Cette publication ne fait pas partie de la bibliothèque YouScribe
Elle est disponible uniquement à l'achat (la librairie de YouScribe)
Achetez pour : 4,46 € Lire un extrait

Lecture en ligne + Téléchargement

Format(s) : EPUB - PDF

sans DRM

DIY Comms and Control for Amateur Space

De
157 pages

Radio spectrum for commanding and recording from our satellites is a shared resource with subtle hurdles. We walk the path originally paved by AMSATs to discuss the steps and licensing needed to set up and operate both a command uplink and a data download station and network. Find out how playing nicely with others maximizes your ability to get your data down.


Voir plus Voir moins
Make: SPACE-READY SYSTEMS DIY Comms and Control for Amateur Space Talking and Listening to Your Satellite
Sandy Antunes
Project Book
Make: DIY Comms and Control for Amateur Space
The picosatellite field has exploded, going from fewer than 10 launched per year to over 100 launches halfway through 2015. You no longer need access to a large university or lab to launch a satellite. Even a motivated high school group can build (and launch) one.
Radio spectrum for commanding (and receiving data from) satel lites is a shared resource with subtle hurdles. This book walks the path originally paved by AMSATs to discuss the steps and licens ing needed to set up and operate both a command uplink and a data download station and network. Find out how playing nicely with others maximizes your ability to get your data down. This book will help you:
 Learn the basics of working with radio  Plan out your ground station  Understand licensing regulation and requirements  Determine your data usage and “link budget”  Design the right antenna for your needs  Prepare to monitor communications and handle anomalies
The fourth part ofSandy Antunes’series for aspiring satellite builders. Be sure to check outDIY Satellite Platforms,Surviv-ing Orbit the DIY Way, andDIY Instruments for Amateur Spacebefore you start sending things up into the skies!
US $9.99 CAN $11.99 ISBN: 9781449310660
Make: makezine.com
DIY Comms and Control for Amateur Space
Sandy Antunes
DIY Comms and Control for Amateur Space by Sandy Antunes
Copyrîght © 2015 Sandy Antunes. All rîghts reserved.
Prînted în the Unîted States o Amerîca.
Publîshed by Maker Medîa Inc. 1160 Battery Street East Suîte 125 San Francîsco CA 94111.
Maker Medîa books may be purchased or educatîonal busîness or sales promo-tîonal use. Onlîne edîtîons are also avaîlable or most tîtles http://saaribookson-line.com. For more înormatîon contact our corporateînstîtutîonal sales depart-ment 800-998-9938 orcorporate@oreilly.com.
Editor:Patrîck Dî Justo Production Editor:Melanîe Yarbrough Proofreader:Charles Roumelîotîs Interior Designer:Davîd Futato Cover Designer:Ellîe Volkhausen Illustrator:Rebecca Demarest
June 2015
Fîrst Edîtîon
Revîsîon Hîstory or the Fîrst Edîtîon
2015-05-27
Fîrst Release
Seehttp://oreilly.com/catalog/errata.csp?isbn=9781449310660or release detaîls.
The Make logo and Maker Medîa logo are regîstered trademarks o Maker Medîa Inc.DIY Comms and Control or Amateur Space,the cover îmage and related trade dress are trademarks o Maker Medîa Inc.
Whîle the publîsher and the author have used good aîth eforts to ensure that the înormatîon and înstructîons contaîned în thîs work are accurate the publîsher and the author dîsclaîm all responsîbîlîty or errors or omîssîons încludîng wîthout lîmîta-tîon responsîbîlîty or damages resultîng rom the use o or relîance on thîs work. Use o the înormatîon and înstructîons contaîned în thîs work îs at your own rîsk. I any code samples or other technology thîs work contaîns or descrîbes îs subject to open source lîcenses or the întellectual property rîghts o others ît îs your responsîbîlîty to ensure that your use thereo complîes wîth such lîcenses andor rîghts.
978-1-449-31066-0
[LSI]
Contents
Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
1/Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Talkîng to Machînes1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Parts o a Comm System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Comm or the Impatîent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Two Walkîe-Talkîes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Flatsat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Bîdîrectîonal Bench Test Hardware6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power, Range, and Lîcensîng. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Hîgher Power Lîcensîng. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Establîshîng a Ground Network10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Breakîng Internatîonal Law12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Housekeepîng Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Housekeepîng: Bus and Instrument Are Separate. . . . . . . . . . . . . . . . . . . . 13 Alerts and Pages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Lîmîts Dîsplays: Green, Yellow, Red14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Data Integrîty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Requîrements Checklîst. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Perormance Requîrements16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Securîty & Antî-Jammîng16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spacecrat Orbîts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Frequency Allocatîon17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Physîcal Constraînts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Archîtecture Choîces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Comparîng a Space-Based Network to a Ground-Based Network18. . . . . . . . . . NASA’s Trackîng and Data Relay Satellîte System (TDRSS)18. . . . . . . . . . . . NASA’s Deep Space Network (DSN)19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Near Earth Network. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2/Radio. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Transceîver Concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Wavelength and Frequency22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dual Band and Modulatîon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
iii
Doppler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Intererence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 ADC28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Packets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 APRS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Sotware-Defined Radîo. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3/Full Ground Station. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Downlînk Only39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operatîons Choîces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Start wîth the Mîssîon Payload41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Comm Quantîtîes43. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ground Network. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Rangîng and Orbît Determînatîon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Ground System Desîgn Products46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mîssîon Phases47. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4/Licensing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Overvîew. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Extended Case: Prîvate Comm Sat52. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Future Ideas53. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Regulatory Solutîons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 IARU. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Smartphones. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Hîgh-Altîtude Balloonîng and Guerrîlla Radîo57. . . . . . . . . . . . . . . . . . . . . . . . Demystîyîng the Basîc Technology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Regulatory and Permîssîons58. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ham Technîcîan’s Lîcense59. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scenarîos. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Saehold63. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ground Sîm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Sotware. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Compare and contrast64. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Relays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Lîne o Sîght/Dîrect to Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Relays67. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prîvate Networks69. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5/Orbits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Definîng Orbîts71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The Sîx Classîc Orbîtal Elements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 TLEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
iv
Contents
Orbît Determînatîon75. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tîme77. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Satellîte Tîme. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Ground Tracks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 Contact Passes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
6/Comm Budgets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 Allocatîons85. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Data Prîorîtîes86. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Extended Example o Command vîa Text Messagîng. . . . . . . . . . . . . . . . . 87 More Realîstîc Bandwîdth Allocatîon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 Encodîng. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Lînk Budget93. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Unîts93. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lînk Budget Equatîon95. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Goîng Deeper97. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Data Budget. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
7/Antenna Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 Antenna Shape103. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Common Spacecrat Antenna105. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Common Ground Statîon Antenna106. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Antenna Sîze and Frequency109. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Impedance and SWR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 Antenna Materîals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 Power, ERP, and EIRP113. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8/Performance Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Data, Error Rates, and Avaîlabîlîty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Securîty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 Hîstorîcal Satellîte Hackîng120. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9/Concept of Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 ConOps121. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hîgh-Level ConOps Desîgn124. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ops Center Network127. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trendîng. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 Scîence Operatîons Center (SOC)130. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scîence Monîtorîng133. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Handlîng Anomalîes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
A/Resources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Contents
v
Afterword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
vi
Contents
Preface
The pîcosatellîte field has exploded goîng rom less than 10 launched per year back în 2009-2011 when I dîd my Callîope buîld to over 100 launchesthis yearalone. We have gone rom requîrîng a large unîversîty or lab to back a project to a poînt where even a motîvated hîgh school can buîld one. We are în a Do-It-Yoursel DIY space age and I’m proud maybe even a bît smug that Callîope has been part o that. In act I’m buîldîng versîon 2 o my hardware usîng advances desîgned by others who were în part înspîred by my Project Callîope!
Whîle waîtîng or launch I’ve wrîtten these our short DIY satel-lîte books orMake: each o whîch has sold several thousand copîes. I get emaîls rom DIY buîlders o CubeSats and TubeSats and PocketQubes askîng my advîce. These emaîls oten start of wîth “I was înspîred by your project and have a technîcal ques-tîon about” ollowed by a technîcal questîon o such complexîty that ît’s clear they are already pushîng the pîcosatellîte rontîer way past what I dîd wîth my lîttle basement-buîld. There are CubeSats flyîng thîs year that înclude my work as an înspîratîon.
I was hîred by Capîtol Technology Unîversîty to teach college students about satellîtes and systems engîneerîng and physîcs. They hîred me to a large degree because attemptîng Callîope împressed them. I am ull-tîme aculty startîng my fith year there and just got promoted to Assocîate Proessor. Because I haven’t launched yet and I’m helpîng college students work towards theîr own satellîtes I donated the bulk o my ground statîon hardware to the not-or-profit Capîtol lab I run. Thîs donated hardware îs jumpstartîng students’ engagement în top-îcs lîke ham radîo and payload commandîng and stuf. My ocus îs on what I can do or the next generatîon o space enthusîasts. In addîtîon I’ve become an advocate or the so-calledSTEAM movement that adds anAor Art înto the usual STEM currîcula.
vii
Lîe îs not a race because the only finîshîng lîne îs the uture and that îs unknown. So why not be the people that create that uture? Read thînk buîld înteract then repeat. As long as you are movîng orward you are goîng somewhere.
Conventions Used in This Book The ollowîng typographîcal conventîons are used în thîs book Italic Indîcates new terms URLs emaîl addresses filenames and file extensîons. Constant width Used or program lîstîngs as well as wîthîn paragraphs to reer to program elements such as varîable or unctîon names databases data types envîronment varîables state-ments and keywords. Constant width bold Shows commands or other text that should be typed lîterally by the user. Constant width italic Shows text that should be replaced wîth user-supplîed val-ues or by values determîned by context.
viii Preface
Thîs element sîgnîfies a tîp suggestîon or general note.
Thîs element îndîcates a warnîng or cautîon.