SATELLITE COMMUNICATIONS SYSTEMS Systems, Techniques and Technology Fourth Edition Gerard Maral Ecole Nationale Superieure des Telecommunications, Site de Toulouse, France

Michel Bousquet Ecole Nationale Superieure de I'Aeronautique et de I'Espace (SUPAERO), Toulouse, France

JOHN WILEY & SONS, LTD

CONTENTS ACKNOWLEDGEMENT

xiii

ACRONYMS

xv

NOTATION

xix

1

INTRODUCTION 1.1 The birth of satellite communications 1.2 Development of satellite communications 1.3 The configuration of a satellite communications system 1.3.1 Communications links 1.3.2 The space segment 1.3.3 The ground segment 1.4 Types of orbit 1.5 Radio regulations 1.5.1 The ITU organisation 1.5.2 Space radiocommunications services 1.5.3 Frequency allocation 1.6 Technology trends 1.7 Services 1.8 The way forward References

l 1 1 3 5 6 9 11 14 14 15 15 17 18 20 21

2

ORBITS A N D RELATED ISSUES 2.1 Keplerian orbits 2.1.1 Kepler's laws 2.1.2 Newton's law 2.1.3 Relative movement of two point bodies 2.1.4 Orbital parameters 2.1.5 The earth's orbit 2.1.6 Earth-satellite geometry 2.1.7 Eclipses of the sun 2.1.8 Sun-satellite conjunction 2.2 Useful orbits for satellite communication 2.2.1 Elliptical orbits with non-zero inclination 2.2.2 Geosynchronous elliptic orbits with zero inclination 2.2.3 Circular geosynchronous orbits with non-zero inclination 2.2.4 Sub-synchronous circular orbits with zero inclination 2.2.5 Geostationary satellite orbits

23 23 23 23 24 28 33 41 48 49 49 50 63 65 68 68

Contents

VI

2.3

Perturbations of the orbit 2.3.1 The nature of the perturbations 2.3.2 The effect of perturbations; orbit perturbation 2.3.3 Perturbations of the orbit of geostationary satellites 2.3.4 Orbit corrections: station keeping of geostationary satellites 2.4 Conclusion References

79 80 83 85 94 112 112

BASEBAND SIGNALS AND QUALITY OF SERVICE (QoS)

115 115 116 123 128 128 129 129 130 131 131 131 132 132 132 133 133 133 135 135

3.1

Baseband signals 3.1.1 Telephone signal 3.1.2 Television signals 3.1.3 Sound signals 3.1.4 Data and multimedia signals 3.2 Performance objectives 3.2.1 Telephone 3.2.2 Television 3.2.3 Sound 3.2.4 Data 3.3 Availability objectives 3.4 Delay 3.4.1 Delay in terrestrial network 3.4.2 Propagation delay over satellite links 3.4.3 Baseband signal processing time 3.4.4 Protocol-induced delay 3.4.5 Echo on telephone circuits 3.5 Conclusion References COMMUNICATIONS TECHNIQUES 4.1 Analogue transmission 4.1.1 Baseband processing 4.1.2 Frequency modulation (FM) 4.1.3 Demodulation of a frequency modulated wave 4.1.4 Telephone transmission on SCPC/FM 4.1.5 Telephone transmission on FDM/FM 4.1.6 Television transmission in SCPC/FM 4.1.7 Energy dispersion 4.2 Digital communications 4.2.1 Encryption 4.2.2 Channel encoding 4.2.3 Scrambling 4.2.4 Digital modulation 4.2.5 Demodulation 4.2.6 Modulation spectral efficiency 4.2.7 Channel decoding 4.2.8 Coded modulation 4.2.9 End-to-end error control 4.3 Conclusion: comparison between analogue and digital transmission 4.3.1 Transmission of telephony 4.3.2 Broadcasting of television References

137 137 139 141 141 143 144 146 148 149 149 150 153 155 162 168 169 175 183 184 184 188 189

Contents 5

U P / D O W N LINK, INTERSATELLITE LINK A N D OVERALL LINK PERFORMANCE 5.1 Configuration of a link 5.2 Antenna parameters 5.2.1 Gain 5.2.2 Radiation pattern and angular beamwidth 5.2.3 Polarisation 5.3 Radiated power 5.3.1 Effective isotropic radiated power (EIRP) 5.3.2 Power flux density 5.4 Received signal power 5.4.1 Power captured by the receiving antenna and free space loss 5.4.2 Example 1: Uplink received power 5.4.3 Example 2: Downlink received power 5.4.4 Additional losses 5.4.5 Conclusion 5.5 Noise power spectral density at the receiver input 5.5.1 The origins of noise 5.5.2 Noise characterisation 5.5.3 Noise temperature of an antenna 5.5.4 System noise temperature 5.5.5 System noise temperature: Example 5.5.6 Conclusion 5.6 Individual link performance 5.6.1 Carrier power to noise power spectral density ratio at receiver input 5.6.2 Clear sky uplink performance 5.6.3 Clear sky downlink performance 5.7 Influence of the atmosphere 5.7.1 Impairments caused by rain 5.7.2 Other impairments 5.7.3 Link impairments relative importance 5.7.4 Link performance under rain conditions 5.7.5 Conclusion: degradation of individual link performance due to rain 5.8 Mitigation of atmospheric impairments 5.8.1 Depolarisation mitigation 5.8.2 Attenuation mitigation 5.8.3 Site diversity 5.8.4 Adaptivity 5.8.5 Conclusion: cost-availability trade-off 5.9 Overall link performance with transparent satellite 5.9.1 Characteristics of the satellite channel 5.9.2 Expression for {C/N0)T 5.9.3 Overall link performance for a transparent satellite without interference or intermodulation 5.10 Overall link performance with regenerative satellite 5.10.1 Linear satellite channel without interference 5.10.2 Non-linear satellite channel without interference 5.10.3 Non-linear satellite channel with interference 5.11 Intersatellite link performance 5.11.1 Frequency bands 5.11.2 Radio-frequency links

Vit

191 192 192 192 194 197 199 199 199 200 200 202 202 203 205 206 206 206 210 214 215 216 216 217 217 220 223 224 237 240 240 241 242 242 242 243 244 245 246 246 250 254 257 258 261 261 263 264 264

Contents

vm 5.11.3

Optical links

265

5.11.4

Conclusionz

272

References

272

MULTIPLE ACCESS

275

6.1

6.2

6.3

6.4

6.5

6.6

6.7

6.8

6.9

Traffic p a r a m e t e r s Traffic intensity

275

6.1.2

Call blocking probability

276

6.1.3

Burstiness

276

6.1.4

Asynchronous transfer mode (ATM)

Traffic r o u t i n g

276 277

6.2.1

One carrier per station-to-station link

278

6.2.2

One carrier per transmitting station

279

6.2.3

Comparison

M u l t i p l e access

279 280

6.3.1

Access to a particular channel

280

6.3.2

Multiple access to the satellite repeater

282

F r e q u e n c y d i v i s i o n m u l t i p l e access ( F D M A )

282

6.4.1

Transmission schemes

283

6.4.2

Adjacent channel interference

285

6.4.3

Intermodulation

286

6.4.4

Throughput of FDMA

289

6.4.5

Intelligible crosstalk

291

6.4.6

Conclusion

T i m e d i v i s i o n m u l t i p l e access (TDMA)

291 291

6.5.1

Burst generation

292

6.5.2

Frame structure

295

6.5.3

Burst reception

295

6.5.4

Synchronisation

297

6.5.5

Throughput of TDMA

302

6.5.6

Conclusion

C o d e d i v i s i o n m u l t i p l e access ( C D M A )

305 306

6.6.1

Direct sequence (DS-CDMA)

306

6.6.2

Frequency hopping (FH-CDMA)

310

6.6.3

Code generation

312

6.6.4

Synchronisation

312

6.6.5

The throughput of CDMA

315

6.6.6

Conclusion

Fixed a n d o n - d e m a n d a s s i g n m e n t

317 318

6.7.1

The principle

318

6.7.2

Comparison between fixed and on-demand assignment

319

6.7.3

Centralised or distributed management of demand assignment

320

6.7.4

Conclusion

320

R a n d o m access

321

6.8.1

Asynchronous protocols

322

6.8.2

Protocols with synchronisation

325

6.8.3

Protocols with assignment on demand (DAMA)

Conclusion

References

275

6.1.1

326 327 328

Contents SATELLITE NETWORKING 7.1

ix 331

Advantages and disadvantages of multibeam satellites 7.1.1 Advantages 7.1.2 Disadvantages 7.1.3 Conclusion 7.2 Interconnection by transponder hopping 7.3 Interconnection by on-board switching (SS/TDMA) 7.3.1 The principle 7.3.2 Frame organisation 7.3.3 Window organisation 7.3.4 Assignment of packets in the frame (burst time plan) 7.3.5 Synchronisation 7.3.6 Frame throughput 7.4 Interconnection by beam scanning 7.5 On-board processing 7.5.1 Downlink coding 7.5.2 Baseband switching 7.5.3 Rate conversion 7.5.4 Beam scanning satellites 7.5.5 FDMA/TDM systems 7.5.6 Conclusion 7.6 Intersatellite links (ISL) 7.6.1 Links between geostationary and low earth orbit satellites (GEO-LEO) 7.6.2 Links between geostationary satellites (GEO-GEO) 7.6.3 Links between low orbit satellites (LEO-LEO) 7.6.4 Conclusion References

