JTRF2014, the JPL Kalman filter and smoother realization of the International Terrestrial Reference System

Abbondanza, Claudio; Chin, T. M.; Gross, R. S.; Heflin, M. B.; Parker, Jay; Soja, Benedikt; Dam, Tonie vanÂ; Wu, Xiaoping

doi:10.1002/2017jb014360

Cited by 43 publications

(25 citation statements)

References 99 publications

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“…Another realization of ITRS is the JTRF2014 developed by Jet Propulsion Laboratory (JPL) based upon the Kalman filter and smoother algorithms (Wu et al 2015, Abbondanza et al 2017. This is a subsecular, time-series based terrestrial reference frame whose origin is at the quasi-instantaneous CM as detected by the SLR technique.…”

Section: Definition Of the Geocenter Motionmentioning

confidence: 99%

Analysis of Systematic Errors in Geocenter Coordinates Determined From GNSS, SLR, DORIS, and GRACE

Kosek

Popiński²,

Wnęk

et al. 2019

Pure Appl. Geophys.

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The goal of this paper is to determine and analyze the common geocenter signal from the geocenter coordinates based on four independent techniques: Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS), Global Navigation Satellite System (GNSS), Gravity Recovery And Climate Experiment with the ocean bottom pressure model, and Satellite Laser Ranging, and to analyze the residuals as the differences between these geocenter coordinates and their common signal. Another objective of this paper is to compute variable amplitudes and phases of the annual and semi-annual oscillations in the geocenter coordinates of these techniques by the combination of the Fourier Transform Band Pass Filter (FTBPF) with the Hilbert Transform (FTBPF + HT) and to compare their mean values with those obtained by other authors. It was assumed that the geocenter time series of individual techniques consist of the common signal of geocenter motion, systematic errors resulting from orbital modeling and noise. Generally, the annual oscillation amplitudes in these techniques computed by the FTBPF + HT vary in time and their mean values are of the order of 2 mm for the X coordinate, 2.4–3.6 mm for the Y coordinate and 2.8–5.6 mm for the Z coordinate and the semi-annual oscillation amplitude is variable and about two times smaller than the annual one. The phases of these two oscillations are also variable, there are differences in their mean values for different techniques and the semi-annual oscillation phases changes throughout the entire phase range. To detect the common geocenter signal the wavelet-based semblance filtering (WBSF) method was applied. The weighted mean model was computed from all geocenter coordinate pairs from individual techniques assuming weights as inversely proportional to the variances of differences between the geocenter coordinates and their corresponding WBSF outputs. The average and median models computed from these outputs show a good agreement with the weighted mean model and generally, the average amplitudes of the annual signal in these models are of the order of 2 mm in each geocenter coordinate. The FTBPF amplitude spectra of these models reveals the retrograde annual oscillation in the XY equatorial plane. The FTBPF and FTBPF + HT amplitude spectra of geocenter time series and their residuals show mainly the maxima of different heights in the annual frequency band. The annual oscillations left in all residuals and oscillations with period less than ~ 120 days in DORIS and GNSS amplitude spectra may be caused by systematic errors of techniques resulting from mis-modeling of satellite orbits.

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Section: Definition Of the Geocenter Motionmentioning

confidence: 99%

Analysis of Systematic Errors in Geocenter Coordinates Determined From GNSS, SLR, DORIS, and GRACE

Kosek

Popiński²,

Wnęk

et al. 2019

Pure Appl. Geophys.

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“…These solutions are derived from the analysis of Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS), Global Positioning System (GPS), satellite laser ranging (SLR), and very long-baseline interferometry (VLBI) observations. Three new recently released ITRS realizations are ITRF2014 (Altamimi et al, 2016), DTRF2014 (Seitz et al, 2016), and JTRF2014 (Abbondanza et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Impact of terrestrial reference frame realizations on altimetry satellite orbit quality and global and regional sea level trends: a switch from ITRF2008 to ITRF2014

Rudenko¹,

Esselborn

Schöne

et al. 2019

Solid Earth

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Abstract. A terrestrial reference frame (TRF) is a basis for precise orbit determination of Earth-orbiting satellites, since it defines positions and velocities of stations, the tracking data of which are used to derive satellite positions. In this paper, we investigate the impact of the International Terrestrial Reference Frame realization ITRF2014, as compared to its predecessor ITRF2008, on the quality of orbits, namely, on root-mean-square (rms) fits of observations and orbital arc overlaps of three altimetry satellites (TOPEX/Poseidon, Jason-1, and Jason-2) in the time interval from August 1992 to April 2015 and on altimetry products computed using these orbits, such as single-satellite altimeter crossover differences, radial and geographically correlated mean sea surface height (SSH) errors and regional and global mean sea level trends. The satellite orbits are computed using satellite laser ranging (SLR) and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) observations of a global network of stations. We have found that using ITRF2014 generally improves the orbit quality as compared to using ITRF2008. Thus, the mean values of the rms fits of SLR observations decreased (improved) by 2.4 % and 8.8 % for Jason-1 and Jason-2, respectively, but are almost not impacted for TOPEX/Poseidon when using ITRF2014 instead of ITRF2008. The internal orbit consistency in the radial direction (as derived from arc overlaps) is reduced (improved) by 6.6 %, 2.3 %, and 5.9 % for TOPEX/Poseidon, Jason-1, and Jason-2, respectively. Single-satellite altimetry crossover analyses indicate reduction (improvement) in the absolute mean crossover differences by 0.2 mm (8.1 %) for TOPEX, 0.4 mm (17.7 %) for Jason-1, and 0.6 mm (30.9 %) for Jason-2 with ITRF2014 instead of ITRF2008. The major improvement of the mean values of the rms of crossover differences (0.13 mm; 0.3 %) has been found for Jason-2. Multi-mission crossover analysis shows slight improvements in the standard deviations of radial errors: 0.1 %, 0.2 %, and 1.6 % for TOPEX, Jason-1, and Jason-2, respectively. The standard deviations of geographically correlated mean SSH errors improved by 1.1 % for Jason-1 and 5.4 % for Jason-2 and degraded by 1.3 % for TOPEX. The change from ITRF2008 to ITRF2014 orbits only has minor effects on the estimation of regional and global sea level trends over the 22-year time series from 1993 to 2015. However, on interannual timescales (3–8 years) large-scale coherent trend patterns are observed that seem to be connected to drifts between the origins of the tracking station networks. This leads to the changes in interannual global mean sea level of up to 0.06 mm yr−1 for TOPEX, 0.05 mm yr−1 for Jason-1, and up to 0.12 mm yr−1 for Jason-2, i.e., up to 4 % of the corresponding sea level signal based on altimetry for timescales of 3 to 8 years. The respective changes in the regional sea level trend on these timescales are up to 0.4 mm yr−1 in the time span from April 1993 to July 2008 and up to 1.0 mm yr−1 in the time span from July 2008 to April 2015.

