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Multi-frequency quadrifilar helix antennas for cm-accurate GNSS positioning / Lambert Wanninger in Journal of applied geodesy, vol 16 n° 1 (January 2022)  

Public [article]  inJournal of applied geodesy > vol 16 n° 1 (January 2022) . - pp 25 - 35 Titre : Multi-frequency quadrifilar helix antennas for cm-accurate GNSS positioning Type de document : Article/Communication Auteurs : Lambert Wanninger, Auteur ; Melanie Thiemig, Auteur ; Walker Frevert, Auteur Année de publication : 2022 Article en page(s) : pp 25 - 35 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] antenne GNSS [Termes IGN] bruit (théorie du signal) [Termes IGN] étalonnage d'instrument [Termes IGN] fréquence multiple [Termes IGN] phase GNSS [Termes IGN] positionnement par GNSS [Termes IGN] précision centimétrique [Termes IGN] signal GNSS [Termes IGN] trajet multiple Résumé : (auteur) For a few years now, GNSS multi-frequency quadrifilar helix antennas (QHA) are available to be used for precise GNSS applications. We performed test measurements with two types of multi-frequency QHA and compared them with a geodetic patch antenna. Although code and carrier phase noise and high-frequent multipath was determined to be larger as compared to the geodetic antenna, the fast-static horizontal coordinate accuracies are on the same level and demonstrate cm-accuracy capability. One of the QHA types exhibited an increased susceptibility to near-field multipath effects which resulted in a degraded accuracy of the vertical coordinate component. Numéro de notice : A2022-054 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2021-0042 Date de publication en ligne : 15/09/2021 En ligne : https://doi.org/10.1515/jag-2021-0042 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99449 [article]

Group delay variations of GPS transmitting and receiving antennas / Lambert Wanninger in Journal of geodesy, vol 91 n° 9 (September 2017)  

Public [article]  inJournal of geodesy > vol 91 n° 9 (September 2017) . - pp 1099 – 1116 Titre : Group delay variations of GPS transmitting and receiving antennas Type de document : Article/Communication Auteurs : Lambert Wanninger, Auteur ; Hael Sumaya, Auteur ; Susanne Beer, Auteur Année de publication : 2017 Article en page(s) : pp 1099 – 1116 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal [Termes IGN] code GPS [Termes IGN] constellation GPS [Termes IGN] erreur [Termes IGN] ionosphère [Termes IGN] mesurage de pseudo-distance [Termes IGN] phase GPS [Termes IGN] récepteur bifréquence [Termes IGN] récepteur GPS [Termes IGN] signal GPS [Termes IGN] teneur totale en électrons Résumé : (auteur) GPS code pseudorange measurements exhibit group delay variations at the transmitting and the receiving antenna. We calibrated C1 and P2 delay variations with respect to dual-frequency carrier phase observations and obtained nadir-dependent corrections for 32 satellites of the GPS constellation in early 2015 as well as elevation-dependent corrections for 13 receiving antenna models. The combined delay variations reach up to 1.0 m (3.3 ns) in the ionosphere-free linear combination for specific pairs of satellite and receiving antennas. Applying these corrections to the code measurements improves code/carrier single-frequency precise point positioning, ambiguity fixing based on the Melbourne–Wübbena linear combination, and determination of ionospheric total electron content. It also affects fractional cycle biases and differential code biases. Numéro de notice : A2017-480 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1012-3 En ligne : https://doi.org/10.1007/s00190-017-1012-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86411 [article]

The future is now GPS + GLONASS + SBAS = GNSS / Lambert Wanninger in GPS world, vol 19 n° 7 (July 2008)

