Consistent realization of Celestial and Terrestrial Reference Frames

Kwak, Younghee; Bloßfeld, M; Schmid, Ralf; Angermann, D; Gerstl, M; Seitz, Matthias

doi:10.1007/s00190-018-1130-6

Cited by 9 publications

(7 citation statements)

References 25 publications

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“…The IAG Resolution 2 at the International Union of Geodesy and Geophysics (IUGG) General Assembly in Melbourne (2011) recommends that the highest consistency between the ICRF, the ITRF and the EOP should be a primary goal in all future realizations of the ICRS (IUGG Website 2022). Although the IUGG recommendation has not yet been fulfilled, research in this direction has been initiated and simultaneous estimation of CRF, TRF, and EOP have been achieved (Seitz et al 2014;Kwak et al 2018). At the international level, this topic is being addressed by the ICRF3 Working Group of the International Astronomical Union and by Sub-Commission 1.4 on the Interaction of Celestial and Terrestrial Reference Frames of the IAG.…”

Section: Unification Of Reference Frames and Earth Rotationmentioning

confidence: 99%

GENESIS: co-location of geodetic techniques in space

Delva

Altamimi

Blazquez

et al. 2023

Earth Planets Space

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Improving and homogenizing time and space reference systems on Earth and, more specifically, realizing the Terrestrial Reference Frame (TRF) with an accuracy of 1 mm and a long-term stability of 0.1 mm/year are relevant for many scientific and societal endeavors. The knowledge of the TRF is fundamental for Earth and navigation sciences. For instance, quantifying sea level change strongly depends on an accurate determination of the geocenter motion but also of the positions of continental and island reference stations, such as those located at tide gauges, as well as the ground stations of tracking networks. Also, numerous applications in geophysics require absolute millimeter precision from the reference frame, as for example monitoring tectonic motion or crustal deformation, contributing to a better understanding of natural hazards. The TRF accuracy to be achieved represents the consensus of various authorities, including the International Association of Geodesy (IAG), which has enunciated geodesy requirements for Earth sciences. Moreover, the United Nations Resolution 69/266 states that the full societal benefits in developing satellite missions for positioning and Remote Sensing of the Earth are realized only if they are referenced to a common global geodetic reference frame at the national, regional and global levels. Today we are still far from these ambitious accuracy and stability goals for the realization of the TRF. However, a combination and co-location of all four space geodetic techniques on one satellite platform can significantly contribute to achieving these goals. This is the purpose of the GENESIS mission, a component of the FutureNAV program of the European Space Agency. The GENESIS platform will be a dynamic space geodetic observatory carrying all the geodetic instruments referenced to one another through carefully calibrated space ties. The co-location of the techniques in space will solve the inconsistencies and biases between the different geodetic techniques in order to reach the TRF accuracy and stability goals endorsed by the various international authorities and the scientific community. The purpose of this paper is to review the state-of-the-art and explain the benefits of the GENESIS mission in Earth sciences, navigation sciences and metrology. This paper has been written and supported by a large community of scientists from many countries and working in several different fields of science, ranging from geophysics and geodesy to time and frequency metrology, navigation and positioning. As it is explained throughout this paper, there is a very high scientific consensus that the GENESIS mission would deliver exemplary science and societal benefits across a multidisciplinary range of Navigation and Earth sciences applications, constituting a global infrastructure that is internationally agreed to be strongly desirable. Graphical Abstract

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Section: Unification Of Reference Frames and Earth Rotationmentioning

confidence: 99%

GENESIS: co-location of geodetic techniques in space

Delva

Altamimi

Blazquez

et al. 2023

Earth Planets Space

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“…The SLR and VLBI NEQs are free from datum constraints and thus only contain the datum information to which the respective observations are sensitive. The SLR and VLBI data processing was carried out with the Orbit Computation (-OC) and Radio Interferometry (-RI) branches of the DGFI Orbit and Geodetic parameter estimation Software (DOGS; Bloßfeld, 2015;Gerstl, 1997;Kwak et al, 2017), respectively. The resulting weekly (SLR) or session-wise (VLBI) NEQs for combination are provided in the SINEX v2.02 format.…”

