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Tropospheric and range biases in Satellite Laser Ranging / Mateusz Drożdżewski in Journal of geodesy, vol 95 n° 9 (September 2021)
Titre : Tropospheric and range biases in Satellite Laser Ranging Type de document : Article/Communication Auteurs : Mateusz Drożdżewski, Auteur ; Krzysztof Sosnica, Auteur Année de publication : 2021 Article en page(s) : n° 100 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] correction troposphérique
[Termes IGN] données Lageos
[Termes IGN] données TLS (télémétrie)
[Termes IGN] erreur systématique
[Termes IGN] géocentre
[Termes IGN] harmonique sphérique
[Termes IGN] retard troposphérique zénithal
[Termes IGN] télémétrie laser sur satelliteRésumé : (auteur) The Satellite Laser Ranging (SLR) technique provides very accurate distance measurements to artificial Earth satellites. SLR is employed for the realization of the origin and the scale of the terrestrial reference frame. Despite the high precision, SLR observations can be affected by various systematic errors. So far, range biases were used to account for systematic measurement errors and mismodeling effects in SLR. Range biases are constant for all elevation angles and independent of the measured distance to a satellite. Recently, intensity-dependent biases for single-photon SLR detectors and offsets of barometer readings and meteorological devices were reported for some SLR stations. In this paper, we study the possibility of the direct estimation of tropospheric biases from SLR observations to LAGEOS satellites. We discuss the correlations between the station heights, range biases, tropospheric biases, and their impact on the repeatability of station coordinates, geocenter motion, and the global scale of the reference frame. We found that the solution with the estimation of tropospheric biases provides more stable station coordinates than the solution with the estimation of range biases. From the common estimation of range and tropospheric biases, we found that most of the systematic effects at SLR stations are better absorbed by elevation-dependent tropospheric biases than range biases which overestimate the total bias effect. The estimation of tropospheric biases changes the SLR-derived global scale by 0.3 mm and the geocenter coordinates by 1 mm for the Z component, causing thus an offset in the realization of the reference frame origin. Estimation of range biases introduces an offset in some SLR-derived low-degree spherical harmonics of the Earth’s gravity field. Therefore, considering elevation-dependent tropospheric and intensity biases is essential for deriving high-accuracy geodetic parameters. Numéro de notice : A2021-621 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-021-01554-0 Date de publication en ligne : 21/08/2021 En ligne : https://doi.org/10.1007/s00190-021-01554-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98237
in Journal of geodesy > vol 95 n° 9 (September 2021) . - n° 100[article]
Titre : Remote sensing by satellite gravimetry Type de document : Monographie Auteurs : Thomas Gruber, Éditeur scientifique ; Annette Eicker, Éditeur scientifique ; Frank Flechtner, Éditeur scientifique Editeur : Bâle [Suisse] : Multidisciplinary Digital Publishing Institute MDPI Année de publication : 2021 Importance : 286 p. Format : 16 x 24 cm ISBN/ISSN/EAN : 978-3-0365-0009-6 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] bilan de masse
[Termes IGN] CHAMP (satellite)
[Termes IGN] champ de pesanteur terrestre
[Termes IGN] données GOCE
[Termes IGN] données GRACE
[Termes IGN] géocentre
[Termes IGN] gradient de gravitation
[Termes IGN] gravimétrie spatiale
[Termes IGN] nivellement par GPS
[Termes IGN] orbitographie
[Termes IGN] télémétrie laser sur satelliteRésumé : (auteur) Over the last two decades, satellite gravimetry has become a new remote sensing technique that provides a detailed global picture of the physical structure of the Earth. With the CHAMP, GRACE, GOCE and GRACE Follow-On missions, mass distribution and mass transport in the Earth system can be systematically observed and monitored from space. A wide range of Earth science disciplines benefit from these data, enabling improvements in applied models, providing new insights into Earth system processes (e.g., monitoring the global water cycle, ice sheet and glacier melting or sea-level rise) or establishing new operational services. Long time series of mass transport data are needed to disentangle anthropogenic and natural sources of climate change impacts on the Earth system. In order to secure sustained observations on a long-term basis, space agencies and the Earth science community are currently planning future satellite gravimetry mission concepts to enable higher accuracy and better spatial and temporal resolution. This Special Issue provides examples of recent improvements in gravity observation techniques and data processing and analysis, applications in the fields of hydrology, glaciology and solid Earth based on satellite gravimetry data, as well as concepts of future satellite constellations for monitoring mass transport in the Earth system. Note de contenu : 1- The GFZ GRACE RL06 monthly gravity field time series: Processing details and quality assessment
2- SLR, GRACE and swarm gravity field determination and combination
