Satellite Constellation Design Research Articles

4-GNSS radio occultation satellite constellation design based on Dual-gate uniformity evaluation index

A brand-new area of low earth orbit satellite constellation research has been expanded by global navigation satellite system (GNSS) radio occultation (RO) atmosphere sounding technology in the last decade. The possibility of reducing the sounding satellites while keeping the amount of atmosphere soundings increasing to produce low-cost meteorological data product is investigated, and a constellation capable of receiving the RO signals from all the 4-GNSS, such as GPS, GLONASS, Galileo, and Compass, is proposed in this paper. This paper focuses on the mathematical problems on the design of 4-GNSS RO satellite constellation. A forward GNSS RO sounding simulation algorithm based on ideal atmosphere model and two-dimensional radial tracing algorithm is presented for a rapidly and accurately sounding performance prediction of 4-GNSS RO satellite constellations. Then, an improved uniformity evaluation factor named Dual-gate is established for 4-GNSS RO satellite constellation optimization design, which is a combination of the uniformity evaluation factors for the latitudinal distribution of RO soundings and those for the gridding uniformity. On the basis of low earth orbit satellite orbit dynamics and spherical geometry, the impacts of partial constellation parameters on the amount and coverage performance accorded with Dual-gate uniformity evaluation index are derived, and a series of design criteria of 4-GNSS RO satellite constellation are summarized. A simplified 4-GNSS RO satellite constellation model is built on the basis of the design criteria, and an improved ant colony algorithm is used to optimize the parameters of a 4-GNSS RO constellation including as many satellites as COSMIC-2. The simulation result shows that this 4-GNSS RO constellation is capable of obtaining near 3000 atmosphere soundings per 3 h. It obtains 13% more soundings than COSMIC-2 with the same 4-GNSS RO sounding devices, and the uniformity of soundings is increased by 9%.

Fundamentals of the route theory for satellite constellation design for Earth discontinuous coverage. Part 1: Analytic emulation of the Earth coverage

This paper opens a series of articles expounding the fundamentals of the route theory for satellite constellation design for Earth discontinuous coverage. In Part 1 of the series the analytical model for Earth coverage by satellites’ swath conforming to the essential of discontinuous coverage, in contrast to continuous coverage, is presented. The analytic relations are consecutively derived for calculation of single- and multi-satellite Earth surface latitude coverage as well as for generating full set of typical satellite visibility zone time streams realized in the repeating latitude coverage pattern for given arbitrary satellite constellation. The analytic relations mentioned are used for developing the method for analysis of discontinuous coverage of fixed arbitrary Earth region for given satellite constellation using both deterministic and stochastic approaches. The method provides analysis of the revisit time for given satellite constellation, as a result of high speed (fractions of a second or seconds) computer calculations in a wide range of possible revisit time variations for different practical purposes with high accuracy which is at least on par with that provided by known numerical simulating methods based on direct modeling of the satellite observation mission, or in a number of cases is even superior to it.

Fundamentals of the route theory for satellite constellation design for Earth discontinuous coverage. Part 2: Synthesis of satellite orbits and constellations

The method for synthesis of satellite orbits and constellations, optimized by given criterion (minimum of required number of satellites in the constellation, or minimum revisit time, or minimum of the satellites' swath width required) for fixed parameters of on-board satellite equipment and constraints for unused criterion parameters of a list of mentioned above is presented. The numerical results demonstrate the possibilities of the method developed basing on analyzing the given satellite constellation revisit time values distributed on the Earth coverage area, and for synthesizing the satellite constellations to minimize revisit time in comparison with the traditional approaches based on constellation design in a priori fixed classes used for continuous coverage. Particularly, it is shown that the suggested synthesis method, basing on the simplest type of Route Constellations considered – Secure Route Constellations, directly leads, as result of high speed calculations for given Earth region coverage (seconds, or minutes as a worst case), to the optimized satellite constellations which provide consistently high performance and are better, or at least on the same level, in comparison with the best Walker constellations for discontinuous coverage. In order to have comprehensive coverage picture, both deterministic, and stochastic approaches are considered for estimation of the coverage characteristics of the given region of arbitrary shape, basing on the results of Earth coverage analytic emulation.

Fundamentals of the route theory for satellite constellation design for Earth discontinuous coverage. Part 3: Low-cost Earth observation with minimal satellite swath

Continuing the series of papers with description of the fundamentals of the Route Theory for satellite constellation design, the general method for minimization of the satellite swath width required under given constraint on the maximum revisit time (MRT), the main quality characteristic of the satellite constellation discontinuous coverage, is presented. The interrelation between MRT and multiplicity of the periodic coverage – the minimum number of the observation sessions realized for the points of observation region during the satellite tracks’ repetition period – is revealed and described. In particular, it is shown that a change of MRT can occur only at points of coverage multiplicity changing. Basic elements of multifold Earth coverage theory are presented and used for obtaining analytical relations for the minimum swath width providing given multifold coverage. The satellite swath width calculation procedure for the multifold coverage of rotating Earth using the iterations on the sphere of stationary coverage is developed. The numerical results for discontinuous coverage with minimal satellite swath, including comparison with some known particular cases and implementations of the method, are presented.

