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AMS Citation

Sheard, S., 2014: The Changing Relationship of Systems and Software in Satellites: A Case Study. Carnegie Mellon University, Software Engineering Institute's Insights (blog), Accessed May 16, 2024, https://insights.sei.cmu.edu/blog/the-changing-relationship-of-systems-and-software-in-satellites-a-case-study/.

APA Citation

Sheard, S. (2014, July 28). The Changing Relationship of Systems and Software in Satellites: A Case Study. Retrieved May 16, 2024, from https://insights.sei.cmu.edu/blog/the-changing-relationship-of-systems-and-software-in-satellites-a-case-study/.

Chicago Citation

Sheard, Sarah. "The Changing Relationship of Systems and Software in Satellites: A Case Study." Carnegie Mellon University, Software Engineering Institute's Insights (blog) . Carnegie Mellon's Software Engineering Institute, July 28, 2014. https://insights.sei.cmu.edu/blog/the-changing-relationship-of-systems-and-software-in-satellites-a-case-study/.

IEEE Citation

S. Sheard, "The Changing Relationship of Systems and Software in Satellites: A Case Study," Carnegie Mellon University, Software Engineering Institute's Insights (blog) . Carnegie Mellon's Software Engineering Institute, 28-Jul-2014 [Online]. Available: https://insights.sei.cmu.edu/blog/the-changing-relationship-of-systems-and-software-in-satellites-a-case-study/. [Accessed: 16-May-2024].

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@misc{sheard_2014, author={Sheard, Sarah}, title={The Changing Relationship of Systems and Software in Satellites: A Case Study}, month={Jul}, year={2014}, howpublished={Carnegie Mellon University, Software Engineering Institute's Insights (blog)}, url={https://insights.sei.cmu.edu/blog/the-changing-relationship-of-systems-and-software-in-satellites-a-case-study/}, note={Accessed: 2024-May-16} }

The Changing Relationship of Systems and Software in Satellites: A Case Study

Sarah Sheard

July 28, 2014.

The role of software within systems has fundamentally changed over the past 50 years. Software's role has changed both on mission-critical DoD systems , such as fighter aircraft and surveillance equipment, and on commercial products, such as telephones and cars . Software has become not only the brain of most systems, but the backbone of their functionality. Acquisition processes must acknowledge this new reality and adapt. This blog posting, the second in a series about the relationship of software engineering (SwE) and systems engineering (SysE) , shows how software technologies have come to dominate what formerly were hardware-based systems. This posting describes a case study: the story of software on satellites, whose lessons can be applied to many other kinds of software-reliant systems.

The Evolution of Satellites to Today and Beyond

My first professional job started in 1980 when I was hired as a satellite systems engineer at Hughes Aircraft Company in the space and communications division. At this time, there were a few career software developers, but individual engineers created most technical software for their own one-time use. The software that engineers developed ran on large and heavy computers that stayed earthbound, so it was not considered part of the satellite system. In contrast, software today provides a large fraction of the operational capability of satellite systems.

Satellite software initially appeared inside some of the hardware boxes, after the needed system functionality was allocated as requirements to the hardware elements. In contrast, in today's software-reliant systems, the logic implemented by the software is the single dominant aspect of capabilities provided by the systems and must be considered early, perhaps before any other capabilities. This posting presents six figures that demonstrate the evolution from satellites that had little to no software in the 1970s, to satellites of today and beyond, which use software-driven services to link existing networks.

In all figures, the blue boxes that represent the satellite system are the same size for simplicity, even though cost, size, or weight have all grown significantly during this time. Red represents the software within the satellite. The amount of red is meant to suggest only roughly whether there is a little or a lot of software: the growth in actual lines of code has been exponential, far greater than the growth shown in the area of red.

The satellites discussed in this post are geostationary communication satellites . These satellites are situated above the equator at the altitude whose orbit period is 24 hours, so the satellite appears always at the same point in the sky with respect to the rotating earth. Geostationary communication satellites have been known as "bent pipes" in the industry because the satellite receives communication signals from the ground and bends the same signals (amplified) back toward the ground.

Since satellites are space systems, they have different constraints from business systems or ground-based weapon systems. Launch weight is a huge determinant of cost ( the rule of thumb in the 1980s was $20,000/pound ). Radiation hardness is required to allow the satellite to pass through the Van Allen radiation belts unscathed and to survive solar winds and other orbital conditions. Temperatures are extreme outside the atmosphere, so satellite components must be qualified to large temperature ranges and/or protected with thermal control equipment, such as Kevlar thermal blankets .

Rocket technology made vast leaps in the 1960s race to the moon, allowing for more economical satellite launches that became commercially affordable. Early satellite technology challenges were hardware-focused, such as how to handle increasing numbers of channels with more output power and with better sensitivity to signals received from the ground, and how to maintain operations for more years (such as by increasing the fuel for orbit maneuvers). The weight constraint meant that technology improvements that shrank hardware, made it from lighter materials, or allowed more functions per box were highly desirable. It is clear now that software was the obvious answer, but it was not clear at the time, mostly because the computers on which the software ran were so heavy.

