Satellite Constellation Design Research Articles

Investigating Regional Communication Network Robustness of an Asymmetric String-of-Pearls Satellite Constellation Design Framework

Appropriate selection of a satellite constellation design framework for a particular mission set requires a priori knowledge about the relative merits and shortcomings of different frameworks. Symmetric satellite constellation frameworks exhibit good properties for missions requiring continuous global coverage, whereas asymmetric satellite constellation frameworks benefit missions focusing on regional coverage. This research compares the performance of an asymmetric “string-of-pearls” common repeating ground track constellation design framework against a Walker constellation design framework for maintaining continuous connectivity between regions of interest. Several examples illustrate that the asymmetric string-of-pearls constellation framework appears to require an average of approximately 1.25 fewer satellites than the Walker constellation, whereas the Walker constellation appears approximately 7.86% more robust to satellite failures.

Multidisciplinary design and optimization of intelligent Distributed Satellite Systems for EARTH observation

Recent advances in small, connected and intelligent satellite systems have created a wide range of opportunities for the adoption of intelligent Distributed Satellite Systems (iDSS) in communication, navigation and Earth Observation (EO) missions. iDSS are goal-oriented systems comprising of multiple satellites or modules that interact, communicate and/or cooperate with each other to accomplish the desired mission goals. The ability to mass-produce low-cost small satellites and contemporary developments in avionics/astrionics technology have spurred interest in iDSS, especially for Low Earth Orbit (LEO) satellite constellations and regional clusters. The SmartSat Cooperative Research Centre (CRC) and Australian space roadmap, as well as the landmark National Space Programme strategy and priorities, encompass EO. To date, insufficient progress and no conclusive outcome was made in terms of how contemporary Multidisciplinary Design Optimization (MDO) models and tools can be best tailored to the new capabilities and specificities of iDSS. The MDO of iDSS is challenging because it introduces new variables and highly non-linear interactions. In this context, we propose an MDO methodology to optimize an iDSS for persistent coverage over the entire Australian landmass. Several aspects of the iDSS are considered in this work, including the constellation model, subsystem models and the coupling interactions between different satellite subsystems and constellation design parameters. The constellation configuration, as well as the subsystems, are modelled using OpenMDAO, which is used to analyze and visualize the planned iDSS EO mission. The iDSS is then optimized using the Multidisciplinary Feasible (MDF) architecture approach and the iDSS interdependencies are numerically treated using the Nonlinear Block Gauss-Seidel (NLBGS) iterative solver. The resulting N2 diagrams are presented and the proposed solution is both spatially and temporally optimized, demonstrating that the proposed iDSS will enable near real-time persistent coverage over the entire Australian continent.

An overview of communication and orbital composition technologies based on starlink LEO satellite constellation from a technical perspective

With the development of fiber optic and communication technology, densely populated areas have been provided with the good network coverage. However, rural, suburban, ocean and airborne areas still lack economical and effective means of network connectivity. Although the concept of low-orbit communication satellite constellations such as Iridium was proposed in the 1990s, it was not successful due to satellite performance and launch costs. Since 2016, SpaceX has envisioned the construction of the Starlink constellation to provide high-speed Internet services worldwide, which is now operational. This study attempts to analyze the basic theory and performance levels of several key Starlink technologies to analyze the basic characteristics of Starlink in orbital deployment, terrestrial communication, and inter-satellite communication. However, Starlink still has difficulties in various technologies. By exploring new research advances in these areas, the performance of the constellation can be optimized or new solutions can be found. An analysis of Starlinks key performance metrics shows that the key to the success of Starlinks project is the industrialization of advanced laboratory technologies and their application to the design and deployment of satellite constellations.

Matheuristics approaches for the satellite constellation design problem

In this paper, we propose two novel matheuristic algorithms, i.e., heuristics based on mathematical formulations of the problem, in order to find a good feasible solution to the satellite constellation design problem for discontinuous coverage with a constrained revisit time. This problem consists in searching for a constellation able to periodically observe several targets at the Earth surface with the smallest number of satellites achievable. A Feasibility Pump approach is described: we specifically adapt the Feasibility Pump procedure to our design problem and we report results highlighting the benefits of this approach compared to the base Mixed Integer Nonlinear Programming (MINLP) algorithm it is derived from. Then, we propose a second matheuristic based on the discretized Mixed Integer Linear Programming (MILP) formulation of the problem, which outperforms the plain MILP formulation.

