Design of formation missions for Earth observation: relative motion model, validation, and application
- Paper number
IAC-06-C1.P.8.01
- Author
Prof. Marco D Errico, Seconda Universita di Napoli, Italy
- Coauthor
Mr. Giancarmine Fasano, University of Naples "Federico II", Italy
- Year
2006
- Abstract
In recent years there has been a growing interest in satellite formation flight and distributed satellite systems, in the context of optical or radar interferometry space missions. This recent flurry of research lead to the development of several sets of equations to predict and understand relative motion between satellites in a cluster, trying to improve Hill-Clohessy-Wiltshire equations (Hill, 1878, Clohessy and Wiltshire, 1960) by including J2 perturbations (Wiesel, 2002, Vadali et al., 2000, Schweighart and Sedwick, 2002). Nevertheless, most models in literature are devoted to control problems rather than to the issue of designing the orbits on the basis of mission requirements. Recently, in this context the authors developed a relative motion model allowing for a time-explicit analytical solution on the basis of orbital parameters’ differences between satellites, which includes J2 secular effects (Fasano and D’Errico, 2006). Two sets of equations were derived, referring to the case of a reference satellite moving on a circular or slightly eccentric reference orbit, respectively. In the proposed paper, first this model is validated through a detailed numerical analysis, which allows to evaluate its errors as a function of satellites’ baselines and orbital parameters. Then, it is applied to the design of tandem missions aimed at both interferometric and bistatic SAR observation. In the case of SAR interferometry, different frequency bands are explored in terms of requirements (height accuracy and height of ambiguity for cross-track interferometry, velocity measurement accuracy and range for along-track interferometry) and consequent orbit design and achievable latitude coverage. Possibilities arising from natural trajectory deformation are pointed out. As for bistatic missions, since they are characterized by larger distances and orbital parameters’ differences between satellites (D’Errico and Moccia, 2001, Fasano and D’Errico, 2005), with respect to interferometric applications, the model is extended by including higher order terms in the derivation process, in order to obtain a satisfying accuracy at higher distances than the ones typically considered in formation flying analyses. This extension, in turn, allows to design dynamical bistatic orbits optimizing orbital parameters’ choice, so that Earth oblateness differential effects can be exploited to the mission advantage.
- Abstract document
- Manuscript document
IAC-06-C1.P.8.01.pdf (🔒 authorized access only).
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