Dynamics of Spacecraft

In this paper we present results from the NEFOCAST project, funded by the Tuscany Region, aiming at detecting and estimating rainfall fields from the opportunistic use of the rain-induced excess attenuation incurred in the downlink channel by a commercial DVB satellite signal. The attenuation is estimated by reverse-engineering the effects of the various propagation phenomena affecting the received signal, among which, in first place, the perturbations factors affecting geostationary orbits, such as the gravitational attraction from the moon and the sun and the inhomogeneity in Earth mass distribution and, secondly, the small-scale irregularities in the atmospheric refractive index, causing rapid fluctuations in signal amplitude. The latter impairments, in particular, even if periodically counteracted by correction maneuvers, may give rise to significant departures of the actual satellite position from the nominal orbit. A further problem to deal with is the daily and seasonal random fluctuation of the rain height and altitude/size of the associated melting layer. All of the above issues lead to non-negligible random deviations from the dry nominal downlink attenuation, that can be misinterpreted as rain events. In this paper we show how to counteract these issues by employing two differentially-configured Kalman filters designed to track slow and fast changes of the received signal-to-noise ratio, so that the rain events can be reliably detected and the relevant rainfall rate estimated.

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“…Furthermore, Fig. 11 plots the cumulated rain (in mm) obtained by integrating the in- 27 stantaneous rain rates displayed in Fig. 10.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…In practice, a satellite is subject to many sources of perturbations that make it impossible to maintain its orbit perfectly stable. One of the main orbit perturbations is related to the gravitational effects of the moon and the sun that cause a progression of the orbit inclination [27]. These pertur-  Sun transit.…”

Section: Satellitementioning

confidence: 99%

The NEFOCAST System for Detection and Estimation of Rainfall Fields by the Opportunistic Use of Broadcast Satellite Signals

Giannetti

Moretti

Reggiannini

et al. 2019

IEEE Aerosp. Electron. Syst. Mag.

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“…They are derived from the functions that the product should have and flow through the design process where they are reviewed, implemented and verified (Fortescue, 1999). First of all the CubeSat standard requirements dictate the physical properties and environmental performance of the satellite.…”

Section: Requirements Managementmentioning

confidence: 99%

3.4.3 A Comparative Analysis of Project Management and Systems Engineering Techniques in CubeSat Projects

Elstak

Amini

Hamann

2009

INCOSE International Symp

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Abstract. In the year 2000, California Polytechnic State University and Stanford University issued a new standard for small satellites: The CubeSat standard. This standard allowed universities to design, build, test and operate affordable, small, satellites within a time span of two to three years. Both Delft University of Technology (DUT) and Aalborg University (AAU) have used the CubeSat standard to develop a student satellite. In Delft, the Delfi-C 3 and in Aalborg AAUSAT-II satellites were developed. This paper evaluates the different techniques that are used in the Project Management and Systems Engineering of CubeSats. The satellite projects of DUT and AAU, which are highly different in setup, will be used as reference points for this evaluation. AAU has a strong pragmatic approach, while DUT uses a structured industrial standard approach.

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“…This reached a peak of 7.9 tonnes with ESA's EnviSat mission in 2002 [4]. With launch costs to low Earth orbit (LEO) being on average 21 ke/kg, and for geostationary Earth orbits (GEO) 29 ke/kg, for conventional satellites, the missions were mainly developed by national institutions or multi-national partnerships involving substantial investment [5].…”

Section: Introductionmentioning

confidence: 99%

“…The revolution of very-large-scale integration, in 1970, opened the possibility of integrating sophisticated functions into small volumes, with low mass and power, which pave the way for the modern small satellite [5]. This concept was initially demonstrated in 1961 with the Orbiting Satellite Carrying Amateur Radio (OSCAR) 1, and kept growing in sophistication until OSCAR-8, at the end of the 1970s (although still without an on-board computer).…”

Section: Introductionmentioning

confidence: 99%

On small satellites for oceanography: A survey

et al. 2016

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The recent explosive growth of small satellite operations driven primarily from an academic or pedagogical need, has demonstrated the viability of commercial-off-the-shelf technologies in space. They have also leveraged and shown the need for development of compatible sensors primarily aimed for Earth observation tasks including monitoring terrestrial domains, communications and engineering tests. However, one domain that these platforms have not yet made substantial inroads into, is in the ocean sciences. Remote sensing has long been within the repertoire of tools for oceanographers to study dynamic large scale physical phenomena, such as gyres and fronts, bio-geochemical process transport, primary productivity and process studies in the coastal ocean. We argue that the time has come for micro and nano satellites (with mass smaller than 100 kg and 2 to 3 year development times) designed, built, tested and flown by academic departments, for coordinated observations with robotic assets in situ. We do so primarily by surveying SmallSat missions oriented towards ocean observations in the recent past, and in doing so, we update the current knowledge about what is feasible in the rapidly evolving field of platforms and sensors for this domain. We conclude by proposing a set of candidate ocean observing missions with an emphasis on radar-based observations, with a focus on Synthetic Aperture Radar.

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Dynamics of Spacecraft

Cited by 46 publications

References 0 publications

The NEFOCAST System for Detection and Estimation of Rainfall Fields by the Opportunistic Use of Broadcast Satellite Signals

The NEFOCAST System for Detection and Estimation of Rainfall Fields by the Opportunistic Use of Broadcast Satellite Signals

3.4.3 A Comparative Analysis of Project Management and Systems Engineering Techniques in CubeSat Projects

On small satellites for oceanography: A survey

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