Software on satellites through the decades: 1960s and 1970s

In the 1960s satellites had little to no software since computers were too big and heavy to launch into orbit. As computer hardware shrank, it could be included on satellites, and satellite computer software developed. The first satellite computer software was embedded into the computer hardware. My colleague Patrick Place worked on the first reloadable satellite software, which was necessary because the launch window was prior to finalization of the software.

In the 1970s, computers were shrinking in size, and became feasible for use on satellites. The challenge was to obtain space-qualified chips of high capacity and low weight. I had a t-shirt from 1980 that celebrated the space-qualification of a RAM chip with ¼ Kbyte capacity (256 bytes)! Imagine the software constraints posed by that limited capacity, which was state-of-the-art at the time!

By the end of the 1970s, satellites included some processors that performed small amounts of computation. For example, software was part of the subsystem that controlled satellite orientation (attitude control subsystem). The 1970s figure shows one box on a satellite included a little software.

During the 1980s computers were getting smaller, lighter, and more powerful. Engineers of several subsystems found weight savings by using custom, space-qualified computer chips loaded with software. The 1980s figure shows there were a few boxes on the satellite that contain some software, including the attitude control processor, the telemetry and command boxes, and perhaps some payload boxes.

In the mid-1980s, I was involved in studying the tradeoff criteria when power subsystem engineers suggested they could save a great deal of weight by having the attitude control processor take over the logic for switching of solar panels between recharging batteries and supporting the power bus. Software would eliminate 10 power switches and their wire harnesses. The attitude control subsystem engineers were reluctant to take on logic that had nothing whatsoever to do with their subsystem, didn't save them any weight, and complicated the software development and test process. (The outcome was that the switching was done in software).

As a systems engineer in the 1980s, I was only indoctrinated into the discipline by learning on-the-job. At the time, few other resources existed. Few textbooks existed; the Defense Systems Management College (DSMC) guidebook , project management books (also fairly new) and Hatley-Pirbhai structured requirements analysis were some of the few subjects with available instructional material.

By the 1990s, many of the subsystems and units on the satellite included computer hardware and software. More important, the software in many hardware units was beginning to interact with software in other units on the spacecraft, and point-to-point communications was established among them. The 1990s figure shows the boxes starting to communicate with each other.

By 2000, the satellite industry had started to view software as an important aspect of the entire spacecraft. Software within the various subsystems and boxes was being coordinated, protocols were established, and data buses were set up that ensured compatible messaging and rapid communication. In addition, the interfaces to the outside world were being shown on software architecture diagrams. The 2000s figure shows a typical architecture of the software modules in the satellite system.

2010s and Interoperability

Between 2000 and the present, the concept of interoperability of systems has matured. Initially interoperability meant being able to connect to other technological devices. Today, it means the ability to communicate and exchange data, using a common semantic information exchange model so that the numbers do not change meaning at different points in the transmission. Some consider use of open standards to be critical for true interoperability (unencumbered by patents, proprietary claims, or dominance by one market competitor). The need for this interoperability has led to common architectural practices that are known well by software engineers, but not necessarily by systems engineers.

By the 2010s, diagrams of satellites commonly looked like software architecture diagrams, with layers, protocols, and strong interaction with software outside the satellite, both to ground stations and to users beyond the satellite terminals. The 2010s figure shows the strong layering and the relationship of the layers to external software modules. The modules interact to perform much more interesting functions than individual modules would; this means their architecture is more important and depends greatly on their implemented quality attribute requirements.

At this point the satellite system box just looks like a boundary drawn around software. Of course, other views of the satellite exist that depict the electrical power distribution, physical box placement, gain and link budgets, deployment sweeps, propulsion routing, and the like. But importantly, it's becoming more widely accepted that the software or logical view of the satellite should be well-engineered and developed as early as the first hardware specification.

Near Future

The last diagram shows my projection into the future. Satellite hardware is now seen more as a commodity, selected so that the satellite can provide services and interconnectivity of the right kind among existing and new networks. The environment contains large, mature, evolving networks of many types that may be considered as data sources or users of new, possibly fused or mined data. The United States Armed Forces have a number of different wartime and business networks, some built on old technology that should be modernized, and which have various levels of classification. Commercial industry has its own networks. For example, health care is connecting medical devices in doctors' offices, hospitals, pharmacies, and even individuals without necessarily having worked out security implications. Satellites can be seen as deliverers of information among such networks. DARPA's "System F6" or "fractionated spacecraft" program investigates effectively this: whether the tradeoffs to achieve the functionality can be best served if the software is split among multiple hardware nodes (small satellites), or in what cases a single hardware spacecraft is best.

I expect that systems of the 2020s will start with a recognition of what networks exist in the environment relevant to a new system and to its needed capabilities. The systems that will be built will have capabilities that essentially "hang" on the relevant networks like modular kitchen accessories hang on racks at the hardware store. System capabilities will be determined by what functions and responses can be created first by connecting data and processes available on one network with data and processes on others; then the system's capabilities and hardware will be specified and designed.

In the software engineering field, it is time to recognize this evolution in the relationships of systems to software. Satellites are a microcosm of broader trends in both military and commercial system development, whether weapons systems, software embedded in hardware, or business systems. In the past, capability needs led to a plan to acquire systems, and the systems required pieces of software within them. In the future, capabilities will lead to a plan to acquire needed software, to connect existing networks with new kinds of data and processing, and this will drive the need for specific systems. Satellites, of course, are only an example.

Wrapping Up and Looking Ahead

The capabilities of the future demand attention to software, and software architecture, first. Systems engineers who participate in early acquisition must bring software architecture knowledge into early specification of system activities and move toward the day when it is the software architecture of the real world, and secondarily that to be specified within a system, that determines what systems are brought into being. In addition we need to involve systems engineers who bring particular systems into being to help them understand the repercussions of various systems engineering and acquisition decisions as far as software capability is concerned.

Naturally, not only software should be involved early. Systems engineers, with their broad views and customer-needs focus, must drive the early specification of capabilities, but they will not be able to do that without bringing the software engineers in as partners from day one.

In the next post in this series, I will discuss complexity as it relates to systems and software engineering.

Additional Resources

• To read the blog post, The Value of Systems Engineering, by Joe Elm, please visit /blog/the-value-of-systems-engineering/ .
• A seminal systems engineering textbook was published in 1962 by Arthur Hall, A Methodology for Systems Engineering . The methods described in the book seem remarkably current, including eliciting requirements and looking for the business need behind the customer's requests for a new system.
• By 2000, many systems engineering texts had become available including those by Howard Eisner of George Washington University ( Essentials of Project and Systems Engineering Managemen t), Eberhardt Rechtin of the University of Southern California (Systems Architecting), and Richard Stevens et al. in the United Kingdom ( Systems Engineering: Coping with Complexity ). INCOSE had also released the first two versions of its systems engineering handbook by July 2000. None of these documents included much understanding of the important role software had come to play by that point, however.
• In 1994 NCOSE participated in two efforts to define the body of practice of systems engineering: the Systems Engineering Capability Maturity Model (SE-CMM) and the Systems Engineering Capability Assessment Model (SECAM), NCOSE's counterpart. By the late 1990s, NCOSE had become INCOSE, the International Council on Systems Engineering . The organization's membership was growing and had played a role in merging the two systems engineering models and in writing five systems engineering standards .

Author Page

Digital library publications, send a message, more by the author, why software architects must be involved in the earliest systems engineering activities, august 12, 2019 • by sarah sheard , suzanne miller , bill nichols , donald firesmith , mike phillips, an appraisal of the systems engineering journal's treatment of software over the last two decades, february 18, 2019 • by sarah sheard, aircraft systems: three principles for mitigating complexity, june 15, 2015 • by sarah sheard, needed: improved collaboration between software and systems engineering, may 19, 2014 • by sarah sheard, get updates on our latest work..

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Integration between Communication, Navigation and for Space Applications: Case Study on Lunar Satellite Navigation System with Focus on ODTS Techniques

• First Online: 06 April 2023

Cite this chapter

• Cosimo Stallo 12 ,
• Henno Bookmap 13 ,
• Daniele Cretoni 12 ,
• Martina Cappa 14 ,
• Laura De Leo 15 ,
• Mattia Carosi 12 &
• Carmine Di Lauro 12  

Part of the book series: Signals and Communication Technology ((SCT))

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This chapter firstly introduces different examples of Earth applications based on the integration of different communication, navigation and sensing technologies. Then, it focuses on a case study for space applications based on definition of high level concept of a satellite communication and definition architecture for Moon exploration. In particular, it describes different ODTS (Orbit Determination and Timing Synchronisation) technologies able to enable an accurate lunar satellite navigation service. A dedicated analysis for each identified ODTS technique is provided in terms of achievable performances, solution complexity, scalability and near term implementation. Then, a candidate baseline ODTS concept for a precise lunar radio navigation is reported with a detailed performance analysis in terms of SISE (Signal in Space Signal Error), assuming an initial target value of 25 m at 95% as main system design requirement.

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Acknowledgements

The authors would like to thank Daniele Musacchio and Enrico Edoardo Zini, (from Thales Alenia Space) for their contribution to this Chapter, and Pietro Giordano, Richard Swinden and Javier Ventura-Traveset from European Space Agency for their supervision on LRNS ODTS concept baseline conceived in the ESA TDE project “Lunar Radio Navigation System” (LRNS).

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Stallo, C. et al. (2023). Integration between Communication, Navigation and for Space Applications: Case Study on Lunar Satellite Navigation System with Focus on ODTS Techniques. In: Sacchi, C., Granelli, F., Bassoli, R., Fitzek, F.H.P., Ruggieri, M. (eds) A Roadmap to Future Space Connectivity. Signals and Communication Technology. Springer, Cham. https://doi.org/10.1007/978-3-031-30762-1_11

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Swiss TV audiences demand a wide variety of channels in their different languages. However, this has proved challenging for cable access in a country where more than 50% of the territory is covered in mountains and woodlands. Satellite is the only option for the households in these regions. Kabelio's new DTH platform offers Swiss viewers access to the content they want, no matter where they may be.