Fundamentals of the route theory for satellite constellation design for Earth discontinuous coverage. Part 4: Compound satellite structures on orbits with synchronized nodal regression

Basing on the theory results considered in the previous papers of the series for traditional one-tiered constellation formed on the orbits with the same values of altitudes and inclinations for all the satellites of the constellation, the method for constellation design using compound satellite structures on orbits with different altitudes and inclinations and synchronized nodal regression is developed. Compound, multi-tiered, satellite structures (constellations) are based on orbits with different values of altitude and inclination providing nodal regression synchronization. It is shown that using compound satellite constellations for Earth periodic coverage makes it possible to sufficiently improve the Earth coverage, as compared to the traditional constellations based on the orbits with common altitude and inclination for all the satellites of the constellation, and, as a consequence, to get new opportunities for the satellite constellation design for different types of prospective space systems regarding increasing the quality of observations or minimization of the number of the satellites required.

Satellite constellation design with genetic algorithms based on system performance

Satellite constellation design for space optical systems is essentially a multiple-objective optimization problem. In this work, to tackle this challenge, we first categorize the performance metrics of the space optical system by taking into account the system tasks (i.e., target detection and tracking). We then propose a new non-dominated sorting genetic algorithm (NSGA) to maximize the system surveillance performance. Pareto optimal sets are employed to deal with the conflicts due to the presence of multiple cost functions. Simulation results verify the validity and the improved performance of the proposed technique over benchmark methods.

Optimization of small satellite constellation design for continuous mutual regional coverage with multi-objective genetic algorithm

This paper describes the application of an evolutionary optimization method to design satellite constellation for continuous regional coverage without intersatellite links. This configuration, called mutual coverage, is related to some technical limitations that exist on small satellite technology. The coverage of the north Algerian seismological network is taken as an example of application. A Multi Objective Genetic Algorithm (MOGA) is used to make a trade-off between the improvement of the coverage rate, the minimization of the total number of satellites and the reduction of the satellites' altitude. First, some experiments have been performed to find the weight distribution of the fitness function that shows the most significant improvement of the average fitness function. Then, some optimized constellation designs are given for different ranges of altitude and it is shown that the size of the MOGA constellation design is significantly reduced compared to the traditional geometrical design.

Satellite constellation design for telecommunication in Antarctica

Summary This paper addresses the problem of designing a small satellite constellation suitable for communications in Antarctica. This study has been motivated by the increasing international interests in having permanent bases in Antarctica to perform experiments in physics, atmospheric sciences, geology, and biology to name a few key areas. The existing and planned scientific expeditions in Antarctica require continuous and reliable communication services, especially during emergencies. Geostationary Earth orbit satellites do not cover this high latitude adequately, and constellations using circular orbits would require too many satellites to provide continuous regional coverage, thus increasing cost prohibitively. A three-satellite constellation using elliptical orbits is proposed to address this issue. The critical inclination has been selected to predominantly keep the satellites over Antarctica, where the satellites will dwell most of the time. This configuration has been obtained by using the two-dimensional lattice flower constellation design theory: a minimum parameter design methodology that enforces all three satellites in the same trajectory as seen from the Earth rotating frame. This aspect provides the continuous coverage necessary for reliable communications using only a small number of satellites. Copyright © 2015 John Wiley & Sons, Ltd.

Design of flower constellations using necklaces

This paper introduces a new approach in the design of optimal satellite constellations comprising few satellites and characterized by symmetric distribution. Typical examples are missions requiring persistent observation of sites or regions for intelligence or science. To minimize the number of satellites, the mathematical necklace theory is applied to the two-dimensional Lattice Flower Constellation framework. The necklace theory identifies in the phasing space all satellite subsets characterized by symmetric distributions. Mathematically, these subsets are parameterized by necklaces, identifying the actual satellite locations in the first orbital plane and a shifting parameter governing phasing between subsequent orbital planes. This article specifically targets the emerging importance of small satellite formations and constellations.

Elliptic orbits and satellite constellations for coverage of illuminated areas

Synthesis of systems of continuous or periodic cov� erage of the Earth (from global coverage to survey of separate regions) is a traditional approach to the design of satellite constellations (SC). Following this line of research, the methods of ballistic design have been developed for various types of orbits and forms of coverage (1-7). A brief historical overview of develop� ment and modern state of the art of the theory of SC for continuous coverage is presented in (8). The SC in elliptic orbits of the Molniya type (9-11) form a spe� cial class. These orbits are characterized by the use of critical orbit inclination (i = 63.4° or i = 116.6°) and by position of the orbit apogee in the hemisphere including a coverage region. In this class socalled oneroute (or onepath) systems were developed (10) whose paths on the ground surface coincide (i.e., parameters of the orbits and Greenwich longitudes of their ascending nodes are identical). For the systems designed for surveying the Earth's surface and connected with illumination of observed regions by the Sun one can use SC of continuous cov� erage in highly elliptical orbits (11). However, this approach can be nonoptimal as far as the number of required satellites is concerned. The use of SC of peri� odic coverage, as a rule, cannot solve this problem, since arising gaps in survey have cyclic character and are not connected with illumination by the Sun. The goal of this work is to develop the methods of choosing economical SC designed for observation of illumi� nated regions and based on a new type of highly elliptic orbits of Molniya type. The latter are synchronized with the solar day, as opposed to the classical Molniya orbits that are synchronized with the Earth's rotation (i.e., with the sidereal day). It is worthy of noting that such orbits can also be used for the inverse problem: to survey some areas during nighttime (for example, for their illumination). Another possible application is satellite communication systems in which the intervals of visibility, determining the possibility of communi� cation, are connected to the local time with maximum communication traffic. PseudoSunSynchronous Orbits of the Molniya Type. Let us consider a certain region of observation. Let the region center have geographic longitude λН and corresponding local time scale tm. We assume that there is a certain highly elliptical orbit with the orbit period multiple to the solar day duration

Preliminary design of satellite constellations for a Brazilian regional positioning system by means of an evolutionary algorithm

This paper presents and discuss some possibilities concerning to the design of a Regional Positioning System RPS satellite constellation to cover the Brazilian territory. The paper presents an overview of constellation design possibilities for a hypothetical Brazilian Regional Positioning System. Since Brazil is located near the equator plane, the idea is to think about a RPS satellite constellation that takes advantage of this fact in order to design a cost effective regional system that aims at covering primarily only the Brazilian territory. In this sense, three satellite constellation types were considered. The first one is based only on geosynchronous satellites. The second one is based on Medium Earth Orbit MEO satellites placed in the equator plane or near to it, and the third one is composed by Low Earth Orbit LEO satellites with low to moderate orbital plane inclination angles. A preliminary optimization process was run in order to obtain an initial guess of a good design. The obtained design constellations are presented and discussed.

Design of Flower Constellations for Telecommunication Services

Satellite constellation designers take into consideration the entire telecommunication network and their design choices are influenced by many factors including: number of satellites, orbital characteristics, coverage area, network interconnections, system cost, and complexity. When the satellite constellation design method does not include a large number of possible configurations, then the final result of the design process is a suboptimal solution. Flower Constellation (FC) design provides a relatively new design approach which can overcome this problem. The time evolution of the FC theory is here summarized and the fundamental mathematics allowing the constellation design is provided. In particular, the theory is applied to the design and optimization of constellations maximizing the global coverage and the network connectivity via intersatellite links. Performance results are compared to the classical type of satellite constellations, i.e., the Walker Constellations. The performance improvement provided by FC design with respect to Walker Constellation design is shown. Finally, considerations regarding the cost for deployment and orbital control are also provided.

Design of satellite constellations with continuous coverage on elliptic orbits of Molniya type

New methods of choosing the structures of satellite constellations (SC) on elliptical orbits of the Molniya type are presented. The methods, using critical inclination and putting the orbit apogee in the Earth’s hemisphere with an area of continuous coverage, are based on geometrical analysis of two-dimensional representation of the coverage conditions and SC motion in the space of inertial longitude of the orbit ascending node and time. The coverage conditions are represented in the form of a certain region. Dynamics of all satellites in this space is represented by uniform motion along a straight line approximately parallel to the ordinate axis, while the satellite system forms a grid. The problem of choosing a minimal (as far as the number of satellites is concerned) SC configuration can be formulated as a search for the most sparse grid. The contemporary advanced methods of computational geometry serve as an algorithmic basis for the problem solution. Design of SC for continuous coverage of latitude belts with the use of kinematically regular systems is considered. A method of analyzing single-track systems for continuous coverage of arbitrary geographic regions is described, which makes a region at any time instant observable by at least one satellite of the system. As an example, SC on elliptical orbits are considered with periods of ∼4, 12, and 24 hours.

