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Perrotta G.,SpaceSys | Marzano F.,University of Rome La Sapienza | Tognolatti P.,University of L'Aquila | Mugnai A.,CNR Institute of atmospheric Sciences and Climate
International Journal of Remote Sensing | Year: 2011

The article reports on the study results of the NanoROLD (Nano Radio Optical Lightning Detector) project, which was proposed for inclusion in action line 3 (Climatic aspects of clouds and precipitation) of the AeroClouds Programme planned around the year 2004 by the MIUR (Ministry of Education, University and Research). After a short review of the AeroClouds objectives and the lightning geolocation requirements, the article reviews the location accuracies achievable with both single and multiple satellite system configurations, and compares the two approaches from performance and complexity viewpoints. The feasibility of radio frequency (RF) detection of electrical discharges is dealt with first, to demonstrate the feasibility of a high accuracy lightning geolocation mission by means of microsatellites, while the assessment of optical instruments is deferred to a later study phase. The final comparison is then restricted to two candidates: a threesatellite formation exploiting time-of-arrival (TOA) principles; and a single satellite implementing a three-arm radiofrequency interferometer. The expected greater costs of a three-satellite constellation in formation flight are offset by the greater complexity and criticality of the interferometer system based on a single satellite and by its poorer performance in terms of lightning geolocation accuracy. However, for an experimental, fund-limited programme, a demonstration mission based on a single satellite could be more appropriate and an initial baseline design is also provided in the article. © 2011 Taylor & Francis.

Witternigg N.,Joanneum Research | Obertaxer G.,Joanneum Research | Schonhuber M.,Joanneum Research | Palmerini G.B.,University of Rome La Sapienza | And 7 more authors.
Proceedings of the International Astronautical Congress, IAC | Year: 2015

Weak GNSS signals could be exploited in future lunar missions to increase navigation robustness, flexibility and autonomy. In these applications GNSS reception suffers from very low signal levels, partial visibility of the GNSS sources and unfavourable geometry, making use of either secondary lobes or the signals' spill over around the Earth mask. Objective of a recent ESA study was to evaluate the challenges of such a navigation technique using GPS and future Galileo reception with carrier to signal levels as low as 10 to 15 dBHz. Investigated mission phases included transfer orbit, low lunar orbits, lunar ascent and descent as well as surface operation and navigation at the Lagrangian points. The paper presents the approach pursued during the study and shares its main findings, showing first that GNSS can be actually considered as an available and extremely useful navigation resource in all phases, even if part of the missions, and specifically low lunar orbits and descent, will require a mandatory aiding form other sensors. Moreover, external aiding in terms of the content of the data message has been envisaged in order to adopt a snapshot architecture for the receiver and to overcome limits in tracking loops with extremely low carrier to noise ratio. A proof of concept for the proposed receiver has been built and tested in different simulated scenarios. As a final result, a multi-constellation GNSS receiver software can be considered a suitable option to enable autonomous navigation in lunar missions, allowing for large savings in the expensive - and poorly available - ground-based tracking network. Copyright © 2015 by the International Astronautical Federation. All rights reserved.

Perrotta G.,SpaceSys | Stipa M.,SpaceSys | Silvi D.,SpaceSys | Coltellacci S.,SpaceSys | And 10 more authors.
Experimental Astronomy | Year: 2011

The Mission MAGIA (Missione Altimetrica Geofisica GeochImica lunAre) was proposed in the framework of the "Bando per Piccole Missioni" of ASI (Italian Space Agency) in 2007. The mission was selected for a phase A study by ASI on February 7th 2008. The tight budget allocation, combined with quite ambitious scientific objectives, set challenging requirements for the satellite design. The paper gives a fast overview of the payloads complement and of the mission-constrained design drivers, including cost minimization, risk reduction, and AIT flexibility. The spacecraft architecture is then outlined, along with an overview of the key subsystems and trade-offs. Some details are given of a Moon gravitometric experiment based on a mother-daughter satellite configuration with the daughter being a subsatellite released from the MAGIA satellite and intended to circle the Moon at a very low altitude. Budgets are appended at the end of the paper showing the key study results. © 2010 Springer Science+Business Media B.V.

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