Satellite constellation design for 5G wireless networks of mobile communications

SummarySatellite constellation design plays an important role in satellite networks. Network constellation system design can affect the effectiveness of current improvements of the communications link and the management of the entire network. The power requirement of the mobile stations and ground stations is very high in a geostationary Earth orbit communication system, which means the terrestrial terminal is hard to be made handheld for fifth generation mobile communications. The emergence of nongeostationary orbit satellites such as low Earth orbit satellites greatly compensates for the disadvantage of geostationary Earth orbit satellites. Based on the classical constellation design method, the orthogonal circular orbit constellation is proposed. The design objectives considered here are the following: global Earth coverage by low Earth orbit satellites, the duration of continuously covering one mobile station by one satellite is more than 9.57 min, the access satellite link duration time of the mobile station is more than 4.79 min, and the number of satellites and orbits is to be minimum.

Non-Self-Intersecting Trajectories and Their Applications to Satellite Constellation Design and Orbital Capacity

This work focuses on the generation of non-self-intersecting relative trajectories, and their applications to satellite constellation design, slotting architectures, and space traffic management. To that end, this paper introduces three theorems to determine when two spacecraft share the same relative trajectory, to identify the only conditions that allow the existence of non-self-intersecting relative trajectories, and to compute the minimum distances inside these relative trajectories. These results are then applied first to obtain an estimation of the limits of the orbital capacity at a given altitude and, second, in the design of satellite constellations and slotting architectures that present no conjunctions between any element compliant with these space structures.

Mixed integer (non)linear approaches for the satellite constellation design problem

Mixed integer (non)linear approaches for the satellite constellation design problem

Simulation study on inclined orbit constellation of high-resolution electrooptical sensors for enhanced imaging efficiency in region of interest

Traditionally, high-resolution electrooptical (EO) sensors are placed in Sun-synchronous orbits (SSO) as they enable consistent solar illumination during imaging and near-global coverage for various remote sensing applications. However, these sensors inherently offer limited swath coverage resulting in poorer imaging efficiency and often require a large number of satellites in constellation for improving revisit time over region of interest (RoI). Compared with constellation of satellites in SSO, a smaller number of satellites in lower inclination orbits can provide significant advantage in terms of imaging efficiency in the tropical and near-tropical RoIs, which is desirable for many civilian and strategic applications. In this work, detailed analytical simulations have been performed for inclined orbit constellation of high-resolution EO sensors, and higher imaging efficiency has been demonstrated against SSO constellation. Rigorous mathematical models are developed to enable optimization of constellation design with proper fine-tuning of orbital parameters to maximize imaging efficiency in the RoI, and the model output is validated through STK simulation. For quantitative evaluation of imaging efficiency, two figures of merits, namely, average number of access per day and number of days with no access, have been estimated for various design cases. This study shows significant improvements in imaging efficiency parameters up to a factor of 3 in RoI as compared with traditional SSO constellation. This study is generic in nature and is applicable for any inclination angles and latitudes in the tropical and near tropical RoIs. This study can significantly aid in design of satellite constellations for future remote sensing missions.

Technical assessment of an equatorial Low Earth orbit satellite constellation for Egypt

Egypt, the region’s agricultural powerhouse, has the largest irrigation area among the eleven Nile Basin countries. Meanwhile, the demand for water and irrigation management is becoming necessary. The Internet of Things (IoT) plays a key role in smart agriculture and water management to cope with modern water scarcity. This paper presents the methodology of design and assessment of a small IoT satellite constellation providing continuous coverage over Egypt and decides on the optimal location for ground stations to serve IoT sector in Egypt. Moreover, it evaluates the latency analysis and handover time for such constellation.It is shown that a constellation of 9 satellites in a circular equatorial Low Earth Orbit (LEO) can provide continuous coverage for Egypt. The latency analysis showed that two ground stations in southernmost Egypt will provide the optimal latency for such constellation.

Analytical design and performance analysis of LEO mega chain satellite constellation

With the development of microsatellite technology and the growth of ground reconnaissance demand, the rapid design of a LEO constellation with minimum satellite number, low revisit time (within 10 minutes), and permanent inter-satellite links has become a hotspot and difficulty in constellation design. Aiming at the problem to use the minimum satellite number to achieve low revisit time coverage, a LEO (low earth orbit) Walker-chain constellation and its design method is proposed. The difference between the chain constellation and the classical Walker constellation is that it has one or more closed chain configurations. According to the coverage requirements and sensor field of view angle, the analytical design method is derived. A LEO chain constellation containing 132 satellites is designed for the ground reconnaissance mission. Comparing with the classical Walker-δ constellation and repeat ground track constellation, the chain constellation has fewer satellites, lower revisit time and the permanent inter-satellite links.

