Publications associées à Télévision par satellite

A possible dwarf galaxy satellite-of-satellite problem in ?CDM

Dark matter clusters on all scales, and it is therefore expected that even substructure should host its own substructure. Using the Extragalactic Distance Database, we searched for dwarf-galaxy satellites of dwarf galaxies, that is, satellite-of-satellite ...

EDP SCIENCES S A2023

The cis-lunar ecosystem — A systems model and scenarios of the resource industry and its impact

Jean-Paul Richard Kneib

Lunar resources is one of the many new putative business models that may transform space logistics. Yet it competes with Earth-based resources, in a complex trade-off involving both tech development & socioeconomic dynamics. This study models the size vs. ...

2021

QUIC: Opportunities and threats in SATCOM

Ludovic Bernard Gérard Thomas, Emmanuel Qays Dubois

This article proposes a discussion on the strengths, weaknesses, opportunities and threats related to the deployment of QUIC end-to-end from a satellite-operator point-of-view. The deployment of QUIC is an opportunity for improving the quality of experienc ...

IEEE2020

Small satellites for space science A COSPAR scientific roadmap

Volker Gass, Jie Wu, Maurice Borgeaud

This is a COSPAR roadmap to advance the frontiers of science through innovation and international collaboration using small satellites. The world of small satellites is evolving quickly and an opportunity exists to leverage these developments to make scien ...

ELSEVIER SCI LTD2019

Calibration Aspects of INS Navigation

Philipp Clausen

The use of a Bayesian filter (e.g., Kalman filter) for the fusion of information from satellite positioning and inertial navigation is a common approach in many applications, where the knowledge of position, velocity, and attitude in space are of great int ...

EPFL2019

Comparison of L1 and L5 Bands GNSS Signals Acquisition

Cyril Botteron, Jérôme Leclère

Nowadays, civil Global Navigation Satellite System (GNSS) signals are available in both L1 and L5 bands. A receiver does not need to acquire independently the signals in both bands coming from a same satellite, since their carrier Doppler and code delay ar ...

2018

Hypervelocity impact testing on stochastic and structured open porosity cast Al-Si cellular structures for space applications

Andreas Mortensen

A hypervelocity (6.7–7.0 km/s) impact testing campaign was conducted using Ø 2 mm, 95% Al projectiles onto A357 aluminium alloy stochastic foams with 4–5 mm typical pore dimensions, or alternatively diamond cubic periodic structures of cast AlSi12 with a 6 ...

2018

Guidance, Navigation and Control for Autonomous Rendezvous and Docking of Nano-Satellites

Camille Sébastien Pirat

Is it possible to dock CubeSats in Low Earth Orbit? Challenges are associated with the level of miniaturisation: the docking accuracy is driven by the docking mechanism dimensions. The achievable docking performance with the Guidance, Navigation and Contro ...

EPFL2018

3D-printed Ka-band Antenna Based on Stereolithography

Juan Ramon Mosig, Tomislav Debogovic, Maria Garcia Vigueras, Joana Rita Alves dos Santos Silva

This paper presents a circularly-polarized dual-band antenna for Ka-band satellite communications which operates simultaneously in both civil and military downlink (17.7-21.2 GHz) and uplink (27.5-31 GHz) bands. The antenna is composed of a metallic ridged ...

IEEE2017

Study on the cross-correlation of GNSS signals and typical approximations

Pierre-André Farine, Cyril Botteron, Jérôme Leclère

In global navigation satellite system (GNSS) receivers, the first signal processing stage is the acquisition, which consists in detecting the received GNSS signals and determining the associated code delay and Doppler frequency by means of correlations wit ...

Springer Verlag2017

Tunable radiator for small satellite application

Jean-Daniel Landis, Frédéric Bongard, Pedro Robustillo Bayon, Nevena Saponjic, Tomislav Debogovic, Mikaël Krummen

A tunable radiator for space application has been developed to meet stringent requirements in terms of electrical and environmental specifications but also low mass, simple manufacturing and low cost. The element is based on the folded PIFA antenna, with s ...

2016

Autonomous Navigation Of Small Uavs Based On Vehicle Dynamic Model

Jan Skaloud, Mehran Khaghani

This paper presents a novel approach to autonomous navigation for small UAVs, in which the vehicle dynamic model (VDM) serves as the main process model within the navigation filter. The proposed method significantly increases the accuracy and reliability o ...

Copernicus Gesellschaft Mbh2016

3D T 2-weighted imaging at 7T using dynamic kT-points on single-transmit MRI systems

Rolf Gruetter, José Pedro Rebelo Ferreira Marques, Daniel Gallichan, Kieran O'Brien, Florent Eggenschwiler

OBJECTIVES: For turbo spin echo (TSE) sequences to be useful at ultra-high field, they should ideally employ an RF pulse train compensated for the B 1 + inhomogeneity. Previously, it was shown that a single kT-point pulse designed in the small tip-angle re ...

Springer Verlag2016

Point rainfall statistics for ecohydrological analyses derived from satellite integrated rainfall measurements

Andrea Rinaldo

Satellite rainfall measurements, nowadays commonly available, provide valuable information about the spatial structure of rainfall. In areas with low-density rain gage networks, or where these networks are nonexistent, satellite rainfall measurements can a ...

Amer Geophysical Union2015

Modeling of Long-Term Multipactor Evolution in Microwave Components Including Dielectric Layers

Apostolos Sounas

Multipactor is a resonant vacuum discharge occurring in microwave components of satellite systems as well as in particle accelerators. Due to its undesirable effects, multipactor analysis constitutes a mandatory step in the design of modern satellite compo ...

EPFL2015

Multi-band reflectarray antennas in Ku and THz frequency bands

Hamed Hasani

Printed reflectarrays are low-cost, low-profile high gain antennas demonstrating distinctive advantages over conventional parabolic reflectors and phased-arrays. The flat, low weight reflecting surface of a reflectarray makes it an attractive alternative w ...

EPFL2015

Orthogonal multicarrier modulations in satellite uplinks

Stefano Rosati

In this paper, we analyze Orthogonal Frequency-Division Multiple Access and Single-Carrier Frequency Division Multiple Access as alternative physical layer schemes for the up-link of a satellite network. Both orthogonal frequency-division multiple access a ...

Wiley-Blackwell2014

Optimizing Quantize-Map-and-Forward in Slow Fading Relay Networks

Christina Fragouli, Ayan Sengupta, I-Hsiang Wang

Quantize-Map-and-Forward (QMF) relaying has been shown to achieve the optimal diversity-multiplexing trade-off (DMT) for the slow fading single-antenna relay channel, regardless of whether the relay is full-duplex or half-duplex. A key reason for the DMT o ...

Ieee2013

Modeling and Processing Approaches for Integrated Inertial Navigation

Yannick Stebler

The challenge of estimating the position, velocity and orientation in space in a precise and reliable way, at any time, with and without reception of satellite signals, is the core subject of this dissertation. To this end, the use of Bayesian filters whic ...

EPFL2013

24 GHz LNA and Vector Modulator Phase Shifter for Phased-Array Receiver in CMOS Technology

Pierre-André Farine, Cyril Botteron, Gabriele Tasselli, Ban Wang

With the rapid development of the applications in short range communication, phased-array receiver working at 24 GHz can provide enhanced gain performance at desired transmission direction. Also there is the wide signal bandwidth, i.e. 250 MHz free license ...

2013