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Angular orbital elements referred to in this study. Inclination (i) is the angle at which the orbit is tilted out of the equatorial plane. Right ascension of the ascending node (Ω, RAAN) is the angle of rotation around the Earth spin axis referenced by convention to the direction of the sun at the vernal equinox. The argument of perigee (ω) describes the position of the perigee point relative to the point on the orbit which ascends across the equator. True anomaly (ν) is the angle in the orbit plane between a satellite at an instant in time and perigee. In addition to these angular elements, the semimajor axis (a) and eccentricity (e) describe the size and shape of the orbit, respectively.
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Satellite services are fundamental to the global economy, and their design reflects a tradeoff between coverage and cost. Here, we report the discovery of two alternative 4-satellite constellations with 24- and 48-hour periods, both of which attain nearly continuous global coverage. The 4-satellite constellations harness energy from nonlinear orbit...
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... 24-and 48-h-period constellations presented in this study were discovered using multiobjective evolutionary optimization techniques to intelligently search the orbital design space. Figure 5 provides an illustration of orbital elements that must be defined for each of the satellites in the 24-and 48-h-period constellations. These elements define the dynamics and coverage performance. ...
Citations
... Additionally, let's propose integrating signals from ground-based positioning, navigation, and timing (PNT) systems and user-centric sensors. The slight degradation in their coverage has brought a significant reward in operational feasibility [16]. At the same time, during the analysis and processing of the received positioning information, it is required to consider that satellite navigation platforms contain their orbital positioning errors. ...
The object of research is the onboard subsystems of Unmanned Aerial Vehicles (UAVs). The research is aimed at analyzing UAVs, specifically the integration and enhancement of satellite-based positioning systems, including Global Navigation Satellite Systems (GNSS) and Inertial Navigation Systems (INS). The problem concerns traditional satellite-based positioning services, especially those relying solely on medium earth orbit (MEO) satellites, which are insufficient for specific requirements. The study aims to address the limitations of these systems on onboard subsystems of UAVs, especially in challenging environments laden with jammers and interference, and to provide a more accurate, robust, and continuous positioning solution. The research proposes a «multilayer system of systems» approach that integrates signals from various sources, including low Earth orbit (LEO) satellites, ground-based positioning, navigation, and timing (PNT) systems, and user-centric sensors. The combined approach, termed LeGNSS/INS, leverages the strengths of each component, providing redundancy and enhanced accuracy. The system's performance was evaluated using pseudo-real output data, demonstrating its ability to generate quasi-real dynamic trajectories for UAV flight. The error analysis showed that the proposed method consistently outperforms traditional GNSS systems, especially in challenging environments. The enhanced performance of the LeGNSS/INS system can be attributed to integrating multiple satellite systems with INS and applying optimal filtering techniques. The research also employed mathematical modeling to represent the dependencies and interactions when combining data from different sources, such as GPS, LEO, and INS. The Kalman filter is a mechanism to fuse data from multiple sources optimally. The insights from this study apply to various sectors, including aviation, maritime navigation, autonomous drones, and defense. The enhanced positioning accuracy can significantly improve safety, navigation precision, and operational efficiency. However, the study assumes idealized conditions for satellite signal reception, which might not always be accurate in real-world scenarios. Challenges, such as the martial law conditions in Ukraine affecting data collection and potential satellite signal restrictions, were also highlighted. Further research can delve into the impact of more complex environmental factors and the integration of additional satellite systems or sensors to enhance accuracy further.
... Representation of the angular orbital Keplerian elements (i, ω, Ω, ν) which form along with conic's parameters eccentricity e and semimajor axis a the complete set of variables that describe the orbital motion around the central body, namely the Earth[14,15]. ...
This work deals with the modeling and analysis of different disturbing forces acting over the trajectory of a spacecraft with a low-thrust acceleration model using Fourier Series expansion and differential equations of motion with singularities removed by adoption of equinoctial orbital variables. The focus of the analysis is to present a discussing where singularities are removed and with the addition of the forces due to the Earth's flattening at the poles and the third-body perturbation due to the moon in the dynamical system. The outcomes are important for the understanding and design of the dynamics adopted in projects such as transportation of cargo to cislunar region (intended for continuous lunar exploration) and the JAXA's DESTINY+ mission, a initiative planned to escape the Earth in a spiral trajectory, swingby with the Moon and potentially have a flyby with two asteroids. The planned launch date currently is mid of 2024.