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“…Based upon a Kalman filter and smoother algorithm (Soja et al 2016), the JPL team adopts a state vector formulation including position-related variables, Helmert transformation parameters from each individual observing space-geodetic network to the final combined frame and daily EOPs, assimilates the pseudo-observations of position derived from the four space-geodetic techniques at a weekly resolution along with daily EOPs and, when available, site tie observations and realizes a sub-secular TRF (JTRF2014, (Abbondanza et al 2017)) whose origin is at the quasi-instantaneous CM as detected by SLR, whose scale is the weighted average of the quasi-instantaneous scales materialized by fortnightly/weekly SLR and quasi-daily VLBI sessions and whose orientation is defined via application of weekly no-net-rotation (NNR) conditions with respect to ITRF2008.…”

Section: Introductionmentioning

confidence: 99%

“…Parameters and their representation in technique-specific pseudo-observation equation As for the introduction of LTs,(Abbondanza et al 2017) indicated that local tie vectors were applied only once at the epoch of their measurements (as stated in the input SINEX files) for the realization of JTRF2014. For the realization of both ITRF2014 and DTRF2014, the pseudoobservations for the selected LTs were introduced once for the final inter-technique combination.…”

mentioning

confidence: 99%

Weekly inter-technique combination of SLR, VLBI, GPS and DORIS at the solution level

Lian

Wang

Huang

et al. 2018

Res. Astron. Astrophys.

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Constructing and maintaining a stable terrestrial reference frame is one of the key objectives of fundamental astronomy and geodesy. The datum realization for all the global terrestrial reference frame versions such as ITRF2014 and its predecessor ITRF2008, etc. is by assuming linear time evolution for transformation parameters and then imposing some conditions on these Helmert transformation parameters allowing defining the combined frame of the long-term solution at a reference epoch and its time evolution. By definition, ITRF adopted only linear motion of the Helmert parameters with uncertainty, while some publications have shown that translation-related uncertainties are underestimated. In this paper, we investigate a new approach, which is based on weekly estimation of station positions and Helmert transformation parameters from a combination of the solutions of four space-geodetic techniques, i.e., SLR, VLBI, GPS and DORIS. For this study, an interval of one week is chosen because the arc length of the SLR solutions is seven days. The major advantage of this weekly estimated reference frame is that both the non-linear station motions and the non-linear origin motion are implicitly taken into account. In order to study the non-linear behavior of station motions and physical parameters, ITRF2008 is used as a reference. As for datum definition of weekly reference frame, on the one hand SLR is the unique technique to realize the origin and determine the scale together with VLBI, on the other hand the orientation is realized via no net rotation w.r.t ITRF2005 on a subset of core stations. Given the fact that without enough collocations (i.e., at least three co-located stations) an inter-technique combined TRF could not exist, the selection and the relative weight of the local ties surveyed at co-location sites is a critical issue. To get stable results, we first assume that, if there were no events such as equipment changes between the measurement epoch of local tie and that of spacegeodetic solution (this time span called the stable period hereafter), the relative position between the two co-located stations should be invariant and this local tie could be used for computing the inter-technique combined reference frame in those weeks during the stable period of this tie. The resulting time series of both station positions and transformation parameters are studied in detail and are compared with ITRF2008. The residual station positions in the weekly combined reference frame are usually in the range of two millimeters without any periodic characteristic, but the residual station positions by deducting the regularized station position in ITRF2008 may reach a magnitude of a few centimeters and seem to have a significant annual signal. The physical parameters series between the weekly reference frame and the ITRF2008 also show the obvious existence of annual signal and reach a magnitude of one centimeter for origin motion and two ppb for the scale. 2 Li-Zhen Lian et al.

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JTRF2014, the JPL Kalman filter and smoother realization of the International Terrestrial Reference System

Cited by 43 publications

References 99 publications

Analysis of Systematic Errors in Geocenter Coordinates Determined From GNSS, SLR, DORIS, and GRACE

Analysis of Systematic Errors in Geocenter Coordinates Determined From GNSS, SLR, DORIS, and GRACE

Impact of terrestrial reference frame realizations on altimetry satellite orbit quality and global and regional sea level trends: a switch from ITRF2008 to ITRF2014

Weekly inter-technique combination of SLR, VLBI, GPS and DORIS at the solution level

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