3- A new approach to Earth’s gravity field modeling using GPS-derived kinematic orbits and baselines
4- Improved estimates of geocenter variability from time-variable gravity and ocean model outputs
5- An assessment of the GOCE high-level processing facility (HPF) released global geopotential models with regional test results in Turkey
6- Next-generation gravity missions: Sino-European numerical simulation comparison exercise
7- Combination analysis of future polar-type gravity mission and GRACE follow-on
8- Gravity field recovery using high-precision, high–low inter-satellite links
9- High-resolution mass trends of the Antarctic ice sheet through a spectral combination of satellite gravimetry and radar altimetry observations
10- The rapid and steady mass loss of the Patagonian icefields throughout the GRACE era: 2002–2017
11- Downscaling GRACE TWSA data into high-resolution groundwater level anomaly using machine learning-based models in a glacial aquifer system
12- Hydrologic mass changes and their implications in Mediterranean-climate Turkey from GRACE measurements
13- GOCE-derived coseismic gravity gradient changes caused by the 2011 Tohoku-Oki earthquakeNuméro de notice : 28391 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Recueil / ouvrage collectif DOI : 10.3390/books978-3-0365-0009-6 En ligne : https://doi.org/10.3390/books978-3-0365-0009-6 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98720
Titre : Reference system origin and scale realization within the future GNSS constellation “Kepler” Type de document : Article/Communication Auteurs : Susanne Glaser, Auteur ; Grzegorz Michalak, Auteur ; Benjamin Männel, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : n° 117 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] centre de phase
[Termes IGN] constellation Galileo
[Termes IGN] constellation GNSS
[Termes IGN] décorrélation
[Termes IGN] géocentre
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] Kepler, Johannes
[Termes IGN] orbite basse
[Termes IGN] orbite terrestre
[Termes IGN] orbitographieRésumé : (auteur) Currently, Global Navigation Satellite Systems (GNSS) do not contribute to the realization of origin and scale of combined global terrestrial reference frame (TRF) solutions due to present system design limitations. The future Galileo-like medium Earth orbit (MEO) constellation, called “Kepler”, proposed by the German Aerospace Center DLR, is characterized by a low Earth orbit (LEO) segment and the innovative key features of optical inter-satellite links (ISL) delivering highly precise range measurements and of optical frequency references enabling a perfect time synchronization within the complete constellation. In this study, the potential improvements of the Kepler constellation on the TRF origin and scale are assessed by simulations. The fully developed Kepler system allows significant improvements of the geocenter estimates (realized TRF origin in long-term). In particular, we find improvements by factors of 43 for the Z and of 8 for the X and Y component w. r. t. a contemporary MEO-only constellation. Furthermore, the Kepler constellation increases the reliability due to a complete de-correlation of the geocenter coordinates and the orbit parameters related to the solar radiation pressure modeling (SRP). However, biases in SRP modeling cause biased geocenter estimates and the ISL of Kepler can only partly compensate this effect. The realized scale enabling all Kepler features improves by 34% w. r. t. MEO-only. The dependency of the estimated satellite antenna phase center offsets (PCOs) upon the underlying TRF impedes a scale realization by GNSS. In order to realize the network scale with 1 mm accuracy, the PCOs have to be known within 2 cm for the MEO and 4 mm for the LEO satellites. Independently, the scale can be realized by estimating the MEO PCOs and by simultaneously fixing the LEO PCOs. This requires very accurate LEO PCOs; the simulations suggest them to be smaller than 1 mm in order to keep scale changes below 1 mm. Numéro de notice : A2020-736 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01441-0 Date de publication en ligne : 19/11/2020 En ligne : https://doi.org/1https://doi.org/10.1007/s00190-020-01441-0 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96352
in Journal of geodesy > vol 94 n° 12 (December 2020) . - n° 117[article]
Titre : Geodetic VLBI for precise orbit determination of Earth satellites: a simulation study Type de document : Article/Communication Auteurs : Grzegorz Klopotek, Auteur ; Thomas Hobiger, Auteur ; Rüdiger Haas, Auteur ; Toshimichi Otsubo, Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] constellation GNSS
[Termes IGN] données Galileo
[Termes IGN] données Lageos
[Termes IGN] données VGOS
[Termes IGN] géocentre
[Termes IGN] interférométrie à très grande base
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] orbitographie
[Termes IGN] paramètres d'orientation de la Terre
[Termes IGN] quasar
