Results 31 to 40 of about 424 (141)

Observing APOD with the AuScope VLBI Array

Sensors, 2018
The possibility to observe satellites with the geodetic Very Long Baseline Interferometry (VLBI) technique is vividly discussed in the geodetic community, particularly with regard to future co-location satellite missions.
Andreas Hellerschmied, Lucia McCallum, Jamie McCallum, Jing Sun, Johannes Böhm, Jianfeng Cao   +5 more
doaj   +1 more source

Calibrating VLBI Polarization Data Using GPCAL. II. Time-dependent Calibration

The Astrophysical Journal, 2023
We present a new method of time-dependent instrumental polarization calibration for very long baseline interferometry (VLBI). This method has been implemented in the recently developed polarization calibration pipeline GPCAL.
Jongho Park, Keiichi Asada, Do-Young Byun   +2 more
doaj   +1 more source

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

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

FinalKAN: A Dual‐Stream KAN Network Integrating Multisource Features for Radio Telescope Pointing Correction

Advances in Astronomy, Volume 2026, Issue 1, 2026.
This paper investigates the degradation of pointing accuracy in the Kunming 40‐m radio telescope due to long‐term equipment aging and environmental disturbances. Conventional linear pointing models are constrained by their linear modeling framework, making it difficult to accurately represent the nonlinear errors induced by temperature, wind speed, and
Yao He, Longfei Hao, Wei Dai, Fernando Aguado Agelet   +3 more
wiley   +1 more source

The Celestial Reference Frame at K Band: The CRF-K-2025 Catalog

The Astronomical Journal
We present an updated K -band (24 GHz) celestial reference frame (CRF) constructed from ∼3.5 million very long baseline interferometry (VLBI) observations collected during 211 observing epochs between 2002 May and 2025 December using the Very Long ...
David Gordon, Aletha de Witt, Christopher S. Jacobs, Hana Krásná, Alessandra Bertarini, Jamie McCallum, Jonathan Quick, Cristina García-Miró, Taehyun Jung, Jeffrey A. Hodgson, Whee Yeon Cheong, Sang-Sung Lee, Do-Young Byun   +12 more
doaj   +1 more source

Radiometric Interferometry for Deep Space Navigation Using Geostationary Satellites

Aerospace
Deep space navigation, defined as spacecraft position tracking beyond the lunar orbit, presents significant challenges due to the extremely weak Global Navigation Satellite System (GNSS) signals and severe signal attenuation over interplanetary distances.
Moshe Golani, Yoram Rozen, Hector Rotstein   +2 more
doaj   +1 more source

The Short-Arc Precise Orbit Determination of GEO Satellites Using VLBI and Transfer Ranging

Remote Sensing, 2022
It is important for a geostationary Earth orbit (GEO) satellite to rapidly recover its orbit after a maneuver with short-arc precise orbit determination (POD).
Kai Nan, Fen Cao, Jianjun Gong, Hui Lei, Zhigang Li, Xuhai Yang   +5 more
doaj   +1 more source

Very Long Baseline Interferometry in Italy Wide-field VLBI imaging and astrometry and prospects for an Italian VLBI network including the Sardinia Radio Telescope [PDF]

, 2010
In this thesis the use of widefield imaging techniques and VLBI observations with a limited number of antennas are explored. I present techniques to efficiently and accurately image extremely large UV datasets. Very large VLBI datasets must be reduced into multiple, smaller datasets if today’s imaging algorithms are to be used to image them.
openaire   +1 more source

A History of UNAVCO: Four Decades of Advancing Geodesy

Perspectives of Earth and Space Scientists, Volume 6, Issue 1, December 2025.
Abstract UNAVCO was a university‐governed consortium funded by the National Science Foundation (NSF), with support from the National Aeronautics and Space Administration (NASA) and the United States Geological Survey (USGS), to support geoscience research and education using geodesy.
Emily E. Zawacki, Donna J. Charlevoix, Charles M. Meertens, Jeffrey T. Freymueller, Tonie van Dam   +4 more
wiley   +1 more source