scholarly journals Radio Wave Satellite Propagation in Ka/Q Band

2018 ◽  
Vol 62 (2) ◽  
pp. 38-46 ◽  
Author(s):  
László Csurgai-Horváth ◽  
Bernard Adjei-Frimpong ◽  
Carlo Riva ◽  
Lorenzo Luini
Keyword(s):  
European Space Agency ◽  
Atmospheric Effects ◽  
Radio Communication ◽  
Scientific Experiment ◽  
Ground Station ◽  
Atmospheric Propagation ◽  
Space Agency ◽  
University Of Technology ◽  
Communication Experiment ◽  
Italian Space Agency

In 2013 the European Space Agency, in cooperation with Inmarsat, launched the Alphasat communication satellite hosting four Technology Demonstration Payloads (TDPs). One of them is the Aldo Paraboni payload, supported by the Italian Space Agency (ASI) and executed by ESA in the framework of the Advanced Research in Telecommunications Systems (ARTES) 8 Telecom program. In addition to the Communication experiment, it includes the Alphasat Scientific Experiment transmitting coherent beacon signals at Ka-band (19.701 GHz) and Q-band (39.402 GHz). The satellite supports a Europe-wide experiment to investigate the atmospheric propagation effects occurring in Ka and Q bands. The demand for increasing bandwidth in the satellite radio communication domain is moving the communication channels to the higher frequency bands. Hence for both research and commercial purposes is especially important to effectively explore the Q band that is affected by attenuation, depolarization and scintillation due to different atmospheric effects. In 2014 the Department of Broadband Infocommunications and Electromagnetic Theory at Budapest University of Technology and Economics joined the ASAPE (AlphaSat Aldo Paraboni Experimenters) group and developed a ground station to be installed in Budapest. This work was supported by the European Space Agency under its Plan for European Cooperating States program. Our paper gives the background of the Alphasat Scientific Experiment and overviews the design phases of the receiver station in Budapest. We present also the processing and validation of data recorded so far and our future experimenting plans.

scholarly journals Multi-Sensor Satellite Data Processing for Marine Traffic Understanding

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 152 ◽  
Author(s):  
Marco Reggiannini ◽  
Luigi Bedini
Keyword(s):  
Optical Sensors ◽  
European Space Agency ◽  
Observation System ◽  
Surveillance Systems ◽  
Space Agency ◽  
Novel Approach ◽  
Imaging Results ◽  
Early Processing ◽  
Wake Detection ◽  
Italian Space Agency

The work described in this document concerns the estimation of the kinematics of a navigating vessel. This task can be accomplished through the exploitation of satellite-borne systems for Earth observation. Indeed, Synthetic Aperture Radar (SAR) and optical sensors installed aboard satellites (European Space Agency Sentinel, ImageSat International Earth Remote Observation System, Italian Space Agency Constellation of Small Satellites for Mediterranean basin Observation) return multi-resolution maps providing information about the marine surface. A moving ship represented through satellite imaging results in a bright oblong object, with a peculiar wake pattern generated by the ship’s passage throughout the water. By employing specifically tailored computer vision methods, these vessel features can be identified and individually analyzed for what concerns geometrical and radiometric properties, backscatterers spatial distribution and the spectral content of the wake components. This paper proposes a method for the automatic detection of the vessel’s motion-related features and their exploitation to provide an estimation of the vessel velocity vector. In particular, the ship’s related wake pattern is considered as a crucial target of interest for the purposes mentioned. The corresponding wake detection module has been implemented adopting a novel approach, i.e., by introducing a specifically tailored gradient estimator in the early processing stages. This results in the enhancement of the turbulent wake detection performance. The resulting overall procedure may also be included in marine surveillance systems in charge of detecting illegal maritime traffic, combating unauthorized fishing, irregular migration and related smuggling activities.

scholarly journals The TROPOSIF global sun-induced fluorescence dataset from the Sentinel-5P TROPOMI mission

2021 ◽  
Vol 13 (11) ◽  
pp. 5423-5440
Author(s):  
Luis Guanter ◽  
Cédric Bacour ◽  
Andreas Schneider ◽  
Ilse Aben ◽  
Tim A. van Kempen ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
European Space Agency ◽  
Digital Object Identifier ◽  
Atmospheric Effects ◽  
Signal To Noise ◽  
Ancillary Data ◽  
Temporal Sampling ◽  
Space Agency ◽  
Time Period ◽  
Noise Ratio

