Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Technical advances in electromagnetics, signal processing and processing power
have led to a significant increase in sensitivity and accuracy in radio telescopes.
With this increase in sensitivity, radio frequency interference (RFI) has become a
much larger problem. The notable growth in wireless communication as well as
self generated RFI has further escalated this problem. In order to utilise the full
capabilities of modern radio telescopes, RFI mitigation is required on the captured
signals. With the enormous data rates of modern radio telescopes, managing RFI
has become increasingly difficult, and in order to utilise the full captured radio
spectrum, more accurate RFI mitigation strategies will be necessary.
The use of different RFI mitigation strategies is studied in the form of online
and offline techniques. This includes Spectral Kurtosis, Spectral Flatness and the
Var/SumThreshold method. The special case for RFI mitigation in timing pulsars
will also be studied. These techniques are well known in the radio astronomy community;
here, spectral kurtosis and spectral flatness will be implemented on the raw
data as well as the post correlated data. System speed and accuracy will be the
deciding factors when testing these methods as possible solutions to this problem. / AFRIKAANSE OPSOMMING: ‘n Toename in die sensitiwiteit van hedendagse radioteleskope kan toegedra word
aan die tegniese bevordering in elktromagnetika en seinverwerking. Die toename
in sensitiwiteit het egter tot die gevolg dat radiofrekwensiesteuring ‘n groter rol
speel in hedendaagse radioteleskope. Die groei in die gebruik van radioverbindings
asook die gevolge van self gei¨nduseerde radiofrekwensiesteuring dra ook verder
by tot hierdie probleem. Radiofrekwensiesteuring matiging word toegepas op die
opgevangde seine, om sodoende gebruik te maak van die volle kapasiteit van moderne
radioteleskope. Die bestuur van radiofrekwensiesteuring word bemoeilik deur
die groot hoeveelheid intydse data van die radioteleskope. Meer akurate radiofrekwensiesteuring
matigingstegnieke word vereis om die bandwydte ten volle te hanteer.
Daar word op ‘n aantal verskillende matingstegnieke gefokus. Hierdie tegenieke
kan in twee kategorieë verdeel word, naamlik aanlyn- en aflyntegenieke. Onderafdelings
van hierdie kategorieë sluit in: spektrale kurtose, spektrale matheid en
“Var/SumThreshold”. Daar word ook na ‘n spesiale geval van radiofrekwensiesteuring
matiging gekyk, in die opmeeting van tydsberekening-pulsars. Alhoewel
hierdie tegnieke bekend is in die radioastronomie gemeenskap, word spektrale kurtose
en spektrale matheid egter toegepas op die rou data sowel as postgekorreleerde
data. Daar sal op stelsel spoed en akuratheid gefokus word, om vas te stel of hierdie
metodes wel moontlike oplossings bied tot die probleem bespreek.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/86637 |
| Date | 04 1900 |
| Creators | Thompson, Nicholas Christopher |
| Contributors | Davidson, D. B., Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | xii, 101 p : ill. |
| Rights | Stellenbosch University |
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