DIGITAL TELEVISION FOR ALL

Walesi, the Fijian government’s digital television infrastructure company, have connected 333 widely spread islands using the new EUTELSAT 172B high-capacity satellite, ensuring all its citizens have access to digital TV.

COMMUNAL ANTENNAS

Cyfrowy Polsat, Poland’s largest media and telecommunications platform, and the Polish Chamber of Digital Broadcasting (PIRC), discuss how Building Regulations in Poland have helped to create more choice of TV packages and channels for people living in residential buildings.

BRINGING eSPORT MAINSTREAM

Despite the interest, passion and dedication of its viewership, eSports has yet to truly enter as a mainstream sport. Efforts from ESR and Eutelsat are set to challenge this status-quo and position eSports as a social viewing activity for generations to come - and satellite has presented an opportunity to do so.

EVOLVE WITH YOUR AUDIENCE

When Tricolor TV set up in 2005, it had a huge business challenge: how to reach households across the vast territory of Western Russia with an innovative and inexpensive TV offering in a country where many households were still receiving analogue TV and DTT was slow to take off.

TELEHEALTH FOR REMOTE COMMUNITIES

iNET Communications and 19Labs use the Eutelsat ADVANCE satellite broadband solution to bring medical services to communities across Guyana.

EXPANDING ACROSS THE CARIBBEAN

Neptune Communications' suite of new services, provided across highly resilient satellite and mobile infrastructures and entirely independent from existing terrestrial networks, are designed to support the region's most important connectivity requirements.

BRINGING BROADBAND TO PERU'S RAINFOREST

Eutelsat and long-term partner Telespazio provide quality connectivity to the remote regions of the Amazon rainforest. Through Eutelsat’s 117 WEST B satellite and Telespazio’s infrastructure coverage of these previously unreachable areas became possible.

MARITIME CONNECTIVITY

The Statsraad Lehmkuhl needs to be constantly connected - while at sea or docking into one of the 36 different ports around the world. It’s a challenge that most connectivity solutions could not overcome.

EXTENDING CONNECTIVITY

In their mission to make Guyana a more connected country, iNet Communications worked with Eutelsat to bring broadband to eco-lodges using satellite networking.

BACKHAULING MOBILE NETWORKS

Mobile operator Mattel uses satellite connectivity to enable widespread access to mobile and internet services in towns and villages across Mauritania.

INTERNET IN UNSERVED AREAS

Satellite internet provider, Caribsat, explains how they are using IP Easy to provide direct internet connectivity to businesses and schools across the Caribbean.

CONNECTIONS FOR MINING OPERATIONS

With intelligent use of satellite connectivity, portable technology and networking, iNet brings fully scalable internet, voice and data connectivity to Guyana's mining community.

BACKHAULING IOT DATA

Failsafe Controls design industrial control panels for the oil and gas industry to deliver information from remote sites to a client’s central offices. With the remote sites often beyond cellular coverage, they needed a reliable solution to backhaul data to the office environment without worrying about coverage issues and at the same time lowering costs.

SECURING IoT CONNECTIVITY

The Consorzio di Bonifica delle Marche is the public entity responsible for the operations and safety of waterways in the Marche region of Italy. By using Eutelsat’s advanced satellite solutions, the Consorzio di Bonifica delle Marche gained 99% network availability to connect, optimise and operate their remote operations in a region notorious for poor connectivity.

INFLIGHT ENTERTAINMENT

Panasonic Avionics explain how advances in satellite technology are enabling airlines to offer new IFEC services to passengers.

INFLIGHT CONNECTIVITY

When Unicom Air Net wanted to deploy an inflight communications network to provide broadband internet services to mobile platforms, they chose EUTELSAT 172B.

EMERGENCY TELECOMS NETWORKS

Télécoms Sans Frontières, the world’s leading international NGO specialising in technology and telecommunications for humanitarian crises, equips communities and response units with high-speed connectivity in just a few hours.

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Overview of Satellite Communications and its Applications in Telemedicine for the underserved in Nigeria: A case study

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Dynamic Network Formation for FSO Satellite Communication

Satellite network optimization is essential, particularly since the cost of manufacturing, launching and maintaining each satellite is significant. Moreover, classical communication optimization methods, such as Minimal Spanning Tree, cannot be applied directly in dynamic scenarios where the satellite constellation is constantly changing. Motivated by the rapid growth of the Star-Link constellation that, as of Q4 2021, consists of over 1600 operational LEO satellites with thousands more expected in the coming years, this paper focuses on the problem of constructing an optimal inter-satellite (laser) communication network. More formally, given a large set of LEO satellites, each equipped with a fixed number of laser links, we direct each laser module on each satellite such that the underlying laser network will be optimal with respect to a given objective function and communication demand. In this work, we present a novel heuristic to create an optimal dynamic optical network communication using an Ant Colony algorithm. This method takes into account both the time it takes to establish an optical link (acquisition time) and the bounded number of communication links, as each satellite has a fixed amount of optical communication modules installed. Based on a large number of simulations, we conclude that, although the underlying problem of bounded-degree-spanning-tree is NP-hard (even for static cases), the suggested ant-colony heuristic is able to compute cost-efficient solutions in semi-real-time.

On the Security of LEO Satellite Communication Systems: Vulnerabilities, Countermeasures, and Future Trends

<div>In view of the development status of the security of LEO satellite communication system, a comprehensive review, induction, and summary is carried out.<br></div>

Virtualized High Throughput Satellite Gateway with a Global Bandwidth Management Method

With the development of new satellite payload technology, in order to improve the utilization of system resources, research is based on software-defined network (SDN) and network function virtualization (NFV) gateway architecture. Based on this architecture, the system realizes global resource management and overall data distribution, which can solve the problem of resource allocation and maximum/minimum rate guarantee between different VNO terminals under different beams, different gateways, and different satellites. For this, a global bandwidth management method can be used which is mainly a process of management to control the traffic on a communication link. The proposed global resource management and control method can be based on the rate guarantee value of the VNO/terminal configured in the system as the basic limiting condition and reallocate the rate guarantee value limiting parameter according to the resource application status of the online terminal. The method can maximize the resource utilization of the entire satellite communication system and satisfy the resource request of the user terminal as much as possible.

Effectiveness Evaluation Method of Constellation Satellite Communication System with Acceptable Consistency and Consensus Under Probability Hesitant Intuitionistic Fuzzy Preference Relationship

Abstract System effectiveness evaluation is an important part of constellation satellite communication system research, with applications in project verification and optimization as well as tactical and technical measurement argumentation. This paper presents a systematic and comprehensive effectiveness evaluation method for a constellation satellite communication system under a probabilistic hesitant intuitionistic fuzzy preference relationship (PHIFPR), aiming to better address the fuzziness and uncertainty in effectiveness evaluation. First, a proposed definition of PHIFPR describes the hesitancy of evaluators, provides hesitancy distribution information, and depicts the worst negative information and risk preferences in effectiveness evaluation. Then, we deduce the approximate consistency index of PHIFPR and establish a mathematical programming model to increase individual consistency when the approximate consistency index does not reach a predetermined level. In the sequel, a proposed group consensus index uses the PHIFPR-based Hausdorff distance to measure the closeness between evaluators' judgements. Afterwards, a consistency and consensus improvement model is designed to retain the original opinions of evaluators to make the consistency and consensus of PHIFPRs acceptable. Moreover, a goal programming model is established to gain the reliable scheme priority weights by regarding the approximate consistency condition of a PHIFPR as a fuzzy constraint. Finally, an experimental example is offered to highlight the practicability and feasibility of the proposed method, and some comparative analyses with other methods offer insights into the designed method.

Modeling and Fabrication of a Reconfigurable RF Output Stage for Nanosatellite Communication Subsystems

Current small satellite platforms such as CubeSats require robust and versatile communication subsystems that allow the reconfiguration of the critical operating parameters such as carrier frequency, transmission power, bandwidth, or filter roll-off factor. A reconfigurable Analog Back-End for the space segment of a satellite communication subsystem is presented in this work. This prototype is implemented on a 9.5 cm2 6-layer PCB, and it operates from 0.070 to 6 GHz and complies with CubeSat and IPC-2221 standards. The processing, control, and synchronizing stages are carried out on a Software-Defined Radio approach executed on a baseband processor. Results showed that the signal power at the output of the proposed Analog Back-End is suitable for feeding the following antenna subsystem. Furthermore, the emitted radiation levels by the transmission lines do not generate electromagnetic interference.

Satellite Communication Networks

Communication satellite resource scheduling based on improved whale optimization algorithm.

Under the background of increasing pressure of satellite communication support, reasonable and efficient dispatch of communication satellite resources is an important means to improve the utilization efficiency of communication resources. Aiming at the resource scheduling task requirements of geostationary orbit communication satellite system, communication satellite resource scheduling (CSRS) model is established first of all, based on this, advances a kind of CSRS method based on improved whale optimization algorithm. In this method, the detection and search strategy is proposed and the crossover mutation operator is used to avoid the algorithm falling into local optimum. Simulation results show that IWOA can effectively improve the quality and stability of satellite resource scheduling.

