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Auteur Richard S. Gross |
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Affiner la recherche Interroger des sources externesSmoothing and predicting celestial pole offsets using a Kalman filter and smoother / Jolanta Nastula in Journal of geodesy, Vol 94 n°3 (March 2020)
Titre : Smoothing and predicting celestial pole offsets using a Kalman filter and smoother Type de document : Article/Communication Auteurs : Jolanta Nastula, Auteur ; T. Mike Chin,, Auteur ; Richard S. Gross, Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] filtre de Kalman
[Termes IGN] International Earth Rotation Service
[Termes IGN] lissage de données
[Termes IGN] mission spatiale
[Termes IGN] mouvement du pôle
[Termes IGN] nutation
[Termes IGN] orientation de la Terre
[Termes IGN] précession
[Termes IGN] radar JPL
[Termes IGN] rotation de la Terre
[Termes IGN] série temporelleRésumé : (auteur) It has been recognized since the early days of interplanetary spaceflight that accurate navigation requires taking into account changes in the Earth’s rotation. In the 1960s, tracking anomalies during the Ranger VII and VIII lunar missions were traced to errors in the Earth orientation parameters. As a result, Earth orientation calibration methods were improved to support the Mariner IV and V planetary missions. Today, accurate Earth orientation parameters are used to track and navigate every interplanetary spaceflight mission. The approach taken at JPL (Jet Propulsion Laboratory) to provide the interplanetary spacecraft tracking and navigation teams with the UT1 and polar motion parameters that they need is based upon the use of a Kalman filter to combine past measurements of these parameters and predict their future evolution. A model was then used to provide the nutation/precession components of the Earth’s orientation. As a result, variations caused by the free core nutation were not taken into account. But for the highest accuracy, these variations must be considered. So JPL recently developed an approach based upon the use of a Kalman filter and smoother to provide smoothed and predicted celestial pole offsets (CPOs) to the interplanetary spacecraft tracking and navigation teams. The approach used at JPL to do this and an evaluation of the accuracy of the predicted CPOs is given here. For assessing the quality of JPL’s nutation predictions, we compare the time series of dX, dY provided by JPL with the predictions obtained from the IERS Rapid Service/Prediction Centre. Our results confirmed that the approach recently developed by JPL can be used for the successful nutation prediction. In particular, we show that after 90 days of prediction, the estimated errors are 43% lower for dX and 33% lower for dY than in the case of the official IERS products, and an average improvement is 19% and 22% for dX and dY, respectively. Numéro de notice : A2020-156 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01349-9 Date de publication en ligne : 15/02/2020 En ligne : https://doi.org/10.1007/s00190-020-01349-9 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94806
in Journal of geodesy > Vol 94 n°3 (March 2020)[article]
Titre de série : Springer Handbook of Global Navigation Satellite Systems, ch. 36 Titre : Geodesy Type de document : Chapitre/Contribution Auteurs : Zuheir Altamimi Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2017 Importance : pp 1039 - 1061 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] coordonnées GNSS
[Termes IGN] Global Geodetic Observing System
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] International Terrestrial Reference SystemRésumé : (auteur) Continuous geodetic observations are fundamental to characterize changes in space and time that affect the Earth system. The advent of global navigation satellite systems (GNSS s), starting with the Global Positioning System (GPS ) in the early 1980s, has significantly increased the range of geodetic applications and their precision. Significant improvements have progressively been made in the GNSS software packages developed by research institutes, leading to the determination of high-precision geodetic parameters and their temporal variations. The proliferation of dense GNSS networks (local, national, continental and global), composed of continuously observing stations, allows for a variety of geodetic and Earth science applications. Most areas of science, Earth observation, georeferencing applications, and society at large, today depend on being able to determine positions to millimeter-level precision. Point positions, to be meaningful and fully exploitable, have to be determined and expressed in a well-defined reference frame. All current global and regional reference frames rely on the availability of the international terrestrial reference frame (ITRF ), which is the most accurate realization of the international terrestrial reference system (ITRS ). One of the major modern achievements in geodesy today is the ability to determine highly precise global and regional terrestrial reference frames based on GNSS observations, fully connected to the ITRF. This chapter describes the use and applications of GNSS in geodesy, focusing on its role in the International Association of Geodesy’s (IAG’s) global geodetic observing system (GGOS) for monitoring our planet in space and time, GNSS-based reference frame implementation, Earth rotation and sea level monitoring. Numéro de notice : H2017-028 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Chapître / contribution nature-HAL : ChOuvrScient DOI : 10.1007/978-3-319-42928-1_36 En ligne : https://doi.org/10.1007/978-3-319-42928-1_36 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91918 
Titre : KALREF, a Kalman filter and time series approach to the International Terrestrial Reference Frame realization Type de document : Article/Communication Auteurs : Xiaoping Wu, Auteur ; Claudio Abbondanza, Auteur ; Zuheir Altamimi Année de publication : 2015 Article en page(s) : pp 3775 - 3802 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] filtre de Kalman
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] point de liaison (géodésie)
[Termes IGN] série temporelle
