Karoo Array Telescope site shielding : laboratory, computational and multi-copter studies

Pienaar, Hardie (2015-12)

Thesis (PhD)--Stellenbosch University, 2015.

Thesis

ENGLISH ABSTRACT: The Northern Cape in South Africa has been chosen to host the Square Kilometre Array (SKA) due to the area’s overall radio quietness. As part of the supporting systems for the Karoo Array Telescope (KAT), a processing building has been constructed on the site. With the Karoo Array Processing Building (KAPB) now in place, investigating the radio frequency interference (RFI) of the building has become a high priority. If successful, understanding of RFI propagation on-site will shape policies and contribute to the sustainability of on-site radio quietness. This dissertation focuses on understanding the shielding and propagation characteristics of both the KAPB building, as well as a man-made soil berm. On-site measurements, scale models and computational models will be used to investigate the local electromagnetic environment. Additionally, a Multi-copter vehicle is developed to support on-site measurement campaigns. Using data measured on-site it was possible to develop empirical models for local shielding estimations. It was found that the shielding performance of the berm was primarily affected by diffraction. Also, the developed computational model makes it possible to investigate alternative terrestrial structures. The work done in this dissertation will permit off-site analysis of propagation over terrestrial structures. Moreover, the development of a Multi-copter measurement platform creates more efficient metrology. Finally, empirical models are designed so that shielding budgets can be calculated for noise sources to the nearest receivers.

AFRIKAANSE OPSOMMING: Die Noord Kaap in Suid Afrika is gekies om ‘n gedeelte van die Square Kilometre Array (SKA) te huisves. Die besluit is gedeeltelik gemaak as gevolg van die skoon radio omgewing in die Noord Kaap. ‘n Ondergrondse gebou, genaamd die Karoo Array Processing Building (KAPB), is gebou as deel van die ondersteunende infrastrukture van die Karoo Array Telescope (KAT). Met die oprigting van die Karoo Array Processing Building (KAPB), het dit belangrik geraak om radio frekwensie steuring (RFI) te ondersoek. Indien die studie suksesvol is, sal die begrip van RFI voortplanting in die omgewing help om beleid te vorm ten opsigte van die volhoubaarheid van die skoon RFI omgewing. Hierdie proefskrif fokus op die verstaan van beskermings verm¨oe van beide die KAPB gebou en die mensgemaakte keerwal asook plaaslike radio frekwensie voortplantings karakteristieke. Metings geneem in hierdie area, skaalmodelle sowel as numeriese elektromagnetiese modellering (CEM) is gebruik om die plaaslike elektromagnetiese omgewing te ondersoek. Verder is ’n Multi-kopter platvorm ontwikkel vir die ondersteuning van metings veldtogte. Deur gebruik te maak van gemete data wat geneem is in die area, kon empiriese modelle ontwikkel word wat gebruik is om die plaaslike RFI beskerming te beraam. Daar is gevind dat die beskerming van die heuwel hoofsaaklik geaffekteer word deur die diffraksie daaroor. ’n CEM model is ook ontwikkel om die ondersoek van ander heuwelagtige strukture moontlik te maak. Die werk in hierdie proefskrif sal dit moontlik maak om analise, weg van die Karoo omgewing te doen. Addisioneel, het die ontwikkeling van ’n Multi-kopter platvorm dit moontlik gemaak om metings vinniger te doen. Die uiteinde is dat empiriese modelle dit moontlik maak om ’n beskermings verm¨oe begroting uit te werk vir ’n geraas bron tot die naaste MeerKAT ontvanger.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/97811
This item appears in the following collections: