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Testing software receivers / A. Mitelman in GPS world, vol 20 n° 12 (December 2009)
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Titre : Testing software receivers Type de document : Article/Communication Auteurs : A. Mitelman, Auteur ; J. Almqvist, Auteur ; R. Hakanson, Auteur ; et al., Auteur Année de publication : 2009 Article en page(s) : pp 28 - 34 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] analyse comparative
[Termes IGN] instrument de géodésie
[Termes IGN] logiciel de post-traitement GPS
[Termes IGN] récepteur GPS
[Termes IGN] traitement de données GNSS
[Termes IGN] validité des donnéesRésumé : (Auteur) To meet the challenges inherent in producing a low-cost, highly CPU-efficient software receiver, the multiple offset post-processing method leverages the unique features of software GNSS to greatly improve the coverage and statistical validity of receiver testing compared to traditional, hardware-based testing setups, in some cases by an order of magnitude or more. Copyright Questex Media Group Numéro de notice : A2009-479 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30108
in GPS world > vol 20 n° 12 (December 2009) . - pp 28 - 34[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-09121 SL Revue Centre de documentation Revues en salle Disponible Coherent integration time : the longer, the better / T. Pany in Inside GNSS, vol 4 n° 6 (November - December 2009)
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Titre : Coherent integration time : the longer, the better Type de document : Article/Communication Auteurs : T. Pany, Auteur ; Bernhard Riedl, Auteur ; J. Winkel, Auteur Année de publication : 2009 Article en page(s) : 10 p. ; pp 52 - 61 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] centrale inertielle
[Termes IGN] filtre de Kalman
[Termes IGN] géonavigateur
[Termes IGN] GPS assisté pour la navigation (technologies)
[Termes IGN] intégration de données
[Termes IGN] magnétomètre
[Termes IGN] navigation à l'estime
[Termes IGN] positionnement en intérieur
[Termes IGN] positionnement par WiFi
[Termes IGN] prototype
[Termes IGN] récepteur GNSS
[Termes IGN] récepteur GPS
[Termes IGN] traitement du signal
[Termes IGN] WiFiRésumé : (Auteur) A common assumption in GNSS receiver design is that the coherent integration time should be less than a few dozens of milliseconds. This makes perfect sense for today’s commercial receivers due to data bit transitions, oscillator jitter, and user dynamics. However, a coherent integration time of several seconds would mitigate three important indoor positioning problems: multipath, cross-correlation false locks, and the squaring loss. Extending the integration time has a price, typically requiring an assistance data link providing data bits (or the use of pilot signals), a stable oscillator, and a sophisticated GNSS/INS integration to compensate for non-linear user motion. This column describes how those issues have been solved and the resulting benefits as demonstrated by a recently built prototype with a sensitivity of around 1.5 dBHz , more than 10 decibels beyond the current state of the art. Copyright Gibbons Media & Research LLC Numéro de notice : A2009-670 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33552
in Inside GNSS > vol 4 n° 6 (November - December 2009) . - 10 p. ; pp 52 - 61[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 159-09061 SL Revue Centre de documentation Revues en salle Disponible Documents numériques
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Coherent integration time ... - pdf éditeurAdobe Acrobat PDF Improving the GNSS positioning stochastic model in the presence of ionospheric scintillation / M. Aquino in Journal of geodesy, vol 83 n° 10 (October 2009)
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Titre : Improving the GNSS positioning stochastic model in the presence of ionospheric scintillation Type de document : Article/Communication Auteurs : M. Aquino, Auteur ; João F.G. Monico, Auteur ; A.H. Dodson, Auteur ; et al., Auteur Année de publication : 2009 Article en page(s) : pp 953 - 966 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] modèle stochastique
[Termes IGN] positionnement par GNSS
[Termes IGN] propagation ionosphérique
[Termes IGN] récepteur GNSS
[Termes IGN] scintillation
