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An economical do - it - yourself ground station for school pupilsNel, Francois 12 1900 (has links)
Thesis (MScEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The aim of the thesis is the design of an economical do - it - yourself ground station for
school pupils to communicate with SUNSAT 1. The ground station should also be more
economical than a hand - held transceiver radio. The do - it - yourself requirement is
there to arouse an interest in electronics, radio frequency electronics and satellite communications
in school pupils.
A system-level design was done for a ground station consisting of modules which may be
bought individually as do - it - yourself kits to eventually produce a full set. The modules
are a VHF receiver, a VHF transmitter, a UHF down converter and a modem. Each
module has functions which aid in the process of communications (data as well as voice)
between the satellite and the ground station.
A VHF receiver was designed and implemented to be capable of receiving RF signals
from SUNSAT 1. A crystal controlled oscillator was designed that oscillates with a frequency
tolerance of less than or equal to ± 0.003 % when aligned without the necessary
IlF equipment. An economical Broadband Signal Generator was implemented with a
74ACT14 logic IC, which may be used to align the receiver. The higher harmonics of a
square wave with a fundamental frequency of 4 kHz are used as a RF source.
A sound card was utilised as a modem to receive 1200 baud AFSK (AX.25 protocol) data
and the software was also used to display the data on PC. The data was transmitted from
another ground station / AFRIKAANSE OPSOMMING: Die doel van die tesis is die ontwerp van 'n ekonomiese doen - dit - self - grondstasie
vir skoolkinders om met SUNSAT I te kan komunikeer. Die grondstasie moet ook meer
ekonomies wees as 'n handstelradio. Die doel van die doen - dit - self - beginsel is om die
belangstelling in elektronika, RF elektronika and satelliete by skoolkinders aan te moedig.
'n Stelsel ontwerp van 'n grondstasie is gedoen wat bestaan uit modules wat afsonderlik
as doen - dit - self - modules aangeskaf kan word om so tot 'n totale grondstasie op te bou.
Die modules is die "VHF" - ontvanger, "VHF" - sender, UHF - afmenger en 'n modem.
Elke module verskaf funksies wat bydra om met SUNSAT I te kan kornmunikeer.
'n VHF - ontvanger wat in staat is om RF - seine vanaf SUNSAT I te ontvang is ontwerp
en gebou. 'n Kristal b heerde ossillator is ontwerp met 'n frekwensie toleransie van kleiner
en gelyk aan ± 0.003 % wanneer dit ingestem word sender die nodige RF toerusting. 'n
Ekonomiese wyeband - seingenerator is gemplementeer met 'n 74ACT14 logiese vlokkie
om as 'n RF - bron gebruik te word om die ontvanger in te stel. Die boonste (hoer)
harmoniek van die 4 kHz vierkantsgolf word as 'n "RF bron" gebruik.
'n Klankkaart is suksesvol gebruik as 'n modem om 1200 baud AFSK data (AX.25 protokol)
te ontvang en die data met die nodige sagteware op 'n skerm te vertoon. Data is
uitgcstuur vanaf 'n ander grondstasie.
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Micro-satellite data handling : a unified information modelVan der Merwe, Benjamin 04 1900 (has links)
Thesis (MScEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: This thesis describes various software technologies implemented, or specifically developed,
for the SUNSAT micro-satellite mission.
