Upgraded modelling for the determination of centre of mass corrections of geodetic SLR satellites: impact on key parameters of the terrestrial reference frame

Rodríguez, José; Appleby, G. M.; Otsubo, Toshimichi

doi:10.1007/s00190-019-01315-0

Cited by 25 publications

(28 citation statements)

References 30 publications

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“…Despite a large area of the ring retroreflector, the precision of the SLR measurements should be better for single-photon detectors because the probability of the reflection from each corner cube is the same. Therefore, when an SLR station collects hundreds or thousands of single full-rate reflections and generates one normal point based on 300 s of observations, the mean SLR observation corresponds to the centroid of the LRA onboard the GLONASS-K1 (Sośnica et al 2015;Rodríguez et al 2019). The future GLONASS-K2 will be equipped with ring LRAs with the number of corner cubes reduced to 36.…”

Section: Glonassmentioning

confidence: 99%

Quality assessment of experimental IGS multi-GNSS combined orbits

et al. 2020

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The International GNSS Service (IGS) Analysis Center Coordinator initiated in 2019 an experimental multi-GNSS orbit combination service by adapting the current combination software that has been used for many years for IGS GPS and GLONASS combinations. The multi-GNSS orbits are based on individual products generated by IGS and multi-GNSS Pilot Project analysis centers. However, the combinations are not yet considered to be the final products at this time. The goal of this research is to provide a quality assessment of the very first IGS experimental multi-GNSS combined orbits based on Satellite Laser Ranging (SLR) observations and the mean position errors from the orbit combinations. The errors available in the combined orbit files provide information about the consistency between orbits from different analysis centers, whereas SLR provides independent orbit validation results even for those satellites which are considered only by one analysis center, and thus, the quality of the combination is not provided in the orbit files. We found that the BeiDou-3 satellites manufactured by China Academy of Space Technology and Shanghai Engineering Center for Microsatellites are characterized by opposite SLR residual dependencies with respect to the position of the sun which means that the orbit models for BeiDou-3 need further improvement. Smallest SLR residuals are obtained for Galileo, GLONASS-K1, and GLONASS-M+. However, the latter is characterized by a bias of + 29 mm. The mean standard deviations of SLR residuals are 23, 29, 87, 51, 40, and 72 mm for Galileo, GLONASS, BeiDou GEO, BeiDou IGSO, BeiDou MEO, and QZSS, respectively. The mean orbit combination errors in the radial direction are three times lower than those from SLR residuals in the case of MEO satellites and vary between 8 and 14 mm, whereas the orbit errors are four times lower than SLR residuals in the case of GEO and IGSO and equal to 11-21 mm.

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Section: Glonassmentioning

confidence: 99%

Quality assessment of experimental IGS multi-GNSS combined orbits

et al. 2020

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“…With the advent of system-dependent CoM corrections for the spherical geodetic satellites (Otsubo and Appleby 2003;Otsubo et al 2015), it became clear that the assumption made in previous studies (i.e., using a single "standard" value for each satellite regardless of the detector types and the ranging policies of SLR stations) could no longer be considered valid at mm levels of precision. These corrections still represent an ongoing area of concern for years to come (Rodríguez et al 2019). Thus, unless treating a selected number of ranging stations as error-free, as was done in Appleby et al (2016), sharpening the numerical value of G M remains illusive.…”

Section: Contextmentioning

confidence: 99%

Self-consistent determination of the Earth’s GM, geocenter motion and figure axis orientation

