sigma level in all three coordinate components. Compared with the results of ambiguity-float, kinematic PPP, the positioning biases of ambiguity-fixed PPP were improved by about 78.2, 20.8, and 65.1 % in east, north, and up. The RMS of LEO PPP test was improved by about 23.0, 37.0, and 43.0 % for GRACE-A and GRACE-B in radial, tangential, and normal directions when AR was applied to the same data set. These results demonstrated that the SGG FCB products can be produced with high quality for users anywhere around the world to carry out ambiguity-fixed PPP solutions. Numéro de notice : A2016--029 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-015-0483-z En ligne : http://dx.doi.org/10.1007/s10291-015-0483-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83931
in GPS solutions > vol 20 n° 4 (October 2016) . - pp 771 - 782[article]Long-term soil moisture dynamics derived from GNSS interferometric reflectometry: a case study for Sutherland, South Africa / Sibylle Vey in GPS solutions, vol 20 n° 4 (October 2016)
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Titre : Long-term soil moisture dynamics derived from GNSS interferometric reflectometry: a case study for Sutherland, South Africa Type de document : Article/Communication Auteurs : Sibylle Vey, Auteur ; Jens Wickert, Auteur Année de publication : 2016 Article en page(s) : pp 641 - 654 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] Afrique du sud (état)
[Termes IGN] analyse diachronique
[Termes IGN] humidité du sol
[Termes IGN] rapport signal sur bruit
[Termes IGN] récepteur GNSS
[Termes IGN] réflectométrie par GNSS
[Termes IGN] signal GNSS
[Termes IGN] variation temporelleRésumé : (Auteur) Soil moisture is a geophysical key observable for predicting floods and droughts, modeling weather and climate and optimizing agricultural management. Currently available in situ observations are limited to small sampling volumes and restricted number of sites, whereas measurements from satellites lack spatial resolution. Global navigation satellite system (GNSS) receivers can be used to estimate soil moisture time series at an intermediate scale of about 1000 m2. In this study, GNSS signal-to-noise ratio (SNR) data at the station Sutherland, South Africa, are used to estimate soil moisture variations during 2008–2014. The results capture the wetting and drying cycles in response to rainfall. The GNSS Volumetric Water Content (VWC) is highly correlated (r2 = 0.8) with in situ observations by time-domain reflectometry sensors and is accurate to 0.05 m3/m3. The soil moisture estimates derived from the SNR of the L1 and L2P signals compared to the L2C show small differences with a RMSE of 0.03 m3/m3. A reduction in the SNR sampling rate from 1 to 30 s has very little impact on the accuracy of the soil moisture estimates (RMSE of the VWC difference 1–30 s is 0.01 m3/m3). The results show that the existing data of the global tracking network with continuous observations of the L1 and L2P signals with a 30-s sampling rate over the last two decades can provide valuable complementary soil moisture observations worldwide. Numéro de notice : A2016--026 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-015-0474-0 En ligne : http://dx.doi.org/10.1007/s10291-015-0474-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83927
in GPS solutions > vol 20 n° 4 (October 2016) . - pp 641 - 654[article]A new ZTD model based on permanent ground-based GNSS-ZTD data / M. Ding in Survey review, vol 48 n° 351 (October 2016)
[article]
Titre : A new ZTD model based on permanent ground-based GNSS-ZTD data Type de document : Article/Communication Auteurs : M. Ding, Auteur ; W. Hu, Auteur ; X. Jin, Auteur ; L. Yu, Auteur Année de publication : 2016 Article en page(s) : pp 385 - 391 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] correction troposphérique
[Termes IGN] données GNSS
[Termes IGN] réseau neuronal artificiel
[Termes IGN] retard troposphérique zénithal
[Termes IGN] RussieRésumé : (Auteur) Tropospheric delay has a major effect on the accuracy of navigation and positioning when using the Global Navigation Satellite System (GNSS). Zenith tropospheric delay (ZTD) modelling has been used to weaken the influence of the atmosphere. The work reported here focused on ZTD modelling based on real-time surface meteorological parameters, traditionally represented by the Saastamoinen model. However, Saastamoinen accuracy only reaches scale of centimetres, even to scale of centimetres when the water vapour is active, whereas the scale of ground-based GNSS-ZTD data (i.e. ZTD derived from ground GNSS data) is on the millimetre scale and is considered to be the ‘true’ value. An important direction in GNSS studies is how to make good use of ground-based GNSS-ZTD data to improve the accuracy of the Saastamoinen model. Authors studied the residuals in the Saastamoinen model using high-precision GNSS-ZTD data provided by the International GNSS Service (IGS) product and then carried out modelling based on a back propagation neural network. A new ZTD model (ISAAS) based on real-time surface meteorological parameters is proposed based on this method. The ISAAS model has good accuracy: its BIAS and root mean square error (RMSE) at the test area in Russia were -4.4 and 20.4 mm, respectively, which are lower than the results obtained using the Saastamoinen model (-10.4 and 23.3 mm, respectively). The ISAAS model can improve the ZTD prediction accuracy by more than 12.4% and therefore has important implications for precision engineering measurements in Russia. Numéro de notice : A2016-821 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1179/1752270615Y.0000000034 En ligne : https://doi.org/10.1179/1752270615Y.0000000034 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82636
