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It's not all bad, understanding and using GNSS multipath / A. Bilich in GPS world, vol 20 n° 10 (October 2009)

Public [article]  inGPS world > vol 20 n° 10 (October 2009) . - pp 31 - 39 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 multiple Résumé : (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 [article]

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