[Termes IGN] rotation de la TerreRésumé : (auteur) Recent efforts of tracking low Earth orbit and medium Earth orbit (MEO) satellites using geodetic very long baseline interferometry (VLBI) raise questions on the potential of this novel observation concept for space geodesy. Therefore, we carry out extensive Monte Carlo simulations in order to investigate the feasibility of geodetic VLBI for precise orbit determination (POD) of MEO satellites and assess the impact of quality and quantity of satellite observations on the derived geodetic parameters. The MEO satellites are represented in our study by LAGEOS-1/-2 and a set of Galileo satellites. The concept is studied on the basis of 3-day solutions in which satellite observations are included into real schedules of the continuous geodetic VLBI campaign 2017 (CONT17) as well as simulated schedules concerning the next-generation VLBI system, known as the VLBI Global Observing System (VGOS). Our results indicate that geodetic VLBI can perform on a comparable level as other space-geodetic techniques concerning POD of MEO satellites. For an assumed satellite observation precision better than 14.1 mm (47 ps), an average 3D orbit precision of 2.0 cm and 6.3 cm is found for schedules including LAGEOS-1/-2 and Galileo satellites, respectively. Moreover, geocenter offsets, which were so far out of scope for the geodetic VLBI analysis, are close to the detection limit for the simulations concerning VGOS observations of Galileo satellites, with the potential to further enhance the results. Concerning the estimated satellite orbits, VGOS leads to an average precision improvement of 80% with respect to legacy VLBI. In absolute terms and for satellite observation precision of 14.1 mm (47 ps), this corresponds to an average value of 17 mm and 7 mm concerning the 3D orbit scatter and precision of geocenter components, respectively. As shown in this study, a poor satellite geometry can degrade the derived Earth rotation parameters and VLBI station positions, compared to the quasar-only reference schedules. Therefore, careful scheduling of both quasar and satellite observations should be performed in order to fully benefit from this novel observation concept. Numéro de notice : A2020-342 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01381-9 Date de publication en ligne : 11/06/2020 En ligne : https://doi.org/10.1007/s00190-020-01381-9 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95221
in Journal of geodesy > vol 94 n° 6 (June 2020)[article]
Titre : Impact of network constraining on the terrestrial reference frame realization based on SLR observations to LAGEOS Type de document : Article/Communication Auteurs : Radoslaw Zajdel, Auteur ; Krzysztof Sosnica, Auteur ; Mateusz Drożdżewski, Auteur ; Grzegorz Bury, Auteur ; D. Strugarek, Auteur Année de publication : 2019 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] géocentre
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] Lageos
[Termes IGN] réseau de contraintes
[Termes IGN] rotation de la Terre
[Termes IGN] station TLS (télémétrie)
[Termes IGN] système de référence géodésique
[Termes IGN] système de référence local
[Termes IGN] télémétrie laser sur satellite
[Termes IGN] transformation de HelmertRésumé : (auteur)
The Satellite Laser Ranging (SLR) network struggles with some major limitations including an inhomogeneous global station distribution and uneven performance of SLR sites. The International Laser Ranging Service (ILRS) prepares the time-variable list of the most well-performing stations denoted as ‘core sites’ and recommends using them for the terrestrial reference frame (TRF) datum realization in SLR processing. Here, we check how different approaches of the TRF datum realization using minimum constraint conditions (MCs) and the selection of datum-defining stations affect the estimated SLR station coordinates, the terrestrial scale, Earth rotation parameters (ERPs), and geocenter coordinates (GCC). The analyses are based on the processing of the SLR observations to LAGEOS-1/-2 collected between 2010 and 2018. We show that it is essential to reject outlying stations from the reference frame realization to maintain a high quality of SLR-based products. We test station selection criteria based on the Helmert transformation of the network w.r.t. the a priori SLRF2014 coordinates to reject misbehaving stations from the list of datum-defining stations. The 25 mm threshold is optimal to eliminate the epoch-wise temporal deviations and to provide a proper number of datum-defining stations. According to the station selection algorithm, we found that some of the stations that are not included in the list of ILRS core sites could be taken into account as potential core stations in the TRF datum realization. When using a robust station selection for the datum definition, we can improve the station coordinate repeatability by 8%, 4%, and 6%, for the North, East and Up components, respectively. The global distribution of datum-defining stations is also crucial for the estimation of ERPs and GCC. When excluding just two core stations from the SLR network, the amplitude of the annual signal in the GCC estimates is changed by up to 2.2 mm, and the noise of the estimated pole coordinates is substantially increased.Numéro de notice : A2019-610 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-019-01307-0 Date de publication en ligne : 17/10/2019 En ligne : https://doi.org/10.1007/s00190-019-01307-0 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94794
in Journal of geodesy > vol 93 n°11 (November 2019)[article]Combination of GNSS and SLR measurements : contribution to the realization of the terrestrial reference frame / Sara Bruni (2016)
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