Results 51 to 60 of about 822 (179)

Ionospheric Data Fusion With GNSS, GNSS‐RO and Satellite Altimetry Based on Machine Learning

Journal of Geophysical Research: Machine Learning and Computation, Volume 3, Issue 3, June 2026.
Abstract Global Ionospheric Maps (GIMs) are essential in Global Navigation Satellite System (GNSS) applications, particularly for correcting ionospheric delays in single‐frequency positioning. GIMs are mainly derived from dual‐frequency GNSS observations, but the uneven distribution of ground stations—sparse over oceans—reduces accuracy in these ...
Marcel Iten, Shuyin Mao, Benedikt Soja
wiley   +1 more source

Frequency Standard Contributions to Limitations on the Signal‐to‐Noise Ratio in Very Long Baseline Interferometric Observations

Radio Science, Volume 61, Issue 6, June 2026.
Abstract Since its observation in 2019, the first image of a super‐massive black hole using Very Long Baseline Interferometry (VLBI) with an Earth‐scale baseline has generated much scientific and public interest. Work is now underway to extend the baseline into space to obtain higher image resolution.
E. A. Burt, T. A. Ely, G. C. Bower, T. J. W. Lazio, M. Anderson, S. Hernandez   +5 more
wiley   +1 more source

РАДИОСТРУКТУРА ИСТОЧНИКА 1803÷784

Odessa Astronomical Publications, 2011
Results of processing of data of ground-space VLBI experiment titled V053 are presented. These observations were made in 1997 October with 10 antennas of American interferometer VLBA and with Japan space telescope VSOP (VLBI Space Orbit Program).
A. А. Чуприков
doaj   +1 more source

Effects of Surface Errors of Antennas on Detection Performance of Space VLBI

Aerospace, 2022
This work investigates the effects of the surface errors of the satellite antenna on the detection performance of the space VLBI system. First, the relationship between the surface errors and the antenna gain loss is analyzed, and then the influence of ...
Yangyang Zhang, Huijie Liu, Xingfu Liu
doaj   +1 more source

The AuScope geodetic VLBI array [PDF]

Journal of Geodesy, 2013
Journal of Geodesy, March ...
Lovell, J., McCallum, J., Reid, P., McCulloch, P., Baynes, B., Dickey, J., Shabala, S., Watson, C., Titov, O., Ruddick, R., Twilley, R., Reynolds, Cormac, Tingay, Steven, Shield, P., Adada, R., Ellingsen, S., Morgan, John, Bignall, Hayley   +17 more
openaire   +3 more sources

Improving the Accuracy of Polar Motion Prediction by Combining Least Squares and the iTransformer Model

Earth and Space Science, Volume 13, Issue 5, May 2026.
Abstract Polar motion prediction is an important means to study the dynamics of Earth's rotation and detect the internal structure of the Earth. This paper proposes an LS + iTransformer method that combines the least squares (LS) method with the iTransformer deep learning model. Using IERS EOP 20 C04 data from 2000 to 2022, Fast Fourier Transform (FFT)
Huizhong Zhu, Yi Yang, Chunhua Jiang, Wenfeng Nie, Zhenyu Luo, Zhangzhen Sun   +5 more
wiley   +1 more source

VLBI with TDRSS [PDF]

International Astronomical Union Colloquium, 1990
AbstractVLBI observations using a satellite in earth orbit and ground antennas in Japan and Australia were conducted in 1986, 1987, and 1988. Sources were detected on space-ground baselines at both observing frequencies: 2.3 and 15 GHz. The coherence on space-ground baselines for 340 s was 90% at 2.3 GHz and 76% at 15 GHz.
openaire   +1 more source

Describing the uncertainties in VLBI images [PDF]

Proceedings of 11th European VLBI Network Symposium & Users Meeting — PoS(11th EVN Symposium), 2016
We are investigating a new approach to modelling uncertainties in individual pixels of Very Long Baseline Interferometry (VLBI) intensity (Stokes I, Q, U) images. Comparison of distributions of our calculated uncertainties for model sources with the results of Monte Carlo simulations shows that our method correctly reproduces the overall level and ...
Coughlan, Colm P., Gabuzda, Denise C.
openaire   +2 more sources

Research on Polar Motion Prediction Accuracy Based on ETH and GFZ Angular Momentum Forecast Products

Earth and Space Science, Volume 13, Issue 5, May 2026.
Abstract Polar motion (PM), a critical element of Earth Orientation Parameters (EOP), is essential for high‐precision applications such as deep space exploration and satellite navigation. Recent advances in prediction methods utilizing Effective Angular Momentum (EAM) data have become a key pathway for enhancing PM forecast accuracy.
Xishun Li, Yuanwei Wu, Qiaoli Kong, Hai‐Hua Qiao, Tangrenjie Ye, Haiyan Yang, Zhizhuo Zhang, Xuan Cheng, Xuhai Yang, Xiaohui Li, Shougang Zhang   +10 more
wiley   +1 more source

Evaluate the Prediction Level of Polar Motion Interpolation for 6 hr in Ideal and Real Environments

Earth and Space Science, Volume 13, Issue 1, January 2026.
Abstract With the increasing demands for global development, deep space exploration missions are taking place more frequently, rendering the traditional 24‐hr Polar Motion (PM) predictions inadequate for supporting the frequent operations of spacecraft.
Wei Miao, Xueqing Xu, Yonghong Zhou
wiley   +1 more source