... Proliferated low Earth orbit (P-LEO) satellite constellations that deliver broadband internet services have seen a sharp uptick in interest from both commercial and defense sectors. 1 Such systems have attracted rapid user growth due to their flexibility of use cases which include: rural backhauling, 2 disaster observation and response, 3 military communications, 4 maritime and aviation connectivity, 5 and retail consumer usage. 6 However, developing such expensive and complex networks of hundreds, if not thousands, of satellites come with increased risk. Market competition, a high probability of cyber-security attacks, and physical congestion of LEO space all pose critical risks to P-LEO constellation profitability. ...
As the market of proliferated low Earth orbit (P-LEO) satellite constellations continues to expand, indirect competition between constellation operators offering broadband services becomes increasingly nuanced and difficult to model. Modeling such unknown dynamics can require extensive game and economic analysis, while not ensuring the existence of any equilibria between competitors. Although comparisons of static P-LEO constellation performances have been made and broad economic impacts of select P-LEO constellations have been considered, the temporal dynamics associated with constellation development under competitive market conditions have not been modeled. By utilizing principles of game design, we are able to iteratively model these complex, multi-agent environments. We created a table-top board game that simulates both the system design of P-LEO constellations and the economic dynamics between constellation operators (players within the board game). By representing market interactions as game mechanics and incrementally improving the complexity of the overall game, we are able to rapidly detect and modify trivial strategies and modeling edge cases to better represent actual market dynamics. This process has led to the development of a robust multi-player game that can be used to examine and test complex P-LEO constellation development strategies while reducing the time required for development and play-testing.
... Satellite FSO communication, with its wide bandwidth and no electromagnetic spectrum constraints, has become an effective means to solve the bandwidth bottleneck of satellite microwave communication [3,4]. Currently, the Laser Communications Relay Demonstration (LCRD) proposed by the National Aeronautics Space Administration (NASA) aims to showcase the unique capabilities of optical communications, providing a new technology [5]. Similarly, the Japan Aerospace Exploration Agency (JAXA) already launched the Japanese Data Relay System (JDRS) into geosynchronous Earth orbit (GEO) in 2020 with the measured data acquired via laser communications [6]. ...
Satellite free-space optical (FSO) communication is very promising in improving the bandwidth and capacity of space information networks in the future. However, the inter-satellite transmission distance of over 1000 km leads to unstable optical beam pointing, acquisition, and tracking and then generates optical power jitter by a large margin before detection–demodulation. Therefore, it is difficult to realize high-stability and long-time FSO communication between satellites due to the generated bit error rate (BER) by jitter. In this paper, we report an autonomously self-designed and high-integration laser communication payload (LCP) and on-orbit-demonstrated inter-satellite 145 min, zero-BER FSO stable communication with a line rate of 2.8 Gbps. Moreover, based on the inter-satellite laser communication link, a video phone was clearly implemented for more than 10 min, and authentic user data transmitted 459,149 packets, achieving results of zero-packet loss. Summarily, this on-orbit experiment demonstrated an excellent performance of the LCP owing to the distinctive design of integrating a high-power amplifier and low-noise amplifier optical amplification function. Our space mission was successfully completed, and the on-orbit demonstration results may offer a significant reference for the field of satellite laser communication and space information networks.
... Some research, such as Refs. [11][12][13] has contributed towards solving similar problems significantly and this research is an extension of the same vision insofar as it presents the impact of the trajectory enhancement of small satellites in a constellation. ...
The complex and dynamic space environment is both exciting and challenging in this NewSpace era. In particular, Low-Earth Orbits are being realigned and reinvented for various purposes using suitable technological advancement. This paper is focused on the major parameters that can be analyzed to attain orbit control and autonomy of small-satellite constellations for real-time applications. By applying industry experience to graduate research, this work addresses the related concerns in a realistic manner. Currently, global small-satellite constellation solutions are too expensive and inaccessible for many nations to help in their data reception requirements. This issue was addressed, and some of the main aspects relating to low-cost and high-benefit technical synthesis, in addition to utilization for deep-space missions, were also discussed in detail. In conclusion, this paper demonstrated a strategic approach to optimize the coverage and performance, and reduce the cost of small-satellite constellations, compared with present day constellations, allowing the data to be relayed faster and with precision. This will benefit the industry in the development of low-cost constellations, and effectively assist in disaster management and deep-space communication relays. Autonomous orbit selection and navigation can be established for better path alignment for satellites to efficiently propagate and deliver the required data.
... In addition, those will be cheaper to replace in the less protective atmospheres of the Moon and Mars. Based on analysis performed in [11,12], we can estimate the required number of nanosatellites to provide ubiquitous coverage (from a few of kbps until a few Mbps) in the Moon and Mars with the ratio of surface areas of the Moon and Mars to the Earth. This calculation results in a number of about 400 and 200 for Mars and the Moon, respectively. ...
Celestial bodies of our solar system remain as a major unexplored and unexploited reserve of natural resources available to humans. Furthermore, those constitute a valuable source of information about the origins and evolution of the solar system and an alternative to establish human settlements in the future. Observation and understanding of the land conditions of those celestial bodies is vital to learn more about those celestial bodies, to generate accurate maps of them, to look for natural resources of interest, and to evaluate the feasibility and help in the preparation of future land missions. A satellite constellation constitutes an important infrastructure element to observe those celestial bodies and to transmit the retrieved information back to Earth. Nonetheless, the operation of sensing satellites in other planets needs understanding of the requirements to perform such observations. In this paper, we discuss those sensing requirements from the point of view of orbits and payload requirements for one of our closest neighbors of the solar system (Moon, Mars). To analyze the orbit of the sensing satellite, we discuss the required altitude to facilitate ground observation, the orbit’s conditions (such as radiation levels and orbital perturbations, among others), suitable orbit configurations, required number of satellites, and ways to estimate the required time to perform full observation of the celestial body. To evaluate suitable payloads, we discuss available information in the literature (such as known atmospheric and land conditions) to determine the best observation frequencies and determine the best kind of payload (such as sensors, a camera, or a lower frequency observation payload) to study that celestial body. Finally, we discuss some important considerations such as the requirements of satellite communication link to transmit the retrieved information back to Earth.
... The MSAT system consists of multiple satellites connected by constraint mechanisms. Owing to the special characteristics, the MSAT system is capable to construct the satellite constellations in low Earth orbit for communication, navigation, and so on [5][6][7][8][9]. To achieve the goal of successful separation deployment, the security of the mission should be guaranteed. ...
This paper investigates the dynamics of the separation deployment for a multi-satellite system using elastic ejection mechanisms. To circumvent the difficulties in dynamic modeling of the complex system, a dynamic model is established using the automatic dynamic analysis of mechanical system software. In addition, separation deployment strategies are developed to achieve the non-collision between the satellites. In consideration of the practical engineering, soft ejection mechanisms are utilized to execute the separation manuever. Finally, parametric studies are performed to evaluate the influences of system parameters on the separation and to validate the effectiveness of the proposed separation strategies.
... There are many constellation design studies based on optimization but none for a lunar GNSS. Finally, we note the prevalence of evolutionary algorithms in the constellation design literature (Buzzi et al., 2019;Ferringer et al., 2007;Ferringer & Spencer, 2006;Singh et al., 2020;Whittecar & Ferringer, 2014). ...
