Results 61 to 70 of about 4,598 (208)

An Experiment on Radio Location of Objects in the Near-Earth Space with VLBI in 2012

Open Astronomy, 2013
An experiment on radar location of space debris objects using of the method of VLBI was carried out in April, 2012. The radar VLBI experiment consisted in irradiation of some space debris objects (4 rocket stages and 5 inactive satellites) with a signal ...
Nechaeva M., Antipenko A., Bezrukovs V., Bezrukov D., Dementjev A., Dugin N., Konovalenko A., Kulishenko V., Liu X., Nabatov A., Nesteruk V., Pupillo G., Reznichenko A., Salerno E., Shmeld I., Shulga O., Sybiryakova Y., Tikhomirov Yu., Tkachenko A., Volvach A., Yang W.-J.   +20 more
doaj   +1 more source

An Ionospheric Disturbed Index Based on ROTI

Space Weather, Volume 23, Issue 6, June 2025.
Abstract The ionosphere has significant impacts on wireless communication, satellite navigation, and space weather. Based on hundreds of global GNSS observation stations, we calculate the rate of TEC index (ROTI). Through the analysis of ROTI, we establish a global ionospheric disturbed index (IDI) to directly characterize ionospheric disturbances ...
Cheng Wang, Xiaoxue Min, Hong Hu
wiley   +1 more source

Satellite Ephemeris Parameterization Methods to Support Lunar Positioning, Navigation, and Timing Services

Navigation
Plans to establish a satellite network around the Moon to support communication, position, navigation, and timing services are rapidly evolving. Satellites that are part of this system broadcast their ephemeris as finite parameters to lunar users for ...
Marta Cortinovis, Keidai Iiyama, Grace Gao   +2 more
doaj   +1 more source

First Results of the VLBI Experiment on Radar Location of the Asteroid 2012 DA14

Open Astronomy, 2013
An international VLBI experiment on radio location of the asteroid 2012 DA14 was organized on 2013 February 15–16, during its flyby close to Earth. The purpose of observations was to investigate and specify orbital parameters of the asteroid, as well as ...
Nechaeva M., Antipenko A., Bezrukov D., Bezrukovs Vl., Dementjev A., Dugin N., Jekabsons N., Khutornoy R., Klapers M., Konovalenko A., Kulishenko V., Nabatov A., Nesteruk V., Pupillo G., Reznichenko A., Salerno E., Shmeld I., Skirmante K., Tikhomirov Yu., Voytyuk V.   +19 more
doaj   +1 more source

Cross‐Scale Interactions Between ULF Waves, VLF Waves, and Electrons

Geophysical Research Letters, Volume 52, Issue 10, 28 May 2025.
Abstract Wave‐particle interactions are essential for energy transport in the magnetosphere. In this study, we investigated an event during which electrons interact simultaneously with waves in different scales, using data from the Magnetospheric Multiscale mission.
Xing‐Yu Li, Qiu‐Gang Zong, Shan Wang, Xu‐Zhi Zhou, Chao Yue, Li Li, Zhi‐Yang Liu, Yong‐Fu Wang, Ze‐Fan Yin, Yi‐Xin Sun, Yi‐Xin Hao, Craig Pollock, Christopher T. Russell, Robert E. Ergun, Per‐Arne Lindqvist   +14 more
wiley   +1 more source

Signal in Space Error and Ephemeris Validity Time Evaluation of Milena and Doresa Galileo Satellites

Sensors, 2019
In August 2016, Milena (E14) and Doresa (E18) satellites started to broadcast ephemeris in navigation message for testing purposes. If these satellites could be used, an improvement in the position accuracy would be achieved.
Umberto Robustelli, Guido Benassai, Giovanni Pugliano   +2 more
doaj   +1 more source

The Evolution of Titan's Cold South Polar Cloud

Geophysical Research Letters, Volume 52, Issue 9, 16 May 2025.
Abstract Early during Titan's southern fall, images captured by Cassini's Imaging Science Subsystem revealed the formation of a large cloud above Titan's south pole. Subsequent analysis of Cassini data revealed the cloud contained HCN ice, but the cloud's evolution has not been examined.
Lavender Elle Hanson, Robert S. French, Darryn W. Waugh, Erika L. Barth, Carrie M. Anderson   +4 more
wiley   +1 more source

A Map of Potential Topographic Anomalies on Venus

Journal of Geophysical Research: Planets, Volume 130, Issue 5, May 2025.
Abstract The most recent, highest‐resolution, global estimate of the topography of Venus is the Global Topographic Data Record (GTDR), a gridded representation of the altimetry data from the Magellan space mission. This product is impaired by an occasional pattern; a series of visually striking topographic “pits,” often referred to as spuriously low ...
Gerard Gallardo i Peres, Philippa J. Mason, Richard C. Ghail   +2 more
wiley   +1 more source

Studying the Inner Heliosphere Using Radio Signals Transmitted From Spacecraft Orbiting Mars

Space Weather, Volume 23, Issue 5, May 2025.
Abstract In this campaign, we used very long baseline interferometry (VLBI) radio telescopes to track the carrier radio signal transmitted from spacecraft orbiting Mars during the Mars solar conjunction. The campaign extended from September 6th $6\text{th}$ to November 6th $6\text{th}$ 2021 and targeted the Mars Express (MEX) and Tianwen‐1 (TIW ...
J. Edwards, G. Molera Calvés, P. Kummamuru, N. M. M. Said, M. Ma   +4 more
wiley   +1 more source

A Low Earth Orbit Satellite-Orbit Extrapolation Method Based on Multi-Satellite Ephemeris Coordination and Multi-Stream Fractional Autoregressive Integrated Moving Average

Aerospace
The low Earth orbit (LEO) satellite internet network (LEO-SIN) has become a heated issue for the next generation of mobile communications, serving as a crucial means to achieve global wide-area broadband coverage and, especially, mobile phone directly to
Wenliang Lin, Jian Yi, Tong Wang, Ke Wang, Zexi Huang, Zhongliang Deng, Yang Liu, Yicheng Liao, Heng Kang, Zeyang Liu, Junyu Zhang   +10 more
doaj   +1 more source