[Termes IGN] teneur totale en électronsRésumé : (Auteur) Ionospheric scintillations are caused by time- varying electron density irregularities in the ionosphere, occurring more often at equatorial and high latitudes. This paper focuses exclusively on experiments undertaken in Europe, at geographic latitudes between ~50°N and ~80°N, where a network of GPS receivers capable of monitoring Total Electron Content and ionospheric scintillation parameters was deployed. The widely used ionospheric scintillation indices S4 and {\sigma_{\varphi}} represent a practical measure of the intensity of amplitude and phase scintillation affecting GNSS receivers. However, they do not provide sufficient information regarding the actual tracking errors that degrade GNSS receiver performance. Suitable receiver tracking models, sensitive to ionospheric scintillation, allow the computation of the variance of the output error of the receiver PLL (Phase Locked Loop) and DLL (Delay Locked Loop), which expresses the quality of the range measurements used by the receiver to calculate user position. The ability of such models of incorporating phase and amplitude scintillation effects into the variance of these tracking errors underpins our proposed method of applying relative weights to measurements from different satellites. That gives the least squares stochastic model used for position computation a more realistic representation, vis-a-vis the otherwise ‘equal weights’ model. For pseudorange processing, relative weights were com- puted, so that a ‘scintillation-mitigated’ solution could be performed and compared to the (non-mitigated) ‘equal weights’ solution. An improvement between 17 and 38% in height accuracy was achieved when an epoch by epoch differential solution was computed over baselines ranging from 1 to 750 km. The method was then compared with alternative approaches that can be used to improve the least squares stochastic model such as weighting according to satellite elevation angle and by the inverse of the square of the standard deviation of the code/carrier divergence (sigma CCDiv). The influence of multipath effects on the proposed mitigation approach is also discussed. With the use of high rate scintillation data in addition to the scintillation indices a carrier phase based mitigated solution was also implemented and compared with the conventional solution. During a period of occurrence of high phase scintillation it was observed that problems related to ambiguity resolution can be reduced by the use of the proposed mitigated solution. Copyright Springer Numéro de notice : A2009-430 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-009-0313-6 En ligne : https://doi.org/10.1007/s00190-009-0313-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30061
in Journal of geodesy > vol 83 n° 10 (October 2009) . - pp 953 - 966[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-09091 SL Revue Centre de documentation Revues en salle Disponible It's not all bad, understanding and using GNSS multipath / A. Bilich in GPS world, vol 20 n° 10 (October 2009)
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Titre : It's not all bad, understanding and using GNSS multipath Type de document : Article/Communication Auteurs : A. Bilich, Auteur ; K. Larson, Auteur Année de publication : 2009 Article en page(s) : pp 31 - 39 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal
[Termes IGN] humidité du sol
[Termes IGN] mesurage de phase
[Termes IGN] positionnement par GNSS
[Termes IGN] rapport signal sur bruit
[Termes IGN] récepteur GNSS
[Termes IGN] trajet multipleRésumé : (Editeur) [...] Although the FM "capture effect" provides some margin against multipath, it is not uncommon to lose stereo reception or to experience fading out of the signal while driving in built-up areas as a result of reflections. This same multipath phenomenon also affects GNSS signals. Unlike satellite TV antennas, the antennas feeding our GNSS receivers are omnidirectional. So we have the possibility of not only receiving a direct, line-of-sight signal from a GNSS satellite but also any indirect signal from the satellite that gets reflected off nearby buildings or other objects or even the ground. GNSS antenna and receiver manufacturers have developed techniques to minimize the impact of multipath on the GNSS observables. Nevertheless, there is typically some residual multipath afflicting the pseudorange and carrier-phase observables that limits the precision and accuracy of position