[Termes IGN] vitesseRésumé : (auteur) The current International Terrestrial Reference Frame is based on a piecewise linear site motion model and realized by reference epoch coordinates and velocities for a global set of stations. Although linear motions due to tectonic plates and glacial isostatic adjustment dominate geodetic signals, at today's millimeter precisions, nonlinear motions due to earthquakes, volcanic activities, ice mass losses, sea level rise, hydrological changes, and other processes become significant. Monitoring these (sometimes rapid) changes desires consistent and precise realization of the terrestrial reference frame (TRF) quasi-instantaneously. Here, we use a Kalman filter and smoother approach to combine time series from four space geodetic techniques to realize an experimental TRF through weekly time series of geocentric coordinates. In addition to secular, periodic, and stochastic components for station coordinates, the Kalman filter state variables also include daily Earth orientation parameters and transformation parameters from input data frames to the combined TRF. Local tie measurements among colocated stations are used at their known or nominal epochs of observation, with comotion constraints applied to almost all colocated stations. The filter/smoother approach unifies different geodetic time series in a single geocentric frame. Fragmented and multitechnique tracking records at colocation sites are bridged together to form longer and coherent motion time series. While the time series approach to TRF reflects the reality of a changing Earth more closely than the linear approximation model, the filter/smoother is computationally powerful and flexible to facilitate incorporation of other data types and more advanced characterization of stochastic behavior of geodetic time series. Numéro de notice : A2015--006 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Autre URL associée : http://onlinelibrary.wiley.com/doi/10.1002/2014JB011622 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1002/2014JB011622 Date de publication en ligne : 07/04/2015 En ligne : http://dx.doi.org/10.1002/2014JB011622 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80479
in Journal of geophysical research : Solid Earth > vol 120 n° 5 (May 2015) . - pp 3775 - 3802[article]Documents numériques
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KALREF, a Kalman filter ... - pdf éditeurAdobe Acrobat PDF
Titre : Three-Corner Hat for the assessment of the uncertainty of non-linear residuals of space-geodetic time series in the context of terrestrial reference frame analysis Type de document : Article/Communication Auteurs : Claudio Abbondanza, Auteur ; Zuheir Altamimi Année de publication : 2015 Article en page(s) : pp 313-329 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] co-positionnement
[Termes IGN] corrélation temporelle
[Termes IGN] estimation de cohérence
[Termes IGN] hauteur ellipsoïdale
[Termes IGN] incertitude de position
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] série temporelle
[Termes IGN] signal GPSRésumé : (auteur) We discuss the application of the Three-Corner Hat (TCH) to time series of space-geodetic station position residuals with the purpose of characterizing the uncertainties of GPS, VLBI, SLR, DORIS for the International Terrestrial Reference Frame (ITRF) determination. Adopting simulations, we show that, in the absence of time-correlated errors, TCH is able to fully recover the nominal uncertainties of groups of observations whose intrinsic precisions are remarkably dissimilar to one another, as is the case for the space-geodetic techniques. When time-correlated errors are predominant, as it happens with GPS, TCH is affected by the increased variance of the observations and its estimates are positively biased. TCH applied to 16 ITRF co-located sites confirms that GPS, albeit affected by time-correlated errors, is the most precise of the space-geodetic techniques. GPS median uncertainties are 1.1, 1.2 and 2.8 mm, for the north, east and height component, respectively. VLBI performs particularly well in the horizontal component, the median uncertainties being ≈2 mm. The height component is ∼3 times larger than the GPS one. SLR and DORIS median uncertainties exceed by far the 7 mm level on all of the three components. Comparing TCH results with station position repeatabilities, we find that the two metrics are in striking agreement for VLBI and DORIS, but not for SLR and GPS. The inconsistencies between TCH and station repeatabilities for co-located GPS and SLR point to the presence of either specific station-dependent biases or low-quality co-locations. Scaling factors derived adopting the ratio between TCH and median formal errors on the positions suggest the station position covariances have to be up-scaled for VLBI, SLR, DORIS and down-scaled for GPS. Numéro de notice : A2015-340 Affiliation des auteurs : LASTIG LAREG+Ext (2012-mi2018) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-014-0777-x Date de publication en ligne : 18/11/2014 En ligne : https://doi.org/10.1007/s00190-014-0777-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76709
in Journal of geodesy > vol 89 n° 4 (April 2015) . - pp 313-329[article]
Titre : Accuracy of the International Terrestrial Reference Frame origin and Earth expansion Type de document : Article/Communication Auteurs : X. Wu, Auteur ; Xavier Collilieux Année de publication : 2011 Article en page(s) : 5 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] International Terrestrial Reference FrameRésumé : (auteur) The International Terrestrial Reference Frame (ITRF) is a fundamental datum for high‐precision orbit tracking, navigation, and global change monitoring. Accurately realizing and maintaining ITRF origin at the mean Earth system center of mass (CM) is critical to surface and spacecraft based geodetic measurements including those of sea level rise and its sources. Although ITRF combines data from satellite laser ranging (SLR), Very Long Baseline Interferometry (VLBI), Global Positioning System (GPS), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS), its origin is currently realized by the single technique of SLR. Consequently, it is difficult to independently evaluate the origin accuracy. Also, whether the solid Earth is expanding or shrinking has attracted persistent attention. The expansion rate, if any, has not been accurately determined before, due to insufficient data coverage on the Earth's surface and the presence of other geophysical processes. Here, we use multiple precise geodetic data sets and a simultaneous global estimation platform to determine that the ITRF2008 origin is consistent with the mean CM at the level of 0.5 mm yr−1, and the mean radius of the Earth is not changing to within 1σ measurement uncertainty of 0.2 mm yr−1. Numéro de notice : A2011-590 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1029/2011GL047450 Date de publication en ligne : 08/07/2011 En ligne : https://doi.org/10.1029/2011GL047450 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90909
in Geophysical research letters > vol 38 n° 13 (July 2011) . - 5 p.[article]