in Survey review > vol 48 n° 351 (October 2016) . - pp 385 - 391[article]On the significance of periodic signals in noise analysis of GPS station coordinates time series / Janusz Bogusz in GPS solutions, vol 20 n° 4 (October 2016)
[article]
Titre : On the significance of periodic signals in noise analysis of GPS station coordinates time series Type de document : Article/Communication Auteurs : Janusz Bogusz, Auteur ; Anna Klos, Auteur Année de publication : 2016 Article en page(s) : pp 655 - 664 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] analyse diachronique
[Termes IGN] bruit (théorie du signal)
[Termes IGN] coordonnées cartésiennes géocentriques
[Termes IGN] GIPSY-OASIS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] série temporelle
[Termes IGN] signal GPS
[Termes IGN] station GPS
[Termes IGN] variation saisonnière
[Termes IGN] vitesseRésumé : (Auteur) Each of the GPS-derived time series consists of the deterministic (functional) and stochastic part. We propose that the deterministic part includes all periodicities from 1st to 9th harmonics of residual Chandler, tropical and draconitic periods and compare it with commonly used calculations of the annual and semi-annual tropical curve. Then, we address the issues of whether all residual periodicities, as proposed here, need to be taken into consideration when performing noise analysis. We use the position time series from 180 International GNSS Service stations obtained at the Jet Propulsion Laboratory using the GIPSY-OASIS software in a Precise Point Positioning mode. The longest series has 22.1 years of GPS daily solutions. The spectral indices range from –0.12 to –0.92, while the median values of “global” spectral indices are equal to: –0.41 ± 0.15, –0.38 ± 0.12 and –0.33 ± 0.18 for North, East and Up components, respectively. All non-modelled geophysical processes or non-included artificial effects in time series lead to an underestimation of errors of velocities, but also to changes in the velocity values themselves. The proposed assumption of seasonals subtraction caused the Akaike information criterion values to show a decrease in the median value of 30 %, which in fact means that all the seasonals mentioned here must be taken into account when analyzing noises. Finally, we noticed that there are some of the GPS stations that improved their velocity uncertainty even of 56 %. Numéro de notice : A2016--027 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-015-0478-9 En ligne : http://dx.doi.org/10.1007/s10291-015-0478-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83929
in GPS solutions > vol 20 n° 4 (October 2016) . - pp 655 - 664[article]Outlier detection by using fault detection and isolation techniques in geodetic networks / U.M. Durdag in Survey review, vol 48 n° 351 (October 2016)PermalinkA conventional value for the geoid reference potential W0 / L. Sánchez in Journal of geodesy, vol 90 n° 9 (September 2016)PermalinkGalileo cycle-slip detection : How four frequencies help when the ionosphere is disturbed / Laura Van de Vyver in GPS world, vol 27 n° 9 (September 2016)PermalinkGNSS interferometric radio occultation / Manuel Martín-Neira in IEEE Transactions on geoscience and remote sensing, vol 54 n° 9 (September 2016)PermalinkMonitoring the oldest datum / John Stenmark in GEO: Geoconnexion international, vol 15 n° 8 (September 2016)PermalinkA novel methodology for identifying environmental exposures using GPS data / Andreea Cetateanu in International journal of geographical information science IJGIS, vol 30 n° 9-10 (September - October 2016)PermalinkReal-time cycle-slip detection and repair for BeiDou triple-frequency undifferenced observations / Y.-F. Yao in Survey review, vol 48 n° 350 (September 2016)PermalinkTaking correlations in GPS least squares adjustments into account with a diagonal covariance matrix / Gaël Kermarrec in Journal of geodesy, vol 90 n° 9 (September 2016)PermalinkUse of a GPS-derived troposphere model to improve InSAR deformation estimates in the San Gabriel Valley, California / Nicolas Houlié in IEEE Transactions on geoscience and remote sensing, vol 54 n° 9 (September 2016)PermalinkA new method to improve the performance of multi-GNSS pseudorange positioning in signal-degraded environment / Hui Liu in Advances in space research, vol 58 n° 4 (August 2016)PermalinkAutomatic extraction of road networks from GPS traces / Jia Qiu in Photogrammetric Engineering & Remote Sensing, PERS, vol 82 n° 8 (August 2016)PermalinkEstimation of satellite antenna phase center offsets for Galileo / Peter Steigenberger in Journal of geodesy, vol 90 n° 8 (August 2016)PermalinkGalileo and the Brexit effect : Tension grows over the public regulated service / Tim Reynolds in GPS world, vol 27 n° 8 (August 2016)PermalinkA geometry-free and ionosphere-free multipath mitigation method for BDS three-frequency ambiguity resolution / Dezhong Chen in Journal of geodesy, vol 90 n° 8 (August 2016)PermalinkInterference mitigation in the E5A Galileo band using an open-source simulator / Diego Alonso in Inside GNSS, vol 11 n° 4 (July - August 2016)PermalinkBenefits of the third frequency signal on cycle slip correction / Xiaohong Zhang in GPS solutions, vol 20 n° 3 (July 2016)PermalinkA closed-form formula to calculate geometric dilution of precision (GDOP) for multi-GNSS constellations / Yunlong Teng in GPS solutions, vol 20 n° 3 (July 2016)PermalinkA comparative analysis of measurement noise and multipath for four constellations: GPS, BeiDou, GLONASS and Galileo / Changsheng Cai in Survey review, vol 48 n° 349 (July 2016)PermalinkDirection-of-arrival estimation of VHF signals recorded on the international space station and simultaneous observations of optical lightning / Hiroshi Kikuchi in IEEE Transactions on geoscience and remote sensing, vol 54 n° 7 (July 2016)PermalinkIdentifying a low-frequency oscillation in Galileo IOV pseudorange rates / Daniele Borio in GPS solutions, vol 20 n° 3 (July 2016)Permalink