Topic
Satellite system
About: Satellite system is a research topic. Over the lifetime, 3378 publications have been published within this topic receiving 26395 citations.
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Patent•
11 Mar 1992
TL;DR: In this paper, the authors propose a satellite communications system consisting of one or more orbiting satellites, each carrying a database of users, destination codes and call codes, within a satellite service area, a satellite control center, and a plurality of terrestrial communications links.
Abstract: A wireless telephone system capable of servicing a roaming wireless telephone user includes a satellite communications system consisting of one or more orbiting satellites, each carrying a database of users, destination codes and call codes, within a satellite service area, a satellite control center, and a plurality of terrestrial communications links. The system operates by effecting communication between a terrestrial wireless telephone end user transceiver apparatus and a terrestrial communications link via a single relay through a single satellite or a succession of satellites wherein the relay station may be in motion relative to the end user transceiver apparatus and the terrestrial communications link, wherein the orbiting relay station effects the ultimate decision on linking based on stored on-board information and on-board processing, and wherein the end user transceiver apparatus, the orbiting satellite and the terrestrial communications link are operative in cooperation with the on-board database to effect hand-off from a first orbiting satellite to a second orbiting satellite. The satellite system is a single satellite or preferably a constellation of satellites orbiting near the earth, all of which are capable receiving requests for calls and participating in the call routing and call setup on an autonomous basis. The satellites are capable of decoding the calls, switching, handing off of calls to other satellites, and updating databases of users based on information provided by network control.
329 citations
Book•
01 Jan 2014
TL;DR: In this article, the authors present a detailed analysis of the satellite link performance with respect to different types of satellite links, including transparent satellite, regenerative satellite, and multibeam antenna coverage vs moonbeam coverage.
Abstract: ACKNOWLEDGEMENT ACRONYMS NOTATION 1 INTRODUCTION 11 Birth of satellite communications 12 Development of satellite communications 13 Configuration of a satellite communications system 14 Types of orbit 15 Radio regulations 16 Technology trends 17 Services 18 The way forward References 2 ORBITS AND RELATED ISSUES 21 Keplerian orbits 22 Useful orbits for satellite communication 23 Perturbations of orbits 24 Conclusion References 3 BASEBAND SIGNALS AND QUALITY OF SERVICE 31 Baseband signals 32 Performance objectives 33 Availability objectives 34 Delay 35 Conclusion References 4 DIGITAL COMMUNICATIONS TECHNIQUES 41 Baseband formatting 42 Digital modulation 43 Channel coding 44 Channel coding and the power-bandwidth trade-off 45 Coded modulation 46 End-to-end error control 47 Digital video broadcasting via satellite (DVB-S) 48 Second generation DVB-S 49 Conclusion References 5 UPLINK, DOWNLINK AND OVERALL LINK PERFORMANCE INTERSATELLITE LINKS 51 Configuration of a link 52 Antenna parameters 53 Radiated power 54 Received signal power 55 Noise power spectral density at the receiver input 56 Individual link performance 57 Influence of the atmosphere 58 Mitigation of atmospheric impairments 59 Overall link performance with transparent satellite 510 Overall link performance with regenerative satellite 511 Link performance with multibeam antenna coverage vs moonbeam coverage 512 Intersatellite link performance References 6 MULTIPLE ACCESS 61 Layered data transmission 62 Traffic parameters 63 Traffic routing 64 Access techniques 65 Frequency division multiple access (FDMA) 66 Time division multiple access (TDMA) 67 Code division multiple access (CDMA) 68 Fixed and on-demand assignment 69 Random access 610 Conclusion References 7 SATELLITE NETWORKS 71 Network reference models and protocols 72 Reference architecture for satellite networks 73 Basic characteristics of satellite networks 74 Satellite on-board connectivity 75 Connectivity through intersatellite links (ISL) 76 Satellite broadcast networks 77 Broadband satellite networks 78 Transmission control protocol 79 IPv6 over satellite networks 710 Conclusion References 8 EARTH STATIONS 81 Station organisation 82 Radio-frequency characteristics 83 The antenna subsystem 84 The radio-frequency subsystem 85 Communication subsystems 86 The network interface subsystem 87 Monitoring and control auxiliary equipment 88 Conclusion References 9 THE COMMUNICATION PAYLOAD 91 Mission and characteristics of the payload 92 Transparent repeater 93 Regenerative repeater 94 Multibeam antenna payload 95 Introduction to flexible payloads 96 Solid state equipment technology 97 Antenna coverage 98 Antenna characteristics 99 Conclusion References 10 THE PLATFORM 101 Subsystems 102 Attitude control 103 The propulsion subsystem 104 The electric power supply 105 Telemetry, tracking and command (TTC) and on-board data handling (OBDH) 106 Thermal control and structure 107 Developments and trends References 11 SATELLITE INSTALLATION AND LAUNCH VEHICLES 111 Installation in orbit 112 Launch vehicles References 12 THE SPACE ENVIRONMENT 121 Vacuum 122 The mechanical environment 123 Radiation 124 Flux of high energy particles 125 The environment during installation References 13 RELIABILITY OF SATELLITE COMMUNICATIONS SYSTEMS 131 Introduction of reliability 132 Satellite system availability 133 Subsystem reliability 134 Component reliability INDEX
322 citations
TL;DR: In this paper, an elegant formulation of the linearized equations of relative motion is discussed and adopted for satellite formation design, and the concept of eccentricity/inclination-vector separation is extended to low-Earth-orbit (LEO) formations.
