Next Generation Mega Satellite Networks for Access Equality: Opportunities, Challenges, and Performance

In mega low Earth orbit (LEO) satellite constellations, guaranteeing deterministic communication performance is essential for mission-critical applications and reliable service delivery. Unlike terrestrial networks, these large-scale satellite networks present unique challenges: highly dynamic topologies, significant propagation delays, limited on-board processing capabilities, and cumulative jitter uncertainty that increases with hop count. In this case, traditional deterministic mechanisms, i.e., Time-sensitive networking (TSN), become ineffective due to their inability to handle both the scale and dynamics of mega constellations. To address this issue, we propose a TSN-enabled LEO satellite network, whereby we derive single-hop delay upper bounds using network calculus, specifically accounting for high-priority preemption and dynamic satellite characteristics. Then we propose DomainR, a novel domain-based deterministic routing framework that effectively manages large-scale satellite networks through strategic network decomposition and adaptive routing. DomainR consists of two phases: first, a domain-based network compression phase that partitions mega constellations into manageable domains while preserving path continuity and routing efficiency, and, second, a delay budget-aware dynamic routing phase that adaptively allocates delay budgets based on aforementioned delay upper bounds and real-time network conditions. Through rigorous mathematical analysis, we derive the optimal domain sizing rules and establish a theoretical minimum domain count. Comprehensive simulations demonstrate that DomainR significantly reduces end-to-end jitter, improves network resource utilization, and capacity in mega LEO constellations.

This paper presents a theoretical analysis of the potential risk posed by artificial debris clouds in low Earth orbit (LEO) from mega-constellations, modeled after current communication constellations such as Starlink and OneWeb with 750 satellites each. The analysis examines three different constellation designs: a low-altitude LEO, a high-altitude LEO, and a medium Earth orbit (MEO) constellation, which will be positioned using the Walker-Delta design. The study is based on physics-based digital mission engineering and a Monte Carlo simulation framework. The simulation involves debris generated from a single breakup of one randomly selected satellite per run, but does not consider cascading debris events. This debris cloud is propagated for 1 week and how it interacts with the mega-constellation is recorded. The results show an average of 705.65 potential conjunctions within the LEO constellation, with 14.40% of those being considered catastrophic, and an average of 165.5 conjunctions in the MEO constellation, with 0.72% considered catastrophic.

As small satellites become more capable through miniaturized electronics and on-board processing, constellations of low-cost satellites lunched in Low-Earth Orbit (LEO) become feasible. The increase in the number of LEO satellites drives the need for frequency coexistence between the LEO constellation systems with the already existing geostationary (GSO) satellite networks. In this context, it is crucial to design the communication links paying special attention to interference analysis. This is particularly true when the LEO satellite constellation exploit inter-satellite communication links (ISL). In this paper, a radio frequency interference analysis based on simulation of the dynamic satellite constellation is presented and the design parameters of the inter-satellite links are analyzed. The results suggest that carefully choosing the design parameters of the intersatellite links, spectrum coexistence of LEO and GSO networks may be possible.

Global Navigation Satellite Systems (GNSSs) are by far the most widespread technology for Position Navigation and Timing (PNT). They have been traditionally deployed exploiting Medium Earth Orbit (MEO) or Geostationary Earth Orbit (GEO) satellite constellations. To meet future demands and overcome MEO and GEO limitations, GNSSs based on Low Earth Orbit (LEO) constellations have been investigated as a radical system change. Although characterized by a higher Doppler effect, a PNT service supplied by means of LEO satellites can provide received signals that are about 30 dB stronger. Moreover, existing LEO constellations and the forthcoming mega-constellations, which are designed for broadband internet coverage, can be exploited to provide a piggybacked PNT service. With this cost-effective solution, a secondary PNT service might be subject to an economical use of resources, which may result in substantial bandwidth limitations. At the same time, the introduction of meta-signals in the GNSS literature has brought a new receiver signal processing strategy, particularly effective in terms of available bandwidth exploitation. It allows to increase the positioning accuracy exploiting a wideband processing approach, which might be challenging under severe Doppler conditions. A narrowband implementation of the meta-signal concept, namely Virtual Wideband (VWB) can tolerate harsh Doppler conditions while also reducing the processed bandwidth. It is thus more effective when addressing a secondary PNT service, where a limited frequency occupation might be an essential requirement. The aim of this work is to show the applicability of a VWB receiver architecture on signals provided by a piggybacked PNT service, hosted on a broadband LEO constellation. We demonstrate the capability of this implementation to bear high Doppler conditions while empowering the potential of LEO PNT.