Parallel Evolutionary Multi-Objective Optimization on Large, Heterogeneous Clusters: An Applications Perspective

Real-world operational use of parallel multi-objective evolutionary algorithms requires successful searches in constrained wall-clock periods, limited trial-and-error algorithmic analysis, and scalable use of heterogeneous computing hardware. This study provides a cross-disciplinary collaborative effort to assess and adapt parallel multi-objective evolutionary algorithms for operational use in satellite constellation design using large dedicated clusters with heterogeneous processor speeds/architectures. A statistical, metric-based evaluation framework is used to demonstrate how time-continuation, asynchronous evolution, dynamic population sizing, and epsilon dominance archiving can be used to enhance both simple master–slave parallelization strategies and more complex multiple-population schemes. Results for a benchmark constellation design coverage problem show that simple master– slave schemes that exploit time-continuation are often sufficient and potentially superior to complex multiple-population schemes.

Satellite Constellation Design for Complex Coverage

Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.

Satellite Constellation Design with Adaptively Continuous Ant System Algorithm

The ant system algorithm (ASA) has proved to be a novel meta-heuristic algorithm to solve many multivariable problems. In this paper, the earth coverage of satellite constellation is analyzed and a ▪-fold coverage rate is put forward to evaluate the coverage performance of a satellite constellation. An optimization model of constellation parameters is established on the basis of the coverage performance. As a newly developed method, ASA can be applied to optimize the constellation parameters. In order to improve the ASA, a rule for adaptive number of ants is proposed, by which the search range is obviously enlarged and the convergence speed increased. Simulation results have shown that the ASA is more quick and efficient than other methods.

Efficient and Accurate Evolutionary Multi-Objective Optimization Paradigms for Satellite Constellation Design

Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.

Optimal reconfiguration of satellite constellations with the auction algorithm

Traditionally, satellite constellation design has focused on optimizing global, zonal or regional coverage with a minimum number of satellites. In some instances, however, it is desirable to deploy a constellation in stages to gradually expand capacity. This requires launching additional satellites and reconfiguring the existing on-orbit satellites. Also, a constellation might be retasked and reconfigured after it is initially fielded for operational reasons. This paper presents a methodology for optimizing orbital reconfigurations of satellite constellations. The work focuses on technical aspects for transforming an initial constellation A into a new constellation, B, typically with a larger number of satellites. A general framework was developed to study the orbital reconfiguration problem. The framework was applied to low Earth orbit constellations of communication satellites. This paper specifically addresses the problem of determining the optimal assignment for transferring on-orbit satellites in constellation A to constellation B such that the total Δ V for the reconfiguration is minimized. It is shown that the auction algorithm, used for solving general network flow problems, can efficiently and reliably determine the optimum assignment of satellites of A to slots of B. Based on this methodology, reconfiguration maps can be created, which show the energy required for transforming one constellation into another as a function of type (Street-of-Coverage, Walker, Draim), altitude, ground elevation angle and fold of coverage. Suggested extensions of this work include quantification of the tradeoff between reconfiguration time and Δ V , multiple successive reconfigurations, balancing propellant consumption within the constellation during reconfiguration as well as using reconfigurability as an objective during initial constellation design.

Topological dynamics characterization for LEO satellite networks

The highly topological dynamics characterizes the most fundamental property of satellite networks with respect to terrestrial ones. The manifest feature directs the researches on various aspects of satellite networks, including protocol architecture investigations, routing protocol and reliable transmission control protocol design and enhancement, etc. This paper systematically quantifies the dynamical activities of regular low earth orbit (LEO) satellite network topologies. The number and length of network snapshots are formulated concisely. With this work, it compensates for the simplified topological assumptions in many LEO satellite network related researches. The thorough understanding of this basic feature not only provides for an accurate quantification of network behavior for researchers on satellite network community, but also could act as a guidance for future satellite constellation design and optimization.

Design and Deployment of a Satellite Constellation Using Collaborative Optimization

A study of collaborative optimization as a systematic, multivariable, multidisciplinary method for the conceptual design of satellite constellations is presented. Collaborative optimization was selected because it is well suited to a team-oriented environment, such as often found in the constellation design process. The method provides extensive and formal exploration of the multidisciplinary design space and a scalable formulation of the problem without compromising its subsystems’ flexibility or eliminating opportunities for collaboration. The feasibility and benefits of the collaborative optimization architecture are highlighted by the successful convergence of an application notional problem to design and deploy elements of a space-based infrared system that provides early missile warning. Furthermore, this study contributes to the existing knowledge of the collaborative optimization method by verifying the feasibility of nongradient optimization algorithms as both system and subsystem optimizers within the architecture. Finally, the demonstrated convergence of this problem, which involves integer variables, also demonstrates the flexibility of the architecture for handling mixed-discrete nonlinear multidisciplinary problems.