The Experts below are selected from a list of 48483 Experts worldwide ranked by ideXlab platform
P Stauning - One of the best experts on this subject based on the ideXlab platform.
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a comparative analysis of low latitude pi2 pulsations observed by orsted and Ground Stations
Journal of Geophysical Research, 2004Co-Authors: Desheng Han, Toshihiko Iyemori, M Nose, H Mccreadie, Yufen Gao, Fuxi Yang, Satoru Yamashita, P StauningAbstract:[1] Orsted is a low-altitude polar orbiting satellite, which is advantageous for investigating the spatial structure of low-frequency events like Pi2 pulsations. Using 1-s vector magnetic field data from April 1999 to May 2002 obtained from Orsted and Kakioka magnetic observatories, we found that the field aligned component (B∥) of Pi2 pulsations at the satellite height is highly correlated with the H component on the Ground, but the other two components, i.e., eastward component (BE) and radial component (BR), do not show a clear correlation with the Ground observations. The observed results for nightside events provide evidence that nightside Pi2s at low latitude are generated from cavity resonance. Two cases observed by Orsted when it was located on the dawnside or duskside also show cavity resonance properties. However, when Orsted was on the dayside, the oscillations observed by the satellite are out of phase with that observed on the Ground, suggesting that the dayside Pi2s are more likely related to some dayside ionospheric current systems rather than that caused by a global cavity resonance mode. The amplitude variation recorded by Orsted shows a peak in the equatorial region, which, for the first time, gives clear observational support for earlier model calculations. We also estimated the screening effect of the ionosphere on MHD waves and suggest that when the cavity resonance mode is valid for generation of Pi2 pulsations at low latitudes, the screening effect is negligible; that is, the compressional waves are seen directly as Pi2 pulsations at the Ground.
Luca Perregrini - One of the best experts on this subject based on the ideXlab platform.
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high frequency radomes for polar region Ground Stations the state of the art and novel developments of radome technologies
IEEE Antennas and Propagation Magazine, 2017Co-Authors: Andrea Martellosio, Marco Pasia, Luca Perregrini, Luca Piffe, Roberto Riccardi, Filippo Concaro, Piermario EssoAbstract:Satellite communications with the ability to provide a downlink channel with high bit rates are needed, and this need is driving frequency upscaling toward bands higher than the X band. A number of these satellites requires Ground Stations at the polar region, which are usually protected against the harsh environment using radomes.
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electromagnetic analysis of high frequency radomes for Ground Stations in polar regions
European Conference on Antennas and Propagation, 2017Co-Authors: Andrea Martellosio, Marco Pasian, Luca Perregrini, Roberto Riccardi, Filippo Concaro, L Piffer, Piermario BessoAbstract:At lower frequencies, e.g., at S-band, the radome design for Ground Stations can be considered consolidated, and the microwave transparency can be often obtained with minimal compromises on the structure stiffness. Conversely, at K-band frequencies and above the two domains, electromagnetics and mechanics, require a joint design to achieve best performance, especially when installations at environmentally extreme locations are required. Notably, next-generation satellites for Earth Observation, aimed to provide large amount of data exploiting high frequencies, require Ground Stations at Polar latitudes, where the combination of high-speed winds and low temperature is particularly severe. This paper provides a comparison between two possible solutions for the radome, discussing the two most common radome technologies (Metal Space Frame and Multilayer) suitable for this kind of installation, on the Grounds of preliminary electromagnetic analyses. In particular, both the transparency of radome walls and the Induced Field Ration of radome interconnections are evaluated using analytical equations and full-wave solvers. As a test case, a radome to be installed in Svalbard for a European Space Agency Ground station is discussed.
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Multiphysics design and experimental verification of a quad-band dichroic mirror for deep space Ground Stations
IET Microwaves Antennas & Propagation, 2013Co-Authors: Marco Pasian, Marco Formaggi, Fabio Carli, Glafkos Philippou, Maurizio Bozzi, Luca Perregrini, Guillaume DauronAbstract:This study presents the multi-disciplinary approach used to study a quad-band dichroic mirror to be installed in the European Space Agency deep space antennas. Traditional electromagnetic (EM) analyses based on a uniform plane wave incidence were augmented by advanced numerical techniques to investigate the impact of the dichroic mirror on the overall antenna performance. In addition, along with the EM design, a parallel study considering mechanical, thermal and power-handling aspects allowed their impact on the EM behaviour of the dichroic mirror to be evaluated. This comprehensive study permitted an optimum design to be achieved for the dichroic mirror, which accounts for the actual operational conditions of the mirror itself when installed in the antenna. The device was manufactured and measured, verifying also the mechanical and thermal theoretical predictions, obtaining an excellent agreement between simulations and experimental results.
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future architectures for european space agency deep space Ground Stations antenna applications corner
IEEE Antennas and Propagation Magazine, 2012Co-Authors: Maurizio Bozzi, Marco Pasian, Luca Perregrini, M Cametti, M Fornaroli, P Maguire, S Marti, Steve RawsonAbstract:Space communications between distant spacecraft and the Earth are mainly based on large reflector antennas, such as the 35-m Deep-Space Antennas of the European Space Agency. These provide the required G T and EIRP to existing missions, such as, for example, Rosetta, Mars Express, and Venus Express. However, future missions to Mars and to outer planets (Jupiter and Saturn) are going to require higher performance for the Ground segment that current Stations cannot offer. This paper presents the results carried out in the framework of a strategic feasibility study promoted by the European Space Agency to identify the best architecture for future deep-space Ground Stations. Technical, economic, and operating aspects are described, deriving high-level specifications for future Ground Stations, and discussing in detail the antenna options and the subsystem devices. As an outcome, two different Ground-station architectures, based on arrays of reflector antennas, are proposed and discussed in detail. These indicate the roadmaps that are going to pave the road to the final implementation.
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low cost dichroic mirrors for future deep space Ground Stations
International Journal of Microwave and Wireless Technologies, 2011Co-Authors: Marco Pasian, Maurizio Bozzi, Luca PerregriniAbstract:Future Deep Space (DS) Ground Stations envisioned by running projects funded by major space agencies are based on arrays of reflector antennas operating in different frequency bands. Therefore, a multi-band feeding system is required for each antenna, and a possible solution foresees the use of dichroic mirrors to separate/combine different beams. This paper presents a low-cost and fast manufacturing process for the fabrication of dichroic mirrors, usually referred to as punching technique or metal stamping. In particular, the specific advantages and limits of this fabrication technique are outlined and discussed, showing both electrical performance and manufacturing accuracy measurements from a test prototype. In addition, a typical scenario for future DS Ground Stations is described, showing the impact of these low-cost dichroic mirrors on the final Ground station performance and cost, compared to the standard approach for dichroic mirror manufacturing based on more expensive and time-consuming technologies (e.g. milling machining).
Shkelzen Cakaj - One of the best experts on this subject based on the ideXlab platform.
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the range and horizon plane simulation for Ground Stations of low earth orbiting leo satellites
Int'l J. of Communications Network and System Sciences, 2011Co-Authors: Shkelzen Cakaj, Bexhet Kamo, Vladi Kolici, Olimpjon ShurdiAbstract:Communication via satellite begins when the satellite is positioned in the desired orbital position. Ground Stations can communicate with LEO (Low Earth Orbiting) satellites only when the satellite is in their visibility region. The Ground station’s ideal horizon plane is in fact the visibility region under 0˚ of elevation angle. Because of natural barriers or too high buildings in urban areas, practical (visible) horizon plane differs from the ideal one. The duration of the visibility and so the communication duration varies for each LEO satellite pass at the Ground station, since LEO satellites move too fast over the Earth. The range between the Ground station and the LEO satellite depends on maximal elevation of satellite’s path above the Ground station. The dimension of the horizon plane depends on satellite’s orbital attitude. The range variations between the Ground station and the satellite, and then Ground station horizon plane simulation for low Earth orbiting satellites as a function of orbital attitude is presented. The range impact and horizon plane variations on communication duration between the Ground station and LEO satellites are given.
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rain attenuation impact on performance of satellite Ground Stations for low earth orbiting leo satellites in europe
Int'l J. of Communications Network and System Sciences, 2009Co-Authors: Shkelzen CakajAbstract:Low Earth Orbits (LEO) satellites are used for public communication and for scientific purposes. These satellites provide opportunities for investigations for which alternative techniques are either difficult or impossible to apply. Ground Stations have to be established in order to communicate with such satellites. Usually these satellites communicate with Ground Stations at S-band. The communication quality depends on the performance of the satellite Ground station, in addition to that of satellite. The performance of the satellite Ground Stations is expressed through Figure of Merit. The aim of this paper is to analyze the rain attenuation impact on the performance of the respective Ground station. Rain attenuation depends on geographical location where the satellite Ground station is implemented. In order to compare this effect on satellite Ground station performance, some cities of Europe are considered. Finally, the rain attenuation impact on the satellite Ground station Figure of Merit for the hypothetical satellite Ground station installed in Prishtina is analyzed.