331 332 337 339 339 339 339 342 342 342 345 347 348 348 349 349 350 351 351 353 353 354 354 359 360 360

E A R T H STATIONS 8.1 Station organisation 8.2 Radio-frequency characteristics 8.2.1 Effective isotropic radiated power 8.2.2 Figure of merit of the station 8.2.3 Standards defined by international organisations 8.3 The antenna subsystem 8.3.1 Radiation characteristics (main lobe) 8.3.2 Side-lobe radiation 8.3.3 Antenna noise temperature 8.3.4 Types of antenna 8.3.5 Pointing angles of an earth station antenna 8.3.6 Mountings to permit antenna pointing 8.3.7 Tracking 8.4 The radio-frequency subsystem 8.4.1 Receiving equipment 8.4.2 Transmission equipment 8.4.3 Redundancy 8.5 Communication subsystems 8.5.1 Frequency translation 8.5.2 Amplification, filtering and equalisation 8.5.3 Modulation and demodulation 8.5.4 Additional functions 8.5.5 Time division multiple access terminals

363 363 364 365 366 367 373 374 374 375 382 387 390 397 408 408 411 417 418 418 422 423 425 426

Contents

X

8.6

The network interface subsystem 8.6.1 Multiplexing and demultiplexing 8.6.2 Digital speech interpolation (DSI) 8.6.3 Digital circuit multiplication equipment (DCME) 8.6.4 Echo suppression and cancellation 8.6.5 Equipment specific to SCPC transmission 8.7 Monitoring and control; auxiliary equipment 8.7.1 Monitoring, alarms and control (MAC) 8.7.2 Electrical power 8.8 Conclusion References

429 429 430 432 435 436 437 437 438 438 439

THE COMMUNICATION PAYLOAD 9.1 Mission and characteristics of the payload 9.1.1 Functions of the payload 9.1.2 Characterisation of the payload 9.1.3 The relationship between the radio-frequency characteristics 9.2 Transparent repeaters 9.2.1 Characterisation of non-linearities 9.2.2 Repeater organisation 9.2.3 Equipment characteristics 9.3 Multibeam satellite repeater 9.3.1 Fixed interconnection 9.3.2 Reconfigurable (semi-fixed) interconnection 9.3.3 On-board time domain switching 9.3.4 On board frequency domain switching 9.4 Regenerative repeater 9.4.1 Application and examples of on-board processing regenerative satellites 9.4.2 Equipment for regenerative repeaters 9.5 Solid state equipment technology 9.5.1 The specific environment 9.5.2 Analogue microwave component technology 9.5.3 Digital component technology 9.6 Antenna coverage 9.6.1 Service zone contour 9.6.2 Geometrical contour 9.6.3 Global coverage 9.6.4 Reduced or spot coverage 9.6.5 Evaluation of antenna pointing error 9.6.6 Conclusion 9.7 Antenna characteristics 9.7.1 Antenna functions and characteristics 9.7.2 The radio-frequency coverage 9.7.3 Circular beam 9.7.4 Elliptical beams 9.7.5 The influence of depointing 9.7.6 Shaped beams 9.7.7 Multiple beams 9.7.8 Types of antenna 9.7.9 Antenna technologies

441 441 441 442 443 444 444 455 462 473 474 474 477 481 482 482 488 493 493 493 494 495 495 499 499 502 504 515 516 516 518 519 522 524 526 529 532 535

Contents

XI

9.8 Conclusion References

546 546

THE PLATFORM 10.1 Subsystems 10.2 Attitude control 10.2.1 Attitude control functions 10.2.2 Attitude sensors 10.2.3 Attitude determination 10.2.4 Actuators 10.2.5 The principle of gyroscopic stabilisation 10.2.6 Spin stabilisation 10.2.7 'Three-axis' stabilisation 10.3 The propulsion subsystem 10.3.1 Characteristics of thrusters 10.3.2 Chemical propulsion 10.3.3 Electric propulsion 10.3.4 Organisation of the propulsion subsystem 10.3.5 Electric propulsion for station keeping and orbit transfer 10.4 The electric power supply 10.4.1 Primary energy sources 10.4.2 Secondary energy sources 10.4.3 Conditioning and protection circuits 10.4.4 Example calculations 10.5 Telemetry, tracking and command (TTC) and on-board data handling (OBDH) 10.5.1 Frequencies used 10.5.2 The command links (TC links) 10.5.3 Telemetry links (TM links) 10.5.4 Command (TC) and telemetry (TM) message format standards 10.5.5 On-board data handling (OBDH) 10.5.6 Tracking 10.6 Thermal control and structure 10.6.1 Thermal control specifications 10.6.2 Passive control 10.6.3 Active control 10.6.4 Structure 10.6.5 Conclusion 10.7 Developments and trends References

