Earth rotation and network geometry optimization for very long baseline interferometers

Dermanis, Athanasios; Mueller, Ivan I.

doi:10.1007/bf02521695

Cited by 11 publications

(6 citation statements)

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“…Detailed consideration of this equation which can be found e.g. in Dermanis and Mueller (1978), Ma (1978), Nothnagel et al (1994), Schuh (2000), along with a joint analysis of the set of Eqs.…”

Section: Introductionmentioning

confidence: 99%

“…1 .This study begins with the computation of an about 10.7-year EOP series for the period from July 1996 till February 2007, 1440 24-hour sessions in total. The start epoch of the investigated time series was chosen to be the same as the start epoch of the IGS EOP series igs00p03.erp used hereafter for accuracy assessment of the VLBI terrestrial pole coordinates.…”

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confidence: 99%

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On comparison of the Earth orientation parameters obtained from different VLBI networks and observing programs

Malkin

2008

J Geod

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In this paper, a new geometry index of Very Long Baseline Interferometry (VLBI) observing networks, the volume of network V , is examined as an indicator of the errors in the Earth orientation parameters (EOP) obtained from VLBI observations. It has been shown that both EOP precision and accuracy can be well described by the power law σ = aV c in a wide range of the network size from domestic to global VLBI networks. In other words, as the network volume grows, the EOP errors become smaller following a power law. This should be taken into account for a proper comparison of EOP estimates obtained from different VLBI networks. Thus performing correct EOP comparison allows us to accurately investigate finer factors affecting the EOP errors. In particular, it was found that the dependence of the EOP precision and accuracy on the recording data rate can also be described by a power law. One important conclusion is that the EOP accuracy depends primarily on the network geometry and to lesser extent on other factors, such as recording mode and data rate and scheduling parameters, whereas these factors have stronger impact on the EOP precision.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

On comparison of the Earth orientation parameters obtained from different VLBI networks and observing programs

Malkin

2008

J Geod

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“…Also, the current combination by exploits the second approach where NEQs of both VLBI and GNSS are used, unlike the work by Nilsson et al (2013), where the estimates of the rapid GNSS product are adjusted in NEQs of VLBI Intensives by means of a Kalman filter. Moreover, an approach for an ultrarapid ERP determination is given in Haas et al (2017). For the approach in this study, a common parameterization of all EOPs in each technique-specific NEQ is required.…”

Section: The Combination At the Observation Level Of The Gauß-mentioning

confidence: 99%

Combination of VLBI Intensive Sessions with GNSS for generating Low latency Earth Rotation Parameters

Hellmers¹,

Thaller²,

Bloßfeld³

et al. 2019

Adv. Geosci.

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Abstract. The Earth Orientation Parameters (EOPs) are published by the Earth Orientation Centre of the International Earth Rotation and Reference Systems Service (IERS). They are provided as the low-latency Bulletin A and the 30 d latency long-term EOP time series IERS 14 C04. The EOPs are a combined product derived from different geodetic space techniques, namely Global Navigation Satellite Systems (GNSS), Satellite Laser Ranging (SLR) and Lunar Laser Ranging (LLR), Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) and Very Long Baseline Interferometry (VLBI). Since not all techniques are equally sensitive to every EOP, several parameters rely on specific observation techniques. As an example, dUT1 can only be estimated from VLBI observations. This means VLBI is an essential part of the estimation procedure for consistent EOPs. Within this paper, we are performing a combination of two low-latency space geodetic techniques as they enable the estimation of the full set of Earth Rotation Parameters (ERPs; polar motion, dUT1 and the corresponding rates). In particular, we focus on the development of a robust combination scheme of 1 h VLBI Intensive sessions with so-called GNSS Rapid solutions on the normal equation level of the Gauß-Markov model. The aim of the study is to provide highly accurate low-latency ERPs. So far, a latency of approximately only 1–3 d cold be reached since the main limiting factor is still the latency of the input data. The mathematical background of the applied algorithm is discussed in detail and evaluated by numerical results of empirical investigations. The combination yields a numerical stabilization of the equation system as well as an improvement (reduction) of the corresponding root mean square deviation of the epoch-wise estimated parameters w.r.t. the IERS 14 C04 reference time series.

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“…The dUT1 parameter is the most variable quantity among the EOP with significant unpredictable variations (Dermanis and Mueller 1978;Artz et al 2014). These can only be measured with the quasi space-fixed technique VLBI (Thaller 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Due to the sparse network and short observation time, the INT sessions are not suitable for the determination of other EOP components. The big advantages of these sessions are, however, the latency of two days or even less as well as the scheduling for each day (Nothnagel and Schnell 2008;Nothnagel et al 2017;Dermanis and Mueller 1978). Figure 1 illustrates the weekly session distribution of the GNSS and both VLBI observation campaigns used for our combination.…”

Section: Introductionmentioning

confidence: 99%

On the Improvement of Combined EOP Series by Adding 24-h VLBI Sessions to VLBI Intensives and GNSS Data

Lengert

Thaller

Flohrer

et al. 2022

International Association of Geodesy Symposia

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The publicly available Earth Orientation Parameter (EOP) time series provided by the Earth Orientation Centre of the IERS (e.g., IERS Bulletin A, IERS 14 C04) result from the combination of individual space-geodetic solutions on a daily basis, i.e., a parameter-level combination. Current activities of the Federal Agency for Cartography and Geodesy (BKG) focus on the development of a combination strategy, the main objective of which is to improve the consistency between the space-geodetic techniques through common parameters, i.e., mainly EOP, but also station coordinates and tropospheric parameters using local ties and atmospheric ties, respectively. In this study, we present our combination strategy and the results of the combination of VLBI data available within approximately two weeks (i.e., Intensive and R1/R4 sessions) with data from the global GNSS network. The combination is done at the normal equation (NEQ) level on a daily and multi-day basis. We compare our EOP solutions with the respective daily and multi-day single-technique EOP solutions as well as with the low-latency inter-technique EOP time series (COMBI RAP) examined in previous studies, which is based on the combination of GNSS and VLBI Intensive data only. We found regarding the dUT1 solution, that the addition of the VLBI R1/R4 sessions to the VLBI Intensives and GNSS data has a positive impact on the entire 7-day solution, and especially stabilizes the dUT1 estimates of the boundary days of the multi-day continuous polygon. The dUT1 estimates of the left and right boundary day compared to IERS Bulletin A and COMBI RAP reveal an improvement in terms of WRMS of the residuals by 2.3 μs and 1.4 μs, respectively. For the pole coordinates, the consistency of the estimates with external reference series is almost at the same level as for the COMBI RAP solution.

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Earth rotation and network geometry optimization for very long baseline interferometers

Cited by 11 publications

References 2 publications

On comparison of the Earth orientation parameters obtained from different VLBI networks and observing programs

On comparison of the Earth orientation parameters obtained from different VLBI networks and observing programs

Combination of VLBI Intensive Sessions with GNSS for generating Low latency Earth Rotation Parameters

On the Improvement of Combined EOP Series by Adding 24-h VLBI Sessions to VLBI Intensives and GNSS Data

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