Proceedings of the Third International Mobile Satellite Conference (IMSC 1993)

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial cellular communications services. While the first and second International Mobile Satellite Conferences (IMSC) mostly concentrated on technical advances, this Third IMSC also focuses on the increasing worldwide commercial activities in Mobile Satellite Services. Because of the large service areas provided by such systems, it is important to consider political and regulatory issues in addition to technical and user requirements issues. Topics covered include: the direct broadcast of audio programming from satellites; spacecraft technology; regulatory and policy considerations; advanced system concepts and analysis; propagation; and user requirements and applications

DEVELOPMENT OF NEW ITU APPROACH TO INTERNATIONAL FREQUENCY SPECTRUM MANAGEMENT AND STANDARDIZATION PROCESSES

Mednarodna Unija za telekomunikacije (ITU) je specializirana organizacija Združenih Narodov za telekomunikacije s sedežem v Ženevi, ki med drugim skrbi za učinkovito in usklajeno upravljanje z radiofrekvenčnim spektrom (10kHz-3000GHz) in to na način, da so zagotovljene pravice in enake možnosti njegovega izkoriščanja vsem uporabnikom, državam članicam (193). Vse od njene ustanovitve leta 1865 je tehnološki napredek motiviral oblikovanje ITU mednarodnih standardov za izgradnjo in funkcioniranje telekomunikacijskih sistemov in omrežij in kasneje tudi za izkoriščanje radiofrekvenčnega spektra. Tehnološki razvoj je uravnaval dinamiko aktivnosti in pogojeval organizacijske spremembe in statutarne reforme. Strokovna priporočila pa so postala univerzalna referenca za uspešen razvoj in standardizacijo telekomunikacijskih sistemov. Pa vendar je že nekaj časa opaziti, da je učinkovitost ITU v vse večjem razkoraku z evolucijo in preobrazbo telekomunikacijskega okolja, pri čemer ni skrivnost, da so številni poskusi zadnjih let, kako uskladiti strukturo in delovanje ITU z dinamičnim razvojem okolja, bili neuspešni. Inertnost, pa tudi oportunizem različnih subjektov, je bila in je še vedno močna ovira, da bi se ITU uspešno spopadala z izzivi časa. Radiofrekvenčni spekter in orbitalne pozicije, ki pripadajo različnim radiofrekvenčnim alokacijam, so edinstvena naravna dobrina, katere usklajena in transparentna mednarodna regulativa je permanentna skrb vsake suverene države. Učinkoviti procesi standardizacije v globalnem okolju pa so ključ za uspešno pot k hitremu razvoju telekomunikacijske infrastrukture v času, ko je tehnološka konvergenčnost izbrisala meje med tehnologijo, telekomunikacijskimi sistemi in telekomunikacijskimi aplikacijami. Disertacija ponuja podrobno analizo aktivnosti ITU na dveh osrednjih segmentih, t.j. radiokomunikacije in standardizacija. Na osnovi dolgoletnega opazovanja in proučevanja dela in učinkovitosti ITU, zaključki nedvoumno kažejo na potrebo po strukturnih reformah, pot do katerih pa je zaradi politične dimenzije, ki je vedno prisotna v medvladnih organizacijah, izjemno zapletena. V sodobnem telekomunikacijskem okolju, kjer tehnološki razvoj prehiteva počasne vladne odločitve, so potrebne jasne strateške orientacije in trdna odločenost držav članic, da se pristopi k vsebinskim spremembam. S tem namenom je predstavljen tudi predlog novega konstitutivnega in organizacijskega modela ITU, katerega implementacija bi omogočila boljše pogoje za doseganje zastavljenih ciljev. Sedanje težave v funkcioniranju te specializirane organizacije OZN so v največji meri posledica njenega zaostalega organizacijskega koncepta, ki sodi v zgodovinsko okolje. Države članice imajo še vedno izključno vlogo pri pomembnih odločitvah, žal pa njihove vlade ne premorejo več strokovnega potenciala za doseganje znanstvenega napredka. V ta prostor so vstopili drugi kreativni deležniki (iz industrije in nevladnih organizacij) ki so postali gonilna sila vsega razvoja. To so tisti ki želijo ustvarjati v drugačnem okolju, kjer bodo suvereni v odločanju na področjih njihove izključne kompetentnosti. Pogosto zapletena razmerja med državami članicami z različnimi interesi, velikimi in malimi, razvitimi in manj razvitimi, sposobnimi in odsotnimi, egoističnimi in kooperativnimi – onemogočajo univerzalne rešitve, ko gre za učinkovito in transparentno uporabo radiofrekvenčnega spektra. Na področju standardizacije ICT sistemov in aplikacij so razmere še bolj zapletene, saj so ti procesi v zadnjih desetletjih spremenili vsebino zaradi potreb po hitrem regionalnem razvoju in predvsem zaradi hitrega tehnološkega napredka, kateremu tradicionalni in klasično počasni ITU pristop k standardizaciji ni mogel več slediti. Dinamika razvoja pa kliče po odprtju in inovacijah tistih, ki so teh inovacij sposobni in ki imajo za te aktivnosti tudi primerne finančne in intelektualne vire. Državne strukture so v standardizacijskih postopkih in razvoju postale irelevantne, čeprav se še vedno z veliko silo oklepajo starih prerogativov. V zadnjih dveh desetletjih se je v znanstvene študije, analize in v izpeljavo tehničnih programov nenapovedano in samovoljno vrinila še »politizacija dogovarjanja« na različnih nivojih mednarodnega tehničnega sodelovanja. Ta realnost je dodatno poslabšala razmere v sicer arhaičnih strukturah ITU. Cilj disertacije je nov pristop k mednarodni regulativi uporabe spektra in njegovi mednarodni zaščiti na način, da bo koriščenje frekvenčnega spektra kar najbolj učinkovito in usklajeno. Radiofrekvenčni spekter je univerzalna dobrina, katere uporabnost ni v lasti nikogar in kjer akademske študije in dosežki odpirajo nove dimenzije za njegovo praktično uporabo. V okolju globalnega dogovarjanja in univerzalnega izkoriščanja spektra so pomembni odgovori na spodnja vprašanja, ki nas lahko pripeljejo k novi paradigmi: Kako zagotoviti transparentnost in učinkovitost pri planiranju, razdeljevanju in dodeljevanju frekvenčnega spektra? Kako pritegniti h kreativnemu sodelovanju nove Partnerje (industrija in privatni sektor) in jim zagotoviti pogoje za inovativne rešitve v standardizaciji ICT. Kako ustvariti homogeno in konvergenčno okolje, ki bi zagotavljalo nenehno evolucijo ICT k racionalnim in globalnim usmeritvam pri določanju komunikacijske politike?The convergence of fast developing technologies (ICT), the globalisation of telecommunications in general and availability of new services, have profoundly changed the telecommunication environment and related national policies. The ITU constituencies are Member States and the Organisation strategic decisions are taken exclusively by the Governments. However, in the changing environment it became impossible to ignore the non-governmental partners’ views while discussing the global policies and action plans that should be leading to important decisions. The appearance of strategic alliances, privatization of telecommunication infrastructures and market liberalization are the phenomena that brought new elements in telecommunication development and had substantially modified the role of Governments. These phenomena influenced the Union operational model to great extent where voices of partners are claiming more balanced share in the decision making processes and rational distribution of responsibilities, i.e. between the administrations of Members States, national regulators, telecommunication operators and industry. The necessary transparency of regulatory policy together with simplified Frequency Spectrum Management and universally recognized standardisation activities may be endangered, if no constitutional reforms intervene in the next two or three plenipotentiary cycles. The situation is calling for open review of governmental responsibilities in order to make realistic projection of reforms that should allow ITU to preserve its technical sovereignty and global credibility through its important mission. The ITU structure and its mode of operation in the field of radiocommunications and ICT standardisation today appear to be archaic and not synchronized neither with the environment nor with Members and other user’s needs. National concern for harmonious development of Information and Communication Infrastructure (ICT) remain high on each Government agenda due to its substantial impact on national economies. There is strategic interest to build up and preserve well-coordinated international regulatory regime on Frequency Spectrum/Orbit Management and global/universal and transparent ICT standardisation processes. And the present thesis is a modest contribution to make it happen

A Survey on Non-Geostationary Satellite Systems: The Communication Perspective

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-the-art 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

The telecommunications and data acquisition report

Developments in Earth based radio technology with applications to space communications, geodynamics, and astrophysics are reported

Proceedings of the Fifth International Mobile Satellite Conference 1997

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments

Research and technology

Activities of the Goddard Space Flight Center are described in the areas of planets and interplanetary media, comets, astronomy and high-energy physics, solar physics, atmospheres, terrestrial physics, ocean science, sensors and space technology, techniques, user space data systems, space communications and navigation, and system and software engineering. Flight projects and mission definition studies are presented, and institutional technology is described

MOOSE: Manned On-Orbit Servicing Equipment

The ability to service satellites has thus far been limited to low earth orbit platforms within reach of the Space Shuttle. Other orbits, such as geosynchronous orbits containing high-value spacecraft have not been attainable by a servicing vehicle. The useful life of a satellite can be extended by replacing spent propellant and damaged orbital replacement units, forestalling the need for eventual replacement. This growing need for satellite on-orbits servicing can be met by the Manned On-Orbit Servicing Equipment (MOOSE). Missions requiring orbit transfer capability, precision manipulation and maneuvering, and man-in-the-loop control can be accomplished using MOOSE. MOOSE is a flexible, reusable, single operator, aerobraking spacecraft designed to refuel, repair, and service orbiting spacecraft. MOOSE will be deployed from Space Station Freedom, (SSF), where it will be stored, resupplied, and refurbished

Study of the Business Model of three Earth Observation (EO) companies already present in the Very Low Earth Orbit market (VLEO)