Section: Satellite Laser Ranging and Very Long Baseline Interferometrymentioning

confidence: 99%

Combination Strategy for the Geocentric Realization of Regional Epoch Reference Frames

et al. 2022

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For high‐resolution regional geodetic applications, the International Terrestrial Reference Frame (ITRF) is complemented by regional densifications. These are realized either as multi‐year solutions related to a tectonic plate (e.g., EUREF for Europe) or as epoch reference frames (ERFs) to capture nonlinear geophysical station motions caused by, for example, earthquakes or non‐tidal loading (e.g., SIRGAS for Latin America). These Global Navigation Satellite Systems (GNSS)‐only based regional reference frames have in common that their geodetic datum is aligned with the ITRF datum at a specific epoch. The consequence is that their origin represents the Earth's center of figure and does not coincide with the instantaneous center of mass. Here, we present studies on a direct geocentric realization of regional ERFs. We propose to realize the geodetic datum for each epoch by combining global GNSS, Satellite Laser Ranging, and Very Long Baseline Interferometry networks via measured local ties at co‐located sites. A uniformly distributed global GNSS network is used to realize the orientation via a no‐net‐rotation constraint with respect to the ITRF and is densified by the stations of the regional subnetwork. The developed combination and filtering strategy aims to guarantee a stable datum realization for each epoch‐wise solution. Validating our results against global reference frames and geophysical loading models relating to the Earth's centers of mass and figure, we show that the realized displacement time series are geocentric and reflect seasonal geophysical processes. As the approach does not need to rely on co‐location sites in the region of interest, it is conceptually transferable to other regions on the globe.

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“…To compensate for the insufficient density of VLBI observations and the unstable GPS solutions, GPS observations from 17 globally distributed and relatively stable IGS sites were processed by GAMIT, and the VLBI observations from the same period were processed by OCCAM (Wei et al 2016). GNSS and VLBI observations from 2005 to 2015 were used to simultaneously estimate the EOP from an intertechnique combined normal equation (NEQ), the results indicated that the standard deviations of the EOP improved by the inter-technique combination, which demonstrates the benefits of a common estimation of all parameters (Kwak et al 2018). The VLBI observations from October 1 to 15, 2020 were estimated and compared with the ERP obtained from the simultaneous GPS data solved by GAMIT, the experimental results revealed that the accuracy of both solutions is in the same order of magnitude (Qian et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Comparative Analysis of Earth Rotation Parameters Using VLBI Observations During CONT and GNSS Observations

Sun

et al. 2022

Preprint

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The Earth rotation parameters mainly include the displacement and rate of the Earth's poles, length of day, which can be estimated based on VLBI and GNSS. In order to obtain the ERP results with higher accuracy, two VLBI data processing schemes were compared. VLBI observations during 2008, 2011, 2014, and 2017 are processed with VieVS. In addition, the experiments to estimate ERP using CONT08, CONT11, CONT14, and CONT17 campaigns were also designed. The results showed that the higher accuracy of ERP were calculated using CONT campaigns. At the same time, ERP estimations using the 86 globally distributed GNSS observatories data during the same period were processed by GAMIT. The ERP results from the CONT campaigns and GNSS observations estimated were then combined in a weighted manner, based on the Helmert variance component estimation and the IERS14 C04 sequences, respectively. The weighted results showed that the Root Mean Square Error (RMSE) of polar motion was about between 0.05 and 0.10 mas, and the RMSE in UT1-UTC ranged from 0.005 and 0.02 ms.

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Consistent realization of Celestial and Terrestrial Reference Frames

Cited by 9 publications

References 25 publications

GENESIS: co-location of geodetic techniques in space

GENESIS: co-location of geodetic techniques in space

Combination Strategy for the Geocentric Realization of Regional Epoch Reference Frames

Comparative Analysis of Earth Rotation Parameters Using VLBI Observations During CONT and GNSS Observations

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