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Practical horizon plane and communication duration for low earth orbiting (LEO) satellite Ground Stations
WSEAS TRANSACTIONS on COMMUNICATIONS archive, 2009Co-Authors: Shkelzen CakajAbstract:Communication via satellite begins when the satellite is positioned in the desired orbital position. Ground Stations can communicate with LEO (Low Earth Orbiting) satellites only when the satellite is in their visibility region. The visibility region is in fact the horizon plane. Because of natural barriers or too high buildings in urban areas, practical horizon plane differs from the ideal one. The duration of the visibility and so the communication duration varies for each satellite pass at the Ground station, specifically for LEO satellites which do move too fast over the Earth. This paper discusses the satellites motion detection, the difference in between ideal and practical horizon and further the variations of the communication duration between the Ground station and LEO satellites. Main objective is determination of practical horizon plane and critical maximal elevation angle related to communication duration. For this paper, data recorded at the Vienna satellite Ground station within the Canadian space observation project "MOST" (Micro variability and Oscillations of Stars) are applied. Vienna Ground station system was set up at the Institute for Astronomy of the University of Vienna in cooperation with the Institute of Communications and Radio-Frequency Engineering of the University of Technology in Vienna.
Marco Pasian - One of the best experts on this subject based on the ideXlab platform.
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electromagnetic analysis of high frequency radomes for Ground Stations in polar regions
European Conference on Antennas and Propagation, 2017Co-Authors: Andrea Martellosio, Marco Pasian, Luca Perregrini, Roberto Riccardi, Filippo Concaro, L Piffer, Piermario BessoAbstract:At lower frequencies, e.g., at S-band, the radome design for Ground Stations can be considered consolidated, and the microwave transparency can be often obtained with minimal compromises on the structure stiffness. Conversely, at K-band frequencies and above the two domains, electromagnetics and mechanics, require a joint design to achieve best performance, especially when installations at environmentally extreme locations are required. Notably, next-generation satellites for Earth Observation, aimed to provide large amount of data exploiting high frequencies, require Ground Stations at Polar latitudes, where the combination of high-speed winds and low temperature is particularly severe. This paper provides a comparison between two possible solutions for the radome, discussing the two most common radome technologies (Metal Space Frame and Multilayer) suitable for this kind of installation, on the Grounds of preliminary electromagnetic analyses. In particular, both the transparency of radome walls and the Induced Field Ration of radome interconnections are evaluated using analytical equations and full-wave solvers. As a test case, a radome to be installed in Svalbard for a European Space Agency Ground station is discussed.
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Multiphysics design and experimental verification of a quad-band dichroic mirror for deep space Ground Stations
IET Microwaves Antennas & Propagation, 2013Co-Authors: Marco Pasian, Marco Formaggi, Fabio Carli, Glafkos Philippou, Maurizio Bozzi, Luca Perregrini, Guillaume DauronAbstract:This study presents the multi-disciplinary approach used to study a quad-band dichroic mirror to be installed in the European Space Agency deep space antennas. Traditional electromagnetic (EM) analyses based on a uniform plane wave incidence were augmented by advanced numerical techniques to investigate the impact of the dichroic mirror on the overall antenna performance. In addition, along with the EM design, a parallel study considering mechanical, thermal and power-handling aspects allowed their impact on the EM behaviour of the dichroic mirror to be evaluated. This comprehensive study permitted an optimum design to be achieved for the dichroic mirror, which accounts for the actual operational conditions of the mirror itself when installed in the antenna. The device was manufactured and measured, verifying also the mechanical and thermal theoretical predictions, obtaining an excellent agreement between simulations and experimental results.
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future architectures for european space agency deep space Ground Stations antenna applications corner
IEEE Antennas and Propagation Magazine, 2012Co-Authors: Maurizio Bozzi, Marco Pasian, Luca Perregrini, M Cametti, M Fornaroli, P Maguire, S Marti, Steve RawsonAbstract:Space communications between distant spacecraft and the Earth are mainly based on large reflector antennas, such as the 35-m Deep-Space Antennas of the European Space Agency. These provide the required G T and EIRP to existing missions, such as, for example, Rosetta, Mars Express, and Venus Express. However, future missions to Mars and to outer planets (Jupiter and Saturn) are going to require higher performance for the Ground segment that current Stations cannot offer. This paper presents the results carried out in the framework of a strategic feasibility study promoted by the European Space Agency to identify the best architecture for future deep-space Ground Stations. Technical, economic, and operating aspects are described, deriving high-level specifications for future Ground Stations, and discussing in detail the antenna options and the subsystem devices. As an outcome, two different Ground-station architectures, based on arrays of reflector antennas, are proposed and discussed in detail. These indicate the roadmaps that are going to pave the road to the final implementation.