The emergence of a new private spaceflight industry has taken the Earth Observation (EO) sector by surprise. NewSpace companies are challenging the traditional satellite sector by addressing their services to mass market requirements of high-quality and low-cost EO. As part of the DISCOVERER project, this study aims to determine the Key Success Factors to consider by a new EO company at Low Earth Orbit (LEO). Hence, three businesses fitting the description were analyzed with the Case Study Methodology to establish their Business Model Canvas (BMC), associated Patterns, and Key Success Factors. The investigation consolidated the newly proposed Democratizing Business Model Pattern and added new characteristics. Successful EO NewSpace firms are getting divided between integrated operators, integrated manufacturers, and end-user specialists. A new EO company should consider the Democratizing Pattern success factors and the Vertically Integrated Strategies (VIS), depending on its disruptive idea and resource capabilities. Further research is needed to identify new factors, strengthen the validity of the Pattern, and VIS tendencies

Design, Modelling and Analysis of Satcoms for UAV operations

Η ανάγκη για άμεση συνεισφορά, απόκριση και ακρίβεια των αποτελεσμάτων οδήγησε στην είσοδο των drones και ιδιαίτερα των μη επανδρωμένων εναέριων οχημάτων (UAV) ως νέα τεχνολογικά οχήματα. Ωστόσο, η ενσωμάτωση ενός τόσο κολοσσιαίου τεχνολογικού αποκτήματος δεν είναι καθόλου εύκολη υπόθεση. Πολλές απαιτήσεις εμφανίζονται σε διάφορους τομείς όπως τηλεπικοινωνίες, προβλήματα ωφέλιμου φορτίου που πρέπει να φέρει το UAV και σχέδια λειτουργίας, απαιτήσεις που πρέπει να πληρούνται για την αποφυγή προβλημάτων ασφάλειας, αποφυγή σύγκρουσης, ασταθείς συνδέσεις και άλλα. Σκοπός της παρούσας διπλωματικής εργασίας είναι να μελετήσει όσο το δυνατόν καλύτερα και αποτελεσματικότερα τη συμβολή των δορυφορικών επικοινωνιών στην επίτευξη αξιόπιστων και ανθεκτικών επιχειρήσεων Μη Επανδρωμένων Αεροσκαφών (UAV). Θα παρουσιαστεί μια ανάλυση τριών επιπέδων που θα αφορά τον Σχεδιασμό, τη Μοντελοποίηση και την Ανάλυση δορυφορικών επικοινωνιών σε συνδυασμό με λειτουργίες UAV με τρόπο που η αποτελεσματικότητα της ζεύξης θα είναι μέγιστη εφικτή. Σε τελική ανάλυση, θα πραγματοποιηθεί ένα πείραμα που θα συζητηθούν τα αποτελέσματα και οι παράμετροι που χρησιμοποιούνται προκειμένου να υπολογιστεί η αποτελεσματικότητα του προϋπολογισμού των ζεύξεων. Είναι σημαντικό να γνωρίζουμε ότι οι κυψελοειδείς επικοινωνίες έχουν παίξει μέχρι στιγμής τον πιο σημαντικό και ακριβή ρόλο τόσο στις επίγειες όσο και στις αεροπορικές επικοινωνίες. Αυτό πρόκειται να αλλάξει καθώς οι δορυφόροι υπόσχονται χαρακτηριστικά που δεν μπορούν να ανταγωνιστούν τα επίγεια δίκτυα, με αποτέλεσμα την ενοποίηση των UAV με τις δορυφορικές επικοινωνίες. Ωστόσο, τα πράγματα είναι ασαφή και οι κίνδυνοι που ενέχουν είτε από την άποψη των προσωπικών δεδομένων είτε από την ασφάλεια και την υγεία μπορούν να λειτουργήσουν ως εμπόδιο στην ανάπτυξη και την αναβάθμιση των επικοινωνιών.The need for immediate contribution, response, and accuracy of results has led to the entry of drones and especially Unmanned Aerial Vehicles (UAVs) as new technological vehicles. However, the integration of such a colossal technological acquisition is by no means an easy task. Many requirements appear in various areas such as telecommunications, payload problems that the UAV must carry, and operations plans, requirements that must be met to avoid safety issues, collision avoidance, unstable connections, and so more. The purpose of this thesis is to study as best as possible and most effectively the contribution of satellite communications to achieve reliable and durable Unmanned Aerial Vehicles (UAVs) operations. A three-level analysis will be presented which will concern the Design, Modeling, and Analysis of satellite communications in combination with UAV operations in a way where efficiency of the link will be maximum. After all, an experiment will take place that results and parameters used will be discussed in order to compute the efficiency of the link budget. It is important to know that cellular communications have so far played the most important and accurate role in both terrestrial and air communications. This is about to change as satellites promise features that cannot compete with terrestrial networks, resulting in the integration of UAVs with satellite communications. However, things are unclear, and the risks posed either from the point of view of personal data or from safety and health can act as an obstacle in developing and upgrading communications

Bibliography of Lewis Research Center technical publications announced in 1986

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1986. All the publications were announced in the 1986 issues of Scientific and Technical Aerospace Reports (STAR) and/or International Aerospace Abstracts (IAA). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses