Simulation experiments on high-precision VGOS time transfer for future geopotential difference determination

Wu, Yifan; Shen, Wenbin

doi:10.1016/j.asr.2021.05.005

Cited by 3 publications

(2 citation statements)

References 42 publications

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“…In the solution, we imposed a constraint of 1.3 cm on the relative variation of the piecewise linear clock, while for the zenith wet delay, this constraint was set at 1.5 cm, and the estimation interval of the respective parameters was set to 60 min [53]. It should be noted that our choice of constraints will have an impact on the results obtained.…”

Section: Estimating Erps From Vlbi Observationsmentioning

confidence: 99%

Estimation of Earth Rotation Parameters Based on BDS-3 and Discontinuous VLBI Observations

Wang,

Sang,

et al. 2024

Remote Sensing

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Earth rotation parameters (ERPs) are fundamental to geodetic and astronomical studies. With its high measurement accuracy and stability, the Very Long Baseline Interferometry (VLBI) plays an irreplaceable role in estimating the ERPs and maintaining the earth reference frame. However, the imperfect global station distribution, observation discontinuity, and vast cost of the VLBI make the GNSS a more attractive technique. In 2020, the third generation of the BeiDou Navigation System (BDS), namely BDS-3, was constructed completely. In this study, we conducted a series of experiments to estimate Earth’s rotation parameters based on the continuous BDS-3 observation data, the discontinuous VLBI observation data, and the combined BDS-3 and discontinuous VLBI observation data. We used two methods, namely the weighted averaging method and the normal equation combination method, to obtain ERP combination solutions. The results are compared with the International Earth Rotation and Reference Systems Service (IERS) EOP 20C04 at 00:00:00 UTC. Final results show that (a) the estimation accuracy becomes stable when the number of BDS-3 tracking stations is more than 40. At the same time, both the number of stations and the volume of polyhedrons formed by the observing stations affect the accuracy of the ERPs estimated by the BDS-3 or VLBI. (b) Results have also shown that the inclusion of the BDS-3 IGSO and GEO satellites contributes little to the ERP estimation. (c) For the BDS-3-only MEO satellites solution, the root mean square (RMS) was 113.2 µas, 102.8 µas, and 13.1 µs/day for X-pole coordinate, Y-pole coordinate, and length of day (LOD), respectively. For the VLBI solution, the RMSs of the X-pole, Y-pole, and LOD were 100.4 µas for the X-pole, 94.2 µas for the Y-pole, and 14.1 µs/day. The RMS was 82.6 µas, 70.3 µas, and 10.5 µs/day for the combined X-pole, Y-pole, and LOD using the weighted averaging method. It was 78.2 µas, 62.6 µas, and 8.6 µs/day when the normal equation combination method was applied. This demonstrates that by taking advantage of the BDS-3 and VLBI technique combinations, accuracy in estimating the ERPs can be improved over that using either of them, in addition to enhanced stability and reliability.

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Section: Estimating Erps From Vlbi Observationsmentioning

confidence: 99%

Estimation of Earth Rotation Parameters Based on BDS-3 and Discontinuous VLBI Observations

Wang,

Sang,

et al. 2024

Remote Sensing

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“…Another approach uses the gravity frequency shift, which is referred to as the gravity frequency shift approach (GSFA), which determines the height difference between two points after measuring their frequency shift [11], [12]. Both the CTA and GSFA are referred to as the relativistic approach and have been extensively examined and validated by scientists over several decades [4], [5], [12]- [20]. To determine the geopotential difference with an accuracy of 0.1 m 2 /s 2 (equivalent to 1 cm in orthometric height), it is required a time (or frequency) measuring system with a stability of 10 −18 .…”

Section: Introductionmentioning

confidence: 99%

Unifying the Regional Height System Using Optic-Fiber Clock Network: A Simulation Test for Southeast Asia

Hoang,

Shen,

Shen

2023

IEEE Access

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Orthometric height datum systems are critical in the geodetic community. Nonetheless, individual nations or local regions maintain their distinct height systems. These systems, primarily determined by conventional spirit leveling, exhibit inhomogeneity, as the mean sea level does not represent an equi-geopotential surface. As such, accurately unifying global height systems is a persistent challenge. The gravity frequency shift equation provides a promising approach to this issue, offering a means to unify global height systems by comparing the frequencies of two distant clocks via optical fibers. In this study, we develop a model based on the Optical Fiber Frequency Transfer (OFFT) method, recognized for its unparalleled precision. We simulated a network of optical clocks interconnected by optical fibers to unify the height system across Southeast Asia. Our study suggests that the optical fiber clock network can realize height propagation between any two height datums at the centimeter level, providing a favorable opportunity for achieving regional height system unification. INDEX TERMS Regional height system; optical clocks network; OFFT; gravity frequency shift; frequency transfer; geopotential.

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Measuring the gravity potential between two remote sites with CVSTT technique using two hydrogen clocks

Wu,

Shen,

Sun

et al. 2023

Geo-spatial Information Science

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Simulation experiments on high-precision VGOS time transfer for future geopotential difference determination

Cited by 3 publications

References 42 publications

Estimation of Earth Rotation Parameters Based on BDS-3 and Discontinuous VLBI Observations

Estimation of Earth Rotation Parameters Based on BDS-3 and Discontinuous VLBI Observations

Unifying the Regional Height System Using Optic-Fiber Clock Network: A Simulation Test for Southeast Asia

Measuring the gravity potential between two remote sites with CVSTT technique using two hydrogen clocks

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