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low cost dichroic mirrors for future deep space Ground Stations
International Journal of Microwave and Wireless Technologies, 2011Co-Authors: Marco Pasian, Maurizio Bozzi, Luca PerregriniAbstract:Future Deep Space (DS) Ground Stations envisioned by running projects funded by major space agencies are based on arrays of reflector antennas operating in different frequency bands. Therefore, a multi-band feeding system is required for each antenna, and a possible solution foresees the use of dichroic mirrors to separate/combine different beams. This paper presents a low-cost and fast manufacturing process for the fabrication of dichroic mirrors, usually referred to as punching technique or metal stamping. In particular, the specific advantages and limits of this fabrication technique are outlined and discussed, showing both electrical performance and manufacturing accuracy measurements from a test prototype. In addition, a typical scenario for future DS Ground Stations is described, showing the impact of these low-cost dichroic mirrors on the final Ground station performance and cost, compared to the standard approach for dichroic mirror manufacturing based on more expensive and time-consuming technologies (e.g. milling machining).
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future architectures for esa deep space Ground Stations antennas
European Conference on Antennas and Propagation, 2011Co-Authors: Steve Rawson, Marco Pasian, Maurizio Bozzi, Luca Perregrini, M Cametti, M Fornaroli, S Marti, P MaguireAbstract:This paper presents the results of an architectural study into future ESA Deep-Space Ground Stations. The objective of the project is to investigate solutions for building Ground Stations for future Deep Space missions for exploration of the outer reaches of the solar system. The study addresses not only the engineering challenges associated with various technical options, but also the cost, with a clear goal of identifying the most cost effective approach.
C A Kletzing - One of the best experts on this subject based on the ideXlab platform.
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pi2 pulsations observed with the polar satellite and Ground Stations coupling of trapped and propagating fast mode waves to a midlatitude field line resonance
Journal of Geophysical Research, 2001Co-Authors: A Keiling, J R Wygant, C A Cattell, K H Kim, C T Russell, D K Milling, M Temerin, F S Mozer, C A KletzingAbstract:Simultaneous measurements from the Polar satellite and several Ground Stations of two substorm-related Pi2 pulsation events (separated by ∼6 min) provide evidence for radially trapped and propagating fast mode waves and a coupled field line resonance (FLR). The Pi2 pulsations were observed at five Ground Stations located between 2130 and 2330 magnetic local time (MLT) ranging from L=1.83 to 3.75, which showed nearly identical waveforms in the H component with a frequency of ∼20 mHz. Five additional Ground Stations located between L=4.48 and ∼15 (on similar meridians) recorded weaker less-correlated signals. The pulsations were also detected both simultaneously and with a time delay of ∼38 s at two low-latitude Stations (L=1.17 and 1.23) on the dayside at ∼1030 and ∼0612 MLT, respectively, indicating the global extend of the pulsations. The nightside Ground data showed an amplitude maximum and a phase reversal in the H component between L=3.4 and 3.75. During the oscillations the Polar satellite moved (on the same meridian as the Ground Stations in the nightside) from 14° to 10° magnetic latitude and from L=4.1 to 3.7. Electric and magnetic field measurements also showed two Pi2 pulsation events (∼20 mHz) in both the compressional (Bz and Ey) and transverse (By and Ex) mode components with waveforms almost identical to the Ground signals. Whereas the first Pi2 had a standing wave structure in the compressional mode, the second Pi2 was a propagating wave. Both Pi2s had standing wave signatures in the transverse mode. The amplitude of the compressional magnetic field component (Bz) was ∼40% of that of the azimuthal component (By). Although the two Pi2 events showed equal amplitudes in the H component of Ground data, Polar recorded much larger oscillations in the azimuthal magnetic field component (By) of the first Pi2 event; the fast mode amplitude (Bz) was nearly unchanged for both Pi2s. This suggests that Polar was at or near a localized FLR excited by the oscillations of the fast mode waves. During the in situ FLR observation, Polar's footpoint was closest to the Ground Stations which recorded the amplitude maximum and the phase reversal in the H component.