Couhert

Bizouard

Mercier

et al. 2020

J Geod

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The very low-degree Earth's gravity coefficients, associated with the largest-scale mass redistribution in the Earth's fluid envelope (atmosphere, oceans and continental hydrology), are the most poorly known. In particular, the first three degree geopotential terms are important, as they relate to intrinsic Earth's mass references: gravitational coefficient (G M) of the Earth (degree 0), geocenter motion (degree 1), Earth's figure axis orientation (degree 2). This paper presents a self-consistent determination of these three properties of the Earth. The main objective is to deal with the remaining sources of altimetry satellite orbit uncertainties affecting the fundamental record of sea surface height measurements. The analysis identifies the modeling errors, which should be mitigated when estimating the geocenter coordinates from Satellite Laser Ranging (SLR) observations. The long-term behavior of the degree-0 and -2 spherical harmonics is also observed over the 34-year period 1984-2017 from the long-time history of satellite laser tracking to geodetic spherical satellites. From the analysis of the evolution of these two coefficients, constraints regarding the Earth's rheology and uncertainties in the value of G M could be inferred. Overall, the influence of the orbit characteristics, SLR station ranging/position biases and satellite signature effects, measurement modeling errors (tropospheric corrections, non-tidal deformations) are also discussed.

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“…Recent work aimed at enhancing the determination of CoM offsets has shown substantial improvements (up to 1 cm) for the Etalon satellites and significant changes in the CoM corrections for LAGEOS (Rodriguez et al 2018). These modeling upgrades will result in the publication and release of revised CoM values for the main spherical geodetic satellites currently tracked by the ILRS network (Rodríguez et al 2019).…”

Section: Systematic Error Sources In Slr Datamentioning

confidence: 99%

“…As noted earlier, the majority of these biases are positive, indicating with a significant probability that the currently used CoM model is in error for some station-satellite pairs. With the release of a new CoM model (Rodríguez et al 2019) for testing, the ASC is now in the process of a final reanalysis of the 1993-2018 data set, using the newly adopted model.…”

Section: State-of-the-art: the New Approach Of Continuous Monitoring Station Systematicsmentioning

confidence: 99%

Systematic errors in SLR data and their impact on the ILRS products

Luceri

Pirri

Rodríguez³

et al. 2019

J Geod

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The satellite laser ranging (SLR) technique has the potential to make extremely precise measurements to retroreflector arrays on orbiting satellites, with normal point range precision at a level of 1 mm for the core tracking stations of the International Laser Ranging Service (ILRS). The main limitation to achieving a similar level of range accuracy is the presence of uncorrected systematic errors, which can be attributed to various sources at the stations (e.g., calibration and/or synchronization procedures, hardware malfunctioning, nonlinearities in the time-of-flight measurement devices), as well as to modeling deficiencies, especially in the ability to refer the range measurements to the center of mass of the spacecraft. The ILRS has always been active in adopting rigorous procedures to detect and remove systematic errors from the data: a group of ILRS analysis centers routinely performs data quality control a few hours after data acquisition; the ILRS Analysis Standing Committee (ASC) is in charge of long-term monitoring and characterization of systematic errors in the observations used for the ILRS products; a Quality Control Board was established in 2015 to address SLR systems' biases and other data issues. In particular, the ASC is devoting efforts on an investigation of an alternative approach whereby a simultaneous estimation of site coordinates and range biases provides station positions that are in principle free of systematic errors. Results using this approach have shown a significant impact on the realization of the TRF, in particular by reducing the existing scale offset between the VLBI and SLR solutions and reaching a closer agreement with the ITRF2014 scale. This paper outlines the work that continues to be done to improve these products and in particular focuses on new research to evaluate rigorously any impact on the strength of coordinate solutions and geophysical inferences when systematic range errors are determined simultaneously with reference frame parameters. Future procedures for handling systematic errors will be informed by the outcome of the current investigations.

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Upgraded modelling for the determination of centre of mass corrections of geodetic SLR satellites: impact on key parameters of the terrestrial reference frame

Cited by 25 publications

References 30 publications

Quality assessment of experimental IGS multi-GNSS combined orbits

Quality assessment of experimental IGS multi-GNSS combined orbits

Self-consistent determination of the Earth’s GM, geocenter motion and figure axis orientation

Systematic errors in SLR data and their impact on the ILRS products

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