Design Coverage Optimization Based on Position of Constellations and Cost of the Launch Vehicle

This research will analyze the tradeoffs between coverage optimization based on Position dilution of precision (PDOP) and cost of the launch vehicle. It adopts MATLAB and STK tools along with multiple objective genetic algorithms (MOGA) to explore the trade space for the constellation designs at different orbital altitudes. The objective of optimal design solutions is inferred to determine the economic and efficient LEO, MEO, HEO or hybrid constellations and simulation results are presented to optimize the design of satellite constellations. The benefits of this research are the optimization of satellite constellation design, which reduces costs and increases regional and global coverage with the least number of satellites. The result of this project is the optimization of the number of constellation satellites in several orbital planes in LEO orbit. Validations are based on reviewing the results of several simulations. The results of graphs and tables are presented in the last two sections and are taken from the results of several simulations.

Design of GNSS Remote Sensing Satellite Constellation

Global Navigation Satellite System (GNSS) remote sensing can provide irreplaceable atmospheric sounding data based on its sounding technology. But the research on satellite constellation design for GNSS remote sensing is relatively backward. In-orbit resources have not been fully utilized, and the design of sounding satellite constellation lacks systematic and theoretical support. Under the assumption of ideal atmosphere model, the effect of configuration parameters of sounding constellation on sounding performance is studied by geometric analysis method. With 200 km×$200 km×$6 h as the reference scale, the design criteria for the new generation of GNSS remote sensing sounding satellite constellation are established. Four of FY-3 satellites are combined to make GNSS remote sensing satellite constellation optimization design results under three kinds of constellation configurations. The results show that the design criteria are feasible and instructive. In combination with the FY-3 satellites, three Walker sub-constellations with inclination of 68^°, 60^° and 24^° have the best performance.

Design of LEO Constellations with Inter-satellite Connects Based on the Performance Evaluation of the Three Constellations SpaceX, OneWeb and Telesat

The idea of designing LEO’s satellite constellations has become very important for internet access. Several LEO satellite constellations have been designed and used for global communications. In this paper, by examining three LEO satellite constellations, namely SpaceX’s 4425 satellites Ku-Kaband system, OneWeb’s 720 satellites Ku-Ka-band system, Telesat’s 117 satellites Ka-band system. And evaluating the power of data transmission and their telecommunications, we come close to a conceptual design area. First with the mathematical modeling and formulation and the design of inter-orbital communications for satellites, intersatellite communications, inter-orbital communications, we get a complete design based on the genetic algorithm for LEO satellite constellation design. And then, using simulations and design software, the final results of the designed model are obtained. Finally, we compare the results of the designed model with other existing LEO satellite constellations.

Towards a Satellite System for Archaeology? Simulation of an Optical Satellite Mission with Ideal Spatial and Temporal Resolution, Illustrated by a Case Study in Scotland

Applications of remote sensing data for archaeology rely heavily on repurposed data, which carry inherent limitations in their suitability to help address archaeological questions. Through a case study framed around archaeological imperatives in a Scottish context, this work investigates the potential for existing satellite systems to provide remote sensing data that meet defined specifications for archaeological prospection, considering both spatial and temporal resolution, concluding that the availability of commercial data is currently insufficient. Tasking a commercial constellation of 12 spacecraft to collect images of a 150 km2 region in Scotland through the month of July 2020 provided 26 images with less than 50% cloud cover. Following an analysis of existing systems, this paper presents a high-level mission architecture for a bespoke satellite system designed from an archaeological specification. This study focuses on orbit design and the number of spacecraft needed to meet the spatial and temporal resolution requirements for archaeological site detection and monitoring in a case study of Scotland, using existing imaging technology. By exploring what an ideal scenario might look like from a satellite mission planning perspective, this paper presents a simulation analysis that foregrounds archaeological imperatives and specifies a satellite constellation design on that basis. High-level design suggests that a system of eight 100 kg spacecraft in a 581 km altitude orbit could provide coverage at a desired temporal and spatial resolution of two-weekly revisit and <1 m ground sampling distance, respectively. The potential for such a system to be more widely applied in regions of similar latitude and climate is discussed.

QoE-Aware Intelligent Satellite Constellation Design in Satellite Internet of Things

In Satellite Internet of Things (SIoT), satellite constellation design is used to satisfy more communication demands with fewer satellites by optimizing satellite orbits in specific areas. However, the diversity of user demands and satellite resource poses a great challenge in evaluating the Quality of Experience (QoE) of the satellite constellation. In this article, a QoE-aware satellite constellation design scheme is proposed to enhance the user satisfaction by constructing QoE factors. First, an SIoT network model is established with low-Earth-orbit (LEO) satellites and ground Internet of Things (IoT) devices, and the problem is formulated to calculate the QoE for different areas after analyzing the dynamic network topology. Then, the QoE factors are defined to assess QoE by taking into account the coverage performance, communication fluency, regional demand capacity, and profitability. Following that, an intelligent optimization algorithm named multilayer tabu search (MLTS) is designed to obtain reasonable satellite orbits with the best QoE, which provides orbit parameters for satellite constellation configuration. The simulation results demonstrate that the designed satellite constellation can effectively improve the users QoE by optimizing the various QoE factors.