With the discussion centered on the Mission Operations System functions of Data Handling
and Mission Control, particular emphasis is placed on data processing aspects such as the
deployed database schema, and the data communications mechanisms implemented as part
of the communications protocol stack. Both the groundsystem architecture and the Flight
Software are discussed, their constituent components are analysed, and recommendations
are made for improvement. Finally, a Unified Information Model for the design and operation
of future, integrated satellite groundsystems is proposed, with suitable implementation
technologies being identified and introduced. / AFRIKAANSE OPSOMMING: Hierdie tesis beskryf die sagteware tegnologieë wat qeirnpternenteer. of spesifiek ontwerp is
vir die SUNSAT mikro-satelliet missie,
Met die bespreking gefokus op die Missie Operasionele Stelsel funksies van Data Hantering
en Missie Beheer, word daar veral klem gelê op data prosesserings aspekte, soos
byvoorbeeld die databasis skema wat ontplooi is, asook die data kommunikasie meganismes
wat qeimplernenteer is as deel van die kommunikasie protokol stapel. Beide die grondstelsel
argitektuur en die Vlugsagteware word bespreek, hulonderskeie komponente word
geanaliseer, en aanbevelings ter verbetering word gemaak, Laastens word daar 'n Verenigde
Informasie Model voorgestel vir die ontwerp en operasionele werking van 'n toekomstige,
qeinteqreerde satelliet grondstelsel. Geskikte tegnologieë vir die implementasie hiervan word
ook qeidentifiseer en voorgelê,
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Development of a high speed PCI data capture card for the SUNSAT I ground stationVan der Westhuizen, W. J. (Willem Joseas) 03 1900 (has links)
Thesis (MScEng)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The primary payload of the University of Stellenbosch's micro-satellite, SUNSAT I,
was a high quality imager, capable of taking stereoscopic images of the surface of
the earth. Although the orbit of SUNSAT I will have the satellite pass over the whole
earth, contact via the SUNSAT I ground station at the University will only be made for
3% of each day. To be able to photograph any part of the earth onboard memory
was provided on the satellite to store the image until it can be downloaded to the
ground station. A high speed downlink was also added to the satellite to be able to
download a complete image from the onboard memory in one pass and also to take
realtime pictures as the satellite passes over the ground station. At that stage there
was no way to capture the data at the ground station. A high speed digital data
capture mechanism was needed. The thesis discusses the development of a high
speed capture card.
Due to the high speeds needed it provided an excellent opportunity to develop the
card using the PCI bus, the first design to do so at the University, as an interface with
a computer. A prototype card was developed first to do proof of concept. It is shown
that the prototype card fulfilled the functional requirements and it was also used to
capture the first image from the complete satellite during the final tests before launch.
Finally a production card for use in the ground station was designed and assembled. / AFRIKAANSE OPSOMMING: Die hoof loonvrag van die Universtieit van Stellenbosch se eerste mikrosatelliet,
SUNSAT I, is "n hoë kwaliteit kamera wat stereoskopiese fotos van die oppervlak van
die aarde kan neem. Alhoewel die satelliet oor die hele oppervlakte van die aarde
gaan beweeg, is dit vir slegs 3% van die dag sigbaar vanaf die grondstasie by die
Universiteit van Stellenbosch. Om 'n foto van enige plek op aarde te kan neem is
daar aanboord geheue op die satelliet geplaas om die foto te stoor totdat dit by die
grondsatsie afgelaai kan word. "n Hoë spoed skakel is ook daargestelom die data
in die geheue van die satelliet in een verbyvlug te kan aflaai. Dit stel die satelliet ook
in staat om intydse fotos gedurende In verbyvlug van die satelliet te kan neem. Op
daardie stadium het daar nog nie "n manier bestaan om die hoë spoed data vas te
lê nie. In Meganisme om die hoë spoed digitale data te vang was nodig. Hierdie
tesis bespreek die ontwikkeling van so In data vang kaart.
Weens die hoë snelhede wat benodig word, het die PCI bus die ideale oplossing
gebied om die data teen "n hoë spoed op In persoonlike rekenaar te stoor. Dit was
ook die eerste ontwerp aan die Universiteit wat van die PCI bus gebruik gemaak het.
In die eerste instansie is In prototipe ontwikkel om te bewys dat dit wel moontlik is om
die data teen die benodigde tempo te kan stoor. Daar word gewys dat die prototipe
aan die behoefte voldoen en dit is ook gebruik om die eerste beeld vanaf die
volledige satelliet te vang voordat dit gelanseer is.
In die tweede instansie word In produksiekaart ontwikkel en aanmekaar gesit.
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