determinations. Telltale signs of multipath are the quasi-periodic fluctuations in the signal-to-noise ratios (SNRs) reported by some GNSS receivers, and in this month's column, we learn how an analysis of SNR values can be used to map and better understand the multipath environment surrounding an antenna. And, although an annoyance for most GNSS users, it turns out that multipath is not all bad. By analyzing the SNR fluctuations due to multipath, characteristics of the reflector can be deduced. If the reflector is the ground, then the amount of moisture in the soil can be measured. GNSS for measuring soil moisture? Who would have thought? Copyright Questex Media Group Numéro de notice : A2009-448 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30079
in GPS world > vol 20 n° 10 (October 2009) . - pp 31 - 39[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-09101 SL Revue Centre de documentation Revues en salle Disponible CONGO: First GPS/GIOVE tracking network for science, research / Oliver Montenbruck in GPS world, vol 20 n° 9 (September 2009)
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Titre : CONGO: First GPS/GIOVE tracking network for science, research Type de document : Article/Communication Auteurs : Oliver Montenbruck, Auteur ; André Hauschild, Auteur ; U. Hessels, Auteur ; Peter Steigenberger, Auteur ; Urs Hugentobler, Auteur Année de publication : 2009 Article en page(s) : 7 p. ; pp 56 - 62 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] récepteur GNSS
[Termes IGN] station de poursuiteRésumé : (Auteur)/d'éditeur : Selected results from the COoperative Network for GIOVE Observation (CONGO) demonstrate how the global network provides early familiarization with the new Galileo signals and access to precise GIOVE orbit and clock information, to develop new processing techniques for multi-constellation, multi-frequency GNSS. Initial results from CONGO, the first network of GNSS receivers for scientific applications offering combined GPS and GIOVE tracking on a continuous and global level, demonstrate orbit determination of the GIOVE satellites at an accuracy level of 1 meter. The resulting products will enable a combined positioning using GPS/GIOVE or GPS/GLONASS/GIOVE measurements now provided by the latest geodetic GNSS receivers. The generation of real-time orbit and clock products is under development. They will help to bridge gaps in the availability of broadcast ephemerides and will enable continuous navigation with the GIOVE satellites. In the next year, at least two new stations will be added to the CONGO network. This will further enhance robustness and improve overall quality of network products. Copyright Questex Media Group Numéro de notice : A2009-349 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29979
in GPS world > vol 20 n° 9 (September 2009) . - 7 p. ; pp 56 - 62[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 067-09091 SL Revue Centre de documentation Revues en salle Disponible GNSS update: interface control / Huibert-Jan Lekkerkerk in Geoinformatics, vol 12 n° 6 (01/09/2009)PermalinkThe soft approach: a recipe for a multi-system, multi-frequency GNSS receiver / Cillian O'Driscoll in Inside GNSS, vol 4 n° 5 (September - October 2009)PermalinkHigh-sensitivity GPS: an availability, reliability and accuracy test / V. Schweiger in Bulletin des sciences géographiques, n° 23 (juin 2009)PermalinkUtilisation d'un SIG nomade couplé à un GPS pour cartographier les paysages du Sud-Ouest toulousain / Yves Auda in XYZ, n° 119 (juin - août 2009)PermalinkDeux ponts sous contrôle GNSS / M. Mayo in Géomètre, n° 2058 (avril 2009)PermalinkInternational Heliophysical Year: GPS Network in Africa / C. Amory-Mazaudier in Earth, Moon, and Planets, vol 104 n° 1-4 (April 2009)PermalinkCombs filtering: improving acquisition and tracking in GNSS receivers / A. Dempster in GPS world, vol 20 n° 3 (March 2009)PermalinkThe design and the development of a hyperspectral and multispectral airborne mapping system / P.V. Gorsevski in ISPRS Journal of photogrammetry and remote sensing, vol 64 n° 2 (March - April 2009)PermalinkThe effects of navigation sensors and spatial road network data quality on the performance of map matching algorithms / M. Quddus in Geoinformatica, vol 13 n° 1 (March 2009)PermalinkGNSS antennas: an introduction to bandwidth, Gain pattern, polarization, and all that / J. Moernaut in GPS world, vol 20 n° 2 (February 2009)Permalink