Papers by Daniel Casanova
Advances in Space Research
Celestial Mechanics and Dynamical Astronomy
2D-Lattice Flower Constellations present interesting dynamical features that allow us to explore ... more 2D-Lattice Flower Constellations present interesting dynamical features that allow us to explore a wide range of potential applications. Their particular initial distribution (lattice) and their symmetries disappear when some perturbations are considered, such as the J 2 effect. The new lattice-preserving Flower Constellations maintain over long periods of time the initial distribution and its symmetries under the J 2 perturbation, which is known as relative station-keeping. This paper deals with the study of the required velocity change that must be applied to the satellites of the constellation to have an absolute station-keeping.
Celestial Mechanics and Dynamical Astronomy, 2015
ABSTRACT
Monthly Notices of the Royal Astronomical Society, 2014
ABSTRACT
Proceedings of the International Astronomical Union, 2014
ABSTRACT
Aerospace Science and Technology, 2014
In this paper, given a certain number of satellites (N sat ), which is limited due to the sort of... more In this paper, given a certain number of satellites (N sat ), which is limited due to the sort of mission or economical reasons, the Flower Constellation with N sat satellites which has the best geometrical configuration for a certain global coverage problem is sought by using evolutionary algorithms. In particular, genetic algorithm and particle swarm optimization algorithm are used. As a measure of optimality, the Geometric Dilution Of Precision (GDOP) value over 30 000 points randomly and uniformly distributed over the Earth surface during the propagation time is used. The GDOP function, which depends on the geometry of the satellites with respect to the 30 000 points over the Earth surface (as ground stations), corresponds to the fitness function of the evolutionary algorithms used throughout this work. Two different techniques are shown in this paper to reduce the computational cost of the search process: one that reduces the search space and the other that reduces the propagation time. The GDOP-optimal Flower Constellations are obtained when the number of satellites varies between 18 and 40. These configurations are analyzed and compared. Owing to the Flower Constellation theory we find explicit examples where eccentric orbits outperform circular ones for a global positioning system.
IEEE Transactions on Aerospace and Electronic Systems, 2014
AIAA/AAS Astrodynamics Specialist Conference, 2012
Celestial Mechanics and Dynamical Astronomy, 2014
2D Lattice Flower Constellations (2D-LFCs) are stable in the Keplerian model. This means that a f... more 2D Lattice Flower Constellations (2D-LFCs) are stable in the Keplerian model. This means that a flower constellation maintains its structure (the lattice) at any instant of time. However, this is not necessarily true when the J 2 harmonic is included in the gravitational potential of the Earth. This paper deals with the new theory of Lattice-preserving Flower Constellations, which shows how 2D-LFC can be designed in such a way that the relative displacement of the orbital parameters of its satellites is invariant even under the presence of the J 2 effect. This is achieved following two different procedures: the first consists of the modification of the semi-major axis of all the satellites in a 2D-LFC slightly to control their orbital period, and the second consists of the modification of the values for the eccentricity and inclination, so that the perturbations result in motion that still preserves the lattice of the flower constellation. The proposed theory of Lattice-preserving Flower Constellations validates the theory of 3D Lattice Flower Constellations and has a wide range of potential applications.
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Papers by Daniel Casanova