Design of agile satellite constellation based on hybrid-resampling particle swarm optimization method

In recent years, on-orbit constellations providing global communication and observation services have attracted widespread attention for economic and military interests. Thus, the design of satellite constellations has become a popular topic, which is mainly approached using different optimization methods. However, there are still some drawbacks to traditional methods, such as poor convergence and long computation time, which usually limit engineering applications. In this paper, a novel optimization method, the hybrid-resampling particle swarm optimization (HRPSO) algorithm, is proposed that provide higher efficiency for constellation design. The simulation results showed that the HRPSO algorithm is more efficient than the standard particle swarm optimization (PSO) algorithm and other improved resampling particle swarm optimization (RPSO) algorithms. Therefore, the HRPSO algorithm is expected to be a practical choice for constellation design.

2D Necklace Flower Constellations applied to Earth observation missions

This work focuses on the nominal design and later maintenance of satellite constellations based on the 2D Necklace Flower Constellations for their application in Earth observation missions. To that end, we introduce a generalization of the 2D Necklace Flower Constellations formulation to adapt the methodology to constellations whose satellites have different mission requirements, while still allowing to reduce the searching space in satellite constellation design. Moreover, this design is combined with its dual distribution in the Earth Centered–Earth Fixed reference frame to obtain additional information about the dynamic of the system, including the sub-satellite point revisiting time, or the relative to Earth distribution. This is used to optimize the constellation in terms of maximum uniformity of the distribution with respect to the Earth. Finally, a detailed example of application of this design methodology is presented, where a constellation based on satellites with different mission requirements is considered.

Design of a Low Earth Orbit Satellite Constellation Network for Air Traffic Surveillance

The satellite constellation with automatic dependent surveillance-broadcast on-board is of great importance for air traffic surveillance due to its multiple advantages compared with traditional methods. Although some research has been conducted on satellite constellation design based on coverage performance, the findings cannot entirely satisfy all the requirements of air traffic surveillance owing to the lack of analysis on inter-satellite links and network transmission. This paper presents a novel design of a low earth orbit satellite constellation network to solve this problem. Based on the requirements of space-based surveillance, an evaluation model of constellation performance is proposed concerning coverage, link and transmission. The simulation results show that the evaluation model can reflect the performance of a satellite constellation network designed for a space-based surveillance system, and a 55-satellite constellation design scheme with fairly good performance can fulfil the function of global real-time air traffic surveillance.

LEO Hybrid Satellite Constellation Design Based on Multi-purpose Genetic Algorithm to Optimize Cost and Reliability of Global Coverage

Assessing the reliability of systems plays an effective role in the constellation design. Genetic Algorithm can be applied for the optimization design of satellite constellation, which are imperative in various fields like communication, surveillance and navigation. Opposite goals, such as optimizing performance and reducing the number of satellites in constellations along with low cost of construction and launch, have been analyzed in this paper. In the design of constellations, launching and replacing unhealthy satellites to avoid breakdown, and the time costing has a major impact on the level of system reliability performance. A method to design hybrid constellation for communication and navigation is proposed in this paper, it takes coverage capability and precession into consideration. According to LEO constellation, The issue of optimizing the number of satellites and other effective panels in constellation design has been discussed. The genetic algorithm is designed to the hybrid LEO constellations design by using a methodology of coverage constellation. It provides the optimal solutions for enhancing capability of communication and navigation. The simulation results confirm the performance of the proposed algorithm and indicates that it is feasible and effective Accordingly, in this paper, after designing the constellations using the genetic algorithm, we draw the final constellation diagram block and evaluating the conspicuous performance and reliability at the time of request.

4D Lattice Flower Constellations

4D Lattice Flower Constellations is a new constellation design framework, based on the previous 2D and 3D Lattice theories of Flower Constellations, that focus on the generation of constellations whose satellites can have different semi-major axis and still present a constellation structure that is maintained during the dynamic of the system. This situation can arise when dealing with satellites with very different instruments, or when it is of interest to coordinate two different constellations. In that sense, 4D Lattice Flower Constellations constitutes the most general representation of the Flower Constellation formulation. In addition, the effects of the J2 perturbation are taken into account in order to generate distributions that maintain their initial design configuration under this perturbation for longer periods of time with a low fuel budget. Finally, examples of application are presented, showing the possibilities in satellite constellation design of this new approach.