Analysis of key technologies for creating multisatellite orbital constellations of small spacecraft

One of the key areas of modern world cosmonautics is the development of cluster space systems for various purposes, consisting of a large number of functioning spacecraft. This became possible due to a decrease in the mass of spacecraft due to the creation and use of new materials, the development of electronics and microelectromechanical systems, the use of the group launch method, the development of multi-agent technologies and inter-satellite communication sys-tems. There are projects of systems consisting of a large number of space objects, such as OneWeb, Planet, Starlink, Satellogic, etc. The main classes of devices used to create such multi-satellite systems are small satellites, including the number of micro (up to 100 kg) and nano (up to 10-15 kg) classes, which have significant advantages over heavy space-craft, especially in terms of the timing and cost of their creation. The deployment of multi-satellite constellations, in-cluding hundreds and thousands of satellites, requires fundamentally new approaches to the creation of spacecraft and the system as a whole at all stages of the life cycle. The article discusses the key technologies used to create multi-satellite orbital constellations based on small satellites at different stages of the life cycle - from the early stages of de-sign to the stage of operation and disposal (information from orbit). The experience of a joint project of Samara Univer-sity and the Progress Rocket and Space Center on the creation of a constellation of small spacecraft of the AIST series is presented.

Load Balancing Routing Algorithm of Low-Orbit Communication Satellite Network Traffic Based on Machine Learning

Satellite communication has become an important research trend in the field of communication technology. Low-orbit satellites have always been the focus of extensive attention by scholars due to their wide coverage, strong flexibility, and freedom from geographical constraints. This article introduces some technologies about low-orbit satellites and introduces a routing algorithm DDPG based on machine learning for simulation experiments. The performance of this algorithm is compared with the performance of three commonly used low-orbit satellite routing algorithms, and a conclusion is drawn. The routing algorithm based on machine learning has the smallest average delay, and the average value is 126 ms under different weights. Its packet loss rate is the smallest, with an average of 2.9%. Its throughput is the largest, with an average of 201.7 Mbps; its load distribution index is the smallest, with an average of 0.54. In summary, the performance of routing algorithms based on machine learning is better than general algorithms.

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Satellite Communications

Home > Satellite Communications > Rural Broadband Connectivity: Challenges, Opportunities, and Case Studies for Satellite Connectivity

Rural Broadband Connectivity: Challenges, Opportunities, and Case Studies for Satellite Connectivity

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• Supporting Articles

In a world increasingly dependent on connectivity, the satellite industry and National Broadband/Rural Connectivity/Social Inclusion programs play a pivotal role in expanding broadband access.

NSR’s Rural Broadband Connectivity:​ Challenges, Opportunities, and Case Studies for Satellite Connectivity report explores the approaches used by the satellite industry and universal service obligation (USO) programs to increase broadband connectivity.

Understanding Broadband Connectivity: At the heart of global connectivity lies the satellite industry and the efforts of USO programs. This report delves into the intricacies of their approaches, shedding light on the strategies employed to overcome barriers and increase broadband connectivity worldwide. By examining five different national case studies, we uncover the impact of these approaches on household broadband penetration rates.

Exploring Business Models: Our report explores the business models available to the satellite industry, offering valuable insights into their strengths, weaknesses, and potential for growth. By understanding these models, stakeholders can make informed decisions to maximize their impact and capitalize on emerging opportunities.

Unlocking Lucrative Opportunities: The satellite industry presents an array of opportunities for those looking to tap into the immense potential of consumer broadband services. Direct-to-consumer connections offer the largest opportunity for businesses, while social inclusion programs provide an additional avenue for lucrative growth. Our report sheds light on these opportunities, empowering stakeholders to make strategic decisions that maximize their market presence and profitability.

Through an in-depth analysis of business models and case studies, this report presents valuable insights, challenges, and recommendations for the satellite connectivity industry.

Key questions are answered in this report?

• What are the major “consumer broadband” business models for satellite connectivity?
• How much revenue will the satellite industry generate from consumer broadband and ‘social inclusion’ programs over the next ten years?
• What terminal and consumer premise equipment pricing strategies are emerging to capture price sensitive customers?
• Where can satellite connectivity co-exist alongside terrestrial-heavy national broadband strategies?

Who Should Purchase this Report:

• Those involved in connectivity strategy initiatives within a satellite connectivity service provider, hardware manufacturer, or other player involved in bridging the digital divide.
• Government, regulatory practices, and industry bodies.
• Investors looking to understand market dynamics for satellite connectivity services aimed at “National Broadband / Rural Connectivity / Social Inclusion” programs.

Readers are also encouraged to explore Analysis Mason’s other coverage of rural connectivity initiatives, such as Rural Coverage Initiatives: Case Studies and Analysis

Covered in this Report:

• Tailored Focused on the Rural Broadband Satellite Connectivity Strategies.
• Nigeria – Hotspots and an Emphasis on Affordability
• Ireland – Heavy Focus on Terrestrial Services
• Mexico – Rapid Deployments of Hotspot Model
• Australia – Satellite Essential, looking for the ‘next solution’.
• Sweden – Direct-to-Household and “last 2%”

Other Reports Related to this Subject Matter

• Executive Summary
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• Case Studies
• About the Authors and NSR an Analysys Mason Company

RBC Bottom Lines

Starlink-telstra partnership: a new route to rural connectivity, satellite opportunity for connecting the unconnected – nsr, privacy overview.