The success of future lunar missions depends on quality positioning, navigation, and timing (PNT) information. Earthbound GNSS signals can be received at lunar distances but suffer from poor geometric dilution of precision (GDOP) and provide no coverage of the lunar far side. This article explores the design space of a dedicated GNSS system in lunar orbit by using a multi-objective evolutionary algorithm framework to optimize GDOP, availability, space segment cost, station-keeping ΔV, and robustness to single-satellite failure. Results show that Pareto approximate solutions that achieve a global GDOP availability (GDOP ≤ 6.0) greater than 98% contain a minimum of 24 satellites
in near-circular polar orbits at an altitude of ~2 lunar radii. The impact
of single-satellite failure on GDOP outage is analyzed and a no-maneuver scenario is considered. Design rules characterizing optimal solutions are identified and trade-offs between station-keeping maneuver frequency, performance, anddesign lifetime are discussed.
... This study employs the Borg Multiobjective Evolutionary Algorithm (MOEA) , which has been particularly successful across a range of difficult problems in water resources (Gupta et al., 2020;Hadka & Reed, 2012;Reed et al., 2013;Zatarain Salazar et al., 2016) and engineering design (Singh et al., 2020;Woodruff et al., 2013). The Borg MOEA includes novel components such as adaptive search operator selection, adaptive population sizing, stagnation detection via epsilon-progress, and epsilon-dominance archiving. ...
Hydrologic variability can present severe financial challenges for organizations that rely on water for the provision of services, such as water utilities and hydropower producers. While recent decades have seen rapid growth in decision‐support innovations aimed at helping utilities manage hydrologic uncertainty for multiple objectives, support for managing the related financial risks remains limited. However, the mathematical similarities between multi‐objective reservoir control and financial risk management suggest that the two problems can be approached in a similar manner. This paper demonstrates the utility of Evolutionary Multi‐Objective Direct Policy Search for developing adaptive policies for managing the drought‐related financial risk faced by a hydropower producer. These policies dynamically balance a portfolio, consisting of snowpack‐based financial hedging contracts, cash reserves, and debt, based on evolving system conditions. Performance is quantified based on four conflicting objectives, representing the classic tradeoff between “risk” and “return” in addition to decision‐makers’ unique preferences toward different risk management instruments. The dynamic policies identified here significantly outperform static management formulations that are more typically employed for financial risk applications in the water resources literature. Additionally, this paper combines visual analytics and information theoretic sensitivity analysis to improve understanding about how different candidate policies achieve their comparative advantages through differences in how they adapt to real‐time information. The methodology presented in this paper should be applicable to any organization subject to financial risk stemming from hydrology or other environmental variables (e.g., wind speed, insolation), including electric utilities, water utilities, agricultural producers, and renewable energy developers.
... In addition to the NGSO unique capabilities in providing global coverage, low-latency communication, and high-speed Internet access points, these systems can ameliorate the way satellite missions are designed and operated in the near future [20]. In particular, the recent technological progress has evolved the possibility of constructing a chain production of cheaper NGSO satellites with very short lifespans [21]. Accordingly, the satellite infrastructure will be more regularly upgraded, and thus, the payload design can be more innovative in terms of on-board technologies [22]. ...
The next phase of satellite technology is being characterized by a new evolution in non-geostationary orbit (NGSO) satellites, which conveys exciting new communication capabilities to provide non-terrestrial connectivity solutions and to support a wide range of digital technologies from various industries. NGSO communication systems are known for a number of key features such as lower propagation delay, smaller size, and lower signal losses in comparison to the conventional geostationary orbit (GSO) satellites, which can potentially enable latency-critical applications to be provided through satellites. NGSO promises a substantial boost in communication speed and energy efficiency, and thus, tackling the main inhibiting factors of commercializing GSO satellites for broader utilization. The promised improvements of NGSO systems have motivated this paper to provide a comprehensive survey of the state-of-theart NGSO research focusing on the communication prospects, including physical layer and radio access technologies along with the networking aspects and the overall system features and architectures. Beyond this, there are still many NGSO deployment challenges to be addressed to ensure seamless integration not only with GSO systems but also with terrestrial networks. These unprecedented challenges are also discussed in this paper, including coexistence with GSO systems in terms of spectrum access and regulatory issues, satellite constellation and architecture designs, resource management problems, and user equipment requirements. Finally, we outline a set of innovative research directions and new opportunities for future NGSO research.
