Results 81 to 90 of about 134,911 (241)
The White Dwarf in AE Aqr Brakes Harder [PDF]
Mon.Not.Roy.Astron.Soc.369:1983-1987,2006, 2006 Taking advantage of the very precise de Jager et al. optical white dwarf orbit and spin ephemerides; ASCA, XMMN, and Chandra X-ray observations spread over 10 yrs; and a cumulative 27 yr baseline, we have found that in recent years the white dwarf in AE Aqr is spinning down at a rate that is slightly faster than predicted by the de Jager et al.
arxiv +1 more source
Space Weather, Volume 23, Issue 2, February 2025.Abstract With the onset of solar activities of the 25th solar cycle, ionospheric perturbations have become increasingly frequent, posing significant challenges to various applications of Global Navigation Satellite Systems (GNSS). The Rate of Total Electron Content (TEC) Index (Rate of TEC Index (ROTI)), commonly derived from GNSS data sampled at 30‐s ...
Zhouyu Zhang +6 more
wiley +1 more source
Izračun položaja GPS-satelita iz podatkov oddanih efemerid : GPS-Orbit Computation from Broadcast Ephemeris Data [PDF]
Geodetski Vestnik, 2004 The article describes the theoretical point of view of the GPS-broadcast ephemerides application. Beside the raw GPS observations, any kind of GPS ephemerides represents indispensable data in the GPS processing engine.
Bojan Stopar +1 more
doaj
Sensors, 2017 The failure to detect anomalies and maneuvering of the orbits of navigation satellite sensors will deteriorate the performance of positioning and orbit determination.
Fei Ye +3 more
doaj +1 more source
Adaptive Fault‐Tolerant Multiplicative Attitude Filtering for Small Satellites
International Journal of Adaptive Control and Signal Processing, Volume 39, Issue 1, Page 152-162, January 2025.This study presents a probabilistic adaptive Kalman filter for small satellite attitude determination, demonstrating superior fault tolerance by effectively correcting sensor faults and outperforming conventional and other adaptive filters. ABSTRACT This study tackles the problem of fault‐tolerant attitude estimation for small satellites.
Hasan Kinatas, Chingiz Hajiyev
wiley +1 more source
Stability Tests for the Network of Permanent GNSS Stations of the Republic of Srpska
AGG+, 2020 The network of permanent GNSS stations of the Republic of Srpska is located in a fairly seismic area and belongs to different sides of regional faults.
Tanja Fržović +2 more
doaj +1 more source
Engineering Reports, Volume 7, Issue 1, January 2025.ABSTRACT Due to the long transmission distance of the constellation network represented by the low‐orbit satellite system, the satellite‐to‐ground link is subject to large path loss and limited communication performance. This paper uses multi‐satellite and multi‐beam joint transmission technology to form a virtual multiplex network with ground multi ...
Yuyang Liu, Tong Shi, Hua Wang
wiley +1 more source
Chinese Astronomy and Astrophysics, 2009 Abstract The satellite-borne GPS receivers dedicated to precise orbit determination are now being carried by more and more low earth orbit (LEO) satellites and the satellite-borne GPS has become one of the main means for the precise orbit determination of low earth orbit satellites.
Dong-ju, P., Bin, W.
openaire +4 more sources
A New Asynchronous RTK Method to Mitigate Base Station Observation Outages
Sensors, 2019 Real-time kinematic (RTK) positioning is a satellite navigation technique that is widely used to enhance the precision of position data obtained from global navigation satellite systems (GNSS).
Yuan Du +4 more
doaj +1 more source
Visibility Analysis of Domestic Satellites on Proposed Ground Sites for Optical Surveillance [PDF]
Journal of Astronomy and Space Sciences, 2011 The objectives of this study are to analyze the satellite visibility at the randomly established ground sites, to determine the five optimal ground sites to perform the optical surveillance and tracking of domestic satellites, and to verify the ...
Jung Hyun Jo1 +7 more
doaj +1 more source