Results 41 to 50 of about 9,456 (175)

Precision tracking systems of the immediate future: A discussion [PDF]

, 1972
The present status and future expectations of four satellite tracking systems, satellite-to-satellite tracking, lasers, very long baseline interferometry (VLBI) and geoceiver are briefly ...
Smith, D. E.
core   +1 more source

The Gould's Belt Distances Survey

, 2012
Very Long Baseline Interferometry (VLBI) observations can provide the position of compact radio sources with an accuracy of order 50 micro-arcseconds. This is sufficient to measure the trigonometric parallax and proper motions of any object within 500 pc
Loinard, Laurent
core   +1 more source

Deep Space Network Radio Science and Ground‐Based Planetary Radar in the Next Decade

Radio Science, Volume 60, Issue 7, July 2025.
Abstract The Deep Space Network (DSN) has been a core operational element of NASA's crewed and robotic exploration of the Solar System since the early 1960s. The primary role of the DSN has been to acquire telemetry and navigation data, but over the years, its radiometric and radar capabilities have expanded to form a system for obtaining unique ...
R. S. Park, J. E. Riedel, N. Rodriguez‐Alvarez, M. Brozovic, L. A. M. Benner, P. Vergados, D. Buccino, C. S. Jacobs, L. S. Locke, S. W. Asmar, R. Castano, T. J. W. Lazio, J. Jao, C. Lee   +13 more
wiley   +1 more source

1.6 GHz VLBI Observations of SN 1979C: almost-free expansion

, 2009
We report on 1.6 GHz Very-Long-Baseline-Interferometry (VLBI) observations of supernova SN 1979C made on 18 November 2002. We derive a model-dependent supernova size.
A. Alberdi, Bartel, Bartel, Bartel, Chevalier, Chevalier, E. Ros, Ferrarese, I. Martí-Vidal, J. C. Guirado, J. M. Marcaide, K. W. Weiler, M. A. Perez-Torres, Marcaide, Murray, Young   +15 more
core   +1 more source

Enhanced Global Ionospheric Mapping Using Deep Ensemble Neural Networks With Uncertainty Quantification

Space Weather, Volume 23, Issue 7, July 2025.
Abstract Global ionospheric mapping is essential for ionospheric research. However, conventional approaches often struggle to accurately capture small‐scale ionospheric variations. This study proposes a deep ensemble method based on neural networks (NNs) that generates high‐accuracy global vertical total electron content (VTEC) maps along with ...
Shuyin Mao, Yuanxin Pan, Grzegorz Kłopotek, Matthias Schartner, Hana Krásná, Aletha de Witt, Benedikt Soja   +6 more
wiley   +1 more source

Preparation of the VIRAC Radio Telescope RT-32 for e-VLBI Observations

Open Astronomy, 2013
A fully steerable parabolic antenna RT-32 with the mirror diameter 32 m owned by the Ventspils International Radio Astronomy Centre (VIRAC) is available for fundamental and applied research in radio astronomy.
Skirmante K., Bezrukovs Vl., Jekabsons N., Shmeld I.   +3 more
doaj   +1 more source

Calibrating VLBI Polarization Data Using GPCAL. I. Frequency-dependent Calibration

The Astrophysical Journal, 2023
In this series of papers, we present new methods of frequency- and time-dependent instrumental polarization calibration for very long baseline interferometry (VLBI).
Jongho Park, Keiichi Asada, Do-Young Byun   +2 more
doaj   +1 more source

e-VLBI observations of Circinus X-1: monitoring of the quiescent and flaring radio emission on AU scales [PDF]

, 2011
A recent detection of the peculiar neutron star X-ray binary Circinus X-1 with electronic very long baseline interferometry (e-VLBI) prompted the suggestion that compact, non-variable radio emission persists through the entire 16.6-day orbit of the ...
A. K. Tzioumis, A. Moin, Blandford, C. J. Phillips, C. Reynolds, Calvelo, Deller, Fender, Fomalont, G. D. Nicolson, Greisen, Haynes, Haynes, Heinz, Homan, Iaria, J. C. A. Miller-Jones, Jonker, Jonker, Kaluzienski, Linares, Murdin, Nicolson, Oosterbroek, Phillips, Preston, R. P. Fender, S. J. Tingay, Shepherd, Shirey, Soleri, Soleri, Stewart, Tudose, Tudose, van der Laan   +35 more
core   +2 more sources

Correcting Non‐Tidal Atmospheric and Oceanic Loading Displacements at the Observation, Normal Equation, and Parameter Levels in GNSS Data Analysis

Journal of Geophysical Research: Solid Earth, Volume 130, Issue 6, June 2025.
Abstract Non‐tidal loading (NTL) introduces surface deformation on the Earth and increases the variability in coordinates measured by space geodetic techniques. Correcting NTL displacements in Global Navigation Satellite Systems (GNSS) analysis has been discussed extensively, commonly at the parameter level.
Jungang Wang, Kyriakos Balidakis, Henryk Dobslaw, Benjamin Männel, Maorong Ge, Robert Heinkelmann, Harald Schuh   +6 more
wiley   +1 more source

3 mm GMVA Observations of Total and Polarized Emission from Blazar and Radio Galaxy Core Regions

Galaxies, 2017
We present total and linearly polarized 3 mm Global mm-VLBI Array (GMVA; mm-VLBI: Very Long Baseline Interferometry observations at millimetre wavelengths) images of a sample of blazars and radio galaxies from the VLBA-BU-BLAZAR 7 mm monitoring program ...
Carolina Casadio, Thomas P. Krichbaum, Alan P. Marscher, Svetlana G. Jorstad, José L. Gómez, Iván Agudo, Uwe Bach, Jae-Young Kim, Jeffrey A. Hodgson, Anton J. Zensus   +9 more
doaj   +1 more source