The analytical model for Earth coverage by the satellites’ swath conforming to essential of discontinuous coverage, in contrast to continuous coverage, is presented. The analytic relations are consecutively derived for calculation of singleand 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 modelling of the satellite observation mission, or in a number of cases is even superior to it (due to the fact that when using the analytic procedures observation sessions cannot be missed). 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 methods developed for analyzing the given satellite constellation revisit time values distributed on the fixed Earth coverage area, and for synthesizing the satellite constellations 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 method for synthesis of Secure Route Constellations, using deterministic and stochastic basis, directly leads to the optimized satellite constellations which provide consistently high performance and are at least on the same level, or better, in comparison with the best Walker constellations for discontinuous coverage.

A low earth orbit (LEO) observation satellite offers a shorter distance to the target area, low cost, and low communication latency. The low orbit translates to high orbital speed and results in short observation and communication contact periods. Swarms of multiple satellites offer extended coverage and spatial resolution for applications such as earth observation and monitoring. LEO communication satellite constellations create a network that includes hundreds to tens of thousands of satellites with onboard processing capabilities (as routing nodes) connected by Inter-Satellite Links (ISL) that provide continuous coverage of the earth. The LEO constellations aim to provide end-to-end routing between multiple gateways and terminals. This paper assumes the LEO constellation satellite payload includes sensors and processing capabilities. We explore the problem of managing an autonomous LEO virtual satellite swarm that will provide continuous and adjustable coverage. We preset a novel virtual swarm: a subset of the constellation satellites is dynamically assigned to the swarm when they cover the target area. The virtual swarm algorithm provides distributed data synchronization among the swarm virtual satellites and a distributed dynamic assignment of physical satellites to the virtual swarm satellites.

In this chapter, we survey communication related issues arising in the context of Low Earth Orbit (LEO) satellite constellations. In particular, we study the impact of the predictable movement of the satellites on the techniques used in topological design, routing, and hand-over strategies.

Today most operational Earth observing satellites reside in low Earth orbits (LEO) at less than 1,000 km altitude, and in geostationary Earth orbits (GEO) at ~35,800 km altitude. These orbits have been the venues of choice for observations, albeit for very different reasons. LEO provides high spatial resolution with low temporal resolution while GEO provides for low spatial resolution, but high temporal resolution. NOAA utilizes both venues for their environmental satellites. The NOAA Polar-orbiting Operational Environmental Satellites (POES) reside in LEO Sun synchronous orbits at approximately 830 km in altitude, as do the Defense Meteorological Satellite Program (DMSP) satellites of the Department of Defense. In the near future the POES and DMSP satellites will be merged into a new satellite system referred to as the National Polar-orbiting Operational Environmental Satellite System (NPOESS). The NOAA Geostationary Operational Environmental Satellite (GOES) system, as the name specifies, resides at the other preferred observational venue of GEO. The Jet Propulsion Laboratory (JPL), under contract to NOAA, has been studying the characteristics of medium Earth orbits (MEO), at altitudes between 1000 and 35,800 km, as an observation venue to answer the question as to whether MEO might capture the attributes of the two traditional venues. This on-going study initially focused on determining the optimal altitude for MEO observations, through numerous trade studies involving altitude, instrument complexity, coverage, radiation environment, data temporality, revisit time, data rates, downlink requirements and other parameters including cost and launch complexity. Once the optimal altitude of 10,400 km had been determined the study proceeded to explore single through multiple MEO satellite constellation performance capabilities using two instrument types, a visible through infrared (IR) imager and IR sounder as the satellites’ payload. The MEO performance capabilities were compared to comparable LEO and GEO satellite constellation capabilities. This portion of the study concluded that indeed for global coverage a constellation of satellites operating in the MEO venue could capture the attributes of those operating in the LEO and GEO venues. Three 8-satellite constellations configurations - Walker, ICO, and Equatorial-Polar (EP) - then were studied to develop more constellation coverage statistics including robustness to individual satellite failure. That study phase concluded that the EP constellation was superior to both the ICO and Walker configurations. The study is presently examining if, and to what extent, the equatorial portion of the EP constellation might provide substantive supplemental data to that collected by the NPOESS and GOES satellite constellations.

Any robust communication system can be defined as one that can provide ubiquitous connectivity with lower latency periods. Since 1990, Low Earth Orbit (LEO) satellite constellations have proven to be plausible and efficient alternatives to high altitude GEO satellites in delivering seamless voice and data communication services. This is due to some of their important advantages over geo- stationary such as low power requirement, efficient utilization of frequency spectrum and, low propagation delays pertaining to the satellite’s closer proximity to the ground station. On the downside, the difference in the mobility speed of a LEO satellite and a user on earth is so high that the user can be considered constant, unless he/she is on a fast-moving vehicle. This calls for strategical user handover mechanisms between LEOs to avoid call drops, as usually the service time for a user tend to be higher than the coverage time of a typical non-stationary LEO. Consequently, it is admissible to claim that the quality of service provided by such a network is limited by the performance of LEO handoff algorithms (generally based on parameters like Probability of call blocking/call termination, Throughput, Delay in transmission). In this paper, we will discuss the LEO handoff algorithms developed over the years and particularly delve into the most commendable satellite handover techniques exploiting the property of satellite diversity, that fall with Acceptable Forced termination of existing calls and dropping of new calls.

The rapid expansion of low Earth orbit (LEO) satellite networks to improve global internet access has raised concerns about their environmental impact compared to terrestrial infrastructure. This study conducts a panel lifecycle assessment (LCA) and econometric analysis to compare the carbon intensity of LEO satellite and terrestrial fibre-optic networks across 100 countries from 2005 to 2023. Using ISO 14040-compliant LCA, we find LEO systems emit 0.1–0.5 kg CO₂e/GB, significantly higher than terrestrial systems (0.05–0.20 kg CO₂e/GB), with these emissions generated primarily during the launch (40%) and operational (35%) phases. Fixed-effects regression reveals that internet usage increases CO₂ emissions per capita (β = 0.1435, p < 0.01), while the share of renewable energy reduces emissions (β = –95.1288, p < 0.05), with LEO penetration having only a minimal impact (β = 0.0012, p = 0.332). Advanced two-stage least squares, Arellano-Bond generalized method of moments, Moran’s I (I = 0.12, p = 0.08), and random forest analyses confirm these findings, highlighting renewables and internet usage as key drivers of emissions. The findings suggest that emissions reporting frameworks and renewable energy integration may play an important role in aligning digital connectivity expansion with climate goals. These results highlight the need for sustainable digital infrastructure to balance global connectivity with planetary boundaries.

The Global Navigation Satellite System (GNSS) is strongly dependent on the choice of the satellite constellation. At the present time, the GNSS space segment is made by the following satellite constellations: GPS, GLONASS and a set of geostationary satellites. In a medium-long term future, a new GNSS could substitute the existing satellite navigation system, or, in any way, there will be an overlapping and an integration between the current system and the next one.Alenia Aerospazio, is studying, since 1990, the possibility to identify new navigation satellite constellations able to verify the Required Navigation Performance (RNP) for all users. Particular attention has been focused on airspace users, due to the fact that the accuracy requirements during the aircraft landing phases are very stringent, and the existing GPS system is not able to guarantee the desired RNP.In this paper a new satellite constellation with 75 satellites in Low Earth Orbit (LEO) at a common altitude of 2700 Km, and a common inclination of about 66°, has been identified. It is able to comply with the RNP (i.e. accuracy, availability, continuity, and integrity) up to CAT I landing.The transition phase between the co-existence of the current GNSS space segment and the evolving LEO constellation is discussed and analysed in this paper, outlining the advantages, with respect to the previous system, coming from the progressive implementation, in a step-wise fashion, of this LEO space segment, until its completion.KeywordsGlobal Navigation Satellite SystemGlobal Navigation Satellite SystemOrbital PlaneTime PercentageSatellite ConstellationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Inter-satellite link technologies and applications in Low Earth Orbit satellite networks

Low-cost and fast-response LEO(Low-Earth orbit) satellite network is an important technical means to meet the needs of communication and transmission services with periodic continuous coverage in specific regions. Aiming at this kind of problem, a method of LEO(Low-Earth orbit) constellation design combining analytical method and optimization method is proposed in this paper. Firstly, a regression orbit model and a typical sensor coverage model are established. Secondly, taking the optimal coverage effect of a specific region as the performance index, particle swarm optimization (PSO) was used to optimize and solve the orbit parameters of a single satellite. Finally, the orbit parameters of the constellation are solved by analytical method. This method can take into account the computational efficiency of analytical method and the universality of optimization method, and can realize the rapid solution of low-earth orbit constellation with periodic continuous coverage in local region, which has good engineering application value.KeywordsLEO (Low-Earth orbit)Periodic continuous coverageConstellationParticle swarm optimization (PSO)

Low Earth Orbit (LEO) constellations have recently gained tremendous attention in the navigational field due to their larger constellation size, faster geometry variations, and higher signal power levels than Global Navigation Satellite Systems (GNSS), making them favourable for Position, Navigation, and Timing (PNT) purposes. Satellite signals are heavily attenuated from the atmospheric layers, especially from the ionosphere. Ionospheric delays are, however, expected to be smaller in signals from LEO satellites than GNSS due to their lower orbital altitudes and higher carrier frequency. Nevertheless, unlike for GNSS, there are currently no standardized models for correcting the ionospheric errors in LEO signals. In this paper, we derive a new model called Interpolated and Averaged Memory Model (IAMM) starting from existing International GNSS Service (IGS) data and based on the observation that ionospheric effects repeat every 11 years. Our IAMM model can be used for ionospheric corrections for signals from any satellite constellation, including LEO. This model is constructed based on averaging multiple ionospheric data and reflecting the electron content inside the ionosphere. The IAMM model’s primary advantage is its ability to be used both online and offline without needing real-time input parameters, thus making it easy to store in a device’s memory. We compare this model with two benchmark models, the Klobuchar and International Reference Ionosphere (IRI) models, by utilizing GNSS measurement data from 24 scenarios acquired in several European countries using both professional GNSS receivers and Android smartphones. The model’s behaviour is also evaluated on LEO signals using simulated data (as measurement data based on LEO signals are still not available in the open-access community; we show a significant reduction in ionospheric delays in LEO signals compared to GNSS. Finally, we highlight the remaining open challenges toward viable ionospheric-delay models in an LEO-PNT context.

"Newspace" mega-constellations, such as Starlink and OneWeb are gaining tremendous popularity, with the promising potential to provide high-capacity and low-latency communication globally. However, very little is known about the architecture and performance of such emerging systems, the workload they have to face, as well as the impact of topological options on the attainable network performance. This paper presents StarPerf, a mega-constellation performance simulation platform that enables constellation manufacturers and content providers to estimate and understand the achievable performance under a variety of constellation options. The proposed platform integrates two key techniques: (1) performance simulation for mega-constellation, which captures the impact of the inherent high mobility in satellite networks and profiles the area-to-area attainable network performance; (2) constellation scaling, which synthesizes various topological options by scaling the space resource and enables exploration on multiple operating conditions that can not be easily reproduced. To demonstrate the effectiveness of StarPerf on understanding and optimizing satellite networks, we leverage StarPerf to evaluate and compare the performance of several state-of-the-art low earth orbit (LEO) constellations and obtain insights on optimizing the architectural design to improve area-to-area network performance. Finally, to further show how applications can benefit from the proposed simulator, we propose an adaptive relay selection algorithm that can intelligently choose the optimal relay on cloud platforms and LEO satellites to achieve reduced latency. Evaluation results show that by properly selecting a relay in the satellite-cloud integrated infrastructure, end-to-end communication latency can be reduced by up to 62% for typical interactive traffic.