Abstract. The first satellite-based global retrievals of terrestrial sun-induced chlorophyll fluorescence (SIF) were achieved in 2011. Since then, a number of global SIF datasets with different spectral, spatial, and temporal sampling characteristics have become available to the scientific community. These datasets have been useful to monitor the dynamics and productivity of a range of vegetated areas worldwide, but the coarse spatiotemporal sampling and low signal-to-noise ratio of the data hamper their application over small or fragmented ecosystems. The recent advent of the Copernicus Sentinel-5P TROPOMI mission and the high quality of its data products promise to alleviate this situation, as TROPOMI provides daily global measurements at a much denser spatial and temporal sampling than earlier satellite instruments. In this work, we present a global SIF dataset produced from TROPOMI measurements within the TROPOSIF project funded by the European Space Agency. The current version of the TROPOSIF dataset covers the time period between May 2018 and April 2021. Baseline SIF retrievals are derived from the 743–758 nm window. A secondary SIF dataset derived from an extended fitting window (735–758 nm window) is included. This provides an enhanced signal-to-noise ratio at the expense of a higher sensitivity to atmospheric effects. Spectral reflectance spectra at seven 3 nm windows devoid of atmospheric absorption within the 665–785 nm range are also included in the TROPOSIF dataset as an important ancillary variable to be used in combination with SIF. The methodology to derive SIF and ancillary data as well as results from an initial data quality assessment are presented in this work. The TROPOSIF dataset is available through the following digital object identifier (DOI): https://doi.org/10.5270/esa-s5p_innovation-sif-20180501_20210320-v2.1-202104 (Guanter et al., 2021).

scholarly journals A Monte Carlo Analysis for Collision Risk Assessment on Vega Launcher Payloads and LARES Satellite

2016 ◽  
Vol 51 (1) ◽  
pp. 45-54 ◽  
Author(s):  
G. Sindoni ◽  
I. Ciufolini ◽  
F. Battie
Keyword(s):  
European Space Agency ◽  
Monte Carlo Analysis ◽  
Mitigation Measures ◽  
Additional Contribution ◽  
Collision Risk ◽  
Frame Dragging ◽  
Space Agency ◽  
Last Stage ◽  
Italian Space Agency ◽  
Debris Mitigation

Abstract This work has been developed in the framework of the LARES mission of the Italian Space Agency (ASI). The LARES satellite has been built to test, with high accuracy, the frame–dragging effect predicted by the theory of General Relativity, specifically the Lense–Thirring drag of its node. LARES was the main payload in the qualification flight of the European Space Agency launcher VEGA. A concern arose about the possibility of an impact between the eight secondary payloads among themselves, with LARES and with the last stage of the launcher (AVUM). An impact would have caused failure on the payloads and the production of debris in violation of the space debris mitigation measures established internationally. As an additional contribution, this study allowed the effect of the payload release on the final manoeuvers of the AVUM to be understood.

scholarly journals The TROPOSIF global sun-induced fluorescence dataset from the Sentinel-5P TROPOMI mission

2021 ◽  
Author(s):  
Luis Guanter ◽  
Cédric Bacour ◽  
Andreas Schneider ◽  
Ilse Aben ◽  
Tim A. van Kempen ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
European Space Agency ◽  
Digital Object Identifier ◽  
Atmospheric Effects ◽  
Signal To Noise ◽  
Ancillary Data ◽  
Temporal Sampling ◽  
Space Agency ◽  
Noise Ratio ◽  
Spatio Temporal

Abstract. The first satellite-based global retrievals of terrestrial sun-induced chlorophyll fluorescence (SIF) were achieved in 2011. Since then, a number of global SIF datasets with different spectral, spatial and temporal sampling characteristics have become available to the scientific community. These datasets have been useful to monitor the dynamics and productivity of a range of vegetated areas worldwide, but the coarse spatio-temporal sampling and low signal-to-noise ratio of the data hamper their application over small or fragmented ecosystems. The recent advent of the Copernicus Sentinel-5P TROPOMI mission and the high quality of its data products promise to alleviate this situation, as TROPOMI provides daily global measurements at a much denser spatial and temporal sampling than earlier satellite instruments. In this work, we present a global SIF dataset produced from TROPOMI measurements within the TROPOSIF project funded by the European Space Agency. The current version of the TROPOSIF dataset covers the time period between May 2018 and April 2021. Baseline SIF retrievals are derived from the 743–758 nm window. A secondary SIF dataset derived from an extended fitting window (735–758 nm window) is included. This provides an enhanced signal-to-noise ratio at the expense of a higher sensitivity to atmospheric effects. Spectral reflectance spectra at seven 3-nm windows devoid of atmospheric absorption within the 665–785 nm range are also included in the TROPOSIF dataset as an important ancillary variable to be used in combination with SIF. The methodology to derive SIF and ancillary data as well as results from an initial data quality assessment are presented in this work. The TROPOSIF dataset is available through the following Digital Object Identifier (DOI) https://doi.org/10.5270/esa-s5p_innovation-sif-20180501_20210320-v2.1-202104 (Guanter et al., 2021).

scholarly journals Analysis of the Quality of SLR Station Coordinates Determined from Laser Ranging to the LARES Satellite

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 737
Author(s):  
Stanisław Schillak ◽  
Paweł Lejba ◽  
Piotr Michałek
Keyword(s):  
Data Center ◽  
European Space Agency ◽  
Laser Ranging ◽  
Space Agency ◽  
Station Coordinates ◽  
Italian Space Agency ◽  
The Stability ◽  
Better Than ◽  
Observation Results