Abstract: The implementation of synthetic apertures by means of a distributed satellite system requires tight control of the relative motion of the participating satellites. This paper investigates a formation-flying concept able to realize the demanding baselines for aperture synthesis, while minimizing the collision hazard associated with proximity operations. An elegant formulation of the linearized equations of relative motion is discussed and adopted for satellite formation design. The concept of eccentricity/inclination-vector separation, originally developed for geostationary satellites, is here extended to low-Earth-orbit (LEO) formations. It provides immediate insight into key aspects of the relative motion and is particularly useful for orbit control purposes and proximity analyses. The effects of the relevant differential perturbations acting on an initial nominal configuration are presented, and a fuel-efficient orbit control strategy is designed to maintain the target separation. Finally, the method is applied to a specific LEO formation (TanDEM-X/TerraSAR-X), and realistic simulations clearly show the simplicity and effectiveness of the formation-flying concept.
294 citations
TL;DR: The basic performance of BDS-3 is described and some methods to improve the positioning, navigation and timing (PNT) service are suggested and the comprehensive and resilient PNT infrastructures are proposed for the future seamless PNT services.
Abstract: The core performance elements of global navigation satellite system include availability, continuity, integrity and accuracy, all of which are particularly important for the developing BeiDou global navigation satellite system (BDS-3). This paper describes the basic performance of BDS-3 and suggests some methods to improve the positioning, navigation and timing (PNT) service. The precision of the BDS-3 post-processing orbit can reach centimeter level, the average satellite clock offset uncertainty of 18 medium circular orbit satellites is 1.55 ns and the average signal-in-space ranging error is approximately 0.474 m. The future possible improvements for the BeiDou navigation system are also discussed. It is suggested to increase the orbital inclination of the inclined geostationary orbit (IGSO) satellites to improve the PNT service in the Arctic region. The IGSO satellite can perform part of the geostationary orbit (GEO) satellite’s functions to solve the southern occlusion problem of the GEO satellite service in the northern hemisphere (namely the “south wall effect”). The space-borne inertial navigation system could be used to realize continuous orbit determination during satellite maneuver. In addition, high-accuracy space-borne hydrogen clock or cesium clock can be used to maintain the time system in the autonomous navigation mode, and stability of spatial datum. Furthermore, the ionospheric delay correction model of BDS-3 for all signals should be unified to avoid user confusion and improve positioning accuracy. Finally, to overcome the vulnerability of satellite navigation system, the comprehensive and resilient PNT infrastructures are proposed for the future seamless PNT services.
279 citations
TL;DR: In this article, the general design, the coordinate reference system, and the system time basis of the global BeiDou navigation system (BDS-3) are introduced, as well as several new payloads designed to accomplish different objectives and platforms on which they are hosted.
Abstract: China's BeiDou navigation system (BDS) has evolved from the demonstration navigation satellite system (BDS-1) to the regional navigation satellite system (BDS-2). Now, the global BeiDou navigation system (BDS-3) is in construction and is proceeding well. The design and functions of BDS-3 are quite different from those of both BDS-1 and BDS-2. In this paper, the general design, the coordinate reference system, and the system time basis of BDS-3 are introduced. Several new payloads designed to accomplish different objectives are described as well as the platforms on which they are hosted. Since BDS-3 consists of several different constellations, the general service capabilities and special service functions provided by these different constellations are described. The performances of the initial BDS-3 platforms are evaluated based on the available eight-medium Earth orbit (MEO) satellite configuration. The results of satellite orbit determination and prediction with and without the BDS-3 inter-satellite links (ISL) are compared and analyzed.
240 citations