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Quantum Physics

Title: entanglement swapping in orbit: a satellite quantum link case study.

Abstract: Satellite quantum communication is a promising way to build long distance quantum links, making it an essential complement to optical fiber for quantum internetworking beyond metropolitan scales. A satellite point to point optical link differs from the more common fiber links in many ways, both quantitative (higher latency, strong losses) and qualitative (nonconstant parameter values during satellite passage, intermittency of the link, impossibility to set repeaters between the satellite and the ground station). We study here the performance of a quantum link between two ground stations, using a quantum-memory-equipped satellite as a quantum repeater. In contrast with quantum key distribution satellite links, the number of available quantum memory slots m, together with the unavoidable round-trip communication latency t of at least a few milliseconds, severely reduces the effective average repetition rate to m/t -- at most a few kilohertz for foreseeable quantum memories. Our study uses two approaches, which validate each other: 1) a simple analytical model of the effective rate of the quantum link; 2) an event-based simulation using the open source Quantum Internet Simulation Package (QuISP). The important differences between satellite and fiber links led us to modify QuISP itself. This work paves the way to the study of hybrid satellite- and fiber-based quantum repeater networks interconnecting different metropolitan areas.

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Communications solutions and case studies

Delivering high current at very low voltage

Case study: Satellite communications antenna

Need for a small, robust and reliable low profile power solution

Satellite communication usually requires a large dish antenna. In addition, for moving vehicles, planes and boats antenna-positioning motors and controllers are needed to ensure that the antenna accurately tracks the relative position of the satellite. Mounting these cumbersome assemblies in a position to maintain a clear visual satellite connection is often impractical. This customer was developing an electronically steered solid-state phased-array antenna with no positioning motors to significantly reduce the antenna profile. The key goals were:

• The antenna’s processing signals required a well-regulated 1.5V 80A supply
• Provide a small, robust and reliable low profile power solution
• Accommodate future ASIC designs requiring lower core voltage and higher currents

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Factorized power provided a more flexible power architecture

Factorized Power Architecture (FPA) separates the regulation and voltage transformation stages into separate components. The resultant design flexibility simplified the implementation and met the system requirements of small size and a low profile. Fast load response and high switching frequency eliminated many hold-up capacitors saving space. Key benefits were:

• Performance maximized by fast response of FPA to ASIC’s pulsed current demands
• Reduced footprint (11cm 2 ) and ultra-low profile (<7mm)
• Future ASICs with lower voltages (<1V) and higher currents (+100A) can use the same, scalable, small-footprint architecture

Factorized Power Architecture provides high current to the ASIC in the lowest profile

The Vicor VTM (transformation) supplied the high current 1.5V rail and was placed close to the ASIC. The PRM (regulation) was sited at the PCB edge since its 48V output bus to the VTM carried only low currents and provided reduced bus distribution losses. This arrangement saved space and optimized voltage regulation at the ASIC. To analyze this power chain, go to Vicor Whiteboard online tool.

Learn more about the modular approach power .

The power delivery network

PRM pre- and post-transformation regulators

Input: 48V (36 – 75V)

Output: 48V (5 – 55V)

Power: Up to 600W

Efficiency: Up to 97%

As small as 22.0 x 16.5 x 6.73mm

VTM current multipliers

Input: 0 – 60V

Output: 0 – 55V

Current: Up to 115A

Peak efficiency: Up to 97%

As small as 22.83 x 8.52 x 4.9mm

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VideoRay drives safe, effective underwater exploration leveraging AI and today’s newest technologies

Vicor Powering Innovation podcast discusses the proliferation of ROV applications and how VideoRay is responding to new underwater missions

The future of long-haul trucking is accelerating autonomously on a freeway near you

Kodiak autonomous technology revolutionizes long-haul trucking. Learn more about Vicor power modules that drive mission critical ‘seeing’ sensors

Next generation hydrogen powered drones are doing search and rescue, saving lives

Doosan Mobility’s life-saving drones using hydrogen fuel cells and high-density power modules, enabling 5x longer flight time than lithium ion batteries

From toys to construction site tools, OLogic brings robotic ideas to life

OLogic extols high-density power modules to drive today’s robotic revolution

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Global Mobile Satellite System

• What is Satellite Subsystem?
• Advanced Mobile Phone System
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• Difference between GPS and Satellite Navigation System
• Satellite Switched TDMA in Computer Networks
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• What is a Mobile Operating System?
• Indian Regional Navigation Satellite System (IRNSS)
• How to Start Google Maps in Satellite View
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• What is a Distributed System?
• Satellite Image Processing

GMSS stands for Global Mobile Satellite System . An artificial body which is placed in an orbit around the earth for the purpose of communication is known as Communication satellite . GMSS is a system which consists of various artificial communication satellites orbiting around the earth for the purpose of communication. 

A satellite network is a combination of nodes that provides communication from one point on the Earth to another. A node in the network can be Satellite, an Earth station, or an End-user terminal or Telephone. Satellite networks are like cellular networks, they divide the planet into cells. 

The frequencies reserved for the satellite microwave communication are in gigahertz(GHz) range. Each satellite sends and receives over two different bands. Transmission from earth to satellite is called the Uplink. Transmission from the satellite to the earth is called the Downlink.

Satellite frequency bands

Uplink and downlink frequencies must be different to avoid interference. Now, stations at the earth have greater power sources than that of satellite as it has only solar power. Also, higher frequency results in higher attenuation and to compensate with it more power is required. So, uplink uses higher frequency to penetrate the environment. 

Satellite Orbits:  

An artificial satellite needs to have an orbit, the path in which it travels around the Earth. The orbit can be equatorial, inclined or polar.

Satellite process microwaves with bidirectional antennas. Therefore, the signal from the satellite is normally aimed at a specific area called the footprint.

Satellite Categories

Based on the location of the orbit, satellites can be divided into three categories as follows

GEO : 

• GEO stands for Geostationary Earth Orbit.
• The communication satellites in this orbit operates at a distance of about 36000 km above the earth’s surface and their orbital time period is about 24 hours.
• Geostationary Orbit Satellites are used for radio broadcasting.
• To ensure constant communication, the satellite must move at the same speed as the earth, so that it seems to remain fixed above a certain spot. So such satellites are called geostationary.
• One geostationary satellite cannot cover the whole earth. One satellite in orbit has line-of-sight contact with vast number of stations, but the curvature of the Earth still keeps much of the planet out of sight. It takes minimum of three satellites equidistant from each other in geostationary Earth Orbit(GEO) to provide full global transmission.

MEO : 

• MEO stands for Medium Earth Orbit.
• The communication satellites in this orbit operates at a distance of about 5000 to 12000 km above the earth’s surface.
• These satellites are positioned between the two Van Allen belts. A satellite at this orbit takes approximately 6 to 8 hours to circle the Earth.
• One Example of a MEO satellite system is Global Positioning System(GPS), constructed and operated by US Department of Defense, orbiting at an altitude about 18,000 km above the earth.
• The system consists of 24 satellites and is used for land, sea, and air navigation to provide time and locations for vehicle and ships.
• The orbits and the locations of the satellites in each orbit are designed in such a way that, at any time, four satellites are visible from any point on the Earth. A GPS receiver has a almanac that tells the current position of each satellite.
• GPS is based on a principle called Trilateration(also sometimes called Triangulation). Principle states that “On a plane, if we know our distance from three points, we know exactly where we are.”

LEO:  

• LEO stands for Low Earth Orbit.
• The communication satellites in this orbit operates at a distance of about 500 to 1200 km above the earth’s surface and their orbital time period generally ranges between 95 to 120 minutes. The Satellite has a speed of 20,000 to 25,000 km/h. Low Orbit Satellites makes global radio coverage possible.
• An LEO system is made of a constellation of satellites that work together as a network, each satellite acts as a switch. Satellites that are close to each other are connected through inter-satellite links (ISLs). A mobile system communicates with the satellite through a user mobile link(UML). A satellite can also communicate with an Earth station(gateway) through a gateway link(GWL).
• LEO satellites can be divided into three categories: Little LEOs, Big LEOs, and Broad Band LEOs.
• Little LEOs operate under 1GHz. They are mostly used for low-data-rate messaging.
• Big LEOs operate between 1 and 3GHz. Globalstar and Iridium system are examples of Big LEOs.
• Broad Band LEOs provide communication similar to fiber-optic networks. The first broadband LEO system was Teledesic.

IRIDIUM: 

• The concept of Iridium system, a 77-satellite network, was started by Motorola in 1990. The project took 8 years to materialize.
• Finally in 1998, the service was started by 66 satellites. The original name, Iridium, came from the name of the 77th chemical element. A more appropriate name is Dysprosium (the name of 66th element).
• The System has 66 satellites divided into 6 orbits, with 11 satellites in each orbit. The orbits are at an altitude of 750km.
• Iridium is designed to provide direct worldwide voice and data communication using handheld terminals, a service similar to cellular telephony but on a global scale.

Globalstar:

• Globalstar is LEO satellite system that uses 48 satellites in six polar orbits with each orbit hosting eight satellites. The orbits are located at an altitude of almost 1400km.
• The Globalstar system is similar to the Iridium system, the main difference is the relaying mechanism.
• Communication between two distinct users in Iridium system requires relaying between several satellites.
• Globalstar communication requires both satellites and earth station, which means that ground stations can create more powerful signals.  
• Teledesic is a system of satellites that provides fiber-optic like communication.
• Its main purpose is to provide broadband Internet access for users all over the world. It is sometimes called “Internet in the sky”.
• The project was started in1990 by Craig McCaw and Bill Gates, later other investors joined the consortium. Teledesic  has 288 satellites in 12 LEO orbits, each at an altitude of 1350km.
• The commercial failure of the similar Iridium and Globalstar ventures and other systems, along with bankruptcy protection fillings, were the primary factors in halting this project, and Teledesic officially suspended its satellite construction work on 1 October 2002.

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