The LARES (LAser RElativity Satellite) was built by the Italian Space Agency (ASI) and launched on 13 February 2012 by the European Space Agency. It is intended for studying the Lense–Thirring effect resulting from general relativity as well as for geodynamic studies and satellite geodesy. The satellite is observed by most ground laser stations. The task of this work is to determine the station coordinates and to assess the quality of their determination by comparison with the results from the LAGEOS-1 and LAGEOS-2 satellites. Observation results in the form of normal points (396,105 normal points in total) were downloaded from the EUROLAS Data Center for the period from 29 February 2012 to 31 December 2015. Seven-day orbital arcs were computed by the NASA GSFC GEODYN-II software, determining the coordinates of seventeen selected measuring stations. The average Root Mean Square (RMS) (15.1 mm) of the determined orbits is nearly the same as for LAGEOS (15.2 mm). The stability of the coordinates of each station (3DRMS) is from 9 mm to 46 mm (for LAGEOS, from 5 mm to 15 mm) with the uncertainty of determining the coordinates of 3–11 mm (LAGEOS 2–7 mm). The combined positioning for the LARES + LAGEOS-1 + LAGEOS-2 satellites allows for the stability of 5–18 mm with an uncertainty of 2–6 mm. For most stations, this solution is slightly better than the LAGEOS-only one.

scholarly journals Detailed Modeling of Cork-Phenolic Ablators in Preparation for the Post-flight Analysis of the QARMAN Re-entry CubeSat

2021 ◽  
Author(s):  
Claudio Miccoli ◽  
Alessandro Turchi ◽  
Pierre Schrooyen ◽  
Domenic D’Ambrosio ◽  
Thierry Magin
Keyword(s):  
Fluid Dynamics ◽  
Thermal Protection ◽  
A Priori ◽  
European Space Agency ◽  
Thermal Response ◽  
Accurate Method ◽  
Navier Stokes ◽  
Advection Equation ◽  
High Enthalpy ◽  
Space Agency

AbstractThis work deals with the analysis of the cork P50, an ablative thermal protection material (TPM) used for the heat shield of the qarman Re-entry CubeSat. Developed for the European Space Agency (ESA) at the von Karman Institute (VKI) for Fluid Dynamics, qarman is a scientific demonstrator for Aerothermodynamic Research. The ability to model and predict the atypical behavior of the new cork-based materials is considered a critical research topic. Therefore, this work is motivated by the need to develop a numerical model able to respond to this demand, in preparation to the post-flight analysis of qarman. This study is focused on the main thermal response phenomena of the cork P50: pyrolysis and swelling. Pyrolysis was analyzed by means of the multi-physics Computational Fluid Dynamics (CFD) code argo, developed at Cenaero. Based on a unified flow-material solver, the Volume Averaged Navier–Stokes (VANS) equations were numerically solved to describe the interaction between a multi-species high enthalpy flow and a reactive porous medium, by means of a high-order Discontinuous Galerkin Method (DGM). Specifically, an accurate method to compute the pyrolysis production rate was implemented. The modeling of swelling was the most ambitious task, requiring the development of a physical model accounting for this phenomenon, for the purpose of a future implementation within argo. A 1D model was proposed, mainly based on an a priori assumption on the swelling velocity and the resolution of a nonlinear advection equation, by means of a Finite Difference Method (FDM). Once developed, the model was successfully tested through a matlab code, showing that the approach is promising and thus opening the way to further developments.

scholarly journals Applicability of NGGM near-real time simulations in flood detection

2019 ◽  
Vol 9 (1) ◽  
pp. 111-126
Author(s):  
A. F. Purkhauser ◽  
J. A. Koch ◽  
R. Pail
Keyword(s):  
European Space Agency ◽  
Earth System ◽  
The Earth ◽  
Future Mission ◽  
Space Agency ◽  
Flood Detection ◽  
The One ◽  
Real Time Simulations ◽  
Grace Mission ◽  
Gravity Mission

Abstract The GRACE mission has demonstrated a tremendous potential for observing mass changes in the Earth system from space for climate research and the observation of climate change. Future mission should on the one hand extend the already existing time series and also provide higher spatial and temporal resolution that is required to fulfil all needs placed on a future mission. To analyse the applicability of such a Next Generation Gravity Mission (NGGM) concept regarding hydrological applications, two GRACE-FO-type pairs in Bender formation are analysed. The numerical closed loop simulations with a realistic noise assumption are based on the short arc approach and make use of the Wiese approach, enabling a self-de-aliasing of high-frequency atmospheric and oceanic signals, and a NRT approach for a short latency. Numerical simulations for future gravity mission concepts are based on geophysical models, representing the time-variable gravity field. First tests regarding the usability of the hydrology component contained in the Earth System Model (ESM) by the European Space Agency (ESA) for the analysis regarding a possible flood monitoring and detection showed a clear signal in a third of the analysed flood cases. Our analysis of selected cases found that detection of floods was clearly possible with the reconstructed AOHIS/HIS signal in 20% of the tested examples, while in 40% of the cases a peak was visible but not clearly recognisable.

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