551 551 553 553 555 557 561 563 565 568 574 575 577 582 587 591 592 592 599 605 610 612 613 614 615 616 623 627 631 632 634 637 637 640 641 642

SATELL Т Е

645 645 645 647 648 658 663 668 670 673 674

11.1

I N S T A L L A T I O N A N D L A U N C H VEHICLES nstallation in orbit 1.1.1 Basic principles 1.1.2 Calculation of the required velocity increments 1.1.3 Inclination correction and circularisation 1.1.4 The apogee (or perigee) motor 1.1.5 Injection into orbit with a conventional launcher 1.1.6 Injection into orbit from a quasi-circular low altitude orbit 1.1.7 Operations during installation (station acquisition) 1.1.8 Injection into orbits other than geostationary 1.1.9 The launch window

xii

Contents 11.2 Launch vehicles

12

675

11.2.1

China

676

11.2.2

Europe (Ariane)

678

11.2.3

The United States

686

11.2.4

India

695

11.2.5

Japan

696

11.2.6

Commonwealth of Independent States (CIS)

699

11.2.7

Cost of installation in orbit

704

References

704

THE SPACE ENVIRONMENT

707

12.1

12.2

12.3

12.4

12.5

Vacuum

707

12.1.1

Characterisation

12.1.2

Effects

707 708

The mechanical environment

708

12.2.1

The gravitational

12.2.2

The earth's magnetic

field

12.2.3

Solar radiation pressure

12.2.4

Meteorites and material particles

711

12.2.5

Torques of internal origin

712

12.2.6

The effect of communication transmissions

713

12.2.7

Conclusions

field

Radiation

713 713

Solar radiation

714

12.3.2

Earth radiation

715

12.3.3

Thermal effects

715

12.3.4

Effects on materials

717

Flux of h i g h e n e r g y particles

718

12.4.1

Cosmic particles

718

12.4.2

Effects on materials

721

T h e e n v i r o n m e n t d u r i n g installation

721

12.5.1

The environment during launching

721

12.5.2

Environment in the transfer orbit

722 724

13 RELIABILITY OF SATELLITE COMMUNICATIONS SYSTEMS 13.1 Introduction of reliability

13.3

711

12.3.1

References

13.2

708 710

725 725

13.1.1

Failure rate

725

13.1.2

The probability of survival or reliability

726

13.1.3

Failure probability or unreliability

727

13.1.4

Mean time to failure (MTTF)

727

13.1.5

Mean satellite lifetime

728

13.1.6

Reliability during the wear-out period

728

Satellite s y s t e m availability

729

13.2.1

No back-up satellite in orbit

730

13.2.2

Back-up satellite in orbit

730

13.2.3

Conclusion

S u b - s y s t e m reliability

731 731

13.3.1

Elements in series

732

13.3.2

Elements in parallel (static redundancy)

732

Contents

13.4

13.3.3 Dynamic redundancy (with switching) 13.3.4 Equipment having several failure modes Component reliability 13.4.1 Component reliability 13.4.2 Component selection 13.4.3 Manufacture 13.4.4 Quality assurance

INDEX

Xllt 734 738 739 739 739 741 741

745

ACKNOWLEDGEMENT Reproduction of figures extracted from the 1990 Edition of CCIR Volumes (XVIIth Plenary Assembly, Düsseldorf, 1990) the "Handbook on Satellite Communications (ITU Geneva, 1988)" and the ITU-R Recommendations is made with the authorisation of the International Telecommunication Union (ITU) as copyright holder. The choice of the excerpts reproduced remains under the sole responsibility of the authors and does not engage in any way the ITU. The complete ITU documentation can be obtained from: International Telecommunication Union General Secretariat-Sales Section Place des Nations, 1211 GENEVA 20 (Switzerland) Tel: +41 22 730 51 11 Tg: Burinterna Geneva Telefax: 2 / m + 41 22 730 51 94 Tlx: 421 000 uit ch