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POD of small LEO satellites based on precise real-time MADOCA and SBAS-aided PPP corrections / Amir Allahvirdi-Zadeh in GPS solutions, vol 25 n° 2 (April 2021)  

Public [article]  inGPS solutions > vol 25 n° 2 (April 2021) . - 14 p. Titre : POD of small LEO satellites based on precise real-time MADOCA and SBAS-aided PPP corrections Type de document : Article/Communication Auteurs : Amir Allahvirdi-Zadeh, Auteur ; Kan Wang, Auteur ; Ahmed El-Mowafy, Auteur Année de publication : 2021 Article en page(s) : 14 p. Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales [Termes descripteurs IGN] données GNSS [Termes descripteurs IGN] horloge du satellite [Termes descripteurs IGN] orbite basse [Termes descripteurs IGN] orbitographie par GNSS [Termes descripteurs IGN] positionnement ponctuel précis [Termes descripteurs IGN] temps réel Résumé : (Auteur) For real-time precise orbit determination (POD) of low earth orbit (LEO) satellites, high-accuracy global navigation satellite system (GNSS) orbit and clock products are necessary in real time. Recently, the Japanese multi-GNSS advanced demonstration of orbit and clock analysis precise point positioning (PPP) service and the new generation of the Australian/New Zealand satellite-based augmentation system (SBAS)-aided PPP service provide free and precise GNSS products that are directly broadcast through the navigation and geostationary earth orbit satellites, respectively. With the high quality of both products shown in this study, a 3D accuracy of centimeters can be achieved in the post-processing mode for the reduced-dynamic orbits of small LEO satellites having a duty cycle down to 40% and at sub-dm to dm level for the kinematic orbits. The results show a promising future for high-accuracy real-time POD onboard LEO satellites benefiting from the precise free-of-charge PPP corrections broadcast by navigation systems or SBAS. Numéro de notice : A2021-091 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-020-01078-8 date de publication en ligne : 11/01/2021 En ligne : https://doi.org/10.1007/s10291-020-01078-8 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96880 [article]

Determination of the lunar body tide from global laser altimetry data / Robin N. Thor in Journal of geodesy, vol 95 n° 1 (January 2021)  

Public [article]  inJournal of geodesy > vol 95 n° 1 (January 2021) . - n° 4 Titre : Determination of the lunar body tide from global laser altimetry data Type de document : Article/Communication Auteurs : Robin N. Thor, Auteur ; Reinald Kallenbach, Auteur ; Ulrich R. Christensen, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : n° 4 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] altimètre laser [Termes descripteurs IGN] données altimétriques [Termes descripteurs IGN] marée lunaire [Termes descripteurs IGN] Mercure (planète) [Termes descripteurs IGN] mesure géodésique Résumé : (auteur) We use global data from the Lunar Orbiter Laser Altimeter (LOLA) to retrieve the lunar tidal Love number ℎ2 and find ℎ2=0.0387±0.0025. This result is in agreement with previous estimates from laser altimetry using crossover points of LOLA profiles. The Love numbers k2 and h2 are key constraints on planetary interior models. We further develop and apply a retrieval method based on a simultaneous inversion for the topography and the tidal signal benefiting from the large volume of LOLA data. By the application to the lunar tides, we also demonstrate the potential of the method for future altimetry experiments at other planetary bodies. The results of this study are very promising with respect to the determination of Mercury’s and Ganymede’s h2 from future altimeter measurements. Numéro de notice : A2021-029 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01455-8 date de publication en ligne : 23/12/2020 En ligne : https://doi.org/10.1007/s00190-020-01455-8 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96712 [article]

Determination of the under water position of objects by reflectorless total stations / Štefan Rákay in Survey review, vol 53 n°376 (January 2021)  

Public [article]  inSurvey review > vol 53 n°376 (January 2021) . - pp 35 - 43 Titre : Determination of the under water position of objects by reflectorless total stations Type de document : Article/Communication Auteurs : Štefan Rákay, Auteur ; Slavomír Labant, Auteur ; Karol Bartoš, Auteur Année de publication : 2021 Article en page(s) : pp 35 - 43 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bathymétrie [Termes descripteurs IGN] bathymétrie laser [Termes descripteurs IGN] erreur géométrique [Termes descripteurs IGN] lever bathymétrique [Termes descripteurs IGN] mesurage électronique de distances [Termes descripteurs IGN] objet [Termes descripteurs IGN] onde électromagnétique [Termes descripteurs IGN] réfraction de l'eau [Termes descripteurs IGN] scène sous-marine [Termes descripteurs IGN] tachéomètre électronique [Termes descripteurs IGN] vitesse Résumé : (auteur) When surveying through a water surface, a distortion of several centimetres caused by the refraction and the change in the velocity of the electromagnetic waves can be observed. Therefore, neither the position nor the height of an underwater point (object), which can be seen from above the water surface, is correctly measured. The authors want to point out the magnitude of geometric errors when measuring to points under water as well as the computation of correct under water positions of points from measurement through a water layer. A practical experiment was performed for a water depth of 0.16 m. Numéro de notice : A2021-048 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2019.1683488 date de publication en ligne : 03/11/2019 En ligne : https://doi.org/10.1080/00396265.2019.1683488 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96783 [article]

Performance of miniaturized atomic clocks in static laboratory and dynamic flight environments / Ankit Jain in GPS solutions, vol 25 n° 1 (January 2021)  

Public [article]  inGPS solutions > vol 25 n° 1 (January 2021) . - 16 p. Titre : Performance of miniaturized atomic clocks in static laboratory and dynamic flight environments Type de document : Article/Communication Auteurs : Ankit Jain, Auteur ; Thomas Krawinkel, Auteur ; Steffen Schön, Auteur ; Andreas Bauch, Auteur Année de publication : 2021 Article en page(s) : 16 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes descripteurs IGN] décalage d'horloge [Termes descripteurs IGN] fréquence [Termes descripteurs IGN] horloge atomique [Termes descripteurs IGN] horloge du récepteur [Termes descripteurs IGN] oscillateur [Termes descripteurs IGN] récepteur GNSS [Termes descripteurs IGN] stabilité [Termes descripteurs IGN] variance d'Allan Résumé : (auteur) Miniaturized atomic clocks with high frequency stability as local oscillators in global navigation satellite system (GNSS) receivers promise to improve real-time kinematic applications. For a number of years, such oscillators are being investigated regarding their overall technical applicability, i.e., transportability, and performance in dynamic environments. The short-term frequency stability of these clocks is usually specified by the manufacturer, being valid for stationary applications. Since the performance of most oscillators is likely degraded in dynamic conditions, various oscillators are tested to find the limits of receiver clock modeling in dynamic cases and consequently derive adequate stochastic models to be used in navigation. We present the performance of three different oscillators (Microsemi MAC SA.35m, Spectratime LCR-900 and Stanford Research Systems SC10) for static and dynamic applications. For the static case, all three oscillators are characterized in terms of their frequency stability at Physikalisch-Technische Bundesanstalt, Germany's national metrology institute. The resulting Allan deviations agree well with the manufacturer's data. Furthermore, a flight experiment was conducted in order to evaluate the performance of the oscillators under dynamic conditions. Here, each oscillator is replacing the internal oscillator of a geodetic-grade GNSS receiver and the stability of the receiver clock biases is determined. The time and frequency offsets of the oscillators are characterized with regard to the flight dynamics recorded by a navigation-grade inertial measurement unit. The results of the experiment show that the frequency stability of each oscillator is degraded by about at least one order of magnitude compared to the static case. Also, the two quartz oscillators show a significant g-sensitivity resulting in frequency shifts of − 1.2 × 10−9 and + 1.5 × 10−9, respectively, while the rubidium clocks are less sensitive, thus enabling receiver clock modeling and strengthening of the navigation performance even in high dynamics. Numéro de notice : A2021-003 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-020-01036-4 date de publication en ligne : 13/10/2020 En ligne : https://doi.org/10.1007/s10291-020-01036-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96081 [article]

Temporal calibration and synchronization of robotic total stations for kinematic multi-sensor-systems / Tomas Thalmann in Journal of applied geodesy, vol 15 n° 1 (January 2021)  

Public [article]  inJournal of applied geodesy > vol 15 n° 1 (January 2021) . - pp 13 - 30 Titre : Temporal calibration and synchronization of robotic total stations for kinematic multi-sensor-systems Type de document : Article/Communication Auteurs : Tomas Thalmann, Auteur ; Hans Neuner, Auteur Année de publication : 2021 Article en page(s) : pp 13 - 30 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes descripteurs IGN] étalonnage [Termes descripteurs IGN] positionnement cinématique [Termes descripteurs IGN] référentiel [Termes descripteurs IGN] réseau local sans fil [Termes descripteurs IGN] synchronisation [Termes descripteurs IGN] tachéomètre électronique robotisé [Termes descripteurs IGN] tenseur Résumé : (auteur) Despite the increasing interest in kinematic data acquisition, Robotic Total Stations (RTSs) are still relatively seldom used. No matter if Mobile Mapping Systems or Control & Guidance, GNSS is mostly used as position sensor, which limits the application to outdoor areas. For indoor applications, a combination of relative sensors is usually employed. One reason why RTSs are not used is the challenging time referencing and synchronization. In this work we analyze the challenges of a synchronized kinematic application of RTSs and present solutions. Our approach is based on a wireless network synchronization to establish a precise temporal reference frame. The achievable synchronization quality is thoroughly examined. In addition we develop a kinematic model of spherical measurements, that incorporates timing related parameters. To estimate these parameters we propose a temporal calibration utilizing an industrial robot. Both parts of our approach are evaluated using a test setup of two total stations, proofing an overall synchronization accuracy of 0.2 ms. An overall horizontal kinematic point accuracy of 2.3 mm reveals the potential of sufficiently synchronized RTSs. Numéro de notice : A2021-043 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1515/jag-2019-0070 date de publication en ligne : 16/12/2020 En ligne : https://doi.org/10.1515/jag-2019-0070 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96770 [article]

Inclusion of GPS clock estimates for satellites Sentinel-3A/3B in DORIS geodetic solutions / Petr Štěpánek in Journal of geodesy, vol 94 n° 12 (December 2020)  

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Stereophotogrammetry for 2-D building deformation monitoring using Kalman Filter / J.O. Odumosu in Reports on geodesy and geoinformatics, vol 110 n°1 (December 2020)  

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Les anciennes méthodes de levé / François Mazuyer in Géomètre, n° 2184 (octobre 2020)

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Les anciens instruments de mesure / François Mazuyer in Géomètre, n° 2184 (octobre 2020)

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De la bonne interprétation des documents / François Mazuyer in Géomètre, n° 2184 (octobre 2020)

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Combined InSAR and terrestrial structural monitoring of bridges / Sivasakthy Selvakumaran in IEEE Transactions on geoscience and remote sensing, vol 58 n° 10 (October 2020)  

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Evolution of orbit and clock quality for real-time multi-GNSS solutions / Kamil Kazmierski in GPS solutions, Vol 24 n° 4 (October 2020)  

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An offshore real-time precise point positioning technique based on a single set of BeiDou short-message communication devices / Zhixi Nie in Journal of geodesy, vol 94 n° 9 (September 2020)  

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Evaluating the accuracy of ALS-based removal estimates against actual logging data / Ville Vähä-Konka in Annals of Forest Science [en ligne], vol 77 n° 3 (September 2020)  

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GipsyX/RTGx, a new tool set for space geodetic operations and research / Willy I. Bertiger in Advances in space research, vol 66 n° 3 (1 August 2020)  

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