Public [article]  inGPS world > vol 19 n° 7 (July 2008) . - pp 42 - 48 Titre : The future is now GPS + GLONASS + SBAS = GNSS Type de document : Article/Communication Auteurs : Lambert Wanninger, Auteur Année de publication : 2008 Article en page(s) : pp 42 - 48 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] BeiDou [Termes IGN] Global Navigation Satellite System [Termes IGN] positionnement par EGNOS [Termes IGN] positionnement par Galileo [Termes IGN] positionnement par GLONASS [Termes IGN] positionnement par GPS [Termes IGN] système de positionnement par satellites Résumé : (Auteur) We are on the brink of a new era in satellite positioning and navigation. The excitement that was felt 30 years ago when the first GPS satellite was launched is beginning to be felt again. Back then, instantaneous three-dimensional satellite-based positioning was an entirely new concept. Yes, we did have satellite-based positioning before GPS, but it wasn't instantaneous and it wasn't fully 3D - nor was it very accurate. Over the past 30 years, thousands of scientists and engineers have developed an amazing range of GPS applications providing positioning accuracies all the way down to the millimeter level. However, some would argue that many of the recent developments, especially in the area of high-accuracy positioning, are just minor enhancements to existing techniques first introduced or foretold years ago. Been there, done that. But that situation is about to change -and in a big way! New signals and new satellites herald a new era in satellite-based positioning and navigation. Russia's Global'naya Navigatsionnaya Sputnikovaya Sistema (GLONASS) is being revitalized after many years of neglect. With its first launch in 1982, this second global navigation satellite system gave rise to the generic term for all such systems : GNSS. In addition to GLONASS and a modernized GPS featuring new civil and military signals along with new constellations of satellites, we will have Europe's Galileo system (with two GIOVE test satellites already in orbit) and China's Beidou/Compass system (with five satellites already in orbit). Receivers and data-processing techniques will be developed to allow use of all available signals and satellites. The future promises to be just as exciting for GNSS scientists and engineers as the early days of GPS. But do we have to wait for these new or enhanced systems to be in place before benefiting from a multi-signal, multi-constellation global navigation satellite system? Definitely not. As this month's column describes, we can sample the future to day. The existing GPS satellites, along with the revitalized GLONASS constellation and the satellites of the various geostationary satellite-based augmentation systems, already constitute a system of systems. And receivers currently on the market provide the necessary raw measurement data to yield positioning solutions from this system of systems with potentially more continuity and greater accuracy than those obtained using GPS alone. Listen up: the future is now. Copyright Questex Media Group Inc Numéro de notice : A2008-299 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29292 [article]

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Präzise Positionierung in regionalen GPS-Referenzstationsnetzen / Lambert Wanninger (2000)

Public Titre : Präzise Positionierung in regionalen GPS-Referenzstationsnetzen Titre original : [Positionnement de précision dans les réseaux régionaux de stations GPS] Type de document : Thèse/HDR Auteurs : Lambert Wanninger, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2000 Collection : DGK - C Sous-collection : Dissertationen num. 508 Importance : 68 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9556-4 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] ambiguïté entière [Termes IGN] correction atmosphérique [Termes IGN] Europe centrale [Termes IGN] phase GPS [Termes IGN] positionnement par GPS [Termes IGN] précision centimétrique [Termes IGN] réseau géodésique permanent [Termes IGN] station de référence [Termes IGN] station GPS [Termes IGN] station virtuelle [Termes IGN] traitement de données GNSS Résumé : (Auteur) Permanent GPS reference stations produce observation corrections to be used for cm-accurate relative positioning and they establish the connection to a geodetic reference frame. In order to supply observation corrections for larger areas at minimum costs, the number of reference stations should be as small as possible, but large enough to guarantee cm-accuracy. The solution lies in the precise modeling of the distance and direction dependent errors. Error modeling based on GPS phase data requires fixing of the carrier phase ambiguities in the network of reference stations. It could be shown, both theoretically and with real observation data, that a two-dimensional linear interpolation algorithm yields mm-accurate corrections if the reference station distances do not exceed 100 km. However, if regional scale disturbances exist in the ionosphere or in the troposphere, larger errors can be encountered. For the application in Central Europe, it is therefore recommended to limit the reference station distances to some 50 km. The realization of this positioning concept is performed in two steps. In the first one, the observations of the reference stations are preprocessed and separated into observation correction of one base station and correction models for the distance and direction dependent errors. In the second step, virtual observations of a reference station at a selected position are calculated. They can then be used for the positioning of a rover receiver in baseline mode using existing software. The processing of various test data sets showed that in Central Europe and with reference station distances of some 50 km, 1cm accurate horizontal coordinates could be obtained within a few minutes. Since the distance and direction dependent errors can almost completely be corrected, the necessary observation time at a rover site is mainly a function of the rover receiver's data quality. Numéro de notice : 46139 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=58472

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