Results 41 to 50 of about 82,109 (188)
SensorsExperts and scholars from various nations have proposed studying low Earth orbit (LEO) satellite signals as the space-based signals of opportunity (SOPs) for navigation and positioning.
Yanhua Tao +4 more
doaj +1 more source
Serendipitous discovery of RR Lyrae stars in the Leo V ultra-faint galaxy
, 2017 During the analysis of RR Lyrae stars discovered in the High cadence Transient Survey (HiTS) taken with the Dark Energy Camera at the 4-m telescope at Cerro Tololo Inter-American Observatory, we found a group of three very distant, fundamental mode ...
Carlin, Jeffrey L. +11 more
core +1 more source
On Channel Sharing Policies in LEO Mobile Satellite Systems [PDF]
, 2018 We consider a low earth orbit (LEO) mobile satellite system with "satellite-fixed" cells that accommodates new and handover calls of different service-classes. We provide an analytical framework for the efficient calculation of call blocking and handover
Logothetis, Michael +3 more
core +1 more source
Satellite-enabled LTE systems in LEO constellations [PDF]
2017 IEEE International Conference on Communications Workshops (ICC Workshops), 2017 LTE-based satellite systems in LEO constellations are a promising solution for extending broadband coverage to areas not connected to a terrestrial infrastructure. However, the large delays and Doppler shifts over the satellite channel pose severe technical challenges to a traditional LTE system.
GUIDOTTI, ALESSANDRO +8 more
openaire +3 more sources
An Integrity Monitoring Method for Navigation Satellites Based on Multi-Source Observation Links
Remote SensingThe BeiDou-3 navigation satellite system (BDS-3) has officially provided positioning, navigation, and timing (PNT) services to global users since 31 July 2020.
Jie Xin, Dongxia Wang, Kai Li
doaj +1 more source
Crew Transfer Options for Servicing of Geostationary Satellites [PDF]
, 2012 In 2011, NASA and DARPA undertook a study to examine capabilities and system architecture options which could be used to provide manned servicing of satellites in Geostationary Earth Orbit (GEO).
Cerro, Jeffrey A.
core +1 more source
26-GHz data downlink for LEO satellites [PDF]
2012 6th European Conference on Antennas and Propagation (EUCAP), 2012 State-of-the art downlink technology allows Low Earth Orbit (LEO) satellites for Earth observation (EO) to downlink just above 500 Mb/s in the X-band due to bandwidth limitations. X-band is also becoming very congested. The ITU allocates four times more bandwidth in the 26 GHz band (i.e. 25.5 to 27 GHz) for the EO downlink.
J. Rosello +5 more
openaire +2 more sources
The rotationally stabilized VPOS and predicted proper motions of the Milky Way satellite galaxies [PDF]
, 2013 The satellite galaxies of the Milky Way (MW) define a vast polar structure (VPOS), a thin plane perpendicular to the MW disc. Proper motion (PM) measurements are now available for all of the 11 brightest, `classical' satellites and allow an updated ...
Kroupa, Pavel, Pawlowski, Marcel S.
core +1 more source
LTE‐based satellite communications in LEO mega‐constellations [PDF]
International Journal of Satellite Communications and Networking, 2018 SummaryThe integration of satellite and terrestrial networks is a promising solution for extending broadband coverage to areas not connected to a terrestrial infrastructure, as also demonstrated by recent commercial and standardisation endeavours. However, the large delays and Doppler shifts over the satellite channel pose severe technical challenges ...
Guidotti, Alessandro +7 more
openaire +4 more sources
Geo-spatial Information Science, 2021 Low Earth Orbit (LEO) satellite navigation signal can be used as an opportunity signal in the case of a Global Navigation Satellite System (GNSS) outage, or as an enhancement by means of traditional GNSS positioning algorithms.